from __future__ import (absolute_import, print_function, division) import itertools import time from hpack.hpack import Encoder, Decoder from ... import utils from .. import Headers, Response, Request from hyperframe import frame class TCPHandler(object): def __init__(self, rfile, wfile=None): self.rfile = rfile self.wfile = wfile class HTTP2Protocol(object): ERROR_CODES = utils.BiDi( NO_ERROR=0x0, PROTOCOL_ERROR=0x1, INTERNAL_ERROR=0x2, FLOW_CONTROL_ERROR=0x3, SETTINGS_TIMEOUT=0x4, STREAM_CLOSED=0x5, FRAME_SIZE_ERROR=0x6, REFUSED_STREAM=0x7, CANCEL=0x8, COMPRESSION_ERROR=0x9, CONNECT_ERROR=0xa, ENHANCE_YOUR_CALM=0xb, INADEQUATE_SECURITY=0xc, HTTP_1_1_REQUIRED=0xd ) CLIENT_CONNECTION_PREFACE = b'PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n' HTTP2_DEFAULT_SETTINGS = { frame.SettingsFrame.HEADER_TABLE_SIZE: 4096, frame.SettingsFrame.ENABLE_PUSH: 1, frame.SettingsFrame.MAX_CONCURRENT_STREAMS: None, frame.SettingsFrame.INITIAL_WINDOW_SIZE: 2 ** 16 - 1, frame.SettingsFrame.MAX_FRAME_SIZE: 2 ** 14, frame.SettingsFrame.MAX_HEADER_LIST_SIZE: None, } def __init__( self, tcp_handler=None, rfile=None, wfile=None, is_server=False, dump_frames=False, encoder=None, decoder=None, unhandled_frame_cb=None, ): self.tcp_handler = tcp_handler or TCPHandler(rfile, wfile) self.is_server = is_server self.dump_frames = dump_frames self.encoder = encoder or Encoder() self.decoder = decoder or Decoder() self.unhandled_frame_cb = unhandled_frame_cb self.http2_settings = self.HTTP2_DEFAULT_SETTINGS.copy() self.current_stream_id = None self.connection_preface_performed = False def read_request( self, __rfile, include_body=True, body_size_limit=None, allow_empty=False, ): if body_size_limit is not None: raise NotImplementedError() self.perform_connection_preface() timestamp_start = time.time() if hasattr(self.tcp_handler.rfile, "reset_timestamps"): self.tcp_handler.rfile.reset_timestamps() stream_id, headers, body = self._receive_transmission( include_body=include_body, ) if hasattr(self.tcp_handler.rfile, "first_byte_timestamp"): # more accurate timestamp_start timestamp_start = self.tcp_handler.rfile.first_byte_timestamp timestamp_end = time.time() authority = headers.get(':authority', b'') method = headers.get(':method', 'GET') scheme = headers.get(':scheme', 'https') path = headers.get(':path', '/') host = None port = None if path == '*' or path.startswith("/"): form_in = "relative" elif method == 'CONNECT': form_in = "authority" if ":" in authority: host, port = authority.split(":", 1) else: host = authority else: form_in = "absolute" # FIXME: verify if path or :host contains what we need scheme, host, port, _ = utils.parse_url(path) scheme = scheme.decode('ascii') host = host.decode('ascii') if host is None: host = 'localhost' if port is None: port = 80 if scheme == 'http' else 443 port = int(port) request = Request( form_in, method.encode('ascii'), scheme.encode('ascii'), host.encode('ascii'), port, path.encode('ascii'), b"HTTP/2.0", headers, body, timestamp_start, timestamp_end, ) request.stream_id = stream_id return request def read_response( self, __rfile, request_method=b'', body_size_limit=None, include_body=True, stream_id=None, ): if body_size_limit is not None: raise NotImplementedError() self.perform_connection_preface() timestamp_start = time.time() if hasattr(self.tcp_handler.rfile, "reset_timestamps"): self.tcp_handler.rfile.reset_timestamps() stream_id, headers, body = self._receive_transmission( stream_id=stream_id, include_body=include_body, ) if hasattr(self.tcp_handler.rfile, "first_byte_timestamp"): # more accurate timestamp_start timestamp_start = self.tcp_handler.rfile.first_byte_timestamp