HTTP common method (Method)
HTTP / 1.0 Support: GET, POST, HEAD three kinds of the HTTP request method
HTTP/1.1添加：OPTION、PUT、DELECT、TRACE、CONNECT
GET access to resources, the server sends a resource request
HEAD and Get Similarly, the head of the access to information
POST submit resources to send data to the server
TRACE diagnostic request, allowing the client to send a request to view the end of the server (because the intermediate node requests may be modified)
PUT updates the resource, so the server creates a new document requested URL named by the main part of the request. PUT generally used to update the resource as a whole, and only for the resources that have been updated
PATCH updated resource, and PUT except that: PATCH generally used for some of the resources of the update; when the resource does not exist, creates a new resource PATCH
OPTIONS request to the server to inform its supported features (some servers may only support some special types of objects using a specific operation)
DELETE to delete the resource, the requesting server to delete the specified resource
Common status code (Status Code)
200 the OK successful visit
304 Not Modified resources have been found, but did not meet the conditions requested
301 Moved Permanently permanent redirect (generally arise when a domain name is changed)
400 Bad Request service segment can not understand the request
404 Not Found page can not be found (usually URL path error)
502 Bad gateway (usually Nginx can not find Django / Flask program)
