c# - Reading a binary file and using Response.BinaryWrite()

Question

I have an app that needs to read a PDF file from the file system and then write it out to the user. The PDF is 183KB and seems to work perfectly. When I use the code at the bottom the browser gets a file 224KB and I get a message from Acrobat Reader saying the file is damaged and cannot be repaired.

Here is my code (I've also tried using File.ReadAllBytes(), but I get the same thing):

using (FileStream fs = File.OpenRead(path))
{
    int length = (int)fs.Length;
    byte[] buffer;

    using (BinaryReader br = new BinaryReader(fs))
    {
        buffer = br.ReadBytes(length);
    }

    Response.Clear();
    Response.Buffer = true;
    Response.AddHeader("content-disposition", String.Format("attachment;filename={0}", Path.GetFileName(path)));
    Response.ContentType = "application/" + Path.GetExtension(path).Substring(1);
    Response.BinaryWrite(buffer);
}

Answer 1

Try adding

Response.End();

after the call to Response.BinaryWrite().

You may inadvertently be sending other content back after Response.BinaryWrite which may confuse the browser. Response.End will ensure that that the browser only gets what you really intend.