class RedFetcher(RedState):
"""
Fetches the given URI (with the provided method, headers and body) and
calls:
- status_cb as it progresses, and
- every function in the body_procs list with each chunk of the body, and
- done_cb when all tasks are done.
If provided, type indicates the type of the request, and is used to
help set notes and status_cb appropriately.
The done() method is called when the response is done, NOT when all
tasks are done. It can add tasks by calling add_task().
"""
client = RedHttpClient()
def __init__(self, iri, method="GET", req_hdrs=None, req_body=None,
status_cb=None, body_procs=None, name=None):
RedState.__init__(self, name)
self.request = HttpRequest(self.notes, self.name)
self.request.method = method
self.request.set_iri(iri)
self.request.headers = req_hdrs or []
self.request.payload = req_body
self.response = HttpResponse(self.notes, self.name)
self.response.is_head_response = (method == "HEAD")
self.response.base_uri = self.request.uri
self.response.set_decoded_procs(body_procs or [])
self.exchange = None
self.status_cb = status_cb
self.done_cb = None
self.outstanding_tasks = 0
self._st = [] # FIXME: this is temporary, for debugging thor
def __getstate__(self):
state = self.__dict__.copy()
del state['exchange']
del state['status_cb']
del state['done_cb']
return state
def add_task(self, task, *args):
"Remeber that we've started a task."
self.outstanding_tasks += 1
self._st.append('add_task(%s)' % str(task))
task(*args, done_cb=self.finish_task)
def finish_task(self):
"Note that we've finished a task, and see if we're done."
self.outstanding_tasks -= 1
self._st.append('finish_task()')
assert self.outstanding_tasks >= 0, self._st
if self.outstanding_tasks == 0:
if self.done_cb:
self.done_cb()
self.done_cb = None
# clean up potentially cyclic references
self.status_cb = None
def done(self):
"Callback for when the response is complete and analysed."
raise NotImplementedError
def preflight(self):
"""
Callback to check to see if we should bother running. Return True
if so; False if not.
"""
return True
def run(self, done_cb=None):
"""
Make an asynchronous HTTP request to uri, calling status_cb as it's
updated and done_cb when it's done. Reason is used to explain what the
request is in the status callback.
"""
self.outstanding_tasks += 1
self._st.append('run(%s)' % str(done_cb))
self.done_cb = done_cb
if not self.preflight() or self.request.uri == None:
# generally a good sign that we're not going much further.
self.finish_task()
return
if 'user-agent' not in [i[0].lower() for i in self.request.headers]:
self.request.headers.append(
(u"User-Agent", u"RED/%s (http://redbot.org/)" % __version__))
self.exchange = self.client.exchange()
self.exchange.on('response_start', self._response_start)
self.exchange.on('response_body', self._response_body)
self.exchange.on('response_done', self._response_done)
self.exchange.on('error', self._response_error)
if self.status_cb and self.name:
self.status_cb("fetching %s (%s)" % (
self.request.uri, self.name
))
req_hdrs = [
(k.encode('ascii', 'replace'), v.encode('latin-1', 'replace')) \
for (k, v) in self.request.headers
]
self.exchange.request_start(
self.request.method, self.request.uri, req_hdrs
)
self.request.start_time = thor.time()
if self.request.payload != None:
self.exchange.request_body(self.request.payload)
self.exchange.request_done([])
def _response_start(self, status, phrase, res_headers):
"Process the response start-line and headers."
self._st.append('_response_start(%s, %s)' % (status, phrase))
self.response.start_time = thor.time()
self.response.version = self.exchange.res_version
self.response.status_code = status.decode('iso-8859-1', 'replace')
self.response.status_phrase = phrase.decode('iso-8859-1', 'replace')
self.response.set_headers(res_headers)
StatusChecker(self.response, self.request)
checkCaching(self.response, self.request)
def _response_body(self, chunk):
"Process a chunk of the response body."
self.response.feed_body(chunk)
def _response_done(self, trailers):
"Finish analysing the response, handling any parse errors."
self._st.append('_response_done()')
self.response.complete_time = thor.time()
self.response.transfer_length = self.exchange.input_transfer_length
self.response.header_length = self.exchange.input_header_length
self.response.body_done(True, trailers)
if self.status_cb and self.name:
self.status_cb("fetched %s (%s)" % (
self.request.uri, self.name
))
self.done()
self.finish_task()
def _response_error(self, error):
"Handle an error encountered while fetching the response."
