What is Web Services? What is its function and how it is implemented?

Source: Internet
Author: User
Tags wsdl
Web Services
Introduction to Web Services

Web ServicesIs a common model for building applications and running on all operating systems that support Internet communication. Web services enables the best combination of component-based development and web, and component-based object models, such as Distributed Component Object Model (DCOM) and remote Method Invocation (RMI ), internet Inter-ORB Protocol (IIOP) has been released for a long time, but these models depend on the special object model protocol, and Web Services uses soap and XML
These models are further extended in terms of communication to eliminate barriers to special object models.
Web services mainly uses HTTP and soap protocols to transmit commercial data on the Web. Soap calls commercial objects through http to execute remote function calls, web users can use soap and HTTP to call remote objects through web calling methods.

Web services structure

The customer generates a SOAP request message based on the WSDL description. Web services are placed after Web servers (such as IIS). The SOAP requests generated by the customer are embedded in an http post request and sent to the web server. The Web server then forwards these requests to the Web Services request processor. The request processor is used to parse the received SOAP request and call Web Services,
Then generate the corresponding soap response. After the Web server receives a soap response, it sends the information back to the client through HTTP response.

Web Services System

The Web Services system mainly includes the following aspects:
① Web services components. Includes three components:
Service provider: provides services and registers them for service availability;
Service Proxy: the media between the service provider and the service requestor;
Service Requestor: requests services from the Service proxy and calls these services to create applications.
② Web services operations. There are three types of operations:
Publish/unpublished (publish/unpublish): The provider publishes (registers) services to the agent or does not publish (migrate)
Go to) register these services;
Find: the service requestor performs the find operation on the Service proxy. The service requestor describes
Service and Service proxy distribute matching results;
BIND: bind between the service requestor and the service provider.
You can access and call the provider's services.
③ UDDI-General discovery, description, and integration.
This is an Information Registration specification for Web Services. The Discovery Method of UDDI-based Web Services registration can be found: There is a distributed Registration Service on the web, business and services are described in a common XML format. Structured Data in XML is easy to discover, analyze, and operate.
④ WSDL-Web Service Description Language.
Web Service Description Language (WSDL) is an XML syntax that provides service providers with methods to describe the basic formats of web services requests built on different protocols or encoding methods. WSDL is used to describe what a web service can do, where it is located, and how to call it. Assume that soap/HTTP/mime is used as a remote object call mechanism, WSDL will play the largest role. UDDI registration describes the vast majority of Web Services, including service binding details. WSDL can be considered as a subset of the UDDI service description.
WSDL defines a service as a set of network endpoints, or a set of ports. In WSDL, abstract definitions of endpoints and messages are separated from their specific network implementation and data format binding. In this way, you can reuse these abstract definitions: Abstract descriptions of messages and data to be exchanged; abstract set of port types and operations. A reusable binding is formed for specific protocols and data format specifications of a specific port type. A port is defined as a network address and a reusable bound connection. A port set is defined as a service. Therefore, a WSDL document uses the following elements when defining network services:
Type-use a type system (such as XSD) to define a data type container;
Message-A Type Definition of abstract communication data;
Operation-abstract description of actions supported by the service;
Port type-an abstract set of operations supported by one or more endpoints;
Binding-specific protocol specifications and data format specifications for a specific port type;
Port-A single endpoint is defined as a link between a binding and a network address;
Service-a collection of related endpoints.
Therefore, it is not hard to see that WSDL provides a template to help customers describe and bind services.

Definition 1:

Web services are self-contained, modular applications that can be described, published, searched, and called on the Network (usually the Web.

Definition 2:

Web Services is a network-based, distributed modular component that executes specific tasks and complies with specific technical specifications. These specifications Enable Web Services to interoperate with other compatible components.

Definition 3:

Web services are online application services released by enterprises to meet their special business needs. Other companies or application software can access and use this application service over the Internet. (UDDI specification 2.0)

Business Needs
XML Web Services is an important standard for Distributed Computing and a technical trend for future software development. Based on the XML Web Services Standard, cross-platform and cross-programming language connection and interoperability can be achieved between application software. As a basic function of the Microsoft platform ,. based on the XML Web Services Standard. NET development platform can achieve information interconnection between individuals, between individuals and enterprises, and between enterprises, so that people can access and use information anytime, anywhere.

