reference
Xie Xiren's Seventh Edition of Computer Networks (I didn't learn HTTP last semester)
Dark Horse Programmer JavaWeb Course (After watching this semester, I will summarize it by the way)
Organized by me
HTTP：
(concepts and features, must understand)
* Concept (what is HTTP):
Hyper Text Transfer Protocol Hypertext Transfer Protocol
HTTP is the hypertext transfer protocol, so what is the transfer protocol?
* Transmission protocol: defines the format for exchanging data when the client and server communicate
* Features:
1. High-level protocol based on TCP/IP
2. Default port number: 80
3. Based on the request/response model: one request corresponds to one response
4. Stateless: Each request is independent of each other and cannot exchange data
* historic version:
* 1.0: A new connection will be established for each request response
* 1.1: multiplex connection
(The following is the lesson plan taught by the black horse class)
Request:
Client sends message to server
(important, need to be familiar with)
Request message data format
1. Request line
2. Request header: The client browser tells the server some information
3. Request a blank line
4. Request body (text):
1. Request line
Format:
Request method Request url Request protocol/version
GET /login.html HTTP/1.1
* Request methods (7 types): GET and POST are commonly used
2. Request header: The client browser tells the server some information
Format:
Request header name: request header value
* Common request headers:
1. User-Agent: The browser tells the server that I visit the browser version information you use
* The header information can be obtained on the server side to solve browser compatibility issues
2. Referer：http://localhost/login.html
* Tell the server, where did I (the current request) come from?
* Function: 1. Anti-leech 2. Statistical work
3. Request a blank line:
Blank lines are used to separate the request header and request body of the POST request.
4. Request body (text):
* Encapsulate the request parameters of the POST request message
String format:
Let's go to the browser to verify
Response:
Server sends message to client
(important, need to be familiar with)
* Data Format:
1. Response line:
2. Response header:
3. Respond to blank lines:
4. Response body: transmitted data:
1. Response line:Composition: Protocol/Version Response Status Code Status Code Description
Response Status Code: The server tells the client browser a status of this request and response.
Classification:
1. 1xx: The server received the message from the client, but did not complete the acceptance. After waiting for a period of time, it sent 1xx multi-status codes.
2. 2xx: Success. Rep: 200
3. 3xx: Redirection. Representatives: 302 (redirection), 304 (access cache)
4. 4xx: client error.
* stands for: * 404 (the request path does not have a corresponding resource)
* 405: the request method does not have a corresponding doXxx method
5. 5xx: server-side error. Representative: 500 (An exception occurred inside the server)2. Response header:
1. Format: Header name: Value
2. Common response headers:
1. Content-Type: The server tells the client the data format and encoding format of the response body
2. Content-disposition: The server tells the client in what format to open the response body Data
* Value:
* in-line: Default value, open in the current page
* attachment; filename=xxx: Open the response body as an attachment. Download Document
3. Respond to empty lines
4. Response body: transmitted data
Go to the browser to verify