self._st.append('_response_error(%s)' % (str(error)))
self.response.complete_time = thor.time()
self.response.http_error = error
if isinstance(error, httperr.BodyForbiddenError):
self.add_note('header-none', rs.BODY_NOT_ALLOWED)
# elif isinstance(error, httperr.ExtraDataErr):
# res.payload_len += len(err.get('detail', ''))
elif isinstance(error, httperr.ChunkError):
err_msg = error.detail[:20] or ""
self.add_note('header-transfer-encoding', rs.BAD_CHUNK,
chunk_sample=err_msg.encode('string_escape')
)
self.done()
self.finish_task()
class RedFetcher(RedState):
"""
Abstract class for a fetcher.
Fetches the given URI (with the provided method, headers and body) and
calls:
- status_cb as it progresses, and
- every function in the body_procs list with each chunk of the body, and
- done_cb when all tasks are done.
If provided, type indicates the type of the request, and is used to
help set notes and status_cb appropriately.
The done() method is called when the response is done, NOT when all
tasks are done. It can add tasks by calling add_task().
"""
client = RedHttpClient()
robot_files = {} # cache of robots.txt
robot_cache_dir = None
robot_lookups = {}
def __init__(self, iri, method="GET", req_hdrs=None, req_body=None,
status_cb=None, body_procs=None, name=None):
RedState.__init__(self, name)
self.request = HttpRequest(self.notes, self.name)
self.request.method = method
self.request.set_iri(iri)
self.request.headers = req_hdrs or []
self.request.payload = req_body
self.response = HttpResponse(self.notes, self.name)
self.response.is_head_response = (method == "HEAD")
self.response.base_uri = self.request.uri
self.response.set_decoded_procs(body_procs or [])
self.exchange = None
self.status_cb = status_cb
self.done_cb = None # really should be "all tasks done"
self.outstanding_tasks = 0
self.follow_robots_txt = True # Should we pay attention to robots file?
self._st = [] # FIXME: this is temporary, for debugging thor
def __getstate__(self):
state = self.__dict__.copy()
del state['exchange']
del state['status_cb']
del state['done_cb']
return state
def add_task(self, task, *args):
"Remeber that we've started a task."
self.outstanding_tasks += 1
self._st.append('add_task(%s)' % str(task))
task(*args, done_cb=self.finish_task)
def finish_task(self):
"Note that we've finished a task, and see if we're done."
self.outstanding_tasks -= 1
self._st.append('finish_task()')
assert self.outstanding_tasks >= 0, self._st
if self.outstanding_tasks == 0:
if self.done_cb:
self.done_cb()
self.done_cb = None
# clean up potentially cyclic references
self.status_cb = None
def done(self):
"Callback for when the response is complete and analysed."
raise NotImplementedError
def preflight(self):
"""
Callback to check to see if we should bother running. Return True
if so; False if not.
"""
return True
def fetch_robots_txt(self, url, cb, network=True):
"""
Fetch the robots.txt URL and then feed the response to cb.
If the status code is not 200, send a blank doc back.
If network is False, we won't use the network, will return the result
immediately if cached, and will assume it's OK if we don't have a
cached file.
"""
origin = url_to_origin(self.request.uri)
if origin == None:
cb("")
return ""
origin_hash = hashlib.sha1(origin).hexdigest()
if self.robot_files.has_key(origin):
# FIXME: freshness lifetime
cb(self.robot_files[origin])
return self.robot_files[origin]
if self.robot_cache_dir:
robot_fd = CacheFile(path.join(self.robot_cache_dir, origin_hash))
cached_robots_txt = robot_fd.read()
if cached_robots_txt != None:
cb(cached_robots_txt)
return cached_robots_txt
if not network:
cb("")
return ""
if self.robot_lookups.has_key(origin):
self.robot_lookups[origin].append(cb)
else:
self.robot_lookups[origin] = [cb]
exchange = self.client.exchange()
@thor.on(exchange)
def response_start(status, phrase, headers):
exchange.status = status
exchange.res_body = ""
@thor.on(exchange)
def response_body(chunk):
exchange.res_body += chunk
@thor.on(exchange)
def response_done(trailers):
if not exchange.status.startswith("2"):
robots_txt = ""
else:
robots_txt = exchange.res_body
self.robot_files[origin] = robots_txt
if self.robot_cache_dir:
robot_fd = CacheFile(
path.join(self.robot_cache_dir, origin_hash))
robot_fd.write(robots_txt, 60*30)
for _cb in self.robot_lookups[origin]:
_cb(robots_txt)
del self.robot_lookups[origin]
p_url = urlsplit(url)
robots_url = "%s://%s/robots.txt" % (p_url.scheme, p_url.netloc)
exchange.request_start("GET", robots_url,
[('User-Agent', UA_STRING)])
exchange.request_done([])
def run(self, done_cb=None):
"""
Make an asynchronous HTTP request to uri, calling status_cb as it's
updated and done_cb when it's done. Reason is used to explain what the
request is in the status callback.
