Question

Am testing with a client who send me a HTTP request with no content length header but has a content.

How do I extract this content without the help of contentlength header?

Answer 1

I’ve kept the original answer for completeness, but I’ve just been looking in the HTTP RFC (2616) section 4.3:

The presence of a message-body in a request is signaled by the inclusion of a Content-Length or Transfer-Encoding header field in the request’s message-headers. A message-body MUST NOT be included in a request if the specification of the request method (section 5.1.1) does not allow sending an entity-body in requests. A server SHOULD read and forward a message-body on any request; if the request method does not include defined semantics for an entity-body, then the message-body SHOULD be ignored when handling the request.

So if you haven’t got a content length, you must have a Transfer-Encoding (and if you haven’t, you should respond with a 400 status to indicate a bad request or 411 (“length required”)). At that point, you do what the Transfer-Encoding tells you 🙂

Now if you’re dealing with a servlet API (or a similar HTTP API) it may well handle all this for you – at which point you may be able to use the techique below to read from the stream until it yields no more data, as the API will take care of it (i.e. it won’t just be a raw socket stream).

If you could give us more information about your context, that would help.

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Original answer

If there’s no content length, that means the content continues until the end of the data (when the socket closes).

Keep reading from the input stream (e.g. writing it to a ByteArrayOutputStream to store it, or possibly a file) until InputStream.read returns -1. For example:

byte[] buffer = new byte[8192];
ByteArrayOutputStream output = new ByteArrayOutputStream();
int bytesRead;
while ((bytesRead = inputStream.read(buffer)) != -1)
{
    output.write(buffer, 0, bytesRead);
}
// Now use the data in "output"

EDIT: As has been pointed out in comments, the client could be using a chunked encoding. Normally the HTTP API you’re using should deal with this for you, but if you’re dealing with a raw socket you’d have to handle it yourself.

The point about this being a request (and therefore the client not being able to close the connection) is an interesting one – I thought the client could just shut down the sending part, but I don’t see how that maps to anything in TCP at the moment. My low-level networking knowledge isn’t what it might be.

If this answer turns out to be “definitely useless” I’ll delete it…