Multipart forms from C# client

publicclassPostData{privateList<PostDataParam> m_Params;publicList<PostDataParam>Params{
    	get {return m_Params;}set{ m_Params = value;}}publicPostData(){
    	m_Params =newList<PostDataParam>();// Add sample param
    	m_Params.Add(newPostDataParam("email","MyEmail",PostDataParamType.Field));}/// <summary>/// Returns the parameters array formatted for multi-part/form data/// </summary>/// <returns></returns>publicstringGetPostData(){// Get boundary, default is --AaB03xstring boundary =ConfigurationManager.AppSettings["ContentBoundary"].ToString();StringBuilder sb =newStringBuilder();foreach(PostDataParam p in m_Params){
    		sb.AppendLine(boundary);if(p.Type==PostDataParamType.File){
    			sb.AppendLine(string.Format("Content-Disposition: file; name=\"{0}\"; filename=\"{1}\"", p.Name, p.FileName));
    			sb.AppendLine("Content-Type: text/plain");
    			sb.AppendLine();
    			sb.AppendLine(p.Value);}else{
    			sb.AppendLine(string.Format("Content-Disposition: form-data; name=\"{0}\"", p.Name));
    			sb.AppendLine();
    			sb.AppendLine(p.Value);}}

    	sb.AppendLine(boundary);return sb.ToString();}}publicenumPostDataParamType{Field,File}publicclassPostDataParam{publicPostDataParam(string name,string value,PostDataParamType type){Name= name;Value= value;Type= type;}publicstringName;publicstringFileName;publicstringValue;publicPostDataParamTypeType;}

To send the data you then need to:

HttpWebRequest oRequest =null;
oRequest =(HttpWebRequest)HttpWebRequest.Create(oURL.URL);
oRequest.ContentType="multipart/form-data";   					
oRequest.Method="POST";PostData pData =newPostData();byte[] buffer = encoding.GetBytes(pData.GetPostData());// Set content length of our data
oRequest.ContentLength= buffer.Length;// Dump our buffered postdata to the stream, booyah
oStream = oRequest.GetRequestStream();
oStream.Write(buffer,0, buffer.Length);
oStream.Close();// get the response
oResponse =(HttpWebResponse)oRequest.GetResponse();

Here is the FormUpload class:

// Implements multipart/form-data POST in C# http://www.ietf.org/rfc/rfc2388.txt// http://www.briangrinstead.com/blog/multipart-form-post-in-cpublicstaticclassFormUpload{privatestaticreadonlyEncoding encoding =Encoding.UTF8;publicstaticHttpWebResponseMultipartFormDataPost(string postUrl,string userAgent,Dictionary<string,object> postParameters){string formDataBoundary =String.Format("----------{0:N}",Guid.NewGuid());string contentType ="multipart/form-data; boundary="+ formDataBoundary;byte[] formData =GetMultipartFormData(postParameters, formDataBoundary);returnPostForm(postUrl, userAgent, contentType, formData);}privatestaticHttpWebResponsePostForm(string postUrl,string userAgent,string contentType,byte[] formData){HttpWebRequest request =WebRequest.Create(postUrl)asHttpWebRequest;if(request ==null){thrownewNullReferenceException("request is not a http request");}// Set up the request properties.
        request.Method="POST";
        request.ContentType= contentType;
        request.UserAgent= userAgent;
        request.CookieContainer=newCookieContainer();
        request.ContentLength= formData.Length;// You could add authentication here as well if needed:// request.PreAuthenticate = true;// request.AuthenticationLevel = System.Net.Security.AuthenticationLevel.MutualAuthRequested;// request.Headers.Add("Authorization", "Basic " + Convert.ToBase64String(System.Text.Encoding.Default.GetBytes("username" + ":" + "password")));// Send the form data to the request.
        using (Stream requestStream = request.GetRequestStream()){
            requestStream.Write(formData,0, formData.Length);
            requestStream.Close();}return request.GetResponse()asHttpWebResponse;}privatestaticbyte[]GetMultipartFormData(Dictionary<string,object> postParameters,string boundary){Stream formDataStream =newSystem.IO.MemoryStream();
        bool needsCLRF =false;foreach(var param in postParameters){// Thanks to feedback from commenters, add a CRLF to allow multiple parameters to be added.// Skip it on the first parameter, add it to subsequent parameters.if(needsCLRF)
                formDataStream.Write(encoding.GetBytes("\r\n"),0, encoding.GetByteCount("\r\n"));

