Abstract:
The present invention discloses a method and system for creating REST clients using existing REST export information. The invention can provide a wizard able to dynamically generate REST client code. The REST client code can include source code, such as HTML and JAVA SCRIPT starting points that can be further configured by the REST client code recipient. In one embodiment, the automatically created REST client can be a GUI client able to be rendered within a browser. The REST client can include one or more sections, each associated with a particular REST resource. Each resource specific section can include fields for specifying values of each resource parameter. Suitable GUI controls can be associated with each of the fields such as using a checkbox for a Boolean field and a drop down list for an enumerated field.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to the field of Web services and, more particularly, to automatically generating REST clients from REST resources. 
     2. Description of the Related Art 
     Many companies have begun exposing their Web services in a form of Representational State Transfer (REST) services. Each of the rest services is a URL addressed resource. Users can query these exposed resources through HTTP methods, such as GET and POST. REST calls return a response, which are often formatted in eXtensible Markup Language (XML). 
     One way to interact with the REST resource is to dynamically build a URL with URL parameters to query the exposed resource; an example of which is shown in  FIG. 1  (Prior Art). Specifically,  FIG. 1  shows a URL  110  that queries YAHOO!&#39;s Geocoding API. The URL  110  includes a base URI portion  112  and a query portion  114 . The query portion  114  can specify values  118  for parameters. The URI portion  112  identifies the REST resource. The URL  110  can cause a related Web service to return results  120 . Standard Web browsers include features to be able to specify the URL  110  and to view results  120 . 
     Obvious problems exist with accessing a Web service by entering a URL into a Web browser including: a user must have the technical knowledge to specify URL&#39;s and URL parameters, a user must know the URL of a REST resource, a user must know what parameters can be specified for the REST resource, a user must know a proper means for specifying parameter values. Another less obvious problem is that a typical Web browser can fail to support all REST methods, such as PUT, POST, and DELETE methods. 
     A way around these problems is to develop a REST client to interface with a set of one or more REST resources. At present developers must manually create code of a Web client. In order to create a REST client, a developer must look up details on the use of the Web service exposed as a REST resource, to read documentation concerning the service, and then to painstakingly create Web clients specifically designed to submit user input/commands to the Web service and designed to present service results within the client. Accordingly, designing a REST client consumes developer time, which incurs a cost. 
     BRIEF SUMMARY OF THE COMPUTER PROGRAM PRODUCT 
     The present invention discloses a method and system for creating REST clients using existing REST export information. For example, a client creation wizard can be included in a software development tool. When the wizard is selected for a specific Web service, REST client code can be dynamically generated and made available to a wizard user for deployment of the user&#39;s server/client. The REST client code can include source code, such as HTML and JAVA SCRIPT starting points that can be further configured by the REST client code recipient. In one embodiment, the automatically created REST client can be a GUI client able to be rendered within a browser. The REST client can include one or more sections, each associated with a particular REST resource. Each resource specific section can include fields for specifying values of each resource parameter. Suitable GUI controls can be associated with each of the fields such as using a checkbox for a Boolean field and a drop down list for an enumerated field. 
     The present invention can be implemented in accordance with numerous aspects consistent with the material presented herein. For example, one aspect of the present invention can include software for interacting with a REST resource. The software can be configured to dynamically generate a graphical REST client given a REST resource. 
     Another aspect of the present invention can include a method for generating software that interacts with a REST resource. The method can include a step of identifying a REST resource that exposes functionality of a Web service. A request for an interface to remotely interact with the REST resource can be received. Responsive to the received request, at least one input parameter for the REST resource can be detected. Source code for a user interface for remotely interacting with the REST resource can be dynamically built. The source code can define at least one input element and can include an interface submission control. A selection of the interface submission control can cause user provided values entered into the input element to be submitted to the REST resource. The built source code can be conveyed to a remotely located computing device from which the request originated. 
     Still another aspect of the present invention can include a method of obtaining a dynamically generated REST client. In the method, a Hypertext Transfer Protocol (HTTP) request can be submitted to a server. The submitted request can specify a Web service exposed through a REST resource. The server can be configured to dynamically generate a REST client for interacting with the Web service upon receiving the request. Source code for the REST client can be received from the server. The source code can include HyperText Markup Language (HTML) and object-based, client side scripting language source code (e.g., JAVA SCRIPT code). 
