报文的组成部分
报文由三部分组成：对报文进行描述的起始行(start line)、包含属性的首部(header)，以及可选的、包含数据的主体(body)部分。
请求报文格式
<method> <request-URL> <version>
<headers>
<entity-body>
响应报文格式
<version> <status> <reson-phrase>
<headers>
<entity-body>
HTTP方法
主要的HTTP方法有：
| 方法 | 描述 | 是否包含主体 |
| GET | 从服务器获取一份文档 | 否 |
| HEAD | 只从服务器获取文档的首部 | 否 |
| POST | 向服务器发送需要处理的数据 | 是 |
| PUT | 将请求的主体部分存储在服务器上 | 是 |
| TRACE | 对可能经过代理服务器传送到服务器上去的报文进行追踪 | 否 |
| OPTIONS | 决定可以在服务器上执行哪些方法 | 否 |
| DELETE | 从服务器上删除一份文档 | 否 |
另外，HTTP1.1允许扩展规范中没有的方法。
示例
js部分：
var httpMethodTest = (function () {
"use strict";
var _xhr = new XMLHttpRequest();
var _sendXHR = function (method, url, callback) {
_xhr.onreadystatechange = function () {
if (_xhr.readyState === 4 && _xhr.status === 200) {
callback(_xhr);
}
};
_xhr.open(method, url, true);
_xhr.send('');
};
var get = function (url, callback) {
_sendXHR("GET", url, callback);
};
var put = function (url, callback) {
_sendXHR("PUT", url, callback);
};
var post = function (url, callback) {
_sendXHR("POST", url, callback);
};
var head = function (url, callback) {
_sendXHR("HEAD", url, callback);
};
var trace = function (url, callback) {
_sendXHR("TRACE", url, callback);
};
var options = function (url, callback) {
_sendXHR("OPTIONS", url, callback);
};
var deleteMethod = function (url, callback) {
};
return {
get: get,
put: put,
post: post,
head: head,
trace: trace,
options: options,
deleteMethod: deleteMethod
};
})();
var btnGET = document.getElementById("btnGET"),
btnPOST = document.getElementById("btnPOST"),
btnPUT = document.getElementById("btnPUT"),
btnHEAD = document.getElementById("btnHEAD"),
btnOPTIONS = document.getElementById("btnOPTIONS"),
btnTRACE = document.getElementById("btnTRACE"),
headerResultNode = document.getElementById("headerResult"),
bodyResultNode = document.getElementById("bodyResult"),
headerTitleNode = document.getElementById("headerTitle"),
bodyTitleNode = document.getElementById("bodyTitle");
btnGET.onclick = function () {
headerTitleNode.innerHTML = "GET Response Headers:";
bodyTitleNode.innerHTML = "GET Response Body:";
httpMethodTest.get("/home/Test?t=" + Math.random(), methodResult);
}
btnPOST.onclick = function () {
headerTitleNode.innerHTML = "POST Response Headers:";
bodyTitleNode.innerHTML = "POST Response Body:";
httpMethodTest.post("/home/Test?t=" + Math.random(), methodResult);
}
btnPUT.onclick = function () {
headerTitleNode.innerHTML = "PUT Response Headers:";
bodyTitleNode.innerHTML = "PUT Response Body:";
httpMethodTest.put("/home/Test?t=" + Math.random(), methodResult);
}
btnHEAD.onclick = function () {
headerTitleNode.innerHTML = "HEAD Response Headers:";
bodyTitleNode.innerHTML = "HEAD Response Body:";
httpMethodTest.head("/home/Test?t=" + Math.random(), methodResult);
}
//由于ajax中不可以直接发trace请求，所以这里改为发get请求，然后在controller中作代理发trace请求
btnTRACE.onclick = function () {
headerTitleNode.innerHTML = "TRACE Response Headers:";
bodyTitleNode.innerHTML = "TRACE Response Body:";
httpMethodTest.get("/home/Trace?url=" + encodeURIComponent("http://xxxxx/test.php") + "&t" + Math.random(), methodResult);
}
btnOPTIONS.onclick = function () {
headerTitleNode.innerHTML = "OPTIONS Response Headers:";
bodyTitleNode.innerHTML = "OPTIONS Response Body:";
httpMethodTest.options("/home/Test?t=" + Math.random(), methodResult);
}
//从XMLHttpRequest中取出Header及Body数据
function methodResult(xhr) {
var header = {},
response = "",
results = [];
header["status"] = xhr.status;
header["statusText"] = xhr.statusText;
header["Cache-Control"] = xhr.getResponseHeader("Cache-Control");
header["Content-Type"] = xhr.getResponseHeader("Content-Type");
header["Allow"] = xhr.getResponseHeader("Allow");
header["Content-Encoding"] = xhr.getResponseHeader("Content-Encoding");
header["Vary"] = xhr.getResponseHeader("Vary");
header["Server"] = xhr.getResponseHeader("Server");
header["Date"] = xhr.getResponseHeader("Date");
header["Content-Length"] = xhr.getResponseHeader("Content-Length");
for (var key in header) {
if (header[key]) {
results.push("<li>" + key + ": " + header[key] + "</li>");
}
}
headerResultNode.innerHTML = results.join("");
bodyResultNode.value = xhr.responseText;
}
页面部分：
<div>
<input type="button" id="btnGET" value="GET" />
<input type="button" id="btnPOST" value="POST" />
<input type="button" id="btnPUT" value="PUT" />
<input type="button" id="btnHEAD" value="HEAD" />
<input type="button" id="btnTRACE" value="TRACE" />
<input type="button" id="btnOPTIONS" value="OPTIONS" />
</div>
<h3 id="headerTitle">Response Headers:</h3>
<ul id="headerResult" class="list-txt"> </ul>
<h3 id="bodyTitle">Response Body:</h3>
<textarea id="bodyResult" class="list-txt" rows="5" disabled="disabled"></textarea>
controller中发送trace请求：
public void Test()
{
Response.ClearContent();
if (Request.HttpMethod.Equals("OPTIONS"))
{
Response.AddHeader("Allow", "GET, POST, PUT, DELETE, TRACE, OPTIONS");
}
else
{
Response.Write("This is a " + Request.HttpMethod);
}
Response.End();
} public void Trace(string url)
{
HttpWebRequest httpWReq = (HttpWebRequest)WebRequest.Create(url); httpWReq.Method = "TRACE";
httpWReq.ContentType = "application/x-www-form-urlencoded"; HttpWebResponse response = (HttpWebResponse)httpWReq.GetResponse(); string responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();
Response.ClearContent();
Response.Write(responseString);
Response.End();
}
运行结果：
get/put/post的header及body类似，也很常见，这里就不帖图了
HEAD
TRACE
OPTIONS