Abstract:
A client subscribes to a pub/sub service, the client comprises an application program for performing an operation on a published message received from a Pub/Sub service. The operation on the message comprises any one of saving the message to storage, accessing a web service based on information in the received message, authorizing subscription, executing an application identified by the message, filtering the message information for presentation to a user, overriding a message function, transforming the message media format or forwarding the message to another node.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This is a divisional application of Ser. No. 10/207,711 “INTERACTIVE FILTERING ELECTRONIC MESSAGES RECEIVED FROM A PUBLICATION/SUBSCRIPTION SERVICE” filed on Jul. 26, 2002 and assigned to IBM. The disclosure of the forgoing application is incorporated herein by reference. 

   COPYRIGHT NOTICE 
   A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. 
   FIELD OF THE INVENTION 
   The present invention is related to systems and methods for Publication/Subscription, more particularly to systems and methods for distributed computer users to securely subscribe and publish by way of a Pub/Sub channel. 
   BACKGROUND OF THE INVENTION 
     FIG. 1  depicts the elements that make up a typical computer for use in presenting and maintaining an application. The computer  100  consists of a Base Computer  101  which comprises a processor  106 , storage media such as a magnetic disk  107  and a high speed volatile main memory  105 . An operating system and application programs  111  reside on the storage media  107  and are paged into main memory  105  as needed for computations performed by the processor  106 . The Base computer may include optional peripheral devices including a video display  102 , a printer or scanner  110 , a keyboard  104 , a pointing device (mouse)  103  and a connection  108  to a network  109 . In a client environment, a user will interact with a (Graphical User Interface) GUI by use of a keyboard  104  and mouse  103  in conjunction with the display of information on the display  102  under control of an application program (application  1 )  112 . The client application program  112  will then interact with remote users by way of the network  109 . 
   In  FIG. 2  an example Internet system is shown. A user at client  1   201  uses applications on his system. This user (user  1   210 ) at client  1   201  can interact with clients  2 - 4   202 - 204  by way of a client server computer  206 . Applications  112  may be provided by each client  201 - 205  and or the client server  206  or some remote server  208  by way of the network  207 . The user at client  1   201  can interact with a remote user (user  5   211 ) at client  5   205  by way of the Internet  207 . 
   Recently, peer to peer (P2P) interconnection has become an interesting alternative.  FIG. 3  shows an example P2P network  300  wherein peer  1   301  can communicate with other peers directly. Each peer essentially includes client and server function. Thus, Peer  1   301  acts as a client in sending messages to Peer  2   302 . Peer  2  performs some function as a result of receiving the message and may return a message to peer  1 . Thus, peer  2   302  acts as a server for peer  1   301 . P2P grids provide networked computers that cooperate to perform distributed computing. 
   Networked clients comprise applications for communication. E-mail applications provide for sending a message to a mail server that then makes the recipient aware of the waiting message. The recipient then can elect to open the message and view it at his client machine. E-mail messages can be sent to a single recipient or can contain a list of several recipients (one to many). One to many e-mail transactions are popular with advertisers and the use of one to many e-mails has been dubbed “SPAM-ing”. Recently Instant Messaging (IM) has gained popularity in the form of sending text messages directly to another client. A first user composes an IM and selects a second user as the target. A message is then sent directly to the second user and appears on his display as either a message or the notification of a message. IMs are typical one to one messages. 
   Refer now to  FIG. 4  which depicts a logical view of a pub/sub system of the prior art. A pub/sub service  404  receives messages originating from a content service  401 - 403  and delivers them to client subscribers  405   406 . An example message published includes a topic string, a set of property name-value pairs, and a body. A subscriber identifies a topic string pattern and properties test, and receives matching messages according to a standard, for instance JAVA Message Service (JMS). 
   The pub/sub system is made up of a Content Provider application (Service)  401 - 403 , the Subscriber (Client)  405 - 406 , and the Pub-Sub Service  404 . Applications may implement one or more of these roles. The content provider  401 - 403  generates content for distribution through the pub/sub system  400 . Content providers  401 - 403  send structured content to one or more instances of the pub/sub service  404 . The subscriber  405 - 406  sends subscription requests  407  to an instance of the pub/sub service  404  and, subject to acceptance of a particular subscription request, receives content  408  from the pub/sub service. The actual content received will be determined by the subscription and the message selection process. 
   The pub/sub service  404  acts as both a subscription manager  410  and a content distribution agent  411 . Applications implementing the pub/sub service role  404  accept subscription requests  407  from subscribers  405  and, subject to any applicable authentication or access control policies, accept or reject subscription requests; and distribute content  408  to valid subscribers  405 . 
   The actual content sent to each subscriber  405 - 406  by the pub-sub service  404  will be determined by the subscription process  410  and through the message selection process  411 . 
   Applications implementing some aspect of the pub/sub system may act in different roles in different circumstances. For example, an application implementing the pub/sub service role  404  may itself act as a subscriber, subscribing to and receiving content from another instance of the pub-sub service. Similarly, an application acting in the subscriber role may act as a content producer if the end-user of the application wishes to publish a message to the service. 
   The pub/sub system provides for communication among applications implementing the application roles. There are two primary communications in the pub/sub system: messages are sent from content providers to pub/sub services; and pub/sub services send messages to subscribers  408 ,  412 . 
   Content providers  401 - 403  may generate messages from any content source, and subscribers may dispose of messages in any manner they choose. For example, a content provider may simply be a gateway between a raw content source, such as e-mail or web pages, to the pub-sub service. Similarly, a subscriber  405 ,  406  may act as a gateway between the pub/sub service and an external service such as NNTP or e-mail. An application implementing a particular role defined in the Pub/Sub System may implement different roles at different times. 
   For example, an application implementing the pub/sub service role  404  may itself act as a subscriber, subscribing to content through another instance of the pub-sub service and receiving messages from that service. 
   SUMMARY OF THE INVENTION 
   The present invention (Shotgun) teaches a system for publishing electronic information by way of channels. A user subscribes to a “channel” of information similarly to selecting a Television Channel. Messages of information broadcast from that channel are then directed to the subscriber application which comprises filtering mechanisms to selectively permit messages to be passed on to the shotgun client user. The system maintains a database directory of applications, accessed through an administrative SOAP service. The directory contains security information, channel access controls, owner identification, help text and the like. 
   Publish/subscribe systems contain information producers and information consumers. Information producers publish events to the system, and information consumers subscribe to particular categories of events within the system. The “system” ensures the timely delivery of published events to all interested subscribers. In addition to supporting many-to-many communication, the primary requirement met by publish/subscribe systems is that producers and consumers of messages are anonymous to each other, so that the number of publishers and subscribers may dynamically change, and individual publishers and subscribers may evolve without disrupting the entire system. 
   The earliest publish/subscribe systems were subject-based. In these systems, each message belongs to one of a fixed set of subjects (also known as groups, channels, or topics). Publishers are required to label each message with a subject; consumers subscribe to all the messages within a particular subject. For example a subject-based publish/subscribe system for stock trading may define a group for each stock issue; publishers may post information to the appropriate group, and subscribers may subscribe to information regarding any issue. 
   In an embodiment, secure publication and subscription is provided in a system having a pub/sub server having one or more channels, the method comprising the steps of: Providing first subscription access capability to a group channel the first subscription access requiring user authorization; Providing second subscription access capability to a public channel wherein the second subscription access is universally authorized. 
   In another embodiment, a method is provided for invoking a first client application in a system wherein the system includes a pub/sub server and a second client application, the method comprising the steps of: Subscribing to a channel of a pub/sub server; Receiving a message for invoking the first client application at the second client application from the pub/sub server; and Invoking the first client application using information supplied by the message. 
   In another embodiment, a method is provided for dynamic management of pub/sub user applications by a user, the method comprising the steps of: Creating a list of pub/sub user applications available to a user; Using the list of user applications to create a GUI interface to a user, the GUI interface comprising at least one of a first user application identifier, an activate first user application function, a deactivate first user application function, a first user application active indicator or a method for displaying information about the first user application. 
   In one version, the optional step of subscribing to the first user application uses the GUI interface. 
   Another version comprises the step of performing an authorization action in conjunction with the list in order to permit a user application to appear on the GUI interface to the user. 
   In still another version, the subscribing step further comprises the step of permitting subscribing to the first user application only when the user is authorized. 
   It is therefore an object of the present invention to subscribe to messages published by a pub/sub service wherein a received message is provided to a client application for performing an operation on the received message. 
   It is another object of the invention to perform an operation on a message received from a pub/sub service, the operation consisting of any one of filtering the message information for presentation to a user; saving the message to storage; accessing a web service based on information in the received message; authorizing the subscription; executing an application identified by the message; overriding a message function; transforming the message media format; or forwarding the message to another node. 
   It is another object of the invention to operate on messages wherein the message is any one of an instant message, a digital file, an automated agent or an email message. 
   It is yet another object of the invention to perform a Boolean operation on text fields of a pub/sub message received and initiate the operation based on the results of the Boolean operation. 
   It is still another object of the invention to transform a message media format of a received pub/sub message from any one of encrypted, decrypted compressed, decompressed, text, audio, video or image to a form consisting of any one of encrypted, decrypted compressed, decompressed, text, audio, video or image. 
   It is another object of the invention to receive a pub/sub message comprising a subscriber authorizing agent for authorizing a subscription to receive messages from the pub/sub service. 
   It is another object of the invention to receive pub/sub messages comprising a program application module for execution at the client computer. 
   It is another object of the invention to forwarded received messages from a pub/sub service to another node consisting of any one of a computer, a telephone, a radio or a television. 
   The above as well as additional objectives, features, and advantages of the present invention will become apparent in the following written description. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a diagram depicting example components of a computer system; 
       FIG. 2  is a diagram depicting example components of a client-server network; 
       FIG. 3  is a diagram depicting example components of a Peer-to-peer network; 
       FIG. 4  depicts logical components of a pub/sub system; 
       FIG. 5  depicts logical components of a pub/sub system of the present invention; 
       FIG. 6  depicts logical components of a pub/sub system incorporating Instant Messaging of the present invention; 
       FIG. 7  depicts a preferred embodiment of the present invention; 
       FIG. 8  is a flowchart function of a shotgun client of the present invention; 
       FIG. 9  is a flowchart of a shotgun client application of the present invention; 
       FIG. 10  is an example display of a service selection GUI of the present invention; 
       FIG. 11  depicts a second example display of a service selection GUI of the present invention; 
       FIG. 12  is an example display of a channel selection menu; 
       FIG. 13  is an example display of creating filters for selected applications; 
       FIG. 14  is an example of an alert message of the present invention; 
       FIG. 15  is a flowchart example of the publisher function of the present invention; 
       FIG. 16  is a flowchart example of coded messages; 
       FIG. 17  is a flowchart example of setup options; 
       FIG. 18  is a flowchart example of message usage; 
       FIG. 19  is a flowchart example of subscribing to a service; 
       FIG. 20  is a flowchart example of client message processing; 
       FIG. 21  is a logical depiction of interaction between a client and a service according to the invention; 
       FIG. 22  depicts a Web services implementation of Shotgun; 
       FIG. 23  is an example GUI used to elect options; and 
       FIG. 24  is an example GUI used to set a “Plugin”. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The present invention provides a method for publishing electronic messages by way of channels in a pub/sub server system wherein subscription to applications and channels is provided by way of a secure GUI application. The example system employing the present invention is herein called “Shotgun”. 
   In a preferred embodiment, Shotgun comprises a Shotgun server application and a Shotgun client application. The Shotgun server application comprises:
         1. A Pub/Sub component for broadcasting content provided by a Provider Service application.   2. A publisher security component for supporting and authenticating the Provider Service application for publication of content.   4. A subscriber security component for supporting and authenticating a subscriber.   5. An optional subscriber customization component that, in cooperation with a subscriber, customizes activity associated with the subscriber such as filtering broadcast content based on topic, topic tags or message content and the like.       

