Read from basic stream (httpRequestStream)

Question

I have a basic stream which is the stream of HTTP request and

var s=new HttpListener().GetContext().Request.InputStream;

I want to read the stream (which contain non-Character content, because i've sent the packet)

When we wrap this stream by StreamReader then we use the ReadToEnd() function of StreamReader it can read the whole stream and return a string...

HttpListener listener = new HttpListener();
listener.Prefixes.Add("http://127.0.0.1/");
listener.Start();
var context = listener.GetContext();
var sr = new StreamReader(context.Request.InputStream);
string x=sr.ReadToEnd(); //This Workds

but since it has nonCharacter content we cant use StremReader (i tried all encoding mechanisms..using string is just wrong).And i Cant use the function

context.Request.InputStream.Read(buffer,position,Len) 

because I cant get the length of the stream, InputStream.Length always throws an exception and cant be used..and i dont want to create a small protocol like [size][file] and read first size then the file ...somehow the StreamReader can get the length ..and i just want to know how . I also tried this and it didn't work

List<byte> bb = new List<byte>();
var ss = context.Request.InputStream;
byte b = (byte)ss.ReadByte();
while (b >= 0)
{
    bb.Add(b);
    b = (byte)ss.ReadByte();
}

I've solved it by the following

FileStream fs = new FileStream("C:\\cygwin\\home\\Dff.rar", FileMode.Create);
byte[] file = new byte[1024 * 1024];
int finishedBytes = ss.Read(file, 0, file.Length);
while (finishedBytes > 0)
{
    fs.Write(file, 0, finishedBytes);
    finishedBytes = ss.Read(file, 0, file.Length);
}
fs.Close();

thanks Jon , Douglas

Answer 1

Your bug lies in the following line:

byte b = (byte)ss.ReadByte();

The byte type is unsigned; when Stream.ReadByte returns -1 at the end of the stream, you’re indiscriminately casting it to byte, which converts it to 255 and, therefore, satisfies the b >= 0 condition. It is helpful to note that the return type is int, not byte, for this very reason.

A quick-and-dirty fix for your code:

List<byte> bb = new List<byte>();
var ss = context.Request.InputStream;
int next = ss.ReadByte();
while (next != -1)
{
    bb.Add((byte)next);
    next = ss.ReadByte();
}

The following solution is more efficient, since it avoids the byte-by-byte reads incurred by the ReadByte calls, and uses a dynamically-expanding byte array for Read calls instead (similar to the way that List<T> is internally implemented):

var ss = context.Request.InputStream;

byte[] buffer = new byte[1024];
int totalCount = 0;

while (true)
{
    int currentCount = ss.Read(buffer, totalCount, buffer.Length - totalCount);
    if (currentCount == 0)
        break;

    totalCount += currentCount;
    if (totalCount == buffer.Length)
        Array.Resize(ref buffer, buffer.Length * 2);
}

Array.Resize(ref buffer, totalCount);

Answer 2

StreamReader cannot get the length either -- it seems there's some confusion regarding the third parameter of Stream.Read. That parameter specifies the maximum number of bytes that will be read, which does not need (and really cannot) be equal to the number of bytes actually available in the stream. You just call Read in a loop until it returns 0, in which case you know you have reached the end of the stream. This is all documented on MSDN, and it's also exactly how StreamReader does it.

There's also no problem in reading the request with StreamReader and getting it into string; strings are binary safe in .NET, so you 're covered. The problem will be making sense of the contents of the string, but we can't really talk about that since you don't provide any relevant information.