[dry goods | necessary skills for interface testing common interface protocol analysis]

Transfer packets between services , Because of different application scenarios , Use different communication protocols for delivery . For example, website access , Often use HTTP Protocol delivery , File transfer usage FTP, Mail delivery use SMTP. The above three types of protocols are in the application layer of the network model . In addition to the common protocols of the application layer , For the transport layer TCP、UDP agreement , as well as Restful Architectural style 、RPC Basic network knowledge such as protocols should be understood and recognized .

Network protocol introduction
Before understanding the specific agreement , You need to know OSI Seven layer model 、TCP/IP Four layer model 、 Five layer architecture these three different network models .
Network protocol model comparison diagram ：

OSI The reference model is a conceptual framework for developing standards for coordinating interprocess communication , It is not a standard .
TCP/IP The four layer model is the basic communication architecture of the Internet . It's often seen as a simplified seven level OSI Model .
The five layer agreement is OSI and TCP/IP The synthesis of , The practical application is still TCP/IP Four story structure of .
TCP/IP The protocol stack corresponds to TCP/IP The specific network protocol used in the four layer model
TCP agreement
TCP The protocol is in the transport layer , A connection oriented 、 reliable 、 Transport layer communication protocol based on byte stream .TCP The working mode of the protocol is that... Is required when establishing a connection “ Three handshakes ”, When terminating the connection, you need to “ Four waves ”.“ Three handshakes ” and “ Four waves ” yes TCP Important knowledge points of the agreement , In the following chapters, we will combine actual combat with theory , Introduce this important knowledge point in detail .

TCP Connection oriented protocol 、 Error retransmission 、 Congestion control and other characteristics , It is suitable for scenarios with high reliability , For example, data transmission involving user information .

UDP agreement
UDP Once the protocol sends the data sent by the application to the network layer , Do not keep data backups . It's only in IP Multiplexing and data verification fields are added to the header of the packet . therefore UDP Packets are often considered unreliable .
UDP There is no need to establish a connection in advance 、 Implement simple features , It is very suitable for scenes with high real-time performance , Like streaming media 、 Online games, etc .

HTTP agreement
HTTP Protocol is the most common protocol in interface testing , For distributed 、 Application layer protocols for collaborative and hypermedia information systems .HTTP Is the foundation of data communication in the world wide web . The client sends... To the server HTTP request , The server will return the requested data in the response . During the test , It is often necessary to verify the request and response results , So understand HTTP agreement , For interface testing , It's the top priority .

In the following chapters, we will introduce HTTP、HTTPS The difference between agreements , as well as HTTP Basic knowledge information of the agreement .

RESTful framework
origin
Roy Thomas Fielding Doctor Yu 2000 A style of World Wide Web software architecture proposed in his doctoral dissertation in . Its purpose is to facilitate different software to transmit information in the network .RESTful Is based on HTTP A resource request made on top of a protocol 、 The style of operation , To sum up in one sentence is to use URL To locate resources , Use HTTP Verb description operation .
HTTP The request method is RESTful api Typical applications in ：

Be careful ： Different companies are using RESTful There are some differences in architectural style .

RPC agreement
Currently commonly used in the industry RPC The main agreements are as follows ：

Dubbo：
Java High performance based on RPC agreement
gRPC：
High performance general purpose RPC frame , be based on Protocol Buffers
PB It's a language neutral 、 Platform neutral data serialization framework .
Thrift：
And gRPC Similar multilingualism RPC frame .
These are the common interface protocol resolutions for the time being , If you have other knowledge points you want to know, you can also leave a message below ！ Xiaobian tries to meet everyone's needs ~