   A Shotgun client application resides on the client machine. The Shotgun client application provides:
         1. Communication with the Shotgun Server application.   2. GUI interface for a subscriber to: subscribe to a service; supply credentials to the Shotgun server application; and customize information transmitted and received from the Shotgun Server application and/or agent applications.   3. An optional API interface for attaching agent applications.       

     FIG. 5  shows the system of the prior art of  FIG. 4  with a conceptual diagram of one aspect of the present invention added. Shotgun introduces channel and message filtering into a pub/sub environment  404 . A Service  401 - 403  may provide information by way of “channels” to many subscribers by way of the pub/sub service  404 . Channels provide a way for services to partition functionality, thus a Stock Brokering service may provide a channel for stock quotes, and another channel for company profile information. 
   In a preferred embodiment, a channel is a “topic” field appended to a message. The topic may have sub-topic fields associated with it as well. When a subscriber subscribes to a channel of a service, the pub/sub service publishes messages having the selected topic field to the subscriber. Shotgun further provides a filter mechanism to permit the user to define the sub-topics that he is interested in. Shotgun will only publish to the subscriber, messages having topics and sub-topics according to the subscriber&#39;s selection. 
   Shotgun provides a mechanism for allowing a subscriber to subscribe to a service  401 - 403  and to a channel provided by the service. Shotgun also provides a mechanism to allow a user to create filters on channels and message content (message identifying information) published by the pub/sub service such that only selected channel messages (those messages containing identifying information in accordance with predetermined inspection criteria) are received by the user. Thus, a user can create a channel filter to receive only stock quote messages and a message filter to only receive messages that include IBM stock. 
   Services A-C  401 - 403  are available by subscription. Clients  1  and  2   405 - 406  comprise Applications  1  and  2  respectively  503 - 504 . A user at Client  1   405  subscribes by way of Pub/Sub server  404  to Service B  402 . The user performs the Subscription operation using a GUI interface described later herein. Service B  402  sends messages to subscribers by way of Pub/Sub Server  404 . Messages are filtered  501 - 502  by examining the content of the message body for keywords, boolean compares or other methods well known in the art. The filtering criteria is pre-programed by the user of client  1   405  such that only messages containing information of interest to the user appear at the user&#39;s display. Shotgun Application  1   503  controls the filtering criteria but the actual filtering may be done at the pub/sub server in one embodiment or on the client&#39;s  405  machine (App  1   503 ) in another embodiment. Content filtering is performed on the incoming messages based on key words or more complex boolean tests, depending on the implementation. In one embodiment, the user is alerted when a message is available (has passed the filter test) and can elect to receive the full message or discard it. 
   Subscription to a service  401 - 403  persists as long as the shotgun client application is active or can be maintained based on other criteria such as elapsed time or specific user actions (on/off selection for example). In a preferred embodiment, the user optionally enables the Shotgun client application to save subscriber information locally and use it to automatically subscribe to predetermined services with predetermined filtering whenever the client is activated (power on). 
   In a preferred embodiment, shotgun client applications  503 - 504  include an application program interface (API)  508  providing an interface so that adjunct applications can be provided to the shotgun client applications  503 - 504 . This provides similar functionality to application plug-ins used to extend Web Browser functionality in a Web environment. In a preferred embodiment, an instant messaging (IM) application is provided during a session such that clients can communicate with one another using IM facilities. 
   In another preferred embodiment, the shotgun client application  503 - 504  provides a user API  508  enabling a third party application to be plugged into the shotgun client application. 
   In another preferred embodiment, reference  FIG. 6 , Client  1   405  subscribes to Service A  401  by way of the pub/sub server  404 . Service A provides an active agent IM A  602  which interfaces to the system acting like a user. IM A  602  has an IM address (which it supplies to it&#39;s subscribers) and subscribers can communicate with Service A  401  using IM facilities. 
   Using the embodiment above, a shotgun client can receive information from Service A and communicate with other users or Service A as if Service A were another user (client) by way of IM. 
   Shotgun automates the security mechanism for controlling who can publish data and on what channels. Shotgun maintains a database directory of applications, accessed through an administrative SOAP service. (SOAP is a lightweight XML based protocol for exchange of information in a decentralized, distributed environment. It includes an envelope that defines a framework for describing what is in a message and how to process it and transport binding framework for exchanging messages using an underlying protocol.) The directory of applications contains channel access controls, owner identification, help text and other application parameters. 
   The shotgun infrastructure revolves around a publish and subscribe (pub/sub) service. In a preferred embodiment it is an IBM WEBSPHERE service called “MQ Publish &amp; Subscribe”. Any pub/sub application could be used to create a Shotgun service as taught by the present application. The WEBSPHERE service adds Enterprise level of security on top of a common broadcast component. The LDAP (Lightweight Directory Access Protocol) directory provides authentication and a grouping technology provides authorization. The application registration provides an additional level of authorization on top of the free form Corporate architecture. 
   LDAP is a well known directory service protocol that runs over TCP/IP. LDAP provides a method for a client to authenticate or prove its identity to a directory server to help protect the information the server contains. 
   Secure Publisher Preferred Embodiment (WebService Interface): 
   Security (authentication/Authorization) for the publisher is provided by a private LDAP Directory, an application registration database or any appropriate authorization technique. The publisher preferably uses a Web Service SOAP interface and calls the pub/sub service by providing topic (channel), message, user ID and password over HTTPS secure socket. Alternatively, the publisher calls the pub/sub service by providing topic (channel) and message over HTTPS wherein the user name and password are stored in the HTTP specified REMOTE_USER field. 
   Gryphon functionality is available in IBM WEBSPHERE available from INTERNATIONAL BUSINESS MACHINES particularly in the component IBM WEBSPHERE MQEVENT BROKER also available from INTERNATIONAL BUSINESS MACHINES, Gryphon provides a new alternative to subject-based systems is content-based messaging systems. Functionality associated with Gryphon can be found in the following U.S. patents: U.S. Pat. No. 6,216,132 “METHOD AND SYSTEM FOR MATCHING CONSUMERS TO EVENTS” (Chandra et al.); U.S. Pat. No. 6,091,724 “ROUTING MESSAGES WITHIN A NETWORK USING THE DATA CONTENT OF THE MESSAGE” (Chandra et al.); U.S. Pat. No. 6,336,119 “METHOD AND SYSTEM FOR APPLYING CLUSTER-BASED GROUP MULTICAST TO CONTENT-BASED PUBLISH-SUBSCRIBE SYSTEM” (Banavar et al.). Each of these patents is assigned to INTERNATIONAL BUSINESS MACHINES and incorporated herein by reference. 
   A significant restriction with subject-based publish/subscribe is that the selectivity of subscriptions is limited to the predefined subjects. Content-based systems support a number of information spaces, where subscribers may express a “query” against the content of messages published. 
   The Gryphon system provides content-based publish/subscribe functionality. Clients access the system through an implementation of the Java Message Service (JMS) API. The Gryphon message broker is scalable, available, and secure:
         Scalability: Brokers may be added into the network to provide support for additional clients. The configuration support is flexible enough to efficiently support geographic distribution of brokers. Server farms in multiple geographies may be linked through a number of explicit links rather than requiring NxN connectivity between all brokers.   Availability: Gryphon responds to the failure of one broker in a network by rerouting traffic around the failed broker. Reconfiguration is automatic and requires no intervention by an administrator.   Security: Gryphon supports access controls for limiting who may publish and subscribe to portions of the information space. Further, Gryphon currently supports four authentication mechanisms for verifying client identity: simple password (e.g. telnet), mutual secure password authentication (password is never sent over the wire), asymmetric SSL (password sent over a secure SSL connection to the server) and symmetric SSL (both client and server use certificates to authenticate each other). Secrecy and integrity of sensitive messages are protected through state-of-the-art encryption mechanisms.       

