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What this article shares with you is about how to analyze the principle of web service. The editor thinks it is very practical, so I share it with you to learn. I hope you can get something after reading this article.

Web service is a service oriented architecture technology, which provides services through the standard Web protocol to ensure that application services on different platforms can be interoperable.

According to the definition of W3C, Web Service (Web service) should be a software system to support the interaction between different machines in the network. Network services are usually made up of many application program interfaces (API) that execute requests for services submitted by customers over a network, such as the remote server side of the Internet (Internet).

Although the W3C definition covers many different and indistinguishable systems, we usually refer to the transmission of XML messages between master-slave architectures (Client-server) in accordance with the SOAP protocol. Regardless of definition or implementation, in the process of WEB services, the servo machine provides a machine accessible description (usually based on WSDL) to identify the WEB services provided by the servo machine. In addition, although WSDL is not a necessary condition for SOAP service endpoints, current mainstream Java-based WEB service development frameworks often require WSDL to implement client-side source code generation. Some industry standardization organizations, such as WS-I, enforce the inclusion of SOAP and WSDL in WEB service definitions.

SOAP

An extensible message envelope format based on XML that needs to be bound to a network transport protocol at the same time. This protocol is usually HTTP or HTTPS, but it could also be SMTP or XMPP.

WSDL

A document in XML format that describes how the service port is accessed and the details of the protocol used. It is usually used to help generate server and client code and configuration information.

UDDI

A protocol for publishing and searching WEB services by which applications can find the target WEB service at design or run time.

These standards are set by these organizations: the W3C is responsible for XML, SOAP is responsible for UDDI.

Protocol set [edit]

In order to improve the interoperability between WEB services, WS-I also released the WEB Service Protocol set (Profile). The protocol set contains a series of version-specific core definitions, such as SOAP and WSDL, as well as restrictions and constraints on their use. WS-I has also released testing tools and related use cases for deploying protocol set compatible WEB services.

WS- series additional definition [edit]

To extend the capabilities of WEB services, some new standards have been or are being developed. These standards are usually preceded by the prefix WS (short for Web Service). The following is an incomplete list of additional standards in the WS series:

WS Security (WS-Security)

Defines how to use XML encryption or XML signing in SOAP to protect message delivery. It can be used as an alternative or extension of HTTPS protection.

WS Reliability (WS-Reliability)

A standard protocol from OASIS to provide trusted messaging between WEB services.

WS trusted message (WS-ReliableMessaging)

It is also a protocol for providing trusted messages, published by Microsoft, BEA and IBM. At present, OASIS is standardizing it.

WS addressing (WS-Addressing)

Defines how the address of the sender / receiver is described within the SOAP message.

WS transaction (WS-Transaction)

Define how transactions are handled.

Web Service technology enables different applications running on different machines to exchange data or integrate with each other without the help of additional and specialized third-party software or hardware. Applications implemented according to the Web Service specification can exchange data with each other regardless of the language, platform, or internal protocol they use. Web Service is a self-described and self-contained available network module, which can perform specific business functions. Web Service is also easy to deploy because they are based on some conventional industry standards and existing technologies, such as XML, HTTP, a subset of the standard general markup language. Web Service reduces the cost of application interfaces. Web Service provides a common mechanism for the integration of business processes throughout the enterprise and even among multiple organizations.

Web service is an application that exposes an API that can be called through Web. That is to say, you can call the application programmatically through Web.

Web service includes content:

XML and XSD

Extensible markup language (a subset of the standard generic markup language) is the basic format for representing data in the Web service platform. In addition to being easy to build and analyze, the main advantage of XML is that it is both platform-independent and vendor-independent. Irrelevance is more important than technological superiority: software vendors will not choose a technology invented by competitors.

XML solves the problem of data representation, but it does not define a standard set of data types, let alone how to extend them. For example, what exactly does the shaping number represent? 16 bit, 32 bit, or 64 bit? These details are important for interoperability. XML Schema (XSD) formulated by W3C is a set of standards specifically to solve this problem. It defines a standard set of data types and gives a language to extend them. The Web service platform uses XSD as its data type system. When you use a certain language (such as VB. NET or C #) to construct a Web service, in order to comply with the Web service standard, all data types you use must be converted to XSD types. The tool you use may have automatically completed the conversion for you, but you are likely to modify the conversion process according to your needs.

SOAP

After the Web service is built, you or someone else will call it. Simple object access Protocol (SOAP) provides standard RPC methods to call Web service. In fact, SOAP is a bit of a misnomer here: it means that the following Web service is represented as an object, but that's not necessarily the case: you can write your Web service as a series of C functions and still use SOAP to call it. The SOAP specification defines the format of SOAP messages and how to use SOAP through the HTTP protocol. SOAP is also based on XML (a subset of the standard general markup language) and XSD, and XML is the data encoding method of SOAP.

WSDL

How would you tell others about the functions of your Web service and the parameters for each function call? You may write your own set of documentation, and you may even verbally tell people who need to use your Web service. These informal approaches have at least one serious problem: when programmers sit in front of a computer and want to use your Web service, their tools (such as Visual Studio) can't help them because they don't know your Web service at all.

The solution is to provide a formal description document in a way that the machine can read. Web service description language (WSDL) is such a language based on XML (a subset of the standard general markup language), which is used to describe Web service and its functions, parameters, and return values. WSDL is both machine-readable and human-readable, which will be a great advantage. Some of the latest development tools can not only generate WSDL documents based on your Web service, but also import WSDL documents and generate code to call the corresponding Web service.

UDDI

Universal Description, Discovery and Integration

A program to accelerate the promotion of Web Service and enhance the interoperability of Web Service, a standards-based specification for service description and discovery (specification).

The UDDI business registry is operated by multiple operators in the form of Web Service in a resource-sharing manner.

The core component of the UDDI initiative is the UDDI business registration, which uses XML documents to describe the enterprise and the Web Service it provides.

UDDI business registration provides three types of information:

The White Page contains the address, contact method, and known enterprise identity.

Yellow Page contains industry categories based on standard taxonomy.

Green Page contains technical information about the Web Service provided by the enterprise, which may be in the form of pointers to files or URL that serve the service discovery mechanism.

Advantages and disadvantages

Advantages:

1. Across the firewall

two。 Application integration

3. B2B integration

4. Software reuse

Disadvantages:

1. Stand-alone application

two。 Isomorphic applications on LAN

In terms of usage, the use of RPC and soap is decreasing, and the Restful architecture is dominant.

In terms of data format, the use of XML format is decreasing, while the use of lightweight formats such as json is increasing.

In terms of design architecture, more and more third-party software allows users to talk directly to the cloud on the client (that is, browsers), instead of using third-party servers to transfer or process data.

The above is how to analyze the principle of web service. The editor believes that there are some knowledge points that we may see or use in our daily work. I hope you can learn more from this article. For more details, please follow the industry information channel.

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