如何使用 HttpWebRequest 模拟浏览器文件上传
Posted
技术标签:
【中文标题】如何使用 HttpWebRequest 模拟浏览器文件上传【英文标题】：How to simulate browser file upload with HttpWebRequest 【发布时间】：2011-02-17 06:33:56 【问题描述】：伙计们，首先感谢您的贡献，我在这里找到了很好的回应。但是我遇到了一个我无法弄清楚的问题，如果有人可以提供任何帮助，将不胜感激。
我正在用 C# 开发这个应用程序，它可以将图像从计算机上传到用户照片博客。为此，我使用pixelpost 主要用 php 编写的照片博客平台。
我在此处和其他网页上进行了搜索，但那里提供的示例对我不起作用。 这是我在示例中使用的内容：(Upload files with HTTPWebrequest (multipart/form-data)) 和 (http://bytes.com/topic/c-sharp/answers/268661-how-upload-file-via-c-code) 一旦准备就绪，我将在互联网上免费提供它，并且可能还会创建它的 Windows 移动版本，因为我是 pixelpost 的粉丝。
这是我使用的代码：
string formUrl = "http://localhost/pixelpost/admin/index.php?x=login";
string formParams = string.Format("user=0&password=1", "user-String", "password-String");
string cookieHeader;
HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(formUrl);
req.ContentType = "application/x-www-form-urlencoded";
req.Method = "POST";
req.AllowAutoRedirect = false;
byte[] bytes = Encoding.ASCII.GetBytes(formParams);
req.ContentLength = bytes.Length;
using (Stream os = req.GetRequestStream())
os.Write(bytes, 0, bytes.Length);
HttpWebResponse resp = (HttpWebResponse)req.GetResponse();
cookieHeader = resp.Headers["Set-Cookie"];
string pageSource;
using (StreamReader sr = new StreamReader(resp.GetResponseStream()))
pageSource = sr.ReadToEnd();
Console.WriteLine();
string getUrl = "http://localhost/pixelpost/admin/index.php";
HttpWebRequest getRequest = (HttpWebRequest)HttpWebRequest.Create(getUrl);
getRequest.Headers.Add("Cookie", cookieHeader);
HttpWebResponse getResponse = (HttpWebResponse)getRequest.GetResponse();
using (StreamReader sr = new StreamReader(getResponse.GetResponseStream()))
pageSource = sr.ReadToEnd();
// end first part: login to admin panel
long length = 0;
string boundary = "----------------------------" +
DateTime.Now.Ticks.ToString("x");
HttpWebRequest httpWebRequest2 = (HttpWebRequest)WebRequest.Create("http://localhost/pixelpost/admin/index.php?x=save");
httpWebRequest2.ContentType = "multipart/form-data; boundary=" + boundary;
httpWebRequest2.Method = "POST";
httpWebRequest2.AllowAutoRedirect = false;
httpWebRequest2.KeepAlive = false;
httpWebRequest2.Credentials = System.Net.CredentialCache.DefaultCredentials;
httpWebRequest2.Headers.Add("Cookie", cookieHeader);
Stream memStream = new System.IO.MemoryStream();
byte[] boundarybytes = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");
string formdataTemplate = "\r\n--" + boundary + "\r\nContent-Disposition: form-data; name=\"0\";\r\n\r\n1";
string formitem = string.Format(formdataTemplate, "headline", "image-name");
byte[] formitembytes = System.Text.Encoding.UTF8.GetBytes(formitem);
memStream.Write(formitembytes, 0, formitembytes.Length);
memStream.Write(boundarybytes, 0, boundarybytes.Length);
string headerTemplate = "\r\nContent-Disposition: form-data; name=\"0\"; filename=\"1\"\r\nContent-Type: application/octet-stream\r\n\r\n";
string header = string.Format(headerTemplate, "userfile", "path-to-the-local-file");
byte[] headerbytes = System.Text.Encoding.UTF8.GetBytes(header);
memStream.Write(headerbytes, 0, headerbytes.Length);
FileStream fileStream = new FileStream("path-to-the-local-file", FileMode.Open, FileAccess.Read);
byte[] buffer = new byte[1024];
int bytesRead = 0;
while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)
memStream.Write(buffer, 0, bytesRead);
memStream.Write(boundarybytes, 0, boundarybytes.Length);
fileStream.Close();
httpWebRequest2.ContentLength = memStream.Length;
Stream requestStream = httpWebRequest2.GetRequestStream();
memStream.Position = 0;
byte[] tempBuffer = new byte[memStream.Length];
memStream.Read(tempBuffer, 0, tempBuffer.Length);
memStream.Close();
requestStream.Write(tempBuffer, 0, tempBuffer.Length);
requestStream.Close();
WebResponse webResponse2 = httpWebRequest2.GetResponse();
Stream stream2 = webResponse2.GetResponseStream();
StreamReader reader2 = new StreamReader(stream2);
Console.WriteLine(reader2.ReadToEnd());
webResponse2.Close();
httpWebRequest2 = null;
webResponse2 = null;
这里还有 PHP： (http://dl.dropbox.com/u/3149888/index.php) 和 (http://dl.dropbox.com/u/3149888/new_image.php)