            needsCLRF =true;if(param.ValueisFileParameter){FileParameter fileToUpload =(FileParameter)param.Value;// Add just the first part of this param, since we will write the file data directly to the Streamstring header =string.Format("--{0}\r\nContent-Disposition: form-data; name=\"{1}\"; filename=\"{2}\";\r\nContent-Type: {3}\r\n\r\n",
                    boundary,
                    param.Key,
                    fileToUpload.FileName?? param.Key,
                    fileToUpload.ContentType??"application/octet-stream");

                formDataStream.Write(encoding.GetBytes(header),0, encoding.GetByteCount(header));// Write the file data directly to the Stream, rather than serializing it to a string.
                formDataStream.Write(fileToUpload.File,0, fileToUpload.File.Length);}else{string postData =string.Format("--{0}\r\nContent-Disposition: form-data; name=\"{1}\"\r\n\r\n{2}",
                    boundary,
                    param.Key,
                    param.Value);
                formDataStream.Write(encoding.GetBytes(postData),0, encoding.GetByteCount(postData));}}// Add the end of the request.  Start with a newlinestring footer ="\r\n--"+ boundary +"--\r\n";
        formDataStream.Write(encoding.GetBytes(footer),0, encoding.GetByteCount(footer));// Dump the Stream into a byte[]
        formDataStream.Position=0;byte[] formData =newbyte[formDataStream.Length];
        formDataStream.Read(formData,0, formData.Length);
        formDataStream.Close();return formData;}publicclassFileParameter{publicbyte[]File{ get;set;}publicstringFileName{ get;set;}publicstringContentType{ get;set;}publicFileParameter(byte[] file):this(file,null){}publicFileParameter(byte[] file,string filename):this(file, filename,null){}publicFileParameter(byte[] file,string filename,string contenttype){File= file;FileName= filename;ContentType= contenttype;}}}

Here is the calling code, which uploads a file and a few normal post parameters:

// Read file dataFileStream fs =newFileStream("c:\\people.doc",FileMode.Open,FileAccess.Read);byte[] data =newbyte[fs.Length];
fs.Read(data,0, data.Length);
fs.Close();// Generate post objectsDictionary<string,object> postParameters =newDictionary<string,object>();
postParameters.Add("filename","People.doc");
postParameters.Add("fileformat","doc");
postParameters.Add("file",newFormUpload.FileParameter(data,"People.doc","application/msword"));// Create request and receive responsestring postURL ="http://localhost";string userAgent ="Someone";HttpWebResponse webResponse =FormUpload.MultipartFormDataPost(postURL, userAgent, postParameters);// Process responseStreamReader responseReader =newStreamReader(webResponse.GetResponseStream());string fullResponse = responseReader.ReadToEnd();
webResponse.Close();Response.Write(fullResponse);

Building on dnolans example, this is the version I could actually get to work (there were some errors with the boundary, encoding wasn't set) :-)

To send the data:

HttpWebRequest oRequest =null;
oRequest =(HttpWebRequest)HttpWebRequest.Create("http://you.url.here");
oRequest.ContentType="multipart/form-data; boundary="+PostData.boundary;
oRequest.Method="POST";PostData pData =newPostData();Encoding encoding =Encoding.UTF8;Stream oStream =null;/* ... set the parameters, read files, etc. IE:
   pData.Params.Add(new PostDataParam("email", "example@example.com", PostDataParamType.Field));
   pData.Params.Add(new PostDataParam("fileupload", "filename.txt", "filecontents" PostDataParamType.File));
*/byte[] buffer = encoding.GetBytes(pData.GetPostData());

oRequest.ContentLength= buffer.Length;

oStream = oRequest.GetRequestStream();
oStream.Write(buffer,0, buffer.Length);
oStream.Close();HttpWebResponse oResponse =(HttpWebResponse)oRequest.GetResponse();

