Question

所以遇到了一个小问题。我正在创建一个小应用程序来自动化在一个网站上提交表单。但糟糕的是，他们正在使用multipart / form-data。没有文件只上传一些文本字段以供提交。

当然这样做就失败了。

string postData1 = "firstfield="+firststring+"secondfield="+secondstring;

所以我的问题是如何将这些表单字段以多部分形式发布？

在php中发布类似数组：

$postdata = array('firstfield' => $firststring, 'secondfield' => $secondstring);

工作并传递表单，但似乎无法使用c＃

有什么建议吗？

数据提交通过3页（基本的screenscrape）登录/ part1 / part2

到目前为止，我可以成功登录并发布part1（使用普通应用程序/ x-www-form-urlencoded格式）

但是当生病时尝试发布多部分表单时，它会失败并将我发回给part1。所以也许我的代码是错的，但现在是：

string password = "password";
string username = "username";
string link = "http://somelink.com/";
string text = "Blah Blah some text here";
string title = "Blah Blah";
string tags1 = title;
string summary = "Blah Blah summary";
string tags = tags1.Replace(" ", ",");

// Set cookie container
CookieContainer cookieJar = new CookieContainer();

string loginData = "username=" + username + "&password=" + password + "&processlogin=1&return=%2Fsubmit.php";

HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create("http://loginlink.com/login.php");
myRequest.Method = "POST";
        myRequest.ServicePoint.Expect100Continue = false;
myRequest.UserAgent = "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1.4) Gecko/20091016 Firefox/3.5.4 GTB6 (.NET CLR 3.5.30729)";
myRequest.Timeout = 10000;
myRequest.ContentType = "application/x-www-form-urlencoded";
myRequest.ContentLength = loginData.Length;
myRequest.CookieContainer = cookieJar;
myRequest.KeepAlive = true;
myRequest.AllowAutoRedirect = true;

//Write post data to stream
StreamWriter myWriter = new StreamWriter(myRequest.GetRequestStream());
myWriter.Write(loginData);
myWriter.Close();

// Get the response.
HttpWebResponse myResponse = (HttpWebResponse)myRequest.GetResponse();

// Open the stream using a StreamReader for easy access.
StreamReader myReader = new StreamReader(myResponse.GetResponseStream());
// Read the content.
string output = myReader.ReadToEnd();

// Clean up the streams and the response.
myReader.Close();
myResponse.Close();


Match matchkey = Regex.Match(output, "type=\"hidden\" name=\"randkey\" value=\"([^\"]+)\"", RegexOptions.IgnoreCase);
string key1 = matchkey.Groups[1].Value;
Match matchid = Regex.Match(output, "type=\"hidden\" name=\"id\" value=\"([^\"]+)\"", RegexOptions.IgnoreCase);
string id1 = matchid.Groups[1].Value;


string postData = "url=" + link + "&phase=1&randkey=" + key1 + "&id=" + id1;

HttpWebRequest myRequest2 = (HttpWebRequest)WebRequest.Create("http://submitpage1.com/submit.php");
myRequest2.Method = "POST";
myRequest2.ServicePoint.Expect100Continue = false;
myRequest2.UserAgent = "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1.4) Gecko/20091016 Firefox/3.5.4 GTB6 (.NET CLR 3.5.30729)";
myRequest2.Timeout = 10000;
myRequest2.ContentType = "application/x-www-form-urlencoded";
myRequest2.ContentLength = postData.Length;
myRequest2.CookieContainer = cookieJar;
myRequest2.KeepAlive = true;
myRequest2.AllowAutoRedirect = true;


//Write post data to stream
StreamWriter myWriter2 = new StreamWriter(myRequest2.GetRequestStream());
myWriter2.Write(postData);
myWriter2.Close();

// Get the response.
HttpWebResponse myResponse2 = (HttpWebResponse)myRequest2.GetResponse();

// Open the stream using a StreamReader for easy access.
StreamReader myReader2 = new StreamReader(myResponse2.GetResponseStream());
// Read the content.
string output1 = myReader2.ReadToEnd();

// Clean up the streams and the response.
myReader2.Close();
myResponse2.Close();

Match matchkey1 = Regex.Match(output1, "type=\"hidden\" name=\"randkey\" value=\"([^\"]+)\"", RegexOptions.IgnoreCase);
string key2 = matchkey1.Groups[1].Value;
Match matchid1 = Regex.Match(output1, "type=\"hidden\" name=\"randkey\" value=\"([^\"]+)\"", RegexOptions.IgnoreCase);
string id2 = matchid1.Groups[1].Value;

string boundary = "-----------------------------1721856231228";