必填字段是 headline 和 userfile 所以我不知道错误在哪里，因为发送的格式是正确的。我猜发送到表单的八位字节流有问题。 也许这是一个我无法追踪的愚蠢错误，无论如何，如果你能帮助我，那将意味着很多。
谢谢，
【问题讨论】：
登录成功了吗，你找回cookie了吗？ 是的，登录一切正常。我取回 cookie，如果我在控制台中显示 pageSource 字符串，就在“//结束第一部分：登录到管理面板”之前，它包含管理面板的 html 代码。对于第二个请求，当我发送所有表单数据和文件八位字节流时，我能够返回“提交”页面的 HTML，只有标题设置为“图像名称”并且没有图像上传到博客。所以，基本上我无法上传图片。通常，如果出现问题，我应该会收到一条错误消息，而是获得带有标题集的 HTML。 您是否尝试过运行 fiddler 来比较从浏览器提交时的 HTTP 流量与您的代码生成的流量？我通常发现这有助于深入了解此类问题。 非常感谢马丁，提琴手做出了改变。这实际上是提琴手指出的流格式错误。我不得不承认我以前从未使用过它，所以谢谢你的推荐。我将在下面发布更改，也许其他人也有兴趣。祝你好运！ 【参考方案1】：因此，Martin 在这里帮助了我，我能够对上面的代码进行重要更改，以使其正常工作。 Content-Type 必须更改为 image/jpeg。我也使用 C# Image 类型来发送图像流。
还要注意 Stream 格式，因为它不必包含额外的空格或换行符。
这里是修改的部分：
string formUrl = "http://localhost/pixelpost/admin/index.php?x=login";
string formParams = string.Format("user=0&password=1", "username", "password");
string cookieHeader;
HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(formUrl);
req.ContentType = "application/x-www-form-urlencoded";
req.Method = "POST";
req.AllowAutoRedirect = false;
byte[] bytes = Encoding.ASCII.GetBytes(formParams);
req.ContentLength = bytes.Length;
using (Stream os = req.GetRequestStream())
os.Write(bytes, 0, bytes.Length);
HttpWebResponse resp = (HttpWebResponse)req.GetResponse();
cookieHeader = resp.Headers["Set-Cookie"];
string pageSource;
using (StreamReader sr = new StreamReader(resp.GetResponseStream()))
pageSource = sr.ReadToEnd();
string getUrl = "http://localhost/pixelpost/admin/index.php";
HttpWebRequest getRequest = (HttpWebRequest)HttpWebRequest.Create(getUrl);
getRequest.Headers.Add("Cookie", cookieHeader);
HttpWebResponse getResponse = (HttpWebResponse)getRequest.GetResponse();
using (StreamReader sr = new StreamReader(getResponse.GetResponseStream()))
pageSource = sr.ReadToEnd();
long length = 0;
string boundary = "----------------------------" +
DateTime.Now.Ticks.ToString("x");
HttpWebRequest httpWebRequest2 = (HttpWebRequest)WebRequest.Create("http://localhost/pixelpost/admin/index.php?x=save");
httpWebRequest2.ContentType = "multipart/form-data; boundary=" + boundary;
httpWebRequest2.Method = "POST";
httpWebRequest2.AllowAutoRedirect = false;
httpWebRequest2.KeepAlive = false;
httpWebRequest2.Credentials = System.Net.CredentialCache.DefaultCredentials;
httpWebRequest2.Headers.Add("Cookie", cookieHeader);
Stream memStream = new System.IO.MemoryStream();
byte[] boundarybytes = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary);
string headerTemplate = "\r\n--" + boundary + "\r\nContent-Disposition: form-data; name=\"0\"; filename=\"1\"\r\nContent-Type: image/jpeg\r\n\r\n";
string header = string.Format(headerTemplate, "userfile", "Sunset.jpg");
byte[] headerbytes = System.Text.Encoding.ASCII.GetBytes(header);
memStream.Write(headerbytes, 0, headerbytes.Length);
Image img = null;
img = Image.FromFile("C:/Documents and Settings/Dorin Cucicov/My Documents/My Pictures/Sunset.jpg", true);
img.Save(memStream, System.Drawing.Imaging.ImageFormat.Jpeg);
memStream.Write(boundarybytes, 0, boundarybytes.Length);
string formdataTemplate = "\r\nContent-Disposition: form-data; name=\"0\";\r\n\r\n1";
string formitem = string.Format(formdataTemplate, "headline", "Sunset");
byte[] formitembytes = System.Text.Encoding.UTF8.GetBytes(formitem);
memStream.Write(formitembytes, 0, formitembytes.Length);
memStream.Write(boundarybytes, 0, boundarybytes.Length);
httpWebRequest2.ContentLength = memStream.Length;
Stream requestStream = httpWebRequest2.GetRequestStream();
memStream.Position = 0;
byte[] tempBuffer = new byte[memStream.Length];
memStream.Read(tempBuffer, 0, tempBuffer.Length);
memStream.Close();
requestStream.Write(tempBuffer, 0, tempBuffer.Length);
requestStream.Close();
WebResponse webResponse2 = httpWebRequest2.GetResponse();
Stream stream2 = webResponse2.GetResponseStream();
StreamReader reader2 = new StreamReader(stream2);
Console.WriteLine(reader2.ReadToEnd());
webResponse2.Close();
httpWebRequest2 = null;
webResponse2 = null;
再次感谢大家的回答或阅读。
【讨论】：
以上是关于如何使用 HttpWebRequest 模拟浏览器文件上传的主要内容，如果未能解决你的问题，请参考以下文章
vb.net如何使用HttpWebRequest模拟登陆带验证码的网站
HttpWebRequest 保存Cookies,模拟Session登录
如何使用 httpwebrequest 将图像从网站拉到本地文件
转asp.net(c#)使用HttpWebRequest附加携带请求参数以post方式模拟上传大文件(以图片为例)到Web服务器端