The PostData class should look like:

publicclassPostData{// Change this if you need to, not necessarypublicstaticstring boundary ="AaB03x";privateList<PostDataParam> m_Params;publicList<PostDataParam>Params{
        get {return m_Params;}set{ m_Params = value;}}publicPostData(){
        m_Params =newList<PostDataParam>();}/// <summary>/// Returns the parameters array formatted for multi-part/form data/// </summary>/// <returns></returns>publicstringGetPostData(){StringBuilder sb =newStringBuilder();foreach(PostDataParam p in m_Params){
            sb.AppendLine("--"+ boundary);if(p.Type==PostDataParamType.File){
                sb.AppendLine(string.Format("Content-Disposition: file; name=\"{0}\"; filename=\"{1}\"", p.Name, p.FileName));
                sb.AppendLine("Content-Type: application/octet-stream");
                sb.AppendLine();
                sb.AppendLine(p.Value);}else{
                sb.AppendLine(string.Format("Content-Disposition: form-data; name=\"{0}\"", p.Name));
                sb.AppendLine();
                sb.AppendLine(p.Value);}}

        sb.AppendLine("--"+ boundary +"--");return sb.ToString();}}publicenumPostDataParamType{Field,File}publicclassPostDataParam{publicPostDataParam(string name,string value,PostDataParamType type){Name= name;Value= value;Type= type;}publicPostDataParam(string name,string filename,string value,PostDataParamType type){Name= name;Value= value;FileName= filename;Type= type;}publicstringName;publicstringFileName;publicstringValue;publicPostDataParamTypeType;}

http://stackoverflow.com/questions/219827/multipart-forms-from-c-sharp-client

namespace WindowsFormsApplication1{publicstaticclassFormUpload{privatestaticstringNewDataBoundary(){Random rnd =newRandom();string formDataBoundary ="";while(formDataBoundary.Length<15){
                formDataBoundary = formDataBoundary + rnd.Next();}
            formDataBoundary = formDataBoundary.Substring(0,15);
            formDataBoundary ="-----------------------------"+ formDataBoundary;return formDataBoundary;}publicstaticHttpWebResponseMultipartFormDataPost(string postUrl,IEnumerable<Cookie> cookies,Dictionary<string,string> postParameters){string boundary =NewDataBoundary();HttpWebRequest request =(HttpWebRequest)WebRequest.Create(postUrl);// Set up the request properties
            request.Method="POST";
            request.ContentType="multipart/form-data; boundary="+ boundary;
            request.UserAgent="PhasDocAgent 1.0";
            request.CookieContainer=newCookieContainer();foreach(var cookie in cookies){
                request.CookieContainer.Add(cookie);}#region WRITING STREAM
            using (Stream formDataStream = request.GetRequestStream()){foreach(var param in postParameters){if(param.Value.StartsWith("file://")){string filepath = param.Value.Substring(7);// Add just the first part of this param, since we will write the file data directly to the Streamstring header =string.Format("--{0}\r\nContent-Disposition: form-data; name=\"{1}\"; filename=\"{2}\";\r\nContent-Type: {3}\r\n\r\n",
                            boundary,
                            param.Key,Path.GetFileName(filepath)?? param.Key,MimeTypes.GetMime(filepath));

                        formDataStream.Write(Encoding.UTF8.GetBytes(header),0, header.Length);// Write the file data directly to the Stream, rather than serializing it to a string.byte[] buffer =newbyte[2048];FileStream fs =newFileStream(filepath,FileMode.Open);for(int i =0; i < fs.Length;){int k = fs.Read(buffer,0, buffer.Length);if(k >0){
                                formDataStream.Write(buffer,0, k);}
                            i = i + k;}
                        fs.Close();}else{string postData =string.Format("--{0}\r\nContent-Disposition: form-data; name=\"{1}\"\r\n\r\n{2}\r\n",
                            boundary,
                            param.Key,
                            param.Value);
                        formDataStream.Write(Encoding.UTF8.GetBytes(postData),0, postData.Length);}}// Add the end of the requestbyte[] footer =Encoding.UTF8.GetBytes("\r\n--"+ boundary +"--\r\n");
                formDataStream.Write(footer,0, footer.Length);
                request.ContentLength= formDataStream.Length;
                formDataStream.Close();}#endregionreturn request.GetResponse()asHttpWebResponse;}}}

参考

C# Socket 实现的淘宝秒杀器（抢拍器）

http://www.cnblogs.com/chengulv/archive/2013/01/25/2877383.html