   Gryphon is a distributed computing paradigm for message brokering, which is the transferring of information in the form of streams of events from information providers to information consumers. 
   In Gryphon, the flow of streams of events is described via an information flow graph. The information flow graph specifies the selective delivery of events, the transformation of events, and the generation of derived events as a function of states computed from event histories. 
   Message brokering is motivated by the need for efficient delivery of information across a large number of users and applications, in an environment characterized by heterogeneity of computing platforms, anonymity between information producers and consumers, and dynamic change due to system evolution. Within a single business, such as a stock exchange or a weather forecasting agency, there is a dynamically varying number of sub-applications supplying events, and a varying number consuming events. The suppliers and consumers may not necessarily be aware of one another; instead the suppliers may simply be supplying information of a certain type to any interested consumer and each consumer may be interested in subsets of this information having particular properties. For example, in a stock exchange, one consumer may be interested in all stock trades greater than 1000 shares, and another in specific market trends, such as all stock trades representing a drop of more than 10 points from the previous day&#39;s high. 
   There is also a growing need to “glue” together applications within multiple businesses, to support inter-business network commerce or maybe as a result of mergers and acquisitions. For example, a retailer may need to connect to its suppliers and customers, or a customer to various retailers and financial organizations. This may require transforming events from different sources into a compatible form, merging them, and selecting from these events. 
   Message brokering is an extension of publish-subscribe technology. The Gryphon approach augments the publish-subscribe paradigm with the following features:
         1. Content-based subscription, in which events are selected by predicates on their content rather than by pre-assigned subject categories;   2. Event transformations, which convert events by projecting and applying functions to data in events;   3. Event stream interpretation, which allows sequences of events to be collapsed to a state and/or expanded back to a new sequence of events; and   4. Reflection, which allows system management through meta-events.       

   Gryphon technology includes a collection of efficient implementations to support this paradigm and still provide scalability, high throughput and low latency. 
   The Gryphon Model 
   As mentioned earlier, event processing in Gryphon is described via an information flow graph. An information flow graph is a directed acyclic graph constituting an abstraction of the flow of events in the system. In one example, stock trades from two information sources, NYSE and NASDAQ, are combined, transformed, filtered and delivered to a client. The two sources produce events of type (price, volume), which are merged into a single stream. A path computes a new stream of events of type, and another path filters out events with capital less than $1,000,000. 
   A Gryphon information flow graph is an abstraction because Gryphon is free to physically implement the flow any way it chooses, possibly radically altering the flow pattern, provided that the consumers see the appropriate streams of events consistent with the incoming events and the transformations specified by the graph. Gryphon optimizes graphs and deploys them over a network of brokers (or servers). The broker network is responsible for handling client connections and for distributing events. 
   The nodes of the graph are called information spaces. Spaces are either 1. event histories—monotonically growing collections of events, e.g., stock trade events of the form (price, volume), or 2. event interpretations—states representing interpretations of sequences of events, such as a table (latestprice, highestprice). Each information space has a schema defining the structure of the history or state it contains. Each arc (path) in the information flow graph defines an operation to derive the information space at the head from that at the tail. Arcs can be one of the following types:
         “select (P)” specifies that the destination event history contains the subset of events in the source event history that satisfy the predicate P. The two event histories have the same schema.   “transform (T)” specifies that each event in the destination event history is obtained by applying function T to the corresponding event in the source event history.   “merge” combines two or more event histories of the same schema into a single history. This operation is implicit when multiple arcs lead to the same information space.   “interpret (I)” converts a source event history to a destination state by applying an interpretation function I to the history. Each time a new event arrives, this interpretation will be (incrementally) re-evaluated.   “expand (I)” The inversion of interpret: converts a state to an event history which is equivalent to that state under function I. This is a non-deterministic function: in particular, interpreting an event history and re-expanding it with the same I may yield the identical event history, but may also yield a different history which yields an equivalent state under I.       

   The Gryphon system consists of several components for efficiently realizing the information flow graph over a large distributed network of brokers. Areas of interest include:
         Event matching—determining, for each event, the subset of N subscriptions that match the event.   Multicasting—routing the events from source to all destinations while avoiding unnecessary processing of messages at brokers and long message headers on events. Multicast techniques in the prior art use the concept of groups, and do not apply to content-based pub/sub systems.   Graph transformations—reordering the selects, transforms, and interpretations to minimize the number of events sent through the network and the load on the brokers.   Fault-tolerance—preserving the appearance of a persistent information flow graph in the presence of failures. In addition, guaranteeing that, when required, clients have consistent views of information spaces even in the presence of failure so that some clients don&#39;t see that an information space contains a message while others see that the same information space has lost the message.   Ordered delivery—guaranteeing that, when required, clients have consistent view of the order of events in an information space.   Optimistic delivery—when a client&#39;s view of an information space is through an interpretation, exploits the non-determinism of the equivalent state to deliver messages to the client early, out-of-order, or to drop messages.   Compression—when a client&#39;s view of an information space is through an interpretation and the client disconnects and reconnects, exploits the non-determinism of the equivalent state to deliver a compressed sequence of events that captures the same state.   Reconfiguration—allows the physical broker network to be dynamically updated and extended without disturbing the logical view of a persistent information flow graph.   Reflection—capturing events corresponding to requests to change the information flow graph, and confirmed changes to the information flow graph in a special meta-event space.   Security—dealing with issues concerning the lack of full mutual trust between domains in the physical broker network.       