if include_body: timestamp_end = time.time() else: timestamp_end = None response = Response( b"HTTP/2.0", int(headers.get(':status', 502)), b'', headers, body, timestamp_start=timestamp_start, timestamp_end=timestamp_end, ) response.stream_id = stream_id return response def assemble(self, message): if isinstance(message, Request): return self.assemble_request(message) elif isinstance(message, Response): return self.assemble_response(message) else: raise ValueError("HTTP message not supported.") def assemble_request(self, request): assert isinstance(request, Request) authority = self.tcp_handler.sni if self.tcp_handler.sni else self.tcp_handler.address.host if self.tcp_handler.address.port != 443: authority += ":%d" % self.tcp_handler.address.port headers = request.headers.copy() if ':authority' not in headers: headers.fields.insert(0, (b':authority', authority.encode('ascii'))) if ':scheme' not in headers: headers.fields.insert(0, (b':scheme', request.scheme.encode('ascii'))) if ':path' not in headers: headers.fields.insert(0, (b':path', request.path.encode('ascii'))) if ':method' not in headers: headers.fields.insert(0, (b':method', request.method.encode('ascii'))) if hasattr(request, 'stream_id'): stream_id = request.stream_id else: stream_id = self._next_stream_id() return list(itertools.chain( self._create_headers(headers, stream_id, end_stream=(request.body is None or len(request.body) == 0)), self._create_body(request.body, stream_id))) def assemble_response(self, response): assert isinstance(response, Response) headers = response.headers.copy() if ':status' not in headers: headers.fields.insert(0, (b':status', str(response.status_code).encode('ascii'))) if hasattr(response, 'stream_id'): stream_id = response.stream_id else: stream_id = self._next_stream_id() return list(itertools.chain( self._create_headers(headers, stream_id, end_stream=(response.body is None or len(response.body) == 0)), self._create_body(response.body, stream_id), )) def perform_connection_preface(self, force=False): if force or not self.connection_preface_performed: if self.is_server: self.perform_server_connection_preface(force) else: self.perform_client_connection_preface(force) def perform_server_connection_preface(self, force=False): if force or not self.connection_preface_performed: self.connection_preface_performed = True magic_length = len(self.CLIENT_CONNECTION_PREFACE) magic = self.tcp_handler.rfile.safe_read(magic_length) assert magic == self.CLIENT_CONNECTION_PREFACE frm = frame.SettingsFrame(settings={ frame.SettingsFrame.ENABLE_PUSH: 0, frame.SettingsFrame.MAX_CONCURRENT_STREAMS: 1, }) self.send_frame(frm, hide=True) self._receive_settings(hide=True) def perform_client_connection_preface(self, force=False): if force or not self.connection_preface_performed: self.connection_preface_performed = True self.tcp_handler.wfile.write(self.CLIENT_CONNECTION_PREFACE) self.send_frame(frame.SettingsFrame(), hide=True) self._receive_settings(hide=True) # server announces own settings self._receive_settings(hide=True) # server acks my settings def send_frame(self, frm, hide=False): raw_bytes = frm.serialize() self.tcp_handler.wfile.write(raw_bytes) self.tcp_handler.wfile.flush() if not hide and self.dump_frames: # pragma no cover print(frm.human_readable(">>")) def read_frame(self, hide=False): while True: frm = utils.http2_read_frame(self.tcp_handler.rfile) if not hide and self.dump_frames: # pragma no cover print(frm.human_readable("<<")) if isinstance(frm, frame.PingFrame): raw_bytes = frame.PingFrame(flags=['ACK'], payload=frm.payload).serialize() self.tcp_handler.wfile.write(raw_bytes) self.tcp_handler.wfile.flush() continue