HTTP权威指南阅读笔记三：HTTP报文

　　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