Key technologies used by soa xml/soap/UDDI/ESB

The key technologies used in SOA: XML, SOAP, UDDI, and ESB: to implement SOA, you must first understand the relevant technologies required to implement SOA. The main technologies involved include: XML, SOAP, WSDL, UDDI, and ESB.

1. xml
The XML 1.0 (eXtensible Markup Language, eXtensible Markup Language) standard is a text-based World Wide Web Organization (W3C) standard markup language. Unlike HTML, which uses tags to describe the appearance and data, XML strictly defines portable structured data. It can be used as a language that defines the language of data description, such as markup syntax or vocabulary, interchange format, and communication protocol.

2. Soap
Simple Object Access Protocol is an XML-based lightweight protocol for information exchange in a distributed environment. Soap defines a communication protocol between the requester and the provider object. In this way, in the popular object-oriented programming environment, the request object can execute remote method calls on the provided object. Because soap is a platform-independent and vendor-independent standard, although SOA does not have to use soap, in the loose coupling interoperability between partners with independent IT infrastructure, soap is still the best method to support service calls.
W3C soap 1.2 specifications define messages in XML format for communication between service requestor and service provider. Put application requests (in XML) in a SOAP envelope (also XML) and send application requests from the requester to the provider. The responses sent by the provider are also in the same form. Recently, soap is called the Service-Oriented Architecture protocol ).
The advantage of soap is that it is completely independent from the vendor and can be independently implemented relative to the platform, operating system, target model, and programming language. In addition, the selection of transmission and language binding and data encoding parameters is determined by the implementation.

3. WSDL
Web Service Description Language (WSDL) is an XML word that provides standard methods for describing service IDL. The Web Service Description Language (WSDL) Specification defines an XML vocabulary, which defines a contract between service requestor and service provider according to request and response messages. We can define web services as software. This software provides reusable application functions by describing the WSDL document of the SOAP message interface and uses standard transmission protocols for transmission.
The WSDL description contains the necessary details so that the service requestor can use specific services:
Request Message format
Response Message format
Where to send a message.
WSDL is based on XML, so the WSDL document is machine-readable ). In this way, the development environment uses WSDL to automatically process the integration service process to the requester application. For example, WebSphere Studio generates a Java proxy object, which can implement services like local objects, but in fact the proxy object only processes request creation and Response Message Parsing. Regardless of whether the service is implemented in Java, C #, or other languages, the generated Java proxy object can call any web service from the WSDL description. In fact, WSDL cannot describe implementation details like programming languages.

4. UDDI
The universal description, discovery, and integration specifications provide a set of common soap APIs to implement service proxies. UDDI defines a standard interface (based on soap messages) for the services required for service availability and discovery ). The UDDI implementation interprets the SOAP request for publishing and discovering services as a call to the data management function for basic data storage.
To publish and discover other SOA services, UDDI defines standard soap messages to implement service registry ). Registration is a service proxy. It is an intermediary between the service requestor and the provider that publishes the service on UDDI. Once the requester decides to use a specific service, developers usually use development tools (such as Microsoft Visual Studio.. net) and bind the service by creating code to access the service by sending the request and processing the response.
SOA does not need to use UDDI, but since UDDI is built on SOA to complete its own work, it is a good solution for service discovery.

5. ESB
Enterprise Service Bus (ESB) is a pillar Technology of SOA architecture. As a message proxy architecture, it provides a Message Queue System, which is implemented using standard technologies such as soap or JMS (Java Message Service.
　　
Some people describe ESB as an open, standard-based messaging mechanism. Through simple standard adapters and interfaces, they can implement interoperation between coarse-grained applications (such as services) and other components.
The main functions of ESB include communication and message processing, service interaction and security control, service quality and service level management, modeling, management and autonomy, and infrastructure intelligence. -

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