Request and response interface base ----

What interfaces are? ----- interfaces equivalent channel access to resources

　　Explanation: the interface is a channel, data transmission front end to a back end, the channel needs to be transmitted, the rear end of the check, analysis, and then returns a response, the front end receiving the response, the response content is determined, and finally displayed at a front end;

　　An interface is equivalent to a function to call the back end, and the function will return the value as a response to his message back to the client;

　　Corresponds to the client, a browser, a request sent by APP;

A request

　　Process must be requested by a request to the url

1.URL composition

E.g. a url address: 
http://127.0.0.1:8088/docs/ 
format: Protocol IP address or domain name + path + requested 
domain name is resolved to an IP address of the DNS server

• A url address is an interface, the interface is among the largest general use HTTP and HTTPS protocols, a hypertext transfer protocol;
• The domain is behind url path
• HTTP and HTTPS difference:
  • HTTPS is an encrypted protocol, after some encryption algorithm, compared to HTTP safer;
  • The default HTTP port 80
  • HTTPS default port number 443

2. Request Structure

• Request the first line (request line)
• Request header (message header)
• Skip a line
• Request body (request body)

3. Request the first line

Request first line comprising: request method (GET) request address + + protocol version (HTTP / 1.1)

• Request method
  • get
    • Get the server resources (to retrieve data)
    • The corresponding sql statement select
    • No request body
    • Pass parameters: Parameter request (query string query strings) placed url to? key1 = value form of .........
    • Do not use when dealing with sensitive data, such as: account password
  • post
    • Often create (additional) resources
    • Corresponds to insert into sql statement
    • There is a request body
    • Request parameter
      • In the request body parameters (the request body)

　　　　　　　　　　

• • • • text / plain text transmission is HTTP packet body is in plain text format and without any modifications, the server will take its own text processing;
      • Form this is the most common way of transmission parameters, HTML tag corresponding thereto in both form, which itself uses the Key-Value parameter passing mode;
      • json format is more effective than the place can be transmitted Form Object;
      • File transfer a single file
      • Depending on the Content-type, server to read the HTTP Body of parameters are not the same
  • put
    • Modify the server's resources
    • Sql statement corresponds to the total update
    • There is a request body parameters have
  • delete
    
    • Delete server resources
    • Sql statement corresponds to the total delete from
    • There is a request body parameters have
• Request address
• Protocol version (HTTP / 1.1)

4. The request header (message header)

　　User-Agent (the responsibility of children. Hey Gent) :( client type)

• • Browser, mobile client

　　cookie：

• • The equivalent of identity information, generally on the request header
  • It does not save the user's non-sensitive information

The request body (request body)

• The vast majority did not get request requesting body
• The main role of carrying the request parameters

 

Second, the response packet

　　Response message is sent by the server

1. Request Structure

• In response to the first line (the status line)
• Response header (the message header)
• Skip a line
• Body response (response entity)

2, in response to the first line (status line)

include:

• Protocol version number
•  Status of the response it

　　

 The most common status codes and their meanings:

• Successful- 2xx: successful class action is successful acceptance, understanding and adoption
• 200 OK
• Server successfully returned the data requested by the user
• Often in order to simplify the process　　
• After you create a successful POST should return 201

• 404 NOT FOUND
  • Resource not found or path path does not exist

• 500 INTERNAL SERVER ERROR
  • Internal server error　　
  • The most common causes are: internal server hung up　　
  • For example, you pass parameters Some parameters are empty, which led background code can not be resolved, abnormal collapse

Once common response codes and their meanings:

• restful api-style interfaces
• Successful - 2xx: successful class action is successful acceptance, understanding and adoption
• 201 CREATED
  • Create a resource successfully passed POST or PUT
• 204 NO CONTENT
  • Resource successfully modified, but did not return content　　　　
  • DELETE operations commonly used in the return　　　　

• Redirect action type, in order to complete the request need to further perform: 3xx - Redirection.
• 301 permanent redirect
• 302 temporary redirect

• Client Error - 4xx: 客户端错误类，请求包含语法错误或者请求无法实现
• 401 UNAUTHORIZED
  • 没有权限访问该资源　　
  • 典型情况:用户没有登录，没有获得对应的access token而直接访问某资　　
• 403 FORBIDDEN
  • 禁止访问　　
  • 典型情况:虽然用户已登录，但是去更新/删除需要更高权限才能操作的资源　　
• 405 METHOD NOT ALLOWED
  • 方法不允许　　
  • 举例:比如某个资源不允许POST请求，但是你确发起了POST请求

3、响应头（消息报头）

• Content-Type（康泰的太婆）
  • 代表：响应报文返回的数据类型/json格式、HTML格式页面报文　　

• set-Cookie
  • 服务器将用户信息（session-id）放到Set-Cookie，浏览器拿到 set—cookie 然后将其放到浏览器的 Cookie 中保存

4、响应体（响应实体）

• 响应数据
• html页面或者json格式数据
• 前后端分离 开发模式
  • 是以json格式返回数据　　
• 前后端不分离 开发模式
  • 返回HTML的页面，需要后端和前端人员配合　　
• 204 没有响应体，主要看需求文档和开发心情

 

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