While Microsoft builds and implements this. Net-connected platform, many partners and vendors are also developing software products and solutions that can be interconnected and integrated based on XML Web Services standards. These software products and solutions are bringing huge benefits to their customers: enterprise information systems can provide better services for their users, the enterprise's information system can be better connected with the partner's system and provide timely and correct information to the enterprise's employees.

Industry opportunities
Microsoft's. NET connected Logo Program is a global certification program designed to identify software and solutions developed based on XML Web Services. Microsoft-certified software companies can place. NET connected logo patterns in the packaging, documentation, promotional materials and advertising of their certified software products.

The. NET connected identifier indicates that your application software is developed based on. NET Framework and can share data and functions with other software based on XML Web Services standards .. The net connected Logo Program helps customers identify whether application software, systems, and services are optimized to meet the requirements of next-generation Internet computing.

Benefits of participating in the Microsoft. NET connected Logo Program
Microsoft. NET connected logo:

Identifies leading software development technologies and strengths.
Differentiate your applications from other software products.
Take full advantage of Microsoft's extensive market promotion and investment in. net.
Use the. NET connected directory to promote and promote your software products and solutions globally.
Users who use. NET connected products and services will benefit from:

Certified software products and services can be interconnected with other software based on XML Web Services and seamlessly integrated into the enterprise's future information system.
Certified products developed Based on. NET Framework provide excellent performance, stability, and security, which means that this product or service can be trusted.
It helps end users quickly identify technologies that can help them interconnect information anytime and anywhere.
Microsoft. NET connected platinum application requirements:

Applications or services should be based on Microsoft. NET framework development, the main application functions provide Interfaces Based on XML Web Service, the Web service call process must comply with industry standards: XML Schema 1.0, soap 1.1xml schema 1.0, soap 1.1 and WSDL 1.1. Applications should use at least one Microsoft application server, such as SQL Server, Exchange Server, and BizTalk Server.

The. NET connected directory

Microsoft. NET connected Directory provides a central location where users can find information and partners can display software and services that meet. NET connected logo requirements. Even if Microsoft promotes these applications and XML Web Services, partners can continue to maintain and host these services or applications, maintain any payment methods, and handle all issues related to these products.

Generally, if your product has obtained the. NET connected qualification certification, it will be automatically displayed in the directory product list. A partner can choose whether to display their products in. NET connected directory.

The partner's information must be reviewed and approved before being added to the catalog.

Detailed partner URL (URL required)

In order for collaborators to make changes to the items they submit (payment structure, download URL, description, etc.), they do not need to submit the portal again. We need to connect to the partner's website, this URL contains the information listed later. This information not only helps developers get the planned version and download information, but also contains the basic business information of the application software. The partner's webpage contains the following information:

Name of an XML Web Service or application that uses XML Web Service
Describes the features of a product.
Procedure
Connect to the URL of XML schema and browse XML Schema (optional)
WSDL schema version (ie: V1.1)
Soap version (ie: V1.1)
XML Web Service or software cost and payment method
System Requirements (optional)
Works well with which products or requires (optional)
Contact us for user support
Establish a connection to download software (optional)
Directly back to the link http://www.microsoft.com/net/directory for. NET connected directory
Product validity period (if any)
Optional information-answers to frequently asked questions, other information, contact number
The webpage must display the appropriate. NET connected logo
The partner's information must be reviewed and approved before being added to the directory.

Future needs

In the future, the. NET connected Logo Program will produce more advanced standards.

This document is for reference only. Microsoft is not authorized or implied.

Use. net
At its core, Microsoft. NET is about making technology available to people, rather than forcing individuals to adapt to their computer restrictions. With. net, you can always connect to information on your preferred device anytime and anywhere. With. net, you can protect your personal information and enterprise data, and allow others with your authorization to connect to the information.

. Net Value
For individuals (including yourself, your customers, employees, suppliers, and partners), using Microsoft. NET to generate results will be a seamless and attractive experience.
Use. Net for development
With Microsoft Visual Studio. NET and Microsoft. NET frameworks, Microsoft. NET provides the quickest way to generate and deploy the most advanced applications and XML Web Services.
What does. Net Mean to developers?
By using Microsoft? In Visual Studio. NET and. Net frameworks, Microsoft provides developers with a complete set of development tools that allow them to quickly and easily create the most advanced applications and XML Web Services.