if isinstance(frm, frame.SettingsFrame) and 'ACK' not in frm.flags: self._apply_settings(frm.settings, hide) if isinstance(frm, frame.DataFrame) and frm.flow_controlled_length > 0: self._update_flow_control_window(frm.stream_id, frm.flow_controlled_length) return frm def check_alpn(self): alp = self.tcp_handler.get_alpn_proto_negotiated() if alp != b'h2': raise NotImplementedError( "HTTP2Protocol can not handle unknown ALP: %s" % alp) return True def _handle_unexpected_frame(self, frm): if isinstance(frm, frame.SettingsFrame): return if self.unhandled_frame_cb: self.unhandled_frame_cb(frm) def _receive_settings(self, hide=False): while True: frm = self.read_frame(hide) if isinstance(frm, frame.SettingsFrame): break else: self._handle_unexpected_frame(frm) def _next_stream_id(self): if self.current_stream_id is None: if self.is_server: # servers must use even stream ids self.current_stream_id = 2 else: # clients must use odd stream ids self.current_stream_id = 1 else: self.current_stream_id += 2 return self.current_stream_id def _apply_settings(self, settings, hide=False): for setting, value in settings.items(): old_value = self.http2_settings[setting] if not old_value: old_value = '-' self.http2_settings[setting] = value frm = frame.SettingsFrame(flags=['ACK']) self.send_frame(frm, hide) def _update_flow_control_window(self, stream_id, increment): frm = frame.WindowUpdateFrame(stream_id=0, window_increment=increment) self.send_frame(frm) frm = frame.WindowUpdateFrame(stream_id=stream_id, window_increment=increment) self.send_frame(frm) def _create_headers(self, headers, stream_id, end_stream=True): def frame_cls(chunks): for i in chunks: if i == 0: yield frame.HeadersFrame, i else: yield frame.ContinuationFrame, i header_block_fragment = self.encoder.encode(headers.fields) chunk_size = self.http2_settings[frame.SettingsFrame.MAX_FRAME_SIZE] chunks = range(0, len(header_block_fragment), chunk_size) frms = [frm_cls( flags=[], stream_id=stream_id, data=header_block_fragment[i:i+chunk_size]) for frm_cls, i in frame_cls(chunks)] frms[-1].flags.add('END_HEADERS') if end_stream: frms[0].flags.add('END_STREAM') if self.dump_frames: # pragma no cover for frm in frms: print(frm.human_readable(">>")) return [frm.serialize() for frm in frms] def _create_body(self, body, stream_id): if body is None or len(body) == 0: return b'' chunk_size = self.http2_settings[frame.SettingsFrame.MAX_FRAME_SIZE] chunks = range(0, len(body), chunk_size) frms = [frame.DataFrame( flags=[], stream_id=stream_id, data=body[i:i+chunk_size]) for i in chunks] frms[-1].flags.add('END_STREAM') if self.dump_frames: # pragma no cover for frm in frms: print(frm.human_readable(">>")) return [frm.serialize() for frm in frms] def _receive_transmission(self, stream_id=None, include_body=True): if not include_body: raise NotImplementedError() body_expected = True header_blocks = b'' body = b'' while True: frm = self.read_frame() if ( (isinstance(frm, frame.HeadersFrame) or isinstance(frm, frame.ContinuationFrame)) and (stream_id is None or frm.stream_id == stream_id) ): stream_id = frm.stream_id header_blocks += frm.data if 'END_STREAM' in frm.flags: body_expected = False if 'END_HEADERS' in frm.flags: break else: self._handle_unexpected_frame(frm) while body_expected: frm = self.read_frame() if isinstance(frm, frame.DataFrame) and frm.stream_id == stream_id: body += frm.data if 'END_STREAM' in frm.flags: break else: self._handle_unexpected_frame(frm) headers = Headers( [[k.encode('ascii'), v.encode('ascii')] for k, v in self.decoder.decode(header_blocks)] ) return stream_id, headers, body