C# Create MIME Header Information? (Content-Type etc.)

Question

I am reading in a file and want to add MIME header infromation to the top of the file.

For example: I have a text file called test.txt. I read the file into a byte array then want to append the following to the beggining:

Content-Type: text/plain;
     name="test.txt"
Content-Transfer-Encoding: binary
Content-Disposition: attachment;
     filename="test.txt"

How can i get the what the content type is? And how would you reccomend adding this to the beggining of the file? I was planning on creating a string with that information then converting it to a byte array and sticking it on the front of my file buffer but I am worried about running into encoding problems.

How fine grained do you need to get when detecting file type? Are you trying to identify xml, html, jpg, gif, png, exe, pdf, doc etc etc, or just decide between text and binary? — Neil Moss, Jul 15 '10 at 16:03

score 2 · Accepted Answer · edited May 23 '17 at 12:07

You can't add header information into the file itself; it is transmitted along with the file when you are using certain protocols (chiefly SMTP and HTTP).

EDIT: If you wish to work out the content-type (also known as Internet media type) from the file content, you may wish to look at something like mime-util or Apache Tika.

EDIT 2: The answers to this question will help with content-type detection in .NET:

Using .NET, how can you find the mime type of a file based on the file signature not the extension?

EDIT 3: If you know the file format you are working on, you can add any arbitary information you wish to it. You will need to special case each file format though. I can't imagine why you want protocol information inside your file, but that's up to you!

EDIT 4: To add text to the beginning of a text file:

static void WriteBeginning(string filename, string insertedtext)
{
    string tempfile = Path.GetTempFileName();
    StreamWriter writer = new StreamWriter(tempfile);
    StreamReader reader = new StreamReader(filename);
    writer.WriteLine(insertedtext);
    while (!reader.EndOfStream)
        writer.WriteLine(reader.ReadLine());
    writer.Close();
    reader.Close();
    File.Copy(tempfile, filename, true);
}

(credit)

C# Create MIME Header Information? (Content-Type etc.)

1 Answers1