     It should be noted that various aspects of the invention can be implemented as a program for controlling computing equipment to implement the functions described herein, or a program for enabling computing equipment to perform processes corresponding to the steps disclosed herein. This program may be provided by storing the program in a magnetic disk, an optical disk, a semiconductor memory, or any other recording medium. The program can also be provided as a digitally encoded signal conveyed via a carrier wave. The described program can be a single program or can be implemented as multiple subprograms, each of which interact within a single computing device or interact in a distributed fashion across a network space. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       There are shown in the drawings, embodiments which are presently preferred, it being understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. 
         FIG. 1  shows an example of querying a REST service using a dynamically built Uniform Resource Locator (URL) entered into a Web browser. 
         FIG. 2  is a schematic diagram illustrating system where a Representational State Transfer (REST) client generator is able to generate a REST client for at least one REST resource in accordance with an embodiment of the inventive arrangements disclosed herein. 
         FIG. 3  shows a rest client generator able to automatically generate an HTML form for interacting with a REST resource. 
         FIG. 4  illustrates a set of sample graphical user interfaces, which a REST client generator can generate in accordance with an embodiment of the illustrative arrangements disclosed herein. 
         FIG. 5  illustrates a further set of sample of graphical user interfaces (GUIs), which a REST client generator can create. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 2  is a schematic diagram illustrating system  200  where a Representational State Transfer (REST) client generator  246  is able to generate a REST client  234  for at least one REST resource  244  in accordance with an embodiment of the inventive arrangements disclosed herein. In system  200 , a user  214  of a computing device  224  can interact with a Web service server  240  over a network  250 . An additional Web server  230  can also be connected to network  250 , which is able to server REST clients  234 . Each REST client  234  can be configured to permit users to interact with a REST resource  244 . 
     More specifically, user  214  can use a client creation interface  226  to invoke a creation feature of the REST client generator  246  for a developer  214  selected resource  244 . The generator  246  can dynamically generate source code for a REST client able to interact with the selected resource  244 . The code can be conveyed to the computing device  244 , which can be part of a software development platform. The user  214  is then able to modify the automatically generated code as desired. Afterwards, the user  214  can deploy the code for the REST client  235  upon a Web server  230 , which can serve Web pages including ones containing the REST client  235  to authorized users. 
     Thus, software developers  214  can save significant development time over manually creating needed REST clients  234  from scratch. Further, less experienced developers  214  can use the REST client generator  246  to develop a usable REST client  234  even if they lack experience/knowledge to manually develop the client  234  on their own. Additionally, The Web service (exposed as a REST resource  244 ) owner is able to attract more customers to use their REST resources  244 . 
     In fact, in one contemplated arrangement, the generator  246  can dynamically generate clients  234  for use by end-users  214  lacking software development skills. That is, an end user  214  wanting to use a REST resource  244  can use a standard Web browser  228  to interface with the Web service server  240 . These interactions can indicate the user wants to use a feature of a REST resource  244 , which causes the client generator  246  to create a REST client  234 . This client can be a browser  228  displayable HTML form, which the user can utilize. In the end-user situation, the server  240  functions as a Web service server having HTML form creation abilities and as an HTML form server. 
     As used herein, REST refers generally to a technique for exposing a Web service as a URL addressable resource. A REST resource  244  need not respond to each of the basic REST primitive commands (e.g., GET, POST, PUT, and DELETE) but can be designed to only respond to a subset of these commands. For example, in any implementations, the REST client  234  need only respond to queries (e.g., GET) that produce displayable results. Of course, the REST client  234  created by generator  246  can be designed to issue other commands (POST, PUT, and DELETE) to a REST resource  244 , which results in an insertion, update, or removal programmatic action respectively. 
     One implementation of system  200  can implement a more constrained version of REST, where several architectural constraints are imposed that are intended to enhance performance, scalability, and resource abstraction. These constraints can include a statelessness constraint, and cache-ability constraint. The uniform interface constraint signifies that all resources present the same interface to clients. Statelessness signifies that servers keep no state on the client&#39;s behalf, so all requests must carry the pertinent session-oriented information. Caching means that clients or intermediaries are permitted to cache responses that servers mark as cacheable, which can greatly affect performance in a distributed environment and scalability. 
