CN101807204B - Dynamic creation method of processing Web service with remote sensing image - Google Patents

Abstract

The present invention provides a method for dynamically generating web services for remote sensing image processing. When a service provider requests to publish a web service for the first time, the name of the web service and relevant information about the web service are obtained according to the application programming interface of the web service to be published by the service provider. Generate the source code of the Web service, compile and generate the Web service description language document of the Web service, that is, generate the Web service to be published by the service provider. When updating, you only need to re-read the API of the Web service, compare it with the service name and related information read by the current Web service API, and judge whether the Web service name and related information have changed, and if so, regenerate the Web service service source code, and then regenerate the web service from that source code. The invention can automatically and dynamically generate Web services, and reduces the time, manpower and material resources for service generation when a large number of Web services are generated, and improves efficiency.

Description

A Dynamic Generation Method of Web Service for Remote Sensing Image Processing

technical field

The invention belongs to the technical field of remote sensing image processing services, in particular to a method for dynamically generating remote sensing image processing Web services.

Background technique

Web service is a new type of Web application, a self-contained, self-explanatory, modular application that can be published, located, and invoked from anywhere on the Web. Service providers use Web service description language (Webservices description language, WSDL) to describe the services they provide and how to call the services, and then use the unified description, discovery and integration (Universal description discovery integration, UDDI) to register the services in the public registry . The service user or application program discovers the service in the registry and obtains the WSDL describing the service, and then invokes the service in an asynchronous message or remote call mode through the Simple Object Access Protocol (SOAP). Web service has nothing to do with the platform and programming language, it has complete encapsulation, high integration capability, and loose coupling. Therefore, Web services have been valued and applied by all aspects.

Existing web services are generally static. For example, ArcGIS Server is a service product developed on the basis of ArcObject components. It mainly includes two parts: GIS server and ADF (ArcGIS JavaWeb Application Developer Framework, ADF). Among them, the GIS server is a collection of many server objects, and these server objects include the ArcObjects necessary to connect to the GIS server and use the GIS server objects; ADF provides .Net and Java developers respectively with ArcObjects on the GIS server side to build network applications The framework of programs and network services, in which the network controls encapsulate the details of the underlying ArcObjects, and can be embedded into the Visual Studio.net environment for development. With the above platform, it is possible to program, develop and implement Web services in a certain compilation environment, and publish them. Different web services of ArcGIS Server need to be implemented by manual programming, the generated web services are fixed, and the interface parameters of the implemented web services are also fixed. This is a typical static web service, and the generation efficiency is low, especially in the case of massive map service generation. Related literature: Kang Ling, Fu Junfeng, Wang Huaiqing, Cai Jinsong, WebGIS Application System Development Based on ArcGIS Server, Hydropower Energy Science, 2007 Vol.25 No.1.

The early dynamic development of Web services was mainly realized by dynamically generating web pages, that is, the client browser sends an HTTP request to the server, and the server executes and interprets an application program, and transmits the running results to the client in HTML format. On the client side, the client accepts, interprets and displays the generated HTML. The mature ones in the above-mentioned development methods include JSP (JavaServer Page, JSP) and Java Servlet technology, as well as Microsoft's ASP and ASP.NET.

Java Servlet is a server-side program written based on Java, which is mainly used to browse and modify data interactively and generate web content. Its generation process: (1) the client sends a request to the server; (2) the server sends the request information to the Servlet; (3) the Servlet generates the response content and sends it to the server (the response content is dynamically generated, usually depending on the client's request); (4) The server returns the response to the client. Related literature: Yang Zhengquan, Li Yan, Method of Realizing Dynamic Web Pages with Java Servlet Technology [J], Experiment Science&Technology, 2003 Vol.12 No.03.

The built-in scripting language of JSP pages is based on Java and is compiled into Java Servlet, so JSP pages have all the benefits of Java technology, including robust storage management and security, "write once, run everywhere" and the advantages of JavaServlet . When the WEB server encounters a request to access a JSP web page, it first executes the program fragment, and then returns the execution result to the client in HTML or XML format. The program fragment can operate the database, redirect the web page, and send e-mail, etc. Related literature: Li Lei, looking for Kang Shan, Introduction to Java Server Pages Technology, Science & Technology Information, 2008No.20.