With Visual Studio. NET and. Net frameworks, Microsoft. NET allows faster development of software applications and services.
. NET Framework and Visual Studio. NET will provide higher reliability for applications and XML Web Services.
The use of XML Web Services will allow applications and services created on the. NET platform to be integrated more easily and effectively.
XML Web Services
For Microsoft. NET, code is generated in a discrete unit (XML Web Services) that processes a limited set of tasks. XML-based standard interfaces simplify communication between software, so XML Web Services can be integrated into highly specialized applications and experiences. You can use the best XML Web Services from around the world to quickly and easily create the required solutions. Microsoft will provide a set of user-centered Core XML Web Services (Microsoft. NET my services) to provide features such as user identification and calendar access.

 

The development of current applications is slowly shifting from the C/S structure to the B/S structure, and people are beginning to prefer browser-based thin client applications. This is because it avoids the high cost of publishing desktop applications. The cost for publishing desktop applications is high, half because of application installation, configuration, and maintenance, and the other half because of communication between the customer and the server. For the B/S structure, the browser is the standard configuration of almost every client. A perfect solution for communication between the client and the server is to use HTTP protocol. This is because any machine running a web browser is using the HTTP protocol. At the same time, many firewalls are configured to only allow HTTP connections. Many commercial applications face another problem: interoperability with other programs. These programs are developed and run on different platforms in different languages. At the same time, we often find this term in major technical forums or enterprise information system forums: Web Services. At the same time, we will find that most of the technology vendors that come along with this term are major technical suppliers, and all major technical suppliers are not concerned about the development of this field. From Microsoft's. NET architecture to Sun ONE and IBM's IBM Web services, these heavyweight technology providers respect and pay attention to Web Services. These provide opportunities for Web Services, and the development of e-commerce has promoted this development. Web services allow companies to reduce their e-commerce costs, deploy solutions faster, and open up new opportunities. Web services make Application Integration faster, easier, and cheaper than before. Integration occurs at a higher level in the protocol stack. It implements loose integration of business functions based on messages that focus more on service semantics than network protocol semantics. These features are ideal for connecting businesses between enterprises and enterprises through web. They provide a consistent programming model that allows both inside and outside the enterprise to utilize common infrastructure and integrate applications in a common way. What is Web Services? From a technical perspective, Web Services is a new technical architecture and a new software application environment. Its system architecture and implementation technology completely inherit the existing technology. It can be considered that web services is an extension of the Internet and an extension of the existing Internet for better interoperability. 1, Web ServicesWeb Services, literally, are services provided through the Web. We can understand that Web services are self-contained, modular applications that can be described, published, searched, and called on the Network (usually the Web; it can also be understood that web senices is a network-based, distributed modular component that executes specific tasks and complies with specific technical specifications, these specifications Enable Web Sevices to interoperate with other compatible components. You can also understand that Web services are online application services released by enterprises to fulfill their special business needs, other companies or application software can access and use this application service over the Internet. For web services, many people will be confused with Web Services and think that the two refer to the same thing. Otherwise, the former refers to the technical framework used to construct the web service, and the latter refers to the Application Instances created using the Web Services technology. Web services is an interface describing some operations. These operations can be accessed over the network through the standardized XML message transmission mechanism. Web services are described using the standard and standard XML-based WSDL language, which is called the service description of Web Services. This description includes all the details required for interaction with the service, including the Message format (detailed description of the Input and Output Message format of the operation), transmission protocol, and location. This interface hides the details of service implementation and allows you to use this service by means of independent service implementation, independent software and hardware platform, and independent programming language used for service writing. This makes Web Services-based applications loosely coupled, component-oriented, and cross-technology implementation. All Web services perform certain specific services or tasks and can be used together with other Web Services to implement complex business transactions. 2, Web services featuresFrom the perspective of external users, web services is an object and component deployed on the Web. It has the following features: · excellent encapsulation: since Web services are an object deployed on WBB, they are naturally well encapsulated. for users, they can only see the list of functions provided by this object. · The loose coupling feature is also derived from the object/component technology. When the implementation of a Web service changes, the caller will not feel this. For the caller, as long as the Web service call interface remains unchanged, any changes to the implementation of Web services are transparent to them, even when the implementation platform of Web Services is migrated from J2EE. net or the opposite migration process, users can have no idea about this. For a loose pot, especially for Web Services in the Internet environment, a message exchange protocol suitable for the Internet environment is required. xml/soap is currently the most suitable message exchange protocol. · The normative feature of protocols comes from objects, but its interface specifications are more standardized and easier to understand than general objects. First, as a web service, the functions provided by the object interface should be described in a standard descriptive language (such as WSDL). Second, the service interface described by the standard descriptive language should be discoverable. Therefore, this descriptive document must be stored in a private or public registry. At the same time, the Use Agreement described in standard descriptive languages will not only be a service interface, but will be extended to Web Service aggregation, cross-web service transactions, workflows, etc, all of these require QoS Assurance. Secondly, we know the importance of security mechanisms for loosely coupled object environments. Therefore, we need to perform authorization authentication and data integrity (such as signature mechanisms) use standard methods to describe, transfer, and exchange the source authentication and the non-repudiation of transactions. Finally, the processing at all levels should be manageable, so the same mechanism should be applied to the management agreement. · High Integration Capability because Web services adopt simple and easy-to-understand standards, web protocols are used as Component Interface descriptions and collaborative description specifications, completely shielding the differences between different software platforms, both CORBA, DCOM, and EJB can use this standard protocol for interoperability, achieving the highest possible integration in the current environment. 