     The computing device  224  can be any device capable of interacting with the Web service server  240  and/or capable of executing a REST client  234 . For example, the computing device  224  can include a personal computer, a server, a mobile telephone, an internet appliance, an Internet enabled consumer electronic device, a kiosk, an embedded computer system, and the like. 
     The client creation interface  226  can be any user interface, graphical, voice, multimodal, and the like, configured to submit a REST client generation request over network  250  to the Web service server. In one embodiment, the request can be an HTTP request. In another embodiment, a Web page served by server  240  can be rendered as the interface  226  and can permit REST client requests to be submitted. 
     The interface  228  can be any user interface, graphical, voice, multimodal, and the like, able to operate as a REST client to permit user  214  to interact with a Web service exposed by the REST resource  244 . In one embodiment, the interface  228  can be a Web browser that renders REST client code  234  served to the browser  228  by a Web server  230 . For example, the REST client  234  can be implemented as an HTML based form. In another embodiment, the interface  228  can be a Web enabled Widget or Gadget able function as a REST client  234 . Additionally, the interface  228  can be an interface of a Rich Internet Application (RIA). 
     Network  250  can include any hardware/software/and firmware necessary to convey digital content encoded within carrier waves. Content can be contained within analog or digital signals and conveyed through data or voice channels and can be conveyed over a personal area network (PAN) or a wide area network (WAN). The network  250  can include local components and data pathways necessary for communications to be exchanged among computing device components and between integrated device components and peripheral devices. The network  250  can also include network equipment, such as routers, data lines, hubs, and intermediary servers which together form a packet-based network, such as the Internet or an intranet. The network  250  can further include circuit-based communication components and mobile communication components, such as telephony switches, modems, cellular communication towers, and the like. The network  250  can include line based and/or wireless communication pathways. 
     The data stores  232  and  242  can be a physical or virtual storage space configured to store digital information. Data store  232  and/or  242  can be physically implemented within any type of hardware including, but not limited to, a magnetic disk, an optical disk, a semiconductor memory, a digitally encoded plastic memory, a holographic memory, or any other recording medium. Each data store  232  and  242  can be a stand-alone storage unit as well as a storage unit formed from a plurality of physical devices. Additionally, information can be stored within each of the data stores  232  and  242  in a variety of manners. For example, information can be stored within a database structure or can be stored within one or more files of a file storage system, where each file may or may not be indexed for information searching purposes. Further, zero or more of the data stores  232  and  242  can optionally utilize one or more encryption mechanisms to protect stored information from unauthorized access. 
       FIG. 3  shows a rest client generator  300  able to automatically generate an HTML form  330  from a REST resource  320 . The generator  300  can be one implementation of the generator  246 . 
     A REST resource  320  processed by the generator  300  can include various attributes  322  and parameters  324 . These parameters  324  can also include attributes  326 , which impose constraints and further define each parameter. When HTTP Form engine  310  converts the resource into Form  330 . Each parameter  324  can be provided a unique form field  332 . The parameter attributes  326  can define what values are possible for associated fields  332 , which permits the value input elements  334  to be tailored. For example, a value input element  334  for a field labeled P 3  can be a pull down list containing enumerated elements defined by a parameter  326  specific attribute  326 . When an attribute  326  defines a parameter  324  as a Boolean, the input element  334  generated for it can be a check box, as shown by Parameter P 4  of form  330 . Different data types, defined by attributes  326  can have data type constrained input elements  334 . Further, the input elements  334  can be validated and/or constrained to only permit acceptable input, as defined by the appropriate attribute  326 . 
     The general resource  320  attributes  322  can also define what capacities are to be provided in form  330 . For example, when attributes  322  indicate a resource is able to be retrieved, updated, added to, and deleted, execution buttons  336  for these REST methods can be included in form  330 . When attributes  322  indicate that resource  320  is only query-able, different execution buttons  336  can be added to form  330 , such as an “execute” button or a “query” button. Results produced when a REST service is executed can be displayed in a result display region  338  of the generated form  330 . 
