使用JavaScript发送HTTP请求以从MongoDB获取结果

Question

I am running MongoDB in the REST mode and trying to get query results from the MongoDB server through HTTP request. 我在REST模式下运行MongoDB，并尝试通过HTTP请求从MongoDB服务器获取查询结果。 The following is the simple code that I have written: 以下是我编写的简单代码：

<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
   <script type="text/javascript">
    function httpGet(theUrl){
        //document.write(theUrl);
        var xmlHttp = null;
        xmlHttp = new XMLHttpRequest();
        xmlHttp.open("GET", theUrl, false);
        xmlHttp.send(null);
        document.getElementById("response").innerHTML=xmlHttp.responseText;
    }
    </script>
    <title>Connection</title>
</head>
<body>
    <button onclick="httpGet('http://127.0.0.1:28017/test/first/?limit=-1')" >
        Click
    </button>
    <p id="response"> </p>
</body>
</html>

But I am unable to get the response. 但我无法得到答复。 Whereas when I copy and paste the URL in the address bar of the browser I get following as the response: 而当我将URL复制并粘贴到浏览器的地址栏中时，会得到以下响应：

{
  "offset" : 0,
  "rows": [
       { "_id" : { "$oid" : "4d510086ce29000000007d5a" }, "date" : { "$date":60968917800000 } }
    ],

 "total_rows" : 1 ,
 "query" : {} ,
 "millis" : 0
}

Can someone help and tell me what could be the problem. 有人可以帮忙告诉我可能是什么问题。

Answer 1

Is the page on which your code is running also loaded from 127.0.0.1 port 28017? 是否还从127.0.0.1端口28017加载了运行代码的页面？ If not, that's your problem, you're running into the Same Origin Policy . 如果不是这样，那就是您的问题，您正在遇到“ 同源起源策略” 。

If it is (both server and port are the same), I'd recommend using a relative URL, so your 如果是这样（服务器和端口都相同），建议您使用相对网址，因此

httpGet('http://127.0.0.1:28017/test/first/?limit=-1')

becomes 变成

httpGet('/test/first/?limit=-1')

Fundamentally, the code works: http://jsbin.com/awose3 从根本上讲，该代码有效： http : //jsbin.com/awose3

Off-topic : I'd strongly recommend not using synchronous XHR calls (ajax requests). 离题：我强烈建议您不要使用同步XHR调用（ajax请求）。 They lock up the UI of the browser while they're in process, and of course they can take a second or two (or ten) to run, during which the user experience is unpleasant to say the least. 他们在处理过程中会锁定浏览器的UI，当然，它们可能需要一两秒钟（或十秒钟）才能运行，在此期间，用户体验至少是令人不快的。 Instead, use an asynchronous call and a callback on onreadystatechange , like this (obviously, error handling and other complexities have been left out): 相反，应在onreadystatechange上使用异步调用和回调，如下所示（显然，错误处理和其他复杂性已被忽略）：

function httpGet(theUrl){
    //document.write(theUrl);
    var xmlHttp = null;
    xmlHttp = new XMLHttpRequest();
    xmlHttp.open("GET", theUrl, true);
    xmlHttp.onreadystatechange = handleReadyStateChange;
    xmlHttp.send(null);

    function handleReadyStateChange() {
      if (xmlHttp.readyState == 4) {
        if (xmlHttp.status == 200) {
          document.getElementById("response").innerHTML=xmlHttp.responseText;
        }
      }
    }
}

Live example 现场例子

Off-topic 2 : I'd suggest looking at a library like jQuery , Prototype , YUI , Closure , or any of several others . 离题2 ：我建议您查看jQuery ， Prototype ， YUI ， Closure或其他任何一个库。 They'll smooth over browser quirks, simplify various things, and add a number of useful features so that you can concentrate on solving the actual problem you're trying to solve, rather than worrying about things like (random example) Safari mis-reporting the default selected value of an option , and Internet Explorer's habit of leaking memory on event handlers unless you chant, burn incense, and periodically get up and twirl three times as you write your code. 他们将简化浏览器的怪癖，简化各种工作，并添加许多有用的功能，以便您可以专注于解决您要解决的实际问题，而不必担心Safari错误报告之类的问题（随机示例） option的默认选定值，以及Internet Explorer在事件处理程序上泄漏内存的习惯，除非您在编写代码时ch吟，燃烧香气并定期起床并旋转3次。

使用JavaScript发送HTTP请求以从MongoDB获取结果

问题描述

1 个解决方案

解决方案1
3 已采纳 2011-02-16 16:43:46

使用JavaScript发送HTTP请求以从MongoDB获取结果

问题描述

1 个解决方案

解决方案1 3 已采纳 2011-02-16 16:43:46

解决方案1
3 已采纳 2011-02-16 16:43:46