"""
self.outstanding_tasks += 1
self._st.append('run(%s)' % str(done_cb))
self.done_cb = done_cb
if not self.preflight() or self.request.uri == None:
# generally a good sign that we're not going much further.
self.finish_task()
return
if self.follow_robots_txt:
self.fetch_robots_txt(self.request.uri, self.run_continue)
else:
self.run_continue("")
def run_continue(self, robots_txt):
"""
Continue after getting the robots file.
TODO: refactor callback style into events.
"""
if robots_txt == "": # empty or non-200
pass
else:
checker = RobotFileParser()
checker.parse(robots_txt.decode('ascii', 'replace').encode('ascii', 'replace').splitlines())
if not checker.can_fetch(UA_STRING, self.request.uri):
self.response.http_error = RobotsTxtError()
self.finish_task()
return # TODO: show error?
if 'user-agent' not in [i[0].lower() for i in self.request.headers]:
self.request.headers.append(
(u"User-Agent", UA_STRING))
self.exchange = self.client.exchange()
self.exchange.on('response_start', self._response_start)
self.exchange.on('response_body', self._response_body)
self.exchange.on('response_done', self._response_done)
self.exchange.on('error', self._response_error)
if self.status_cb and self.name:
self.status_cb("fetching %s (%s)" % (
self.request.uri, self.name
))
req_hdrs = [
(k.encode('ascii', 'replace'), v.encode('latin-1', 'replace')) \
for (k, v) in self.request.headers
]
self.exchange.request_start(
self.request.method, self.request.uri, req_hdrs
)
self.request.start_time = thor.time()
if self.request.payload != None:
self.exchange.request_body(self.request.payload)
self.transfer_out += len(self.request.payload)
self.exchange.request_done([])
def _response_start(self, status, phrase, res_headers):
"Process the response start-line and headers."
self._st.append('_response_start(%s, %s)' % (status, phrase))
self.response.start_time = thor.time()
self.response.version = self.exchange.res_version
self.response.status_code = status.decode('iso-8859-1', 'replace')
self.response.status_phrase = phrase.decode('iso-8859-1', 'replace')
self.response.set_headers(res_headers)
StatusChecker(self.response, self.request)
checkCaching(self.response, self.request)
def _response_body(self, chunk):
"Process a chunk of the response body."
self.transfer_in += len(chunk)
self.response.feed_body(chunk)
def _response_done(self, trailers):
"Finish analysing the response, handling any parse errors."
self._st.append('_response_done()')
self.response.complete_time = thor.time()
self.response.transfer_length = self.exchange.input_transfer_length
self.response.header_length = self.exchange.input_header_length
self.response.body_done(True, trailers)
if self.status_cb and self.name:
self.status_cb("fetched %s (%s)" % (
self.request.uri, self.name
))
self.done()
self.finish_task()
def _response_error(self, error):
"Handle an error encountered while fetching the response."
self._st.append('_response_error(%s)' % (str(error)))
self.response.complete_time = thor.time()
self.response.http_error = error
if isinstance(error, httperr.BodyForbiddenError):
self.add_note('header-none', rs.BODY_NOT_ALLOWED)
# elif isinstance(error, httperr.ExtraDataErr):
# res.payload_len += len(err.get('detail', ''))
elif isinstance(error, httperr.ChunkError):
err_msg = error.detail[:20] or ""
self.add_note('header-transfer-encoding', rs.BAD_CHUNK,
chunk_sample=err_msg.encode('string_escape')
)
self.done()
self.finish_task()