3, Architecture of Web ServicesThe Web service architecture is based on the interaction between three roles (service provider, service registration center, and service requestor. Interaction involves Publishing, searching, and binding. These roles and operations work together on Web service components: Web service software module and its description. In typical cases, service providers host software modules that can be accessed through the network (an implementation of Web Services ). The service provider defines the service description of the web service and publishes it to the service requestor or service registration center. The service requestor uses the search operation to retrieve the service description from the local or service registration center, and then binds the service description with the service provider and calls the Web service implementation or interacts with it. The service provider and the service requester role are in a logical structure, so the service can have two features. Figure 1 shows these operations, components that provide these operations, and interactions between them. The Web Services architecture has three roles: (1) service provider: from the enterprise perspective, this is the service owner. From the perspective of architecture, this is a platform for hosting access services. (2) Service Requestor: from the enterprise perspective, this is an enterprise that requires a specific function. From the perspective of architecture, this is an application that looks for and calls services, or starts interactions with services. The service requestor role can be assumed by the browser and controlled by a person or a program without a user interface (for example, another Web Service. (3) The Service Registration Center is a searchable service description registration center where service providers publish their service descriptions. During the execution of static binding development or dynamic binding, the service requestor searches for the service and obtains the binding information of the service (in the service description ). For statically bound service requestor, the Service Registration Center is an optional role in the architecture, because the service provider can directly send the description to the service requestor. Similarly, service requestors can obtain service descriptions from sources other than the service registration center. For applications that use web services, the following three actions must occur: publish a service description, query or search for a service description, and bind or call a service according to the service description. These actions can occur once or repeatedly. These operations are as follows: (1) publish a service description to make the service accessible so that the service requestor can search for it. The location of the publish service description can vary according to application requirements. (2) In the search operation, the service requestor directly retrieves the service description or queries the required service type in the service registration. The service requestor may involve search operations in two different lifecycles: retrieving the Service Interface Description for program development during design, check the binding and location description of the service for calling during runtime. (3) The service must be called after binding. In the binding operation, the service requestor uses the binding details in the service description to locate, contact, and call the service, so as to call or start interaction with the service at runtime. 4, Web ServicesBased on the characteristics of today's web applications and web services, we generally think that the implementation of web services can be divided into four categories: (1) business-oriented web services are services for enterprise applications, including internal ERP systems and SCM/CRM among enterprises. When these systems appear in the form of web services in the network (Internet and Intranet), application integration within the enterprise will be easier, the system interconnection among many partners asked by enterprises is no longer an impossible task. Currently, existing solutions and product providers include Bowstreet and epicentric. (2) consumer-oriented web services this kind of service is aimed at the transformation of those original B2C websites, for these Browser-0riented Web applications increased (note is the increase) the Web service application interface enables third-party desktop tools or their own value-added desktop tools to provide desktop services that span multiple B2C services using better user interfaces. This will make it easier for users to use the Internet and provide more convenient services. For example, we can integrate (CALL) The stock price Query Web Service on the Internet in the Personal Financial Management Desktop System, and book a ticket web service, so that the personal financial management application is more automated. (3) device-oriented web services the terminals used for such services are generally handheld devices and household appliances. For the former, the network service architecture can be modified without having, allow previous network services to support terminals other than PCs, such as palm, pocketpc, and mobile phones. In this way, the weather forecast service, email service, and proactive information service will be more effective and convenient. The latter may be the start time of the market for household appliances. With the Web service as the basic framework, smart household appliances will truly receive standard support, this makes it possible to be widely used. (4) system-oriented web services some traditional system services, such as user permission authentication and system monitoring. If they are migrated to the global Internet, or the internal Intranet of an enterprise will be expanded from a single system or a local network to the entire enterprise network or the entire Internet. In this way, different applications based on the same system service can be deployed in the entire internet environment. For example, all online services of multinational enterprises can use the same user permission to authenticate Web Services. A new software architecture technology.
C/S software is only applicable to LAN
Although the B/S software solves the remote application problem, the client can only use the browser