// Build up the post
StringBuilder sb = new StringBuilder();
sb.Append("\r\n" + boundary + "\r\n");
sb.Append("Content-Disposition: form-data; name=\"title\"" + "\r\n");
sb.Append("\r\n");
sb.Append(title);
sb.Append("\r\n--" + boundary + "\r\n");
sb.Append("Content-Disposition: form-data; name=\"tags\"" + "\r\n");
sb.Append("\r\n");
sb.Append(tags);
sb.Append("\r\n--" + boundary + "\r\n");
sb.Append("Content-Disposition: form-data; name=\"bodytext\"" + "\r\n");
sb.Append("\r\n");
sb.Append(text);
sb.Append("\r\n--" + boundary + "\r\n");
sb.Append("Content-Disposition: form-data; name=\"summarycheckbox\"" + "\r\n");
sb.Append("\r\n");
sb.Append("on");
sb.Append("\r\n--" + boundary + "\r\n");
sb.Append("Content-Disposition: form-data; name=\"summarytext\"" + "\r\n");
sb.Append("\r\n");
sb.Append(summary);
sb.Append("\r\n--" + boundary + "\r\n");
sb.Append("Content-Disposition: form-data; name=\"remLen\"" + "\r\n");
sb.Append("\r\n");
sb.Append("125");
sb.Append("\r\n--" + boundary + "\r\n");
sb.Append("Content-Disposition: form-data; name=\"category\"" + "\r\n");
sb.Append("\r\n");
sb.Append("1");
sb.Append("\r\n--" + boundary + "\r\n");
sb.Append("Content-Disposition: form-data; name=\"trackback\"" + "\r\n");
sb.Append("\r\n");
sb.Append("");
sb.Append("\r\n--" + boundary + "\r\n");
sb.Append("Content-Disposition: form-data; name=\"url\"" + "\r\n");
sb.Append("\r\n");
sb.Append(link);
sb.Append("\r\n--" + boundary + "\r\n");
sb.Append("Content-Disposition: form-data; name=\"phase\"" + "\r\n");
sb.Append("\r\n");
sb.Append("2");
sb.Append("\r\n--" + boundary + "\r\n");
sb.Append("Content-Disposition: form-data; name=\"randkey\"" + "\r\n");
sb.Append("\r\n");
sb.Append(key2);
sb.Append("\r\n--" + boundary + "\r\n");
sb.Append("Content-Disposition: form-data; name=\"id\"" + "\r\n");
sb.Append("\r\n");
sb.Append(id2);
sb.Append("\r\n--" + boundary + "--" + "\r\n");

string postData1 = sb.ToString();

HttpWebRequest myRequest3 = (HttpWebRequest)WebRequest.Create("http://submitpage2.com/submit.php");
myRequest3.Method = "POST";
myRequest3.UserAgent = "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1.4) Gecko/20091016 Firefox/3.5.4 GTB6 (.NET CLR 3.5.30729)";
myRequest3.Timeout = 10000;
myRequest3.ServicePoint.Expect100Continue = false;
myRequest3.Referer = "http://bookmarkindo.com/submit.php";
myRequest3.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";
myRequest3.ContentType = "multipart/form-data; boundary=" + boundary;
myRequest3.ContentLength = postData1.Length;
myRequest3.CookieContainer = cookieJar;
myRequest3.KeepAlive = true;
myRequest3.AllowAutoRedirect = true;

//Write out postdata
StreamWriter myWriter3 = new StreamWriter(myRequest3.GetRequestStream());
myWriter3.Write(postData1);
myWriter3.Close();

// Get the response.
HttpWebResponse myResponse3 = (HttpWebResponse)myRequest3.GetResponse();

// Open the stream using a StreamReader for easy access.
StreamReader myReader3 = new StreamReader(myResponse3.GetResponseStream());
// Read the content.
string output2 = myReader3.ReadToEnd();

// Clean up the streams and the response.
myReader3.Close();
myResponse3.Close();

欢迎所有建议

Answer 1

帖子os multipart / form-data类型具有不同的结构，因为它们用于传输数据而不仅仅是纯文本。

以下是格式：

--[random number, a GUID is good here]
Content-Disposition: form-data; name="[name of variable]"

[actual value]
--[random number, a GUID is good here]--

使用HTTPWebRequest，您可以创建具有该格式的请求。这是一个示例：

string boundary = Guid.NewGuid().ToString();
string header = string.Format("--{0}", boundary);
string footer = string.Format("--{0}--", boundary);

StringBuilder contents = new StringBuilder();
contents.AppendLine(header);

contents.AppendLine(header);
contents.AppendLine(String.Format("Content-Disposition: form-data; name=\"{0}\"", "username"));
contents.AppendLine();
contents.AppendLine("your_username");

contents.AppendLine(header);
contents.AppendLine(String.Format("Content-Disposition: form-data; name=\"{0}\"", "password"));
contents.AppendLine();
contents.AppendLine("your_password");

contents.AppendLine(footer);

Answer 2

这是一篇关于multipart form posts in C#的文章，内容更详细。此代码最终合并到RestSharp，这是一个很好的库，可用于生成请求。

Answer 3

代码段显示了用C＃发送多部分表单数据的最佳方法，在这里您看到添加不同类型的内容就像将其添加到包装的多部分内容类型一样简单：

var documentContent = new MultipartFormDataContent();
documentContent.Add(new StringContent("AnalyticsPage.xlsx"), "title");
documentContent.Add(new ByteArrayContent(File.ReadAllBytes("C:\\Users\\awasthi\\Downloads\\AnalyticsPage.xlsx")), "file", "AnalyticsPage.xlsx");

然后只需进行api调用：

using (var client = new HttpClient(new HttpClientHandler() { UseDefaultCredentials = true, CookieContainer = new CookieContainer() }))
{
  response = client.PostAsync(documentAddApi, documentContent).Result;
  var responseContent = response.Content.ReadAsStringAsync().Result;
 }

这里期望您正在调用的其余端点正在接受文件的“标题”字段和名为“文件”的文件的字节数组。

Answer 4

此处列出了multipart/form-data个请求的格式：http://www.w3.org/TR/html401/interact/forms.html#h-17.13.4.2。

c＃multipart / form-data以编程方式提交

4 个答案: