I am trying to get the body of a request in an ASP.NET Core controller as a byte[] array. Here is what I initially wrote:
var declaredLength = (int)request.ContentLength;
byte[] fileBuffer = new byte[declaredLength];
request.Body.Read(fileBuffer, 0, declaredLength);
This code works, but only for small requests (around ~20KB). For larger requests it fills up the first 20,000 or so bytes in the array, then the rest of the array is empty.
I used some code in the top answer here, and was able to read the entire request body successfully after rewriting my code:
var declaredLength = (int)request.ContentLength;
byte[] fileBuffer = new byte[declaredLength];
// need to enable, otherwise Seek() fails
request.EnableRewind();
// using StreamReader apparently resolves the issue
using (var reader = new StreamReader(request.Body, Encoding.UTF8, true, 1024, true))
{
reader.ReadToEnd();
}
request.Body.Seek(0, SeekOrigin.Begin);
request.Body.Read(fileBuffer, 0, declaredLength);
Why is StreamReader.ReadToEnd() able to read the entire request body successfully, while Stream.Read() can't? Reading the request stream twice feels like a hack. Is there a better way to go about this? (I only need to read the stream into a byte array once)
Remember that you're trying to read request.Body before all of the request has been received yet.
Stream.Read behaves like this:
0As you can see, if the whole body hasn't been received yet, request.Body.Read(...) will just return the part of the body that has been received.
StreamReader.ReadToEnd() calls Stream.Read in a loop, until it finds the end of the stream.
You should probably call Stream.Read in a loop as well, until you've read all of the bytes:
byte[] fileBuffer = new byte[declaredLength];
int numBytesRead = 0;
while (numBytesRead < declaredLength)
{
int readBytes = request.Body.Read(fileBuffer, numBytesRead, declaredLength - numBytesRead);
if (readBytes == 0)
{
// We reached the end of the stream before we were expecting it
// Might want to throw an exception here?
}
numBytesRead += readBytes;
}
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