   Referring now to  FIG. 7 , Shotgun  700  is an end-to-end Publish/Subscribe e-Utility. It includes three major components: the IBM GRYPHON “pub/sub” broker  711 , a Web Service publisher  710 , and a generic IBM SASH subscriber application (Shotgun client subscriber application). Working together, these services provide a complete, easy to use solution for applications requiring message broadcast capability. 
   The GRYPHON message brokering system merges Pub/Sub communications and database functionality using “information flow graph” concepts. The information flow graph specifies the selective delivery of events, the transformation of events and the generation of new events from providers to information consumers. In the prior art pub/sub paradigm, events in a distributed environment are classified through a set of subjects (also known as topics, channels or groups). GRYPHON extends this paradigm to allow the selection of events by content (and/or subject) rather than simply subject and to allow event transformations. GRYPHON provides a general structure for message transformation. Events may change format, drop fields or gain new fields. 
   The SASH application, also available from International Business Machines, is a dynamically configurable programming environment for rapidly building and deploying platform-integrated desktop applications using JavaScript and DHTML. This programming environment enables Web programming beyond the browser, and the resulting applications are integrated seamlessly into the common desktop environment and take advantage of the latest standards in Web services. 
   The pub/sub model allows applications to publish data on “channels”, similar to television or radio broadcasting, and clients can “tune in” to listen for data—even listen on many channels at one time. 
   Shotgun supports multiple applications  704 - 706 , all publishing using the same infrastructure, with each application broadcasting data on one or more channels. For example Application A might be analogous to a TV cable company broadcasting to your home several channels of programs, and you might even be watching a ball game and keeping an eye on the weather channel at the same time (e.g. using PIP). Application B might be similar to a radio station broadcasting on both AM and FM channels to your home. And Application C might be analogous to an emergency support vehicle driving through your neighborhood, announcing evacuation procedures using a load speaker—in this case, a “single-channel” broadcast of information, which you may choose to “subscribe” to by opening your window. 
   The Shotgun GRYPHON Web Service  710  provides two major advantages to application developers. First, it provides a convenient SOAP interface to publish messages via the GRYPHON pub/sub server  711 , without the need for incorporating its lower-level API, while supporting the most common broadcast requirements. Secondly, it automates the security mechanism for controlling who can publish data on channels. This is accomplished by integrating Password authorization. 
   Shotgun maintains a DB2 database directory of applications, accessed through an administrative SOAP service (which can be used for controlled self-registration of user-written applications). The directory contains channel access controls, owner identification, help text, and other application parameters used by the Shotgun client. 
   The Shotgun client  701 - 703  is a Sash web application (weblication), that is downloaded from the Web. The Shotgun client serves as a common interface to the GRYPHON server  711  for all pub/sub-enabled weblications running on the client machine. A user can download his choice of shotgun-enabled weblications from the Web, and, using a settings control option from the Shotgun client GUI, can easily select applications and channels, define message filters, and control new message alerts. 
     FIG. 10  depicts a preferred embodiment of the Shotgun client GUI menu display. The display includes a list  1000  of all of the applications  1003  (Java web applications and Sash weblications) that are currently enabled for Shotgun message delivery (i.e., registered in the application directory). The column titles  1002  indicate the function below for each column of the table  1001 . “On/off” indicates whether or not the user is subscribed to the application, “alert” indicates whether the user wants to receive alert messages from the application, “application” is a name of an application, “?” is a user interface (UI) button for requesting information about the application such as a brief description of its function, “Channels” is a UI button for selecting channels within the application and “filters” is a UI button for selecting filtering criteria for the application. As can be seen in the example  1003 , the application “quickpoll” is subscribed to (on/off is checked) and alerts are requested (alert is checked). Other functionality  1004  is common to all selected applications. In the example  1004 , the applications selected start to run at startup time, sound effects are enabled for the selected applications, login automatically is enabled allowing the shotgun system to login to the applications automatically and alert messages are allowed to automatically display. An indication of the network status  1005  shows that the shotgun client is connected to the GRYPHON server. 
   “QuickPoll” and “SkillTap” are implemented as Sash weblications and must be downloaded separately from the Web (Sash Weblication Factory). “TradIt” is a Java Websphere application, which requires no shotgun client download. “Test” is available for users to send test messages to simulate application publishing, and to test alert handling for channel and text filters. As mentioned earlier, some applications support multiple channels and others require no channel selection. In the example  1100 , QuickPoll allows user selection of listening channels. 
   In  FIG. 12 , pressing the “edit” button  1102  for the “quickpoll” application in the “Channels” column brings up a window  1200  at the shotgun client terminal. If the application provides a public broadcast channel (meaning anyone can subscribe), its name is displayed first (“openmic”  1203  in this case). Anyone with a valid ID is allowed to publish on this channel. To listen for messages on the public channel  1203 , the user selects the check box  1203 . Next, if enabled by the application, is the personal channel  1205 , which matches the user&#39;s personal network ID. Only the user can publish on this channel, but others can elect to listen. A check in the Personal box  1205  enables the user to receive any data he publishes. 
   In the preferred embodiment, a user has the option to add as many other personal channels  1208  (i.e., your manager&#39;s Intranet ID) or “group” channels  1207 . Groups  1207  are defined using a program called BlueGroups. The Shotgun GRYPHON Web Service will authenticate the publisher&#39;s network ID to ensure that it is a member of the group and that the channel name on which the data is published matches the group name. In the example  1200 , only members of group “webahead” (defined as a set of department numbers via an LDAP search filter) are allowed to publish on the webahead channel  1207 . 
   Referring now to  FIG. 13 , in addition to channel selection, a user may set message “filters” for any application using the “edit” button  1103  on the settings menu  1001 . The message filter allows the user to test for certain words, phrases, or combinations using simple “AND” and “OR” expressions or even complex programming-style expressions that evaluate to true or false, to determine whether he will be presented with an alert box displaying the incoming message. This allows the user to filter out unwanted messages. 
     FIG. 14  shows two sample filters. The tradeit application filter  1301  alerts the user when a coworker posts an item for trade that the user needs. Here the user has elected to receive messages that contain the key phrases “ethernet switch” or “ethernet hub”. The second example is the SkillTap application filter  1302 , which allows the user to immediately see requests for assistance as posted by fellow employees. Here, only messages that contain any of (“AIX” or “LINUX” or “UNIX”) and also contain any of (“APACHE” or “WEBSPHERE” or “TOMCAT”) will display an “alert” message on the user screen indicating an incoming message. 
   When an “alert” option in the settings menu is checked for an application, messages that contain the information defined by the channel and filter settings will cause a notification window to display rather than displaying the filtered message immediately.  FIG. 14  shows an example alert message  1400  for the “tradeit” application (identified in the alert window  1401 ) that includes the filter criteria “ethernet switch” in the alert message  1402 . The alert display includes an action UI button function  1403  that allows the user to decide whether or not he wants to continue in the application, in which case he hits the “yes” button. 
   The application (“Tradeit” in this case) is shown in the alert window  1400  of  FIG. 14 , along with a “blast” message  1402 , with words highlighted in red that match the filter rule that was fired. The user then has the option  1402  to ignore the event, or select “yes” to trigger a “backfire URL” that was set by the application. In this example, Selecting “yes” will cause an Internet browser window to launch for an HTTP URL (in the case of a web application, such as Tradeit). In another embodiment, another Sash weblication may be launched by the backfire URL (such as QuickPoll or SkillTap). In this case, the Tradeit backfire URL calls a servlet that displays details about the item posted for trade by the responder. Note  1000  that if the “alert” option is unchecked in the selection table, but the application is enabled (via “on/off”), and an incoming message passes the channel and filter rules, the backfire URL will be launched immediately. 
   Table 1 shows example message fields for a preferred embodiment. Table 2 shows an example “request for publish” message and a corresponding “publish” message. 
   
