Uploading image through http form with fields

Question

I have today a program that I can post through to my site, but I need to add file upload support to my program (for jpg). I had such a problem just getting my program to post, and now after many hours I can't get it to work with file upload.

Today my code is not very good but it works and I'm the only one using it. Here is my code, abit stripped but I hope you get the idea what I need help with. Thanks!

("upfile" is the input field name for images)

public static string Post(string url, int id, string message)
{
    try
    {
        string param =
            string.Format(
                "MAX_FILE_SIZE=2097152&id={0}&com={1}&upfile", id, message);

        byte[] bytes = Encoding.ASCII.GetBytes(param);

        var post = (HttpWebRequest)WebRequest.Create(url);

        post.ProtocolVersion = HttpVersion.Version10;
        post.Method = "POST";
        post.AllowAutoRedirect = false;
        post.ContentType = "application/x-www-form-urlencoded";
        post.ContentLength = bytes.Length;

        post.UserAgent =
            "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.0.15) Gecko/2009101601 Firefox/3.0.15 (.NET CLR 3.5.30729)";
        post.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";

        Stream requestStream = post.GetRequestStream();
        requestStream.Write(bytes, 0, bytes.Length);
        requestStream.Close();

        var webResponse = (HttpWebResponse)post.GetResponse();
        var sr = new StreamReader(webResponse.GetResponseStream());
        return sr.ReadToEnd();
    }
    catch (Exception exception)
    {
        return null;
    }
}

Edit: Sorry for my poor explanation here is what I need help with: I use the method above today to post on my site, but I need add support to upload files in my method. I can't change how the webpage works in the close future so it have to be done by using a POST request. I can't get it to work then I try to do it myself, so I'm wondering if anybody could help me with what need to be added to read a image and post it with the request!

Thanks!

I need help how to add so my method can post an image with my form post. The form supports image uploads, but I can't get my form program to post a image with the current code. — Tobias Lindberg, May 23 '12 at 15:22

score 1 · Accepted Answer · edited May 23 '17 at 10:09

1

You need to use the encoding of multipart/form-data instead of application/x-www-form-urlencoded, and then you need to encode the post data accordingly

See Upload files with HTTPWebrequest (multipart/form-data)

edited May 23 '17 at 10:09

Community

1
1

answered May 23 '12 at 15:57

Martin Ernst

5,629
2
17
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Thanks, I got just what I was looking for! – Tobias Lindberg May 23 '12 at 16:27

score 0 · Answer 2 · answered May 23 '12 at 15:18

0

I'm assuming you need a better solution than your current one. If you are on c#, there is a FILE upload control that you can use to upload files. You can even restrict it to the types of valid files that you allow.

Control is FileUpload

answered May 23 '12 at 15:18

edocetirwi

542
5
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Yes I'm on c# but I have to use the form to post. In the closest future I can't get any changes on the website. – Tobias Lindberg May 23 '12 at 15:21
So what exactly is your problem/question? – edocetirwi May 23 '12 at 15:24
My question/problem is: When I try too add the code myself I can't get it right. So really my question is. What do need help with is what code changes needs to be made to post a image with my current code? – Tobias Lindberg May 23 '12 at 15:37

score 0 · Answer 3 · answered May 23 '12 at 16:01

0

Shouldnt your Content type be multipart/form-data; ? If it is possible for you to use a upload class I can make one available to you.

answered May 23 '12 at 16:01

Ademar

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Uploading image through http form with fields

3 Answers3