Diagram http (iv)--HTTP status code for returned results

One, the status code tells the server to return the request result

The function of the code of the State is to describe the result of the request that is returned when the client sends a request to the server. The status code consists of three numbers and a reason, such as a number OK. The first bit in the number specifies the response category, and the category of the status code is as follows:

Digital	Category	Reason Phrases
1XX	Informational (Informational status code)	The received request is being processed
2XX	Success (Success status code)	Request normal processing complete
3XX	Redirection (Redirected status code)	Additional action required to complete the request
4XX	Client error (Customer fault status code)	The server cannot process the request
5XX	Server error (server-side fault status code)	Server Processing Request Error

Ii. frequently occurring 2XX success Status Codes

Status code	Reason	Describe
200	Ok	The client's request was processed properly on the server side.
204	No Content	The request received by the server has been processed successfully, but the response message returned does not contain the body part of the entity, nor does it allow the body of any entity to be returned
206	Partial Content	The client makes a scope request, and the server successfully executes this part of the GET request, and the response message contains the entity content specified by the Content-range range.

iii. frequently occurring 3XX redirect status codes

301	Move Permanently	Permanent redirection, the requested resource has been assigned a new URI and should be used later by the URI specified by the resource now
60W	Found	Temporary redirection, the requested resource has been assigned a new URI, but is temporary in nature and may be changed later,
303	See other	The request resource corresponds to another URI, which should use the Get method to get the requested resource, similar to 302, but explicitly uses the Get method to get the resource
304	Not Modified	When a client sends a request with a condition, the server side allows the request to access the resource, but returns directly if the request does not meet the criteria, such as caching the resource response
307	Temporary Redirect	Temporary redirection, similar to 302, but 302 of the standard is not complied with, 307 will abide by the standard, will not be replaced from post to get

Iv. frequently occurring 4XX client errors

400	Bad Request	There is a syntax error in the request message, and when the error occurs, you need to modify the requested content and send the request again
60s	Unauthorized	The request sent requires authentication information that is authenticated by HTTP, and if 1 requests have been made before, the user authentication fails
403	Forbidden	Access to the requested resource is rejected by the server, such as not obtaining access authorization or article permissions for the file system to reproduce some issues
404	Not Found	The requested resource could not be found on the server

v. Frequently occurring 5XX server-side errors

500	Internal Server Error	The server has an error executing the request, or it may be some bug or malfunction of the web App
503	Service unavailable	The server is temporarily overloaded or is under maintenance and cannot process requests now