Abstract:
A system and method provides automated creation of device resident services. A host computer includes an advertisement listener that receives device service advertisements. One or more service generator processes receive information about the advertised device services and create hosted services acting as proxies for the device services. One or more peripheral devices are linked to the host computer, with each device including a device service. The device advertises the device service to the host computer and provides a device service description describing capabilities of the device and device service to the service generator. A directory service maintains service entries for the hosted services published by the service generators. Clients may search for and select a required service in the directory service table, and the service entries serve as links to the corresponding hosted services which may then be used by the client. A selected hosted service may enhance the corresponding device service and provide augmented services to the client.

Description:
BACKGROUND OF THE INVENTION 
     Modern computer systems, personal computer systems, are often characterized by a main computer or a host device to which one or more peripheral devices may be coupled. Typical peripheral devices that might be used in such a system include keyboards, pointing devices, monitors, printers, mass storage devices, and audio or visual input/output devices. In the past, device drivers, programs or routines which control or manage the flow of data to and from peripheral devices, have been used to control these peripheral devices. Recently, because of improved technology, these devices have become more sophisticated and are now able to offer their own services. For example, modern printers may be able to accept documents in a multitude of formats beyond the native format that the printer normally accepts. Printers capable of printing postscript documents are an example. However, current and future printers may offer additional transformation and document services. 
     Many peripheral devices are able to advertise their services through an advertising protocol offered by the device. Current implementations, however, do not necessarily make use of the advertising protocol. Instead, the implementation might bind to the device and then the host computer itself creates the service that is offered to users. In computer programming in general, the term bind refers to making an association between two or more programming objects or value items for some scope of time and place. As used herein, the terms bind and bound refer to a program connection between a device and a host, or between a device and a user. 
     As peripheral devices become more complex, devices such as printers are able to not only advertise print services, but are also able to offer these print services on their own without being bound to the host. These devices can act as a peer on a network in the network&#39;s environment. This is particularly important considering the explosive growth of computer networks in industry and in the home. When a printer or other device is connected to a computer that is connected to a local area network, a wide area network or even the Internet, the device is able to advertise its services and offer its services to a multitude of computers. Under the current paradigm, the user would look for a particular service by searching and listening for advertisements from a device and then interface with the device and allow the device to directly offer the desired service. The current paradigm, however, has several weaknesses. For example, allowing users to communicate directly with connected devices might create security weaknesses in the system. As another example, a system might have a plurality of printers attached serving as a pool of printers for users. However, the users are unable to take advantage of this in an efficient manner because the users must communicate with individual printers and there is no scheduling mechanism to distribute the load of printing across the individual printers in the pool of printers. Furthermore, the user is limited to the capabilities of the individual printers. 
     SUMMARY OF THE INVENTION 
     In one implementation, a method and system is provided for automated proxy creation of device resident services on a computer system. An advertisement listener listens for device service advertisements provided by connected peripheral devices having device services therein. The advertisement listener informs a service generator of a located device service and the service generator retrieves a device service description for the device service from the associated device. The service generator creates a hosted service, wherein the hosted service acts as a proxy for the device service. The hosted service may be augmented to provide capabilities not available in the device service, and the hosted service may utilize other hosted services in providing service to the client. The service generator also publishes a service entry describing the capabilities of the hosted service. A client searches for a required service and the service entry provides a link to the hosted service. The client then requests services from the hosted service, and the service is performed by the hosted service acting alone, the device service acting alone or the hosted service and device service acting jointly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a networked computer system suitable for incorporation of embodiments of the present invention; and 
         FIG. 2  is a flow diagram illustrating a preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     It will become evident from the following discussion that embodiments of the present application set forth herein, are suited for use in a wide variety of applications, and are not necessarily limited in application to the printing and copying systems described herein. 
     In existing network-connected computing systems, devices such as printers, scanners and other multi-function devices often externalize their capabilities by advertising and providing services directly on a network. While this method may work fine with small administered environments or environments connected to a small local area network (LAN), in enterprise systems connected to larger LANs, wide area networks or large networks such as the Internet, more control is often required in order to install or augment basic services. This has become a particularly important issue with the rapid deployment of networks in enterprise environments and home environments in view of the multitude of networking methods and systems available in the industry today. 
