如何编写 HTTP 请求

Question

您好，我尝试用 C#（Post）编写 HTTP 请求，但我需要帮助解决错误

解释：我想将 DLC 文件的内容发送到服务器并接收解密的内容。

C#代码

public static void decryptContainer(string dlc_content) 
{
    HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://dcrypt.it/decrypt/paste");
    request.Method = "POST";
    request.ContentType = "application/x-www-form-urlencoded";
    request.Accept = "Accept=text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";

    using (StreamWriter writer = new StreamWriter(request.GetRequestStream(), Encoding.ASCII))
    {
        writer.Write("content=" + dlc_content);
    }

    HttpWebResponse response = (HttpWebResponse)request.GetResponse();

    using (StreamReader reader = new StreamReader(response.GetResponseStream()))
    {
        Console.WriteLine(reader.ReadToEnd());
    }
}

这里我收到了 html 请求

<form action="/decrypt/paste" method="post">
    <fieldset>
        <p class="formrow">
          <label for="content">DLC content</label>
          <input id="content" name="content" type="text" value="" />
         </p>
        <p class="buttonrow"><button type="submit">Submit »</button></p>
    </fieldset>
</form>

错误信息：

{
    "form_errors": {
      "__all__": [
        "Sorry, an error occurred while processing the container."
       ]
    }
}

如果有人可以帮助我解决问题，将非常有帮助！

Answer 1

您没有设置内容长度，这可能会导致问题。您也可以尝试将字节直接写入流，而不是先将其转换为 ASCII ..（与您目前的做法相反），例如：

public static void decryptContainer(string dlc_content) 
   {
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://dcrypt.it/decrypt/paste");
        request.Method = "POST";
        request.ContentType = "application/x-www-form-urlencoded";
        request.Accept = "Accept=text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";

        byte[] _byteVersion = Encoding.ASCII.GetBytes(string.Concat("content=", dlc_content));

        request.ContentLength = _byteVersion.Length

        Stream stream = request.GetRequestStream();
        stream.Write(_byteVersion, 0, _byteVersion.Length);
        stream.Close();

        HttpWebResponse response = (HttpWebResponse)request.GetResponse();

        using (StreamReader reader = new StreamReader(response.GetResponseStream()))
        {
            Console.WriteLine(reader.ReadToEnd());
        }
    }

过去，我个人发现这样的帖子有点“烦躁”。您也可以尝试在请求中设置 ProtocolVersion。

Answer 2

我会简化你的代码，像这样：

public static void decryptContainer(string dlc_content) 
{
    using (var client = new WebClient())
    {
        var values = new NameValueCollection
        {
            { "content", dlc_content }
        };
        client.Headers[HttpRequestHeader.Accept] = "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";
        string url = "http://dcrypt.it/decrypt/paste";
        byte[] result = client.UploadValues(url, values);
        Console.WriteLine(Encoding.UTF8.GetString(result));
    }
}

它还确保请求参数被正确编码。

Answer 3

public string void decryptContainer(string dlc_content) //why not return a string, let caller decide what to do with it.
{
    HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://dcrypt.it/decrypt/paste");
    request.Method = "POST";
    request.ContentType = "application/x-www-form-urlencoded";
    request.Accept = "Accept=text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";//sure this is needed? Maybe just match the one content-type you expect.
    using (StreamWriter writer = new StreamWriter(request.GetRequestStream(), Encoding.ASCII))
    {
        writer.Write("content=" + Uri.EscapeDataString(dlc_content));//escape the value of dlc_content so that the entity sent is valid application/x-www-form-urlencoded
    }
    using(HttpWebResponse response = (HttpWebResponse)request.GetResponse())//this should be disposed when finished with.
    using (StreamReader reader = new StreamReader(response.GetResponseStream()))
    {
        return reader.ReadToEnd();
    }
}

实际发送的内容可能仍然存在问题。

Answer 4

我马上看到的一个问题是您需要对 content 参数的值进行 URL 编码。为此使用HttpUtility.UrlEncode()。 除此之外可能还有其他问题，但很难说不知道服务是做什么的。这个错误太笼统了，可能意味着什么

Answer 5

request.ContentLength 也应该设置。

另外，您使用 ASCII 编码与 UTF8 编码有什么原因吗？

Answer 6

首先获取与响应关联的流，然后将其传递给 Streamreader，如下所示：

    Stream receiveStream = response.GetResponseStream();       

    using (StreamReader reader = new StreamReader(receiveStream, Encoding.ASCII))
    {
        Console.WriteLine(reader.ReadToEnd());
    }

Answer 7

因为我无法评论 Jon Hanna 的解决方案。这为我解决了它： Uri.EscapeDataString

        // this is what we are sending
        string post_data = "content=" + Uri.EscapeDataString(dlc_content);

        // this is where we will send it
        string uri = "http://dcrypt.it/decrypt/paste";

        // create a request
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
        request.KeepAlive = false;
        request.ProtocolVersion = HttpVersion.Version10;
        request.Method = "POST";

        // turn our request string into a byte stream
        byte[] postBytes = Encoding.ASCII.GetBytes(post_data);

        // this is important - make sure you specify type this way
        request.ContentType = "application/x-www-form-urlencoded";
        request.ContentLength = postBytes.Length;

        Stream requestStream = request.GetRequestStream();

        // now send it
        requestStream.Write(postBytes, 0, postBytes.Length);
        requestStream.Close();

        // grab te response and print it out to the console along with the status code
        HttpWebResponse response = (HttpWebResponse)request.GetResponse();
        Console.WriteLine(new StreamReader(response.GetResponseStream()).ReadToEnd());
        Console.WriteLine(response.StatusCode);