     
       
             
           
             
             
           
         
             
               TABLE 1 
             
             
                 
             
             
               Message Fields: 
             
             
                 
             
           
           
             
                 
             
           
        
         
             
                 
               Blast 
             
             
                 
                 Possible values: string 
             
             
                 
                 Used as the message present to a user if alert 
             
             
                 
                 mechanism is active 
             
             
                 
               Payload 
             
             
                 
                 Possible values: string 
             
             
                 
                 Non-Shotgun application specific information 
             
             
                 
               Backfire 
             
             
                 
                 Possible values: null, string in the format of 
             
             
                 
                 proto: //params and args 
             
             
                 
                 URI defining action needed to be taken to 
             
             
                 
                 fulfill 
             
             
                 
               Channel (Added by publish mechanism) 
             
             
                 
                 Possible values: null, string 
             
             
                 
                 Channel the message is intended for 
             
             
                 
               Publisher (Added by publish mechanism) 
             
             
                 
                 Possible values: string 
             
             
                 
                 ID of the publisher 
             
             
                 
               Proxy (Added by publish mechanism) 
             
             
                 
                 Possible values: string 
             
             
                 
                 ID of the user the publisher is publishing on 
             
             
                 
                 behalf of 
             
             
                 
                 
             
           
        
       
     
   
   
     
       
             
           
         
             
               TABLE 2 
             
             
                 
             
           
           
             
               “Request for publish” message: 
             
             
                 &lt;shotgun&gt; 
             
             
                 &lt;blast&gt;&lt;![CDATA[This is a blast message.]]&gt;&lt;/blast&gt; 
             
             
                 &lt;payload&gt;&lt;![CDATA[This is a payload message.]]&gt;&lt;/payload&gt; 
             
             
                 &lt;backfire&gt;&lt;![CDATA[sash://{81fb0181-3c37-40b0-8e6d- 
             
             
                 df1602bdd820}, 
             
             
                 {C60A405E-A3C1-4B14-B3A4-C2366ADCF0FC}]]&gt;&lt;/backfire&gt; 
             
             
                 &lt;/shotgun&gt; 
             
             
               Published message: 
             
             
                 &lt;shotgun&gt; 
             
             
                 &lt;channel&gt;w3alert&lt;/channel&gt; 
             
             
                 &lt;publisher&gt;w3alert@us.ibm.com&lt;/publisher&gt; 
             
             
                 &lt;proxy&gt;bgoodman@us.ibm.com&lt;/proxy &gt; 
             
             
                 &lt;blast&gt;&lt;![CDATA[This is a blast message.]]&gt;&lt;/blast&gt; 
             
             
                 &lt;payload&gt;&lt;![CDATA[This is a payload message.]]&gt;&lt;/payload&gt; 
             
             
                 &lt;backfire&gt;sash://{81fb0181-3c37-40b0-8e6d-df1602bdd820}, 
             
             
                 {C60A405E-A3C1-4B14-B3A4-C2366ADCF0FC}&lt;/backfire&gt; 
             
             
                  &lt;/shotgun&gt; 
             
             
                 
             
           
        
       
     
   