The WebServices mode combines the features of C/S and B/S. The client uses applications to remotely access services on the server. Such remote access is based on Internet protocols such as HTTP.
WebServices also designs a standardized remote protocol: soap, and a web service publishing mechanism to make software in this mode more flexible. Web Service is a new Web application branch. It is a self-contained, self-describing, and modular application that can be released, located, and called through the Web. Web services can execute any function from simple requests to complex business processing. After deployment, other Web service applications can discover and call the services deployed by the application.
Web Service is an application that uses standard Internet protocols, such as Hypertext Transfer Protocol (HTTP) and XML, to visually display functions on the Internet and on the enterprise intranet. Web services can be considered as Web component programming.
Web services are built on common protocols, such as HTTP, soap, XML, WSDL, and UDDI. These protocols have no preference when it comes to the selection of operating systems, object models, and programming languages, so they will have a strong vitality. But there are some differences between. NET and J2EE in Web Service programming .. Net web services can be written in C #, VB, JScript, and other languages, and some windows resources can be used. J2EE Web services generally use Java and J2EE resources, such as bean, EJB, and so on. They also have their own characteristics in the programming environment, syntax structure, and management configuration. The inet Web Service uses Java to implement the Web Service APIs provided in the. NET class library. It can port web services developed by users using. Net to Java that is not related to the platform. Because it is Java, Java resources can also be used.
What role does web services play?
These trends mean that more intelligent Processing, operations, and summary of content become very important. Let's look at the four trends predicted from the Web Services perspective:
◆ More dynamic content: A web service must be able to merge content from multiple sources, including stocks, weather, news, and other content in the traditional environment, such as inventory level, purchase orders or directory information are all from the back-end system.
◆ Cheaper bandwidth: Web services can distribute various types of content (such as audio and video streams)
◆ Cheaper storage: Web services must be able to process a large amount of data intelligently, which means that the database, LDAP directory, buffering, and Server Load balancer technologies must be used to maintain scalability.
◆ Universal computing is more important: Web Services does not require customers to use traditional Windows browsers of a certain version. They must support various devices, platforms, browser types, and content types.
To achieve this goal, Web Services uses two technologies:
◆ XML is a great way to transmit structured data on the Web. Web services must operate data in a reliable and automatic manner. HTML does not meet the requirements, XML allows web services to process data conveniently, and its content and representation separation is ideal.
◆ Soap uses XML messages to call remote methods, so that web services can interact with remote machines through the post and get methods of the HTTP protocol. In addition, soap is more robust, flexible, and easy to use.
Other technologies such as UDDI and WSDL are closely integrated with XML and soap for service discovery.
So what is the Web service platform? The most basic platform is XML and HTTP. HTTP is a widely used protocol on the Internet. XML is a metalanguage. You can use it to write specific languages to describe the interaction between customers and services or between components and complex services. After the web server, messages in XML format are converted into requests in middleware, and the returned results are also converted into XML format.
It is necessary to add some services while maintaining simplicity and universality to build the Web into a more powerful platform. The fully functional web services platform can be considered as XML + HTTP + soap + WSDL + UDDI. At a higher level, some unwidely accepted technologies such as XAML, XLANG, XKMS, and XFS may be added.

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