对使用代理的Webrequest进行单元测试 [英] Unit test a webrequest that uses a proxy

问题描述

我正在编写一个通过代理从Web上获取一些数据的应用程序.作为核心功能，我使用 simple-http-此站点上的代理类. (如下所示)

由于我的应用仅以某种方式运行，因此我不知道一切是否按照我的意愿进行，因此我研究了网络，并进行了单元测试.我已经实施了许多测试，但绝对不知道如何测试需要从外部来源输入的内容.

我在网上找到了一些解决方案，但没有解决方案，那就是测试代理"连接.

实际上，我不想测试此课程，但是我希望有人对此提供帮助，因此可以理解它的工作原理.

问候
Delicious_cake

简单的http类:

hi there,

i''m writing an application that is getting some data from the web over a proxy. as core function i use the simple-http-proxy-class from this site. (can be seen below)

as my app is runnning only somehow and i don''t know if everything is going as i want it to, i researched the web and i came accross unit testing. i already implemented many tests, but have absolutly no idea how to test something that would need imput from an external source.

i found some solutions on the web, but there''s no solution, that is testing a "proxified" connection.

actually i don''t want to test this class, but i want somebody to help me with this, so is understand how it would work.

greetings
delicious_cake

the simple http class:

class simplehttp
{
 public string geturl(string url, string proxyip, int port, string proxylogin, string proxypassword)
 {
  HttpWebResponse resp;
  HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
  req.UserAgent = "Mozilla/5.0";
  req.AllowAutoRedirect = true;
  req.ReadWriteTimeout = 5000;
  req.CookieContainer = new CookieContainer();
  req.Referer = "";
  req.Headers.Set("Accept-Language", "en,en-us");
  StreamReader stream_in;

  WebProxy proxy = new WebProxy(proxyip, port);
  //if proxylogin is an empty string then don't use proxy credentials (open proxy)
  if (proxylogin != "") proxy.Credentials = new NetworkCredential(proxylogin, proxypassword);
  req.Proxy = proxy;

  string response = "";
  try
  {
   resp = (HttpWebResponse)req.GetResponse();
   stream_in = new StreamReader(resp.GetResponseStream());
   response = stream_in.ReadToEnd();
   stream_in.Close();
  }
  catch (Exception ex)
  {
  }
  return response;
 }
}

PS:

我已经尝试制作一个本地代理和一个本地Web服务器，并执行诸如集成测试之类的事情.
它的工作原理，如果:
1.代理正确且网址正确->表现得像人所见
2.代理正确，网址不正确->表现符合预期
3.代理不正确，网址正确->表现不符合预期.即使该功能应使用的端口不是本地代理，该功能也会返回url内容

我不知道为什么该函数会使用此设置返回url内容.

PS:

i already tried to make a local proxy and a local webserver and perfom something like an integration test.
its working, if the:
1. proxy is correct and url is correct --> behaves as ecpected
2. proxy is correct and url is incorrect --> behaves as expected
3. proxy is incorrect and url is correct --> don''t behaves as expected. the url content is returned by the function even if the port thats should be used by the function is no local proxy

i have no idea, why the function returns the url content with this setup.

推荐答案

代理通常具有与您要使用的服务不同的端口. br/>
以下是您应该考虑的一些改进:
* SimpleHttp在面向对象的方式中不是真正的类".您仅具有一个包含方法的类.更好:提供一个看起来像这样的IStringDataProvider接口:

The proxy typically has a different port than the service you are trying to consume.

Here are some improvements you should consider:
* SimpleHttp is no real "class" in object-orientated manner. You have simply a class that contains a method. Better: Provide an IStringDataProvider Interface which could look like:

public interface IStringDataProvider
{
  string GetContent();
}

然后，您可以从http以外的其他来源获取内容，并且可以用模拟提供程序替换它，因此测试将更加容易.可以使用依赖项注入将URL传递到http-provider-instance(请参见下面的代码).

* GetUrl听起来像嘿，给我URL！".更好:GetContent或GetContentByUrl
*不要在每个请求上传递所有代理属性.更好:在应用程序启动时设置WebRequest.DefaultWebProxy.然后，您将独立于是否使用代理，并且整个应用程序将使用相同的代理.

*不要吞下异常！您有一个TryGetContent-Method返回操作是否成功，或者您要检查是否发生错误时处理异常-通常在GUI中完成.

放在一起:

Then you are able to get the content from other sources than http - and your testing will be easier as you can replace it with a mock-provider. The url can be passed to the http-provider-instance with dependency injection (see code below).

* GetUrl sounds like "Hey, get me the url!". Better: GetContent or GetContentByUrl
* Dont pass all the proxy-propertys on each request. Better: Set the WebRequest.DefaultWebProxy at application startup. Then you are independent of using a proxy or not and your whole application will use the same proxy.

* Dont swallow exceptions! Either you have a TryGetContent-Method returning whether the operation succeeded or you handle the exception when you want to check whether an error occured - this is typically done in the GUI.

Putting all together:

interface IStringDataProvider
{
    string GetContent();
}

class HttpStringDataProvider : IStringDataProvider
{
    public HttpStringDataProvider(string url) //The url is passed with dependency injection i.e. through parameters on construction
    {
        Url = url;
    }

    public string Url { get; private set; }

    private CookieContainer cookies = new CookieContainer();

    public string GetContent()
    {
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(Url);

        request.UserAgent = "Mozilla/5.0";
        request.AllowAutoRedirect = true;
        request.ReadWriteTimeout = 5000;
        request.CookieContainer = cookies;
        request.Referer = "";
        request.Headers.Set("Accept-Language", "en,en-us");

        HttpWebResponse response = (HttpWebResponse)request.GetResponse();
        StreamReader streamReader = new StreamReader(response.GetResponseStream());
        return streamReader.ReadToEnd();
    }
}

启动时:

On startup:

if (proxyType == "http")
{
    WebProxy proxy = new WebProxy(myProxyHost, myProxyPort);
    proxy.Credentials = new NetworkCredential(myProxyUsername, myProxyPassword);
    WebRequest.DefaultWebProxy = proxy; //This proxy will be used by all HttpWebRequests if their Proxy-Property is not set.
}
else if (proxyType == "system")
{
    WebRequest.DefaultWebProxy = WebRequest.GetSystemWebProxy(); //Settings from Internet Explorer (default)
}
else if (proxyType == "no")
{
    WebRequest.DefaultWebProxy = null; //This will speed up the whole a lot, because the default is the proxy used by IE and otherwise the .Net-Framework tries to gather the IE-proxy settings on each request which is very slow
}

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