     The present application describes an apparatus and method whereby network-connected multi-function devices can advertise their services in a secure manner, wherein the services can be offered in a controlled environment, and wherein their services can be easily augmented to provide composite services. In order to better understand the environment to which concepts of the present invention may be applied, a brief discussion of directory concepts and some of the networking systems available today is provided to aid in understanding concepts of the present application. 
     Directory Service: When a multi-function device such as a printer offers a network service, the network service is often made known to users by means of a directory service. A directory service associates names with objects and also allows such objects to have attributes. Besides being able to look up an object by its name, a user can also get the object&#39;s attributes or search for the object based on its attributes. The directory service provides operations for creating, adding, removing and modifying the attributes associated with objects in a directory. 
     Directory: A directory is a connected set of directory objects. Many examples of directory services are presently available. For example, Novell Directory Service (NDS) is a directory service from Novell that provides information about many networking services such as file and print services. Another example is Network Information Service (NIS) that has a directory service available on the Sun Solaris operating system for storing system-related information such as that related to machines, printers, users, networks, and other such objects. Then there is the Netscape directory which is a general purpose directory service based on the Internet standard lightweight directory access protocol (LDAP). 
     Directory Object: A directory object represents an object in a computing environment and that directory object can be used, for example, to represent a printer, a person, a computer, or any such object on the network or even the network itself. The directory object usually contains attributes that describe the object that it represents and the capabilities of that object. For example, a network-connected printer might be represented by a directory object that has attributes such as speed, resolution and color. 
     When the name of a directory object is known, a user can look up that object in a directory by supplying its name to the directory service. Alternatively, many directories, such as those based on the LDAP protocol, support the notion of searches. When a user searches, the user is not limited to searching by name, but instead, a query may be constructed consisting of a logical expression in which the user specifies the attributes that the object or objects must have. This type of query is called a search filter. This style of searching is sometimes called reverse-lookup or content-based searching. The directory service searches for and returns the objects that satisfy the search filter. For example, a simple query might ask the directory service to find all printers that have color laser printing capabilities. 
     Novell&#39;s NetWare and e-Directory are LDAP enabled directory-based identity management systems that centralize the management of user identities, access privileges and other network resources. A Service Advertising Protocol (SAP) is used within NetWare systems to identify services and addresses of servers attached to the network. Among these services can be services of multi-function devices such as printers and similar devices. 
     Besides the above described, systems and protocols, Sun Microsystems has developed JINI technology as an attempt to provide a simple mechanism for enabling devices to plug together and form an impromptu community, a community that is put together without any planning, installation, or human intervention. In this technology, each device provides services that other devices in the community may use. 
     Microsoft Corporation has also offered its Universal Plug and Play (UPnP) as an opened standard technology for transparently connecting appliances, PCs, and services by extending Plug and Play to support networks peer-to-peer discovery and configuration. As a subset of UPnP, the Simple Service Discovery Protocol (SSDP) provides a mechanism whereby network clients with little or static configuration can discover desired network services. 
     The need to be able to offer services in a network environment is underscored by the efforts being made by major corporations such as Microsoft Corporation and Sun Microsystems. Microsoft has recently offered its .NET environment, which is an environment of software technologies for connecting people, systems and devices. It is intended to allow a new level of software integration through the use of web services. Sun Microsystems has offered, as a counterpoint, its Sun Open Net Environment (Sun ONE) as a standards-based software vision which is an environment for building and applying services on demand. It is a foundation for the next generation of distributed computing models such as web services. 
     The issue of offering device services in a network environment has become important enough that many corporations are joining together in forming forums for the development of common standards. For example, there is a Universal Plug and Play forum which is attempting to define and publish UPnP device and service descriptions in order to enable the emergence of these LAN connected devices and simplifying implementation of corporate networks. The Universal Plug and Play Forum is group of companies and individuals across multiple industries including: consumer electronics, computing home automation home security, appliances, printing, photography, computer networking and others. 
     The Salutation Consortium has been formed as a non-profit corporation with a goal of promoting and distributing royalty free and via open source a Salutation architecture that is a service discovery and session management protocol developed and sponsored by leading information technology companies. Salutation architecture is intended to be independent of operating system communication protocol or hardware platform. It is meant to provide an information exchange among and between different wireless handheld devices and office automation equipment. It is an industry initiative in order to create a platform independent open framework for describing services and discovering services using the Internet as a cross-industry effort driven by all major platform and software providers. 