Microsoft's Active Server Pages (dynamic server homepage, ASP) is embedded in Internet Information Server (IIS), which can interactively and efficiently generate and execute dynamic site server applications, and is also one of the main ways to generate dynamic web pages at present. . ASP mainly realizes the dynamic generation of HTML homepage by combining WWW (World Wide Web, World Wide Web) publishing with database, which is often combined with XML technology and ASP's built-in data access component ActiveX Data Objects (ActiveX Data Objects, ADO) technology To create a page of database information, submit SQL statements to the database in ASP according to user requests, and receive query results through a specific interface and process the data to display the final results. Relevant literature: Liu Guangzhong, Wang Qiangbing, Using ASP to Generate Dynamic Web Pages, Computer Applied to Software, 2001Vol.18 No.4; Yang Jingjing, Utilizing XML and ASP Technology to Display Web Data Dynamically, Fujian Computer, 2004 No.9.

The purpose of the above-mentioned development technologies is mainly to generate web pages that can be browsed. For example, JSP realizes the separation of dynamic pages and static pages, breaks away from the shackles of the hardware platform, and runs after compilation, which greatly improves its execution efficiency and gradually becomes an Internet website. The mainstream development tools on the Internet. In contrast, Web services are independent and self-describing application components that can be used by other applications, not just dynamic web pages that can be browsed, so in a strict sense, the above development techniques cannot See it as the real realization of the dynamic generation of Web services.

There are also some technologies for dynamically generating Web services from clients. Zhou Hongji of ZTE Corporation proposed a method for automatically generating clients. The steps of this invention are: the user initiates a request to obtain Web services; Obtain the Uniform Resource Locator URL address corresponding to the Web service request from the stored corresponding list; find the corresponding Web service description file in the pre-stored corresponding list according to the URL address, and generate the corresponding Web service description file according to the predetermined development environment of the system. The source code of the Web service client is dynamically compiled to generate the execution code of the Web service client, that is, the Web service client is generated. This can only be used as a client-side service-generated method, and does not apply to the server-side.

Related literature: ZTE Corporation, Zhou Hongji, A method for automatically generating network service clients [P], Chinese Patent, 200810098044.7, 2009-11-25.

The generation of Web services for remote sensing image processing requires service providers to write Web service descriptions. At present, most of the Web service generation methods commonly used in remote sensing image processing are manually written source codes to generate WSDL and Web services. Every time a service is released, a manual procedure is required. of writing. In terms of remote sensing image processing, there are often many services deployed. If there are hundreds or thousands of web services, each service needs to be manually coded once, which not only requires a lot of manpower and material resources, but also is inefficient.

Contents of the invention

The problem to be solved by the present invention is to provide an automatic means capable of improving the generation efficiency of web services for remote sensing image processing.

The present invention provides a method for dynamically generating web services for remote sensing image processing, the scheme is as follows:

When a service provider first requests to publish a web service, the following steps are performed,

Step 1.1, obtain the name of the Web service according to the application programming interface of the Web service to be published by the service provider;

Step 1.2, according to the name of the Web service, read out the relevant information of the Web service from the interface function provided by the application programming interface;

Step 1.3, create a Web service, and generate the Web service source code according to the Web service name read out in Step 1.1 and the Web service related information read out in Step 1.2;

Step 1.4, according to the source code of the Web service generated in Step 1.3, compile and generate the Web service description language document of the Web service, that is, generate the Web service to be released by the service provider;

When the service provider updates the application to publish the Web service, perform the following steps,

Step 2.1, reacquire the Web service name from the application programming interface, and compare it with the Web service name obtained before this update. If the Web service name changes, re-read the relevant information of the Web service, and then enter step 2.2; If the service name has not changed, re-read the relevant information of the web service, and compare the relevant information of the web service with the relevant information of the web service read before this update, if the relevant information of the web service has not changed, wait for the next update; If the relevant information of the Web service changes, go to step 2.2;

Step 2.2, regenerate the source code of the Web service according to the relevant information of the Web service read out in Step 2.1;

Step 2.3, according to the source code of the Web service generated in Step 2.2, recompile and generate the Web service description language document of the Web service, that is, regenerate the Web service to be released by the service provider.

Moreover, the Web service-related information includes Web service parameter information, and the parameter information includes attribute parameter names, types, and default values of the Web service.

Moreover, the source code of the Web service is the source code in a predetermined development environment, and the compilation and generation of the Web service description language document of the Web service is implemented in the development environment.

And, described predetermined development environment is Visual Studio or JAVA development environment.

According to the method for automatically generating remote sensing image processing Web services provided by the present invention, the Web services are dynamically generated without manual generation; and when the application program used as the remote sensing image processing Web service changes, the API can be updated to automatically regenerate the Web service. Generate web services. When a large number of Web services are generated, the time, manpower and material resources of service generation are reduced, and the efficiency is improved.

