Http 简明教程

HTTP - Requests

HTTP 客户端以请求消息的形式向服务器发送 HTTP 请求，其中包含以下格式：

An HTTP client sends an HTTP request to a server in the form of a request message which includes following format:

A Request-line
Zero or more header (General|Request|Entity) fields followed by CRLF
An empty line (i.e., a line with nothing preceding the CRLF)
indicating the end of the header fields
Optionally a message-body

以下部分解释了 HTTP 请求消息中使用的每个实体。

The following sections explain each of the entities used in an HTTP request message.

Request-Line

请求行以方法标记开头，后跟请求 URI 和协议版本，并以 CRLF 结尾。各元素之间由空格 SP 字符分隔。

The Request-Line begins with a method token, followed by the Request-URI and the protocol version, and ending with CRLF. The elements are separated by space SP characters.

Request-Line = Method SP Request-URI SP HTTP-Version CRLF

下面讨论请求行中提到的各个部分。

Let’s discuss each of the parts mentioned in the Request-Line.

Request Method

请求 method 指示对由给定的 Request-URI 识别的资源执行的方法。该方法区分大小写，并且始终应大写提及。下表列出了 HTTP/1.1 中支持的所有方法。

The request method indicates the method to be performed on the resource identified by the given Request-URI. The method is case-sensitive and should always be mentioned in uppercase. The following table lists all the supported methods in HTTP/1.1.

S.N.	Method and Description
1	GETThe GET method is used to retrieve information from the given server using a given URI. Requests using GET should only retrieve data and should have no other effect on the data.
2	HEADSame as GET, but it transfers the status line and the header section only.
3	POSTA POST request is used to send data to the server, for example, customer information, file upload, etc. using HTML forms.
4	PUTReplaces all the current representations of the target resource with the uploaded content.
5	DELETERemoves all the current representations of the target resource given by URI.
6	CONNECTEstablishes a tunnel to the server identified by a given URI.
7	OPTIONSDescribe the communication options for the target resource.
8	TRACEPerforms a message loop back test along with the path to the target resource.

Request-URI

Request-URI 是统一资源标识符，用于标识对其应用请求的资源。下面是最常用的 URI 指定形式：

The Request-URI is a Uniform Resource Identifier and identifies the resource upon which to apply the request. Following are the most commonly used forms to specify an URI:

Request-URI = "*" | absoluteURI | abs_path | authority

S.N.	Method and Description
1	GETThe GET method is used to retrieve information from the given server using a given URI. Requests using GET should only retrieve data and should have no other effect on the data.
2	HEADSame as GET, but it transfers the status line and the header section only.
3	POSTA POST request is used to send data to the server, for example, customer information, file upload, etc. using HTML forms.
4	PUTReplaces all the current representations of the target resource with the uploaded content.
5	DELETERemoves all the current representations of the target resource given by URI.
6	CONNECTEstablishes a tunnel to the server identified by a given URI.
7	OPTIONSDescribe the communication options for the target resource.
8	TRACEPerforms a message loop back test along with the path to the target resource.