Uploading Multipart Data to ImageVenue Using C# .NET

WeCi2i

Okay, I have a problem that has been stumping me for weeks. I have tried many different solutions and this is pretty much my last resort. I have seen a lot of good answers give here so I figured I would give it a try.

First of all, I am using Visual Studio 2005 to write my program. I am using C# .NET as the language. I am running Windows XP Professional with all service packs and updates applied.

Now, I have been trying to write a program that batch uploads pictures to the image hosting service ImageVenue, http://www.imagevenue.com (On a side note, I have tried also with ImageShack but also had the same results). I can't seem to get it right because ImageVenue never returns the linking code to the image. I will post my code as well as some other stuff I have grabbed along the way in hopes that somebody can pick out my error. The code I have written has mostly been borrowed from the web but I have also added to it. I am using a class called MultipartFileUpload to do the uploading and I have written a sort of "driver" program to test the class. I will post the MultipartFileUpload code first.

Here is the code for MultipartFileUpload:

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using System;

using System.Collections.Generic;

using System.Text;

using System.Collections.Specialized;

using System.Net;

using System.IO;
 
namespace IVUp

{

    public class MultipartFileUpload

    {

        private Uri uri = null;

        private NameValueCollection parameters = null;

        private NameValueCollection formData = null;

        private String fileDisplayName = null;

        private String fileParameterName = null;

        private FileInfo file = null;

        private NetworkCredential networkCredential = null;

        private String boundary = null;

        private readonly int BUFFER_SIZE = 500;
 
        #region constructors
 
        public MultipartFileUpload()

        {

            parameters = new NameValueCollection();

            formData = new NameValueCollection();
 
            //the boundary signals the we server to look for a new form value or data segment

            boundary = "----------" + DateTime.Now.Ticks.ToString("x");

        }
 
        public MultipartFileUpload(Uri uri) : this()

        {

            this.uri = uri;

        }
 
        #endregion
 
        #region getters and setters
 
        /// <summary>

        /// the destination of the multipart file upload

        /// </summary>
 
        public Uri Uri

        {

            get { return this.uri; }
 
            set { this.uri = value; }

        }
 
        /// <summary>

        /// the parameters to be passed along with the post method — optional

        /// </summary>
 
        public NameValueCollection Parameters

        {

            get { return this.parameters; }
 
            set { this.parameters = value; }

        }
 
        /// <summary>

        /// any form data associated with the post method

        /// </summary>
 
        public NameValueCollection FormData

        {

            get { return this.formData; }
 
            set { this.formData = value; }

        }
 
        /// <summary>

        /// if your web server requires credentials to upload a file, set them here — optional

        /// </summary>
 
        public NetworkCredential NetworkCredential

        {

            get { return this.networkCredential; }
 
            set { this.networkCredential = value; }

        }
 
        #endregion
 
        #region public methods
 
        /// <summary>

        /// adds a parameter to the request, if the parameter already has a value,

        /// it will be overwritten

        /// </summary>
 
        /// <param name="name">name of the parameter</param>

        /// <param name="value">value of the parameter</param>
 
        public void AddParameter(String name, String value)

        {

            if (this.parameters == null)

            {

                this.parameters = new NameValueCollection();

            }

            this.parameters.Set(name, value);

        }
 
        /// <summary>

        /// adds a form value to the request, if the form field already exists, overwrite it

        /// </summary>
 
        /// <param name="name">the name of the form field</param>

        /// <param name="value">value of the form field</param>
 
        public void AddFormValue(String name, String value)

        {

            if (this.formData == null)

            {

                this.formData = new NameValueCollection();

            }

            this.parameters.Set(name, value);

        }
 
        /// <summary>

        /// attach a file to the post method, the parameter name and file can not be null

        /// </summary>
 
        /// <param name="fileDisplayName">the name of the file as it should appear to the web server</param>

        /// <param name="parameterName">the parameter that your web server expects to be associated with a file</param>

        /// <param name="file">the actual file you want to upload</param>

        /// <exception cref="ArgumentNullException">file can not be null, name of the parameter can’t be null</exception>
 
        public void AttachFile(String fileDisplayName, String parameterName, FileInfo file)

        {

            if(file == null)

            {

                throw new ArgumentNullException("file", "You must pass a reference to a file");

            }

            if (parameterName == null)

            {

                throw new ArgumentNullException("parameterName", "You must provide the name of the file parameter.");

            }

            this.file = file;

            if (this.fileDisplayName == null)

            {

                this.fileDisplayName = file.Name;

            }

        }
 
        /// <summary>

        /// performs the actual upload

        /// </summary>

        /// <returns>the response as a string</returns>
 
        public String UploadFileEx()

        {

            //tack on any parameters or just give us back the uri if there are no parameters

            Uri targetUri = CreateUriWithParameters();

            HttpWebRequest webrequest = (HttpWebRequest)WebRequest.Create(targetUri);

            webrequest.Credentials = networkCredential; //fine if it’s null

            webrequest.ContentType = "multipart/form-data; boundary=" + boundary;

            webrequest.Method = "POST";
 
            //encode header

            String postHeader = CreatePostDataString();

            byte[] postHeaderBytes = Encoding.UTF8.GetBytes(postHeader);

            byte[] boundaryBytes = Encoding.ASCII.GetBytes("\r\n–" + boundary + "\r\n");
 
