Finished callback?

[andrew-aladev]

I am using http parser with read_nonblock. I've obtained a timeout or eof exceptions. I was image that on_message_complete is a callback and it will be fired when the request or response has finished. But I was wrong.

it "should abort parser via header complete callback without a body" do
  "GET / HTTP/1.0\r\n" +
  "Content-Length: 0\r\n" +
  "\r\n"
  ...
  expect(@body).to be_empty
  expect(@done).to be false

I have more absurd:

HTTP/1.1 200 Connection established\r\n
Connection: close\r\n
\r\n

The headers has finished but the message hasn't finished. What are you waiting for? Connection has been already closed.

[andrew-aladev]

I am using:

parser.on_headers_complete = method(:on_headers)
parser.on_message_complete = method(:on_complete)
...
def on_headers(headers)
  content_length = headers["Content-Length"]
  complete if content_length.nil? or content_length == 0
end
def on_complete
  completed
end

Is it right?

Hey @andrew-aladev, the semantics of how long the HTTP/1.1 entity body is (and when the message is complete), are bit more complex than that. The tl;dr is the following, and it's valid both for request and response messages. I hope it's helpful.

Transfer-Encoding header

The implicit default for this is identity, which doesn't apply any encoding, and needs out-of-band signaling of the entity body's end. (Out-of-band can mean a Content-Length header, or some signal within the encoding, or within the connection.)

If Transfer-Encoding is chunked, the end is signalled by a zero-length chunk.

If Transfer-Encoding is chunked, there should be no Content-Length header.

Content-Length header

The entity body ends after N bytes, and all following bytes can be disregarded, or parsed as another message. (Think pipelining and keep-alive.)

HEAD response, 204/205 response

These never have an entity body, although they can and should have a Content-Length header. There might be more status codes which affect the entity body semantics. And I'm also not very familiar with the HTTP methods of WebDAV and other extensions.

None of the above

If none of the above apply, the end of the entity body is signalled by closing the connection. This is only really useful for responses from the server to the client.

BTW, I had to look through the code of my old-ish HTTP library, I'm just gonna shamelessly plug it because it might be helpful for you to have a look at: https://github.com/lgierth/httpkit

[andrew-aladev]

I think http_parser.rb will work fine with chunked body. I just want to make sure that some completed method will be called.

def on_headers(headers)
  content_length = headers["Content-Length"]
  transfer_encoding = headers["Transfer-Encoding"]
  complete if transfer_encoding.nil? and (content_length.nil? or content_length == 0)
end