     FIG. 15  represents an example flow depicting shotgun authentication of a content publisher for publishing messages through a pub/sub engine. The content publisher application requesting the publication presents identifying information (group name, channel ID, etc.) via the client/Shotgun interface  1502  in a SOAP envelope. Shotgun decodes the envelope  1503  to extract identifying information and passes it to an authentication/authorization module  1504 . The module  1504  is responsible for checking authorization and authentication and retrieving the predefined application parameters (configuration) associated with the content publisher. Shotgun checks whether the channel is public or read only  1505 , in which case no user authorization is needed. If user authorization is needed, the channel must match the user ID  1506 , the user must be a member of the group identified by the channel name  1507  (via a lookup table for example) or the user must be the application owner  1508 . If these conditions are not met, an error message  1509  is returned  1511  to the client  1501 . 
     FIG. 16  shows an example flow for Shotgun message content filtering. The user, wishing to subscribe to service ‘A’, selects Service ‘A’  1601  from available services  1605  preferably using a GUI window provided by Shotgun. The GUI selection, in one embodiment permits selecting various combinations of services and/or their channels. Channels are sub-topics within a service.  FIG. 19  shows an embodiment flow of user authorization for a Service. Shotgun checks whether the channel is public or not  1902 , if it is, the user needs no authorization  1603 , if it is not, the user supplies credentials for authorization  1901  to Shotgun. If the user&#39;s credentials are correct, the user is subscribed to the service  1603 , otherwise a security action is taken  1905  such as prompting the user for correct credentials, providing a means for the user to obtain credentials (pay a subscription fee, agree to a license and the like), report the attempt for subscription to the service owner and the like. The GUI window supports the user selection of various options  1602  for interacting with the selected service or channel. Options  1606  in  FIG. 17  include setting up message filter parameters  1701  whereby the content of incoming messages from the service or channel are screened for such things as keywords, key phrases, boolean combinations of text, media type, wild cards, comparing images and the like. Throttling parameters  1702  are selected, these include limiting the number or frequency or size or media type of incoming messages from the channel or service (txt, gif, jpg, mpg . . . ), prioritizing incoming messages by content or relative to other channel messages, providing a time based (time window) for presenting channel messages, providing user GUI control of incoming messages (pause/start) and the like. The user can elect invocation options  1703  such as automatic subscription when the user takes an action (such as powering up his computer, time based subscription, reminder message to the user of his current subscription status and the like). Where a service provides channels, they are subscribed to as a group in one embodiment and channel filters  1704  are available to the user to coordinate messages from available channels of a service. Other “custom” options are available such that a programmer can extend the capabilities of Shotgun via an API. 
   The user subscribes to Service ‘A’  1603  preferably by a single action of selecting a ‘subscribe’ button on his Shotgun setup GUI. Once the user has successfully subscribed to the service, the pub/sub engine includes the user in it&#39;s broadcast of messages from the service  1608 . The Shotgun client uses the predefined functions to support interaction of messages  1607  with the user&#39;s GUI  1604 . 
   In a preferred embodiment  FIG. 18 , messages  1609  are displayed at the user&#39;s terminal or forwarded to a custom application  1801  via an API  1803 . The custom application can be one that is supplied in messages from the channel (plug-in), or separately supplied electronically or by other media familiar to one skilled in the art. These applications support  1802  transforming messages to control mechanical machinery, display video or play audio (mpeg), transform from Text to Voice or Voice to text, send electronic mail, invoke a URL using the client&#39;s browser or any other transformation familiar to one skilled in the art. In one embodiment, the local application  1801  optionally  1805  sends an alert signal to the user  1804  announcing invocation of the client application  1801  or message, the user elects  1806  to perform the function of the application  1801  by taking an action or to abort it. 
   In one embodiment  FIG. 20 , the local client application  1801  may invoke an ‘active application’ plug-in that is a content service for a pub/sub engine. The active application  1802  receives messages  2001  from a content provider by way of a pub/sub channel. The active application transmits a second message (may include the message received  2001 ) to a pub/sub service for publication to subscribers. Thus, the user may become a “one to many” re-publisher of published content received from a pub/sub engine. 
     FIG. 21  is a logical depiction of components of a preferred embodiment of the present invention providing two way communication using published messages and responses. A content Service ‘B’  2101  includes an automated agent  2103 . The automated agent  2103  is an application that is running to perform functions ordinarily performed by a user/operator. The automated agent may optionally comprise artificial intelligence that can interact with a user and using AI techniques (inference), can prompt and respond to user&#39;s input. Service ‘B’  2101  further comprises a network interface such that a client application  2106  can communicate with Service ‘B’  2101  by using the appropriate ID/address mechanism  2104  according to the network protocol. The Service  2101  publishes to subscribers via Shotgun  2105  messages including information identifying Service ‘B’ s network ID and address  2104 . Clients  2108  subscribing to Service ‘B’ include applications (App ‘1’  2106 ) for receiving messages published  2015  from Service ‘B’  2101  via the network interface  2107  and communicating with the Service ‘B’  2101  in response. Thus in the embodiment, a service  2010  publishes content through a shotgun pub/sub service  2013  to subscribers  2108  (who may be anonymous to the Service ‘B’  2101 ) each of whom in turn can respond to the service via a network protocol. 
   Web Service Interface: 
   In the World Wide Web (the Web), program applications providing services are called “Web Services”. These are programs (located on remote servers) that may be used by a programmer to perform part of the application he is providing. For example, a programmer may create a Web Page (awebpage.com) that displays regional weather. The programmer can create his web page using HTML and supporting images (jpg, gif for example). For regional weather, the programmer takes advantage of web services to perform the needed function, he “calls” a weather web service program in his awebpage.com HTML. The call provides parameters (such as local post office zip code) to the weather web service over the network. The web service returns the requested information to the client to be displayed by the browser as part of the awebpage.com page. 
   Web services are useful in reducing the amount of code a programmer must write and maintain. He only needs to provide the interface for the service in his program. 
   Recently, a standard XML based interface has been defined (WSDL) that allows programmers to easily interface with web services. 
   In the present invention, refer to  FIG. 22 , secure pub/sub publishing utilizes a web service  2202  to perform the pub/sub service. Thus, shotgun performs various functions including authentication and “calls” the pub/sub service GRYPHON to perform the actual “one to many” publication. 
   Shotgun  2201  running in a client/server environment  2208 , accesses needed services  2202 - 2207  over the web. The function is similar to a function call. When the Shotgun application  2201  has authenticated a content service  2209 , Shotgun “calls” the PUB/SUB service  2202  (a web service, accessed by Shotgun over the Web) to perform the publication function for content provided by the content service  2209  that is published to the list of users (who are subscribers to the content service) by way of the Internet  2210 . 
   Other web services used in a preferred embodiment of the present invention include: 
   Secure Publishing  2202 : 
   (Secure Publishing via the Pub/Sub Server on Channels) 
   This service  2202  is an enabling service. It provides a common interface to publish Shotgun messages over pub/sub infrastructure. Since it is provided by a web service, if the Shotgun protocol changes the web service need not change. Changes would occur at the web service level. Code that calls the web service would stay the same. If GRYPHON were abandoned and a different utility to provide pub/sub were needed, a programmer would substitute the new pub/sub service in place and publishing could continue to occur as is without modification to client code. 
   IIP Check  2207 : 
   (Verifies User Name and Password Against a Corporate LDAP Directory) 
   When the user logs into Shotgun he is using his Corporate ID and Password. Verification (authorization) is performed by a Security web service  2207  on behalf of the user. This allows the programmer to change the back end LDAP server to a DB2 database for example, without disrupting the user. The web service interface stays the same. 
   GroupCheck  2203 : 
   (Verifies Group Membership Against Corporate Directory) 
   GroupCheck service  2203  ensures that users subscribing to pub/sub channels are authorized members of that channel. Instead of distributing this code with every client, the GroupCheck code is provided via the common interface as a web service. This service interfaces with the corporate LDAP servers to verify group membership. If the back end system needed to change it could without modification to the client code. 
   Custom Application Listing  2206 : 
   (Upon Startup an Authenticated Web Service Provides a Custom Application Listing Based on User ID/Group Membership) 
   A custom application listing service  2206  is accessed via the web service interface. The actual data is stored in a DB2 database. Based on the users ID and membership a customized subset of the available applications is marked up in XML and returned as the result to the call to the web service. If the programmer wanted to, he could decide to store the data in LDAP rather than the DB2 database and would effectively be switching web services. The listing change would not require any change to client code. 
   “Groups You Are a Part Of” Listing  2204 : 
   (Ability to Provide a List of All Groups You Are a Member of to Aid in Pub/Sub Channel Subscription) 
   As group membership grows users will need to continue to know what channels/groups they are a part of. This web service  2204  constructs a query that returns a list of all the groups of which a user is a member. The user might be added to a group and not be told of it. With this service the group would be revealed to the user and the provided a UI could be integrated into any application needing Group browsing. 
   Application Reporting System (ARS)  2205 : 
   (Provides a Generic Way to Generate Transaction Logging With/Without Bill-Able Unit Type Information) 
   The ARS  2205  is used behind the scenes to provide “logging”. For example, it logs when a user signed on, what channels he signed up for and when he signed off. This provides clients the ability to log to a central database without needing the dependent DB2 libraries or DB2 code. Instead, they interface with the web service which means that if DB2 is no longer the DB of choice mySQL could be dropped in and every client stays the same. Any changes would be done at the web service. 
   In a preferred embodiment, a “Plugin” module is supported by the Shotgun invention. The module comprises programs that perform additional function. The module is selectively attached to the Shotgun client by way of an application program interface (API) and receives messages directed to the user. 
   An example use of the Plugin method of the present invention is displayed in  FIG. 23 . The user GUI that allows him to elect the channel and filter options he is interested in also permits him to “Set Plugin”  2306 . When he elects this option, a screen  FIG. 24   2401  is displayed. The user is prompted for Plugin information  2402  and he enters into the text window  2403  the function (program) he wants to perform on the incoming messages. 
   In one embodiment, the plugins are predefined functions that can be selected via a GUI prompt. In the present example, the user is allowed to identify the file location of the code he wants to enable (“Forward”) and the parameters he wants the program to use. In the present example, the Forward Plugin module that the user enters into the GUI prompt  2401  is shown in Table 3: 
   
     
       
             
             
           
         
             
                 
               TABLE 3 
             
             
                 
                 
             
           
           
             
                 
               C:\SGplugin\Forward\apl2win -hostwin off -sm piped -input 
             
             
                 
                “‘)load ’‘C:\SGplugin\Forward\MSG.apl’‘’ ‘To’ 
             
             
                 
                ‘EMAIL:9995551212@messaging.sprintpcs.com’ 
             
             
                 
                ‘TOPIC:shotgun/w3alert/*’ 
             
             
                 
                ‘LOG:on,C:\SGplugin\Forward\SGmsglog.txt’ ‘&amp;xml’ ‘)off’” 
             
             
                 
                 
             
           
        
       
     
   
   To forward Shotgun alerts to a mailbox, a SKYTEL pager, or to a cell phone using SMS messaging, a user would copy this code as his Shotgun “plugin” (select “Set plugin”  2306  under the “File”  1101  menu option), replacing the “EMAIL:” tag in the code with his own messaging ID. 
   The example above will forward all Shotgun “w3alert” application messages (‘TOPIC:shotgun/w3alert/*) as SMS alerts to SprintPCS phone number 9995551212. If a user only wants to forward w3alert messages sent to a particular BlueGroup channel, he would replace the “*” (wildcard) with the group name. The “LOG:on,pathname” option turns logging on, so that messages forwarded via the plugin will be logged to the specified file with the return status from the mail-forwarding web service. If the user modifies the default directory during installation, he would need to adjust the pathnames in the appropriate command line above. 
   Table 4 shows example APL code supporting the preferred Forwarding embodiment. 
   
     
       
             
           
             
             
           
             
           
             
             
           
             
           
             
             
           
             
           
             
             
           
             
             
           
             
           
             
             
           
             
             
           
             
             
           
             
           
             
             
           
             
           
             
             
           
             
           
         
             
                 
             
           
           
             
                    )LOAD MOBALERT 
             
             
               SAVED 2002-07-16 13.26.26 (GMT-4) 
             
             
                    ∇To[□]∇ 
             
             
               [0]    To;CH;F;FROM;L;LF;MSG;P;SUBJ;SV1;TF;TO;TOP;XML 
             
             
               [1]    A FORWARD A SHOTGUN ALERT TO A MOBILE DEVICE 
             
             
               [2]     TO          6↓           
             
             
               [3]     TOP          UPC 6↓           
             
             
               [4]     LF          ‘ON,’≡UPC 3↑F          4↓L                     
             
             
               [5]     F          3↓F 
             
             
               [6]     LAST_XML          XML          ∈ΔFV TF                     
             
             
               [7]     DELETE TF 
             
             
               [8]     →(0=ρCH          ‘topic’ XGET XML)/END 
             
             
               [9]    A IS THIS A CHANNEL WE ARE INTERESTED IN? 
             
