Study And Implementation Of Document Verification And Approval System Based On Web Service

In the multilayer system structure of enterprise-level distributed application system, middle business logic layer is the key part of the whole system, which takes charge of implementing the main business flow of the enterprise. However, implementing of the business logic layer lies on how to ensure unstoppable, addressing, end-to-end secure transmission of business information. First, information transmission can pass through the all kinds of firewall. Second, that information must pass through intermediaries of current business flow is assured through dynamically configuring transmission rout. Finally, the secrecy and integrality of the important data must be guaranteed from the beginning to the end.This article precisely launches the work under such background. In the development of design system of distributed oil well construction for Liaohe oilfield, the users requested us to realize the verification and approval flow of construction design documents based on distributed system structure. The system analysis shows that information need pass through all kinds of firewall in the process of verification and approval flow, that design documents of oil well are accessed in form of Microsoft Word, that the design documents must pass through intermediaries which represent first, second, third verification and final approval in turn, and that relevant secure protection measure must be used because of the importance of information. Finally we decide to select Web Service as the way of information transmission. The reasons are as following: First, SOAP (simple object access protocol) is often based on HTTP as the first protocol of Web Service. Therefore SOAP messages can pass through each kind of firewall. Second, WS-Attachments and DIME show how SOAP messages append binary attachment. Third, as the SOAP expanded route standard, WS-Addressing provide powerful support for the definition of the SOAP message transmission route. Finally, as SOAP expanded security standard, WS-Security makes the protection of important information in the SOAP message possible.Taking the Verification and Approval flow of design documents as the main clue, this article proposes a new model of SOAP message which can satisfy several requirements such as addressing, security, processing and attachment etc. In addition, it establishes a frame of transmission based on this message model to simulate the verification and approval flow.Finally, it designs and realizes the construction and design document verification and approval subsystem of oil well for Liaohe oil field. The result indicates that comparing with the B/S model, the intermediary addressing model that the system uses reduces the network reply price through increasing few local processing price. Moreover, it enables the system to have the quite good security and reliability. It's suitable for realizing bussiness logic layer of the distributional application system which takes security and reliability as the goal.