     As new systems are developed for offering service advertising and service discovery, an attempt is underway across the industry to provide standardized protocols for performing these services. Among these protocols is the Services Location Protocol (SLP) which was standardized in the Internet Engineering Task Force (IETF) for providing automatic client configuration for applications and advertisement for network services. Among the charters within the IETF is an Internet Printing Protocol (IPP) charter. There are currently no universal standards for printing and several protocols are in use, but each has limited applicability and none is considered the dominant one. This means that printer vendors have to implement and support a number of different protocols and protocol variances. The Internet Printing Protocol is a client/server type protocol which is intended to allow the server side to be either a separate print server or a printer with embedded networking capabilities. The IPP working group is attempting to define a set of directory attributes that can be used to find printers on the network and to include mechanisms ensuring adequate security protection from materials being printed. 
     As communications, protocols, and message formats are standardized, in the web community it becomes increasingly possible and important to be able to describe the communications in a structured way. Web Services Description Language (WSDL) addresses that need by defining an XML grammar for describing network services as collections of communication endpoints capable of exchanging messages. WSDL service definitions provide documentation for distributed systems and serve as a recipe as automating the details involved in applications communication. A WSDL document defines services as collections of network endpoints or ports. A port is defined by associating a network address with a reusable binding, and a collection of ports defines a service. 
     It is within the rich variety of above-described environments and protocols that concepts of the present invention can be suitably and advantageously employed. A method will be described herein that uses a service description associated with a device advertisement as a template for the creation of a hosted service. The service description is, in essence, an electronic document describing capabilities and interface requirements of device resident services offered by the device. The service generator on the host will create necessary objects on the host to realize a service that will front-end the device. The service generator may also augment the basic service that the device offers in order to provide a richer and more capable service. Once the hosted service has been instantiated, the service generator will then publish the new service in the appropriate directory. 
       FIG. 1  is an illustration of a networked computing system  10  including a host computer  12 , a network attached device  14 , a directory service  16  and a client  18 . Among the processes operating in host computer  12  are: an advertisement listener process  20  and a service generator process  22 . The network connected device  14  includes software which offers a device service  24 . The advertisement listener process  20  listens in an environment specific manner for a device service. Examples of environment specific manner include, but are not limited to: listening for SSDP advertisements in a UPnP environment or listening for SAP advertisements in a NetWare environment. The advertisement listener  20  invokes an appropriate service generator  22  based on the advertised device service  24 . The service generator  22  is specific to a class of device services for which it will create a hosted service  26 . Service generators are automata with knowledge of basic and composite services and the ability to instantiate a hosted service that makes use of device and other hosted services. 
     Once informed of the existence of a device service  24 , the service generator  22  determines the capabilities of the device service. This also happens in an environmentally specific manner. Examples include: receiving a Device Description Document/Service Control Protocol Document (DDD/SCPD) in a UPnP environment for retrieving the printer attributes via a “GetPrinterAttributes” call in an Internet Printing Protocol (IPP) environment. Once the service generator  22  knows the capabilities of the device service  24 , a new service  26  on the host  12  is created and advertised. The service generator  22  can be fully automated or can be under operator control. New composite services created may make use of other services within host  12  to provide a richer set of features than the device service  24  offers. New composite services may optionally also take advantage of other services on the network not within host  12  in order to add new features to the features offered by the device service. 
       FIG. 2 , with continuing reference to  FIG. 1 , is a flow diagram illustrating steps required to create a hosted service, i.e. proxy for a device resident service. Users of the device resident service, therefore, do not communicate directly with the device. Instead, users see the proxy as if it were a device resident service and communicate with the proxy rather than directly with the device. In step  40 , the advertisement listener process  20  listens in an environment specific manner for a device service  24 . Listening in an environment specific manner might include, for example, listening for SSDP advertisements in a UPnP environment or SAP advertising in a NetWare environment. 