            //read in the file as a stream

            FileStream fileStream = file.Open(FileMode.Open, FileAccess.Read);

            long length = postHeaderBytes.Length + fileStream.Length +boundaryBytes.Length;
 
            //the request method needs to know how big the file is before we start the upload

            webrequest.ContentLength = length;

            Stream requestStream = webrequest.GetRequestStream();
 
            // Write out our post header

            requestStream.Write(postHeaderBytes, 0, postHeaderBytes.Length);
 
            // Write out the file contents

            byte[] buffer = new byte[BUFFER_SIZE];

            int bytesRead = 0;

            while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)

            {

                requestStream.Write(buffer, 0, bytesRead);

            }
 
            // Write out the trailing boundary

            requestStream.Write(boundaryBytes, 0, boundaryBytes.Length);

            WebResponse response = webrequest.GetResponse();

            StreamReader sr = new StreamReader(response.GetResponseStream());

            return sr.ReadToEnd(); //response body

        }
 
        #endregion
 
        #region private methods
 
        /// <summary>

        /// helper method to tack on parameters to the request

        /// </summary>

        /// <returns>Uri with parameters, or the original uri if it’s null</returns>
 
        private Uri CreateUriWithParameters()

        {

            if (uri == null) return null;

            if (parameters == null || parameters.Count <= 0)

            {

                return this.uri;

            }
 
            String paramString = "?";

            foreach (String key in parameters.Keys)

            {

                paramString += key + "=" + parameters.Get(key)+"&";

            }
 
            paramString = paramString.Substring(0, paramString.Length - 1); //strip off last &

            return new Uri(uri.ToString() + paramString);

        }
 
        /// <summary>

        /// post data as a string with the boundaries

        /// </summary>
 
        /// <returns>a string representing the form data</returns>
 
        private String CreatePostDataString()

        {

            StringBuilder sb = new StringBuilder();

            for (int i = 0; i < formData.Count; i++)

            {

                sb.Append("–" + boundary + "\r\n");

                sb.Append("Content-Disposition: form-data; name=\"");

                sb.Append(formData.GetKey(i) + "\"\r\n\r\n" + formData.Get(i) + "\r\n");

            }
 
            sb.Append("–" + boundary + "\r\n");

            sb.Append("Content-Disposition: form-data; name=\"" + fileParameterName + "\";");

            sb.Append("filename=\"" + fileDisplayName + "\" Content-Type: application/octet-stream\r\n\r\n");

            return sb.ToString();

        }
 
        #endregion

    }

}

Here is what I have done for the testing part:

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using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Text;

using System.Windows.Forms;

using System.IO;
 
namespace IVUp

{

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }
 
        private void button1_Click(object sender, EventArgs e)

        {

            //MultipartFileUpload Class Code
 
            String UploadResults = "";

            MultipartFileUpload MyMultipart = new MultipartFileUpload();
 
            Uri MyUri = new Uri("http://imagevenue.com/upload.php");
 
            MyMultipart.Uri = MyUri;

            openFileDialog1.ShowDialog();

            FileInfo MyFile = new FileInfo(openFileDialog1.FileName);

            //MyMultipart.AddFormValue("hostval", "10");

            MyMultipart.AttachFile("Test.jpg", "userfile[]", MyFile);

            //MyMultipart.AddFormValue("userfile[]", "C:\\Test.jpg");

            MyMultipart.AddFormValue("imgcontent", "notsafe");

            MyMultipart.AddFormValue("MAX_FILE_SIZE", "");

            MyMultipart.AddFormValue("action", "1");

            MyMultipart.AddFormValue("img_resize", "");
 
            UploadResults = MyMultipart.UploadFileEx();
 
            richTextBox1.Text = UploadResults;

        }

    }

}

I have been using Ethereal to capture packets to see if something is wrong with the http part of the stuff. Here is what a standard upload from firefox looks like:

POST /upload.php HTTP/1.1
Host: imagevenue.com
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.5) Gecko/20070713 ImageShackToolbar/4.2.1 Firefox/2.0.0.5
Accept: text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 300
Connection: keep-alive
Referer: http://imagevenue.com/host.php
Cookie: __utmz=122915731.1183006481.1.1.utmccn=(direct)|ut mcsr=(direct)|utmcmd=(none); pval=1185169867; __utma=122915731.858623389.1183006481.1183006481.1 186080644.2; __utmc=122915731

And here is what the stuff from my program has looked like so far:

POST /upload.php?imgcontent=notsafe&MAX_FILE_SIZE=&actio n=1&img_resize= HTTP/1.1
Content-Type: multipart/form-data; boundary=----------8c9a331c0cc2e10
Host: imagevenue.com
Content-Length: 12888
Expect: 100-continue
Connection: Keep-Alive

Any help on this would be greatly appreciated. Thanks.

WeCi2i

If nobody knows the answer to that question, how about this one: Is the whole WebRequest, HTTPWebRequest, etc. part of Visual Studio just broken when you do form things? I have had several other tasks to perform with forms that also do not work in C# I had been using PHP and CURL to do all these things and I wanted to move to a desktop environment. PHP and CURL made things with forms and HTTP very easy. Apparently C# and .NET do not.

Uploading Multipart Data to ImageVenue Using C# .NET

re: Uploading Multipart Data to ImageVenue Using C# .NET

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