     In one embodiment, the REST client generator  300  can have multiple options for how a particular component of form  330  is to be generated. For example, an enumerated parameter  324  can be implemented as a value constrained text input box, as a pull down list, as a scrollable element selection control, and the like. A configuration engine  312  of the generator  300  can permit an authorized user to specify generation rules/preferences. Different preferences can be configured using the configuration engine  312  for different users, groups, projects, and resource types. 
       FIG. 4  illustrates a set of sample graphical user interfaces (GUIs)  410 ,  430 ,  440 , which a REST client generator can generate in accordance with an embodiment of the illustrative arrangements disclosed herein. Interface  410  can be a Web interface, where a REST client  412  is selected by entering a URL for that client  412 . A REST client  412  can permit interactions with one or more REST resources  420 - 426 . 
     As shown in interface  410 , each resource  420 - 426  can be associated with its own interactive component. For example, in one embodiment, the interface  412  can be a portal and each REST resource  420 - 426  can be implemented as a portlet. In another embodiment, each resource  420 - 426  can be a detachable internet enabled widget or gadget, which can be detachable from a parent interface  412  in which they can be docked. The interface  412  can also implement each REST resource  420 - 426  within a single Web page. 
     Each REST resource can optionally have a number of parameter values, which can be associated with interface fields, which is shown by interfaces  430  and  440 . In these interface  430 ,  440  a REST resource  432  labeled Operation 1  can have fields for a name  434 , a value  436 , and a Boolean  438 . The name  424  is the only required field, as indicated by label  433 . The different attributes of the fields  434 - 438  (including a required  433  or not required attribute) can be automatically determined from published data associated with an REST resource, which a REST client generator used to generate client  430 . Various validation checks can be built into a client  440  by the client generator, such as a check to ensure a value has been supplied in all required fields (e.g., name), when a user executes  444  a method of the client  440 . 
       FIG. 5  illustrates a further sample of graphical user interface (GUIs)  520  and  526 , which a REST client generator can create. Specifically interface  520  can be for a findEmployee service within which a specific person has been entered into an input element  512 . Selection of an execute button  515  can cause the related service to execute, which produces the output shown in results  514 . A default presentation for REST results can be a tree structure  514  since that is a natural for presenting XML formatted data. Other result presentation mechanisms are contemplated and the invention is not limited in this regard. 
     For example, interface  526  shows a different type of output  518  produced when an equivalent operation is executed  516 . The interface  512  can be based upon an extension point contained in source code generated by a REST client generator. For example, the extension point can be supplied with a certain type of business object and a handler for that business object. The handler can determine how the returned results are displayed. For instance a handler for “Map Markers” can be implemented as shown in results  518 . That is, when the returned results are of a type “Map Marker”, a mapping interface can be presented in interface  526  along with appropriate information. In one embodiment, a user can utilize a configuration engine (e.g., engine  312 ) to define handler and presentation options for different types of results produced by a REST resource for the REST client  526 . 
     Unlike conventional approaches where user defined handlers would be directly coded into a REST client, the disclosed solution permits these settings to be established for a client generator, so that they are available to any clients generated in a future. It is contemplated that a number of shared configuration libraries can evolve for the REST client generator, which can be made available to any software developer to define specific library implemented enhancements to automatically generated REST clients. 
     The present invention may be realized in hardware, software, or a combination of hardware and software. The present invention may be realized in a centralized fashion in one computer system or in a distributed fashion where different elements are spread across several interconnected computer systems. Any kind of computer system or other apparatus adapted for carrying out the methods described herein is suited. A typical combination of hardware and software may be a general purpose computer system with a computer program that, when being loaded and executed, controls the computer system such that it carries out the methods described herein. 
     The present invention also may be embedded in a computer program product, which comprises all the features enabling the implementation of the methods described herein, and which when loaded in a computer system is able to carry out these methods. Computer program in the present context means any expression, in any language, code or notation, of a set of instructions intended to cause a system having an information processing capability to perform a particular function either directly or after either or both of the following: a) conversion to another language, code or notation; b) reproduction in a different material form. 
     This invention may be embodied in other forms without departing from the spirit or essential attributes thereof. Accordingly, reference should be made to the following claims, rather than to the foregoing specification, as indicating the scope of the invention.