Description of drawings

Fig. 1 is a flow chart of an embodiment of the present invention when publishing a Web service is required for the first time.

Fig. 2 is a flow chart of the embodiment of the present invention when updating the application program of the Web service to be published.

Specific implementation method

The core problem to be solved by the present invention is: dynamically generate the source code of the Web service according to the Application Programming Interface (API) provided by the service provider, and compile and generate the WSDL document of the Web service. When the remote sensing image processing Web service application changes, update the Web service.

The method for dynamically generating remote sensing image processing Web services of the present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

Referring to accompanying drawing 1, when the service provider requests to publish the Web service for the first time, perform the following steps,

Step 1.1, obtain the name of the Web service according to the application programming interface of the Web service to be released by the service provider.

In order to support the dynamic generation of a large number of Web services, this embodiment obtains the Web service name from the API of each Web service. During specific implementation, the service provider may be required to provide the service name with a character string in a consistent format, so as to identify it when the Web service is dynamically generated later. In the embodiment, after obtaining the Web service names of all Web services, a character string is formed. The specific content of the character string includes the names of remote sensing image processing services provided by all service providers, and the format is to separate different service names with the same delimiter. For example: name of service 1, name of service 2, ..., name of service n.

Step 1.2, according to the name of the Web service, read out the relevant information of the Web service from the interface function provided by the application programming interface.

The service provider publishes an API about service information, which provides interface functions about Web service-related information. In order to provide complete information about Web services, Web service-related information can be set, including parameter information of remote sensing image processing services, parameter information It can be divided into attribute parameter name, type and default value. In the embodiment, firstly, the service name used to identify each remote sensing image processing service is parsed out from the character string obtained in step 1.1. According to the parsed service name, the attribute information strings used to describe the parameter information of each Web service are further read, including the attribute parameter name, type and default value. According to the embodiment, the attributes of a service are separated by uniform characters, the name, type and default value of each attribute are separated by characters different from those between attributes, and the order of each attribute information must be Consistent to avoid parsing errors.

For example: for service 1, according to the service name and the interface function for reading service attributes provided by the API, the attribute information string of service 1 is obtained: attribute 1, type 1, default value 1; attribute 2, type 2; attribute 3, type 2,; property 4, type 3, default 2; property 5, type 3, default 3. Two attributes are separated by ";", and the name, type and default value of each attribute are separated by ",".

During specific implementation, the read service name may contain illegal service variable names (such as spaces or illegal symbols), so after reading the service name used to identify the service, it can be processed accordingly (such as removing spaces and replacing illegal symbols, etc.); the read type name may also be illegal (such as float32), and some corresponding processing can also be performed (such as replacement operation); corresponding processing can also be performed on the default value of the attribute (such as If no default value is provided, it can be set to an empty value).

During specific implementation, the technical scheme of the present invention can be implemented by programming by those skilled in the art, and provided as software for users to use. Therefore, it can be designed to display the names of all remote sensing image processing services and the corresponding attribute information on the software interface, which is convenient for Web service developers to perform visual operations on service information.

Step 1.3, create a Web service, and generate the source code of the Web service according to the name of the Web service read out in Step 1.1 and the related information of the Web service read out in Step 1.2.

The calling and implementation of API, as well as the writing of Web service source code, can be written and implemented in any development environment, using any language required by the service publisher. The invention predetermines the development environment, and generating the source code of the Web service based on the development environment is beneficial to the consistency of each Web service release. The development environment adopted in this embodiment is Visual Studio development environment, and the Web service created under this development environment is ASP.NET Web service. The approach based on the Java development environment is the same as that based on the Visual Studio development environment, except that when the Java development environment is based on the corresponding compilation and generation of the network service description language document of the Web service, tomcat or apatch is used as the agent, and when the Visual Studio development environment is based on IIS.

During specific implementation, in the remote sensing image processing services generated in batches, the Web names and parameter information of different services are different, and only the service names and parameters need to be written. According to the name of each service obtained in step 1.1 and the parameter information of each service obtained in step 1.2, the source code of each Web service can be dynamically generated.

Step 1.4, according to the source code of the Web service generated in Step 1.3, compile and generate a Web Service Description Language (WebServices Description Language, WSDL) document of the Web service, that is, generate the Web service to be published by the service provider.