     In step  42 , the advertisement listener  20  informs an appropriate service generator  22  that an advertised device service  24  has been located. In a preferred embodiment, the service generator(s)  22  are service type specific wherein each service generator  22  will generate services for a specific class of devices. Classes of devices might include, for example, xerographic printers, ink jet printers, fax machines, etc. 
     In step  44 , the service generator  22  retrieves the Device Services Description  28  in an environment specific manner. For example, the service generator might receive a DDD/SCPD in a UPnP environment or it might retrieve the printer attributes via a “GetPrinterAttributes” call in an IPP environment. 
     In step  46 , the service generator  22  transforms the description  28  obtained from the device into a form usable in the environment common to the client and the host and makes the usable form available. Examples here include: a WSDL file in a Web Services environment for the creation of a service template in an SLP environment. 
     In step  48 , service generator  22  creates the service  26  and any associated objects or queues  32  required for this service&#39;s operation. The service generator  22  is not only specific to the device service  24  class, but it is also familiar with the service  26  and associated objects in queues  32  that it is creating and associating with the device service  24 . Additionally, the service  26  is aware, not only of its association with the device service  24 , but also with any other service it may use to augment the capabilities of the device service  24 . For example, the service generator  22  may instantiate an enhanced printer due to its ability to combine a simple print service and a transformation service. To the end user, the enhanced printer can now accept a wider range of document types. The hosted composite service uses the transformation service to convert the document stream into a format acceptable to the printer. 
     In step  50 , service generator  22  publishes its service entry  34  in an environment specific manner. Service entry  34  describes the capabilities of the service  26  either directly or indirectly through a reference to the description  30 . Examples here include: an entry in a Universal Description Discovery and Integration (UDDI) registry for the Web Services environment or a directory entry in Novell&#39;s NDS for a NetWare environment. 
     In step  52 , a client  18  searches for a required service  26  having desired capabilities. The result in service entry  34  provides a link to the service  26 . Examples of this include: browsing a UDDI registry in the Web Services environment or performing an LDAP query in a NetWare environment. 
     In step  54 , the client then uses the service  26  in an environment specific manner. Examples uses include: initiating a SOAP request in a Web Services environment or sending a “PrintJob” request in an IPP environment. 
     In step  56 , the service  26  processes requests from the client  18  by invoking the device service  24  and possibly making use of other local or remote services. Local services would be those services available within host  12  and remote services would be available on other hosts or servers network connected to host  12 . Examples of request processing include: issuing a UPnP action in a UPnP environment or invoking a transformation service in a Web Services environment. 
     It is to be understood that the steps illustrated in  FIG. 2 , although described singularly and in a chronological fashion, are not restricted in any way by the order of description. For example, the steps of advertising and listening are occurring substantially independently. However, steps, such as informing step  42 , only operate when a prerequisite step, such as advertising step  40 , have occurred and advertisement listener  20  has recognized an advertised device service  24 . It is also to be understood that although  FIG. 1  shows a single client, a single device, and a single service, that in preferred embodiments of the present invention, a plurality of devices and a plurality of clients, and a plurality of services will in fact be included in system  10 . It is additionally to be understood that the steps shown in  FIG. 2  are the most essential steps in embodiments of the present invention. Additional steps not shown in  FIG. 2  will include such steps as removing a service  26  when, and if, service generator  22  and/or service  26  recognize that the device service  24  offered by device  14  has become unavailable or inoperative. 
     Described, therefore, is a host-resident listener that receives advertisements of services offered by peripheral devices and then creates a proxy for each of these devices. This, in turn, allows the service to be enhanced. For example, a basic print service gets advertised, a host-based listener receives the service and augments the service with additional capabilities such as print transforms, additional transforms, and the service is then made available in a richer environment in terms of service functionality. The host-based listener can, additionally, pool the services offered by the plurality of printers and then offer the service to users as if it were a single printer with enhanced printing capabilities. The host-based service also takes advantage of the security features of the particular operating system. The host based listener can be configured to restrict the services that it forwards to the service generator to limit the exposure of the system to security breaches that might be inherent in a particular device service. 
     While the invention has been described with respect to specific embodiments by way of illustration, many modifications and changes will occur to those skilled in the art. It is therefore, to be understood that the appended claims are intended to cover all such modifications and changes which fall within the true spirit and scope of the invention.