Question

I recently posted a question asking how I can return a File from a byte[] that I am storing.

The question is here byte[] to File Type in MVC 3

Just for reference, I have resulted to storing the binary for the file as a string.

When I return the document, I am calling the following code:

var data = document.BinData.ToByteArray();
return File(data, document.MIMEType,document.Extension);

where BinData is a string, and ToByteArray() is an extension method I wrote:

public static byte[] ToByteArray(this string data)
    {
        byte[] binData= new byte[data.Length];
        for (var i = 0; i < data.Length; i++)
        {
            binData[i] = (byte)data[i];
        }
        return binData;
    }

The problem I am experiencing is, when I get the file back, I am getting something like the following:

Is there anything you can see that I am doing incorrectly?

Edit, I have changed the following “Upload” code to the following:

var stream = BinData.InputStream;
                byte[] data = new byte[BinData.ContentLength];
                stream.Read(data, 0, BinData.ContentLength);

                string documentData = Convert.ToBase64String(data);

where documentData is the string I am storing:

and the download code is the following:

var data = Convert.FromBase64String(document.BinData);
return File(data,document.MimeType,document.Title + document.Extension);

where document.BinData is the documentData from above

Answer 1

I would wager that the problem is in the line:

Just for reference, I have resulted to storing the binary for the file as a string.

Based on your decoder (ToByteArray), this is not really encoded in a suitable way; note; you cannot treat arbitrary binary data as a string (at least, not in the way you are trying). The preferred way to do this is simply:

byte[] originalData = ...
string asString = Convert.ToBase64String(originalData);
byte[] reconstructedBinary = Convert.FromBase64String(asString);

(although several other approaches – for example hex – would work too)

This should give you back the correct byte[], and all should be good from there.

---

Re your Stream.Read code, and assuming you already have some kind of oversized length check to prevent from DDOS, note that you should loop on Read:

int remaining = BinData.ContentLength, offset = 0, bytesRead;
byte[] data = new byte[remaining];
while((bytesRead = stream.Read(data, offset, remaining)) > 0) {
    offset += bytesRead;
    remaining -= bytesRead;
}
if(remaining > 0) throw new EndOfStreamException();