The embodiment uses the Visual Studio development environment to compile the source code of the Web service, and the generated Web service description language is published on the Internet Information Service (Internet Information Server, IIS) site.

Referring to Fig. 2, in order to deal with updating, the present invention has designed the scheme of dynamic generation Web service, when service provider updates the application program that will issue Web service,

Step 2.1, reacquire the Web service name from the application programming interface (consistent with the specific implementation of step 1.1), compare it with the Web service name obtained before this update, and determine whether the Web service name has changed. If the name of the Web service changes, re-read the relevant information of the Web service, and then go directly to step 2.2. If the name of the Web service has not changed, re-read the related information of the Web service, and compare the related information of the Web service read out this time with the related information of the Web service read before this update, and determine whether the related information of the Web service has changed . If the relevant information of the Web service has not changed, wait for the next update; if the relevant information of the Web service has changed, go to step 2.2. The implementation of re-reading the Web service-related information is consistent with the specific implementation of step 1.2, that is, re-reading the Web service-related information from the interface function provided by the application programming interface.

For example, after the first release, when the first update is performed, the new Web service name obtained this time is compared with the Web service name obtained at the time of the first release. If they are different, the service-related information read out this time is compared with the first release. When performing the second update, the new Web service name read this time is compared with the Web service name read at the first update, and if they are different, the new Web service name read this time is compared. Compare the service-related information read out with the service-related information read out during the first update.

Step 2.2, regenerate the source code of the Web service according to the Web service name and service-related information read out in Step 2.1 (consistent with the specific implementation of Step 1.3).

Step 2.3, recompile and generate the Web service description language document of the Web service according to the Web service source code generated in Step 2.2, that is, regenerate the Web service to be published by the service provider (consistent with the specific implementation of Step 1.4).

That is to say, when the Web service is updated, that is, when the application program of the remote sensing image processing service changes, the technical solution of the present invention automatically updates the description information of the remote sensing image processing service read by the service-related API. The specific process is the same, and the present invention will not repeat them. It can be set that the service publisher only needs to re-read the API, then the software provided according to the technical solution of the present invention can automatically complete the generation of the source code of the Web service, run the source program, and generate WSDL to automatically complete the update of the service. It can be seen that the present invention can dynamically generate Web services in batches without manual intervention; and when the remote sensing image processing Web service application program changes, the Web services can be automatically regenerated through API update. Therefore, the present invention is particularly suitable for being used in the field of remote sensing image processing services, and realizes generating a large number of Web services.

The above description is only an embodiment of the present invention, and is not intended to limit the present invention. All modifications, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (4)

1. A method for dynamically generating remote sensing image processing Web services, characterized in that: When a service provider first requests to publish a web service, the following steps are performed, Step 1.1, obtain the name of the Web service according to the application programming interface of the Web service to be published by the service provider; Step 1.2, according to the name of the Web service, read out the relevant information of the Web service from the interface function provided by the application programming interface; Step 1.3, create a Web service, and generate the Web service source code according to the Web service name read out in Step 1.1 and the Web service related information read out in Step 1.2; Step 1.4, according to the source code of the Web service generated in Step 1.3, compile and generate the Web service description language document of the Web service, that is, generate the Web service to be released by the service provider; When the service provider updates the application to publish the Web service, perform the following steps, Step 2.1, reacquire the Web service name from the application programming interface, and compare it with the Web service name obtained before this update. If the Web service name changes, re-read the relevant information of the Web service, and then go to step 2.2; If the name has not changed, re-read the relevant information of the Web service, and compare the relevant information of the Web service with the relevant information of the Web service read before this update. If the relevant information of the Web service has not changed, wait for the next update; if If the relevant information of the Web service changes, go to step 2.2; Step 2.2, regenerate the source code of the Web service according to the relevant information of the Web service read out in Step 2.1; Step 2.3, according to the source code of the Web service generated in Step 2.2, recompile and generate the Web service description language document of the Web service, that is, regenerate the Web service to be released by the service provider. 2. The method for dynamically generating Web services for remote sensing image processing as claimed in claim 1, wherein said Web service-related information includes parameter information of Web services, and said parameter information includes attribute parameter names, types and default values of Web services. value. 3. The method for dynamically generating web services for remote sensing image processing according to claim 1 or 2, characterized in that: the source code of the web services is the source code in a predetermined development environment, and the compilation and generation of web services is implemented in the development environment The Web Services Description Language document. 4. The remote sensing image processing Web service dynamic generation method as claimed in claim 3, characterized in that: the predetermined development environment is Visual Studio or JAVA development environment.

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