             
               [10]    →(~(UPC CH)MATCH TOP)/END 
             
             
               [11]   A WHO IS THE SENDER? 
             
             
               [12]    FROM          ‘publisher’ XGET XML 
             
             
               [13]     φ (0≠ρP          ‘proxy’ XGET XML)/‘FROM          P’ 
             
             
               [14]     φ (‘&lt;! [CDATA[’≡9↑MSG          ‘blast’ XGET XML)/‘MSG          9↓ — 3↓MSG’ 
             
             
               [15]    SUBJ          ‘Shotgun ’,8↓CH 
             
             
               [16]   A SEND THE ALERT VIA THE SMTP SERVICE 
             
             
               [17]    P          MAIL FROM TO SUBJ MSG 
             
             
               [18]   A LOG THE EVENT IF REQUESTED BY THE USER 
             
             
               [19]    P          P,‘ (From: ’,FROM,‘, To: ’,TO,‘, Subject: ’,SUBJ 
             
             
               [20]     φ LF/‘F LOG P,’‘, Message: ’‘,MSG,’‘)’‘’ 
             
             
               [21]   END: 
             
             
                   ∇ 2002-07-15 14.01.14 (GMT-4) 
             
             
                    ∇XGET[□]∇ 
             
             
               [0]    Z          TAG XGET STRING 
             
             
               [1]     Z          2⊃(‘&lt;’,TAG,‘&gt;’)(‘&lt;/’,TAG,‘&gt;’)EXTRACT STRING 
             
             
                   ∇ 2002-02-09 23.30.09 (GMT-4) 
             
             
                    ∇LOG[□]∇ 
             
             
               [0]    F LOG D;RC 
             
             
               [1]    A SV100          ((−(φF)          ‘\’)↓F),‘\NOW ’,(DBLQUOTE∈D),‘ &gt;&gt; ’,F 
             
             
               [2]    A RC          SV100 
             
             
               [3]     F APPENDFILEV⊂(‘[’,(NICE_DATETIME □TS),‘] ’,∈D 
             
             
                   ∇ |2002-02-25 22.27.52 (GMT-4) 
             
             
                    ∇MATCH[□]∇ 
             
             
               [0]    Z          STR MATCH PAT;I;□IO 
             
             
               [1]    A DOES STRING MATCH PATTERN (WITH           AS WILDCARDS)? 
             
             
               [2]     □IO          0 
             
             
               [3]    LP: 
             
             
               [4]    A EXIT IF FIRST PART OF STRING DOES NOT MATCH 
             
             
               [5]     →(~Z          (I↑STR)≡(I          PAT          ‘          ’)↑PAT)/END 
             
             
               [6]    A PATTERN ENDS WITH WILDCARD AFTER MATCH SO FAR - OK 
             
             
               [7]     →(Z          (0=ρPAT          (I+1)↓PAT)          ‘          ’= — 1↑PAT)/END 
             
             
               [8]    A DONE IF EXACT MATCH OF REMAINING TEXT (NO OTHER           ) 
             
             
               [9]    →(Z          (0=ρSTR          I↓STR)          0=ρPAT)/END 
             
             
               [10]   A NO MATCH IF END OF STRING, BUT NOT END OF PATTERN 
             
             
               [11]    →(~Z          0≠ρSTR)/END 
             
             
               [12]   A NO MATCH IF ≠ STRING END &amp; PATTERN END &amp; NO END            
             
             
               [13]    →(~Z          0≠ρPAT)/END 
             
             
               [14]   A DROP WILDCARD MATCHES, IF NOTHING LEFT, NO MATCH 
             
             
               [15]    →(~Z          0≠ρSTR          ((((PAT          ‘          ’)↑PAT) ∈ STR)          1)↓STR)/END 
             
             
               [16]    →LP 
             
             
               [17]   END: 
             
             
                   ∇ 2002-07-16 13.21.35 (GMT-4) 
             
             
                    ∇MAIL[□]∇ 
             
             
               [0]    Z          MAIL ARGS;FROM;MSG;SUBJ;T;TO 
             
             
               [1]    A SEND MAIL VIA SMTP SERVER, ARGS: FROM TO SUBJ TEXT 
             
             
               [2]    A MAIL ‘me@foo.com’ ‘ed@bar.com’ ‘Shotgun alert’ ‘Hi!’ 
             
             
               [3]     (FROM TO SUBJ MSG)          ARGS 
             
             
               [4]     Z          ‘webservices.ibm.com/soap/servlet/rpcrouter’ ‘’ 
             
             
               [5]     Z          Z,‘urn:BlueMail’ ‘simpleSend’ ‘’ 10 
             
             
               [6]     T          ‘&lt;myTo xsi:type=“xsd:string”&gt;’,TO,‘&lt;/myTo&gt;’ 
             
             
               [7]     T          T,‘&lt;myFrom xsi:type=“xsd:string”&gt;’,FROM,‘&lt;/myFrom&gt;’ 
             
             
               [8]     T          T,‘&lt;mySub xsi:type=“xsd:string”&gt;’,SUBJ,‘&lt;/mySub&gt;’ 
             
             
               [9]     T          T,‘&lt;myMsg xsi:type=“xsd:string”&gt;’,MSG,‘&lt;/myMsg&gt;’ 
             
             
               [10]    Z          Z SOAPWS T 
             
             
               [11]    T          ‘&lt;return’ 
             
             
               [12]     Z          ( — 1+((‘&lt;/’,1↓T) ∈ Z)          1)↑Z          (Z          ‘&gt;’)↓Z          ((T ∈ Z)∈1)↓Z 
             
             
                   ∇ 2002-07-16 13.26.23 (GMT-4) 
             
             
                    ∇SOAPWS[□]∇ 
             
             
               [0]    XML_OUT          PARMS SOAPWS XML_IN;ENDPOINT;ACTION;NAMESPACE; 
             
             
               METHOD;IDPW;TIMEOUT;PROXY;USEPROXY;PORT;HOST;INDX;LEN;REQ;RC; 
             
             
               SOCK;VAR119;SOAP119 
             
             
               [1]    A ISSUE A WEB SERVICE REQUEST VIA SOAP HTTP INTERFACE 
             
             
               [2]    A PARMS: SOAP ENDPOINT URL, SOAP ACTION, NAMESPACE URI, 
             
             
               METHOD NAME, USERID:PW, TIMEOUT [,PROXY URL] 
             
             
               [3]    (ENDPOINT ACTION NAMESPACE METHOD IDPW TIMEOUT PROXY) 
             
             
                          7↑PARMS, ⊂‘’ 
             
             
               [4]    →(2≠RC          119 SVOFFER VAR119          ‘SOAP119’)/ER 
             
           
        
         
             
               [5]    USEPROXY          0≠ρPROXY 
               A USING PROXY? 
             
             
               [6]    PORT          80 
               A DEFAULT EP PORT NUMBER 
             
           
        
         
             
               [7]    →((ρHOST)&lt;INDX          (HOST          (LEN           — 1+ENDPOINT          ‘/’)↑ENDPOINT)           
             
             
               ‘:’)/NOPORT 
             
           
        
         
             
               [8]    PORT          ‘80’ □EA INDX↓HOST 
               A EXTRACT EP PORT NUMBER 
             
             
               [9]    HOST          (INDX−1)↑HOST 
               A AND EP HOST DOMAIN NAME 
             
           
        
         
             
               [10]   NOPORT: 
             
             
               [11]    REQ          (HOST ACTION NAMESPACE METHOD IDPW)SOAPENV XML_IN 
             
             
               [12]    REQ          ‘POST ’,(USEPROXY/‘http://’),((LENx~USEPROXY)↓END 
             
             
               POINT),REQ 
             
           
        
         
             
               [13]    →( — 1≡↑RC          SOCK          GETSOCK ‘’)/ER 
               A GET A SOCKET 
             
             
               [14]    →( — 1≡↑RC          BLOCKING SOCK 0)/ER 
               A NON-BLOCKING MODE 
             
           
        
         
             
               [15]    →( — 1≡↑RC          CONNECT SOCK(↑USEPROXYφPORT,80)(↑USEPROXYφHOST 
             
             
               PROXY))/ER 
             
             
               [16]    →( — 1≡↑RC)          ~(,SOCK)≡2⊃RC          SELECT(,SOCK)‘W’ TIMEOUT)/ER 
             
           
        
         
             
               [17]    →( — 1≡↑RC          SENDALL SOCK REQ)/ER 
               A HTTP POST 
             
           
        
         
             
               [18]    LEN          ρXML_OUT          ‘’ 
               A INIT XML RESPONSE 
             
           
        
         
             
               [19]   RECVLOOP: 
             
             
               [20]    →(( — 1≡↑RC)          ~(,SOCK)≡1⊃RC          SELECT(,SOCK)‘R’ TIMEOUT)/ER 
             
           
        
         
             
               [21]    ( — 1≡↑RC          RECV SOCK)/ER 
               A READ NEXT CHUCK 
             
             
               [22]    XML_OUT          XML_OUT,RC 
               A ADD TO RESPONSE BUFF 
             
           
        
         
             
               [23]    →((LEN          ρXML_OUT)≠LEN)/RECVLOOP 
               A MORE TO RECEIVE? 
             
           
        
         
             
               [24]    →DISCON 
               A COMPLETED, DISCONNECT 
             
             
               [25]   ER: 
             
             
               [26]    XML_OUT          RC 
               A RETURN ERROR CODES 
             
             
               [27]    →EXIT 
             
             
               [28]   DISCON: 
             
             
               [29]    RC          CLOSE SOCK 
               A CLOSE SOCKET 
             
           
        
         
             
               [30]   EXIT: 
             
             
                  ∇ |2002-07-16 13.50.03 (GMT-4) 
             
             
                   ∇SOAPENV[□]∇ 
             
             
               [0]    ENV          PARMS SOAPENV XML_IN;ACTION;HOST;IDPW;NAMESPACE;METHOD 
             
             
               ;NL;XML 
             
             
               [1]    A GENERATE SOAP ENVELOPE FOR HTTP TRANSPORT 
             
             
               [2]    A PARMS: HOST, SOAP ACTION, NAMESPACE URI, METHOD NAME 
             
             
               , USERID:PW 
             
             
               [3]     (HOST ACTION NAMESPACE METHOD IDPW)          PARMS 
             
             
               [4]     NL          □TC[□IO+1 2] 
             
             
               [5]     XML          ‘&lt;?xml version=’‘1.0’‘ encoding=’‘UTF-8’‘?&gt;’ 
             
             
               [6]     XML          XML,‘&lt;SOAP-ENV:Envelope ’ 
             
             
               [7]     XML          XML,‘xmlns:SOAP-ENV=“http://schemas.xmlsoap,org/soap/ 
             
             
               envelope/” ’ 
             
             
               [8]     XML          XML,‘xmlns:xsi=“http://www.w3.org/1999/XMLSchema- 
             
             
               instance” ’ 
             
             
               [9]     XML,          XML,‘xmlns:xsd=“http://www.w3.org/1999/XMLSchema”&gt;’ 
             
             
               [10]    XML          XML,‘&lt;SOAP-ENV:Body&gt;’ 
             
             
               [11]    XML          XML,‘&lt;ns1:’,METHOD, ‘ xmlns:ns1= “’,NAMESPACE,‘” ’ 
             
             
               [12]    XML          XML,‘SOAP-ENV:encodingStyle=“http://schemas.xmlsoap. 
             
             
               org/soap/encoding/”&gt;’ 
             
             
               [13]    XML          XML,XML_IN 
             
             
               [14]    XML          XML,‘&lt;/ns1:’,METHOD,‘&gt;’ 
             
             
               [15]    XML          XML,‘&lt;/SOAP-ENV:Body&gt;’ 
             
             
               [16]    XML          XML,‘&lt;/SOAP-ENV:Envelope&gt;’ 
             
             
               [17]    ENV          ‘ HTTP/1.0’,NL 
             
             
               [18]     φ (0≠ρIDPW)/‘ENV          ENV, ’‘Authorization: Basic ’‘,(BASE64 —   
             
             
               ENCODE IDPW),NL’ 
             
             
               [19]    ENV          ENV,‘Host: ’,HOST,NL 
             
             
               [20]    ENV          ENV,‘Content-Type: text/xml; charset=utE-8’,NL 
             
             
               [21]    ENV          ENV,‘Content-Length: ’,(  φ ρXML),NL 
             
             
               [22]    ENV          ENV,‘SOAPAction: “’,ACTION,‘”’,NL 
             
             
               [23]    ENV          ENV,NL,XML 
             
             
                   ∇ 2001-12-11 23.16.19 (GMT-4) 
             
             
                     ∇BASE64_ENCODE[□]∇ 
             
             
               [0]     BASE64          SPLIT BASE64_ENCODE DATA; □IO;AV64;BINARY 
             
             
               [1]    A Encode using MIME Content-Transfer-Encoding: Base64 
             
             
               as specified in RFC 2045. 
             
           
        
         
             
               [2]    A Arguments: 
               DATA - Network character data to be encoded 
             
             
               [3]    A 
               SPLIT - Whether result should be split in 
             
             
               to 76 byte records 
             
           
        
         
             
               [4]    A Result: Encoded data in network character representaion 
             
             
               [5]     □IO          0 
             
           
        
         
             
               [6]    A□ES(1&lt;ρρDATA)/5 2 
               A Must be scalar or vector 
             
           
        
         
             
               [7]    A□ES(255           .&lt;□AV          DATA)/5 4 A Must be single-byte character 
             
             
               [8]     →(0=ρDATA)/0 BASE64          ‘’ 
             
             
               [9]     SPLIT          ‘0’ □EA ‘SPLIT’ 
             
             
               [10]   A Encoding alphabet 
             
             
               [11]    AV64          ‘ABCEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstu 
             
             
               vwxyz0123456789+/’ 
             
             
               [12]   A Convert alphabet to network character representation 
             
             
               [13]    AV64          HTONC AV64 
             
             
               [14]   A Ensure data is a vector 
             
             
               [15]   DATA          ,DATA 
             
             
               [16]   A Convert to bits 
             
             
               [17]    BINARY          ‘B1 1           ’ RTA DATA 
             
             
               [18]   A Reshape to 6 column bit matrix 
             
             
               [19]    BINARY          ((┌(ρBINARY)÷6),6)ρBINARY,6ρ0 
             
             
               [20]   A Add two columns on the left 
             
             
               [21]    BINARY          (−0 2+ρBINARY)↑BINARY 
             
             
               [22]   A Convert to alphabet selections 
             
             
               [23]    BASE64          AV64[□AF ‘B1 1           ’ ATR,BINARY] 
             
             
               [24]   A Pad to multiple of 4 byte length 
             
             
               [25]    BASE64          (4×┌(ρBASE64)÷4)↑(BASE64,HTONC ‘===’ 
             
             
               [26]    →(SPLIT≡0)/0 
             
             
               [27]   A Partition into 76 byte records 
             
             
               [28]    BASE64          ((ρBASE64)ρ(76↑2,75ρ1))⊂BASE64 
             
             
               [29]   A Add carriage return line feeds 
             
             
               [30]    BASE64          ∈BASE64,‘’⊂HTONC □TC[1 2] 
             
             
                   ∇ 2002-07-16 13.52.53 (GMT-4) 
             
             
                 
             
           
        
       
     
   
   The plugin capability of the present invention vastly extends the functionality of the present invention by permitting customized applications to perform function on incoming messages. It further allows the customized applications to interface with the shotgun application by way of a simple interface (API). In addition, the messages forwarded via the API to the customized application(s) use the powerful Channel and Filtering functions available to the Shotgun application. 
   While the preferred embodiment of the invention has been illustrated and described herein, it is to be understood that the invention is not limited to the precise construction herein disclosed, and the right is reserved to all changes and modifications coming within the scope of the invention as defined in the appended claims.