Mercurial Repository: p/roundup/code: roundup/rest.py comparison

comparison roundup/rest.py @ 7605:5b3ecdfd77f7

refactor(api): extract api rate limit handling; add default val Add handle_apiRateLimitExceeded to simplify dispatch() method. Add default value for pretty_print=True to format_dispatch_output.

author	John Rouillard <rouilj@ieee.org>
date	Wed, 16 Aug 2023 13:35:25 -0400
parents	86ad72b3a258
children	b04e222501b8

comparison

equal deleted inserted replaced

-:d117ddcb0ed1
+:5b3ecdfd77f7
 return RateLimit(calls, timedelta(seconds=interval))
 else:
 # disable rate limiting if either parameter is 0
 return None
+def handle_apiRateLimitExceeded(self, apiRateLimit):
+"""Determine if the rate limit is exceeded.
+If not exceeded, return False and the rate limit header values.
+If exceeded, return error message and None
+"""
+gcra = Gcra()
+# unique key is an "ApiLimit-" prefix and the uid)
+apiLimitKey = "ApiLimit-%s" % self.db.getuid()
+otk = self.db.Otk
+try:
+val = otk.getall(apiLimitKey)
+gcra.set_tat_as_string(apiLimitKey, val['tat'])
+except KeyError:
+# ignore if tat not set, it's 1970-1-1 by default.
+pass
+# see if rate limit exceeded and we need to reject the attempt
+reject = gcra.update(apiLimitKey, apiRateLimit)
+# Calculate a timestamp that will make OTK expire the
+# unused entry 1 hour in the future
+ts = otk.lifetime(3600)
+otk.set(apiLimitKey,
+tat=gcra.get_tat_as_string(apiLimitKey),
+__timestamp=ts)
+otk.commit()
+limitStatus = gcra.status(apiLimitKey, apiRateLimit)
+if not reject:
+return (False, limitStatus)
+for header, value in limitStatus.items():
+self.client.setHeader(header, value)
+# User exceeded limits: tell humans how long to wait
+# Headers above will do the right thing for api
+# aware clients.
+try:
+retry_after = limitStatus['Retry-After']
+except KeyError:
+# handle race condition. If the time between
+# the call to grca.update and grca.status
+# is sufficient to reload the bucket by 1
+# item, Retry-After will be missing from
+# limitStatus. So report a 1 second delay back
+# to the client. We treat update as sole
+# source of truth for exceeded rate limits.
+retry_after = '1'
+self.client.setHeader('Retry-After', retry_after)
+msg = _("Api rate limits exceeded. Please wait: %s seconds.") % retry_after
+output = self.error_obj(429, msg, source="ApiRateLimiter")
+# expose these headers to rest clients. Otherwise they can't
+# respond to:
+#   rate limiting (*RateLimit*, Retry-After)
+#   obsolete API endpoint (Sunset)
+#   options request to discover supported methods (Allow)
+self.client.setHeader(
+"Access-Control-Expose-Headers",
+", ".join([
+"X-RateLimit-Limit",
+"X-RateLimit-Remaining",
+"X-RateLimit-Reset",
+"X-RateLimit-Limit-Period",
+"Retry-After",
+"Sunset",
+"Allow",
+])
+)
+return (self.format_dispatch_output(
+self.__default_accept_type,
+output,
+True  # pretty print for this error case as a
+# human may read it
+), None)
 def dispatch(self, method, uri, input):
 """format and process the request"""
 output = None
 # Before we do anything has the user hit the rate limit.
 # Get the limit here and not in the init() routine to allow
 # for a different rate limit per user.
 apiRateLimit = self.getRateLimit()
 if apiRateLimit:  # if None, disable rate limiting
-gcra = Gcra()
+LimitExceeded, limitStatus = self.handle_apiRateLimitExceeded(
-# unique key is an "ApiLimit-" prefix and the uid)
+apiRateLimit)
-apiLimitKey = "ApiLimit-%s" % self.db.getuid()
+if LimitExceeded:
-otk = self.db.Otk
+return LimitExceeded  # error message
-try:
-val = otk.getall(apiLimitKey)
-gcra.set_tat_as_string(apiLimitKey, val['tat'])
-except KeyError:
-# ignore if tat not set, it's 1970-1-1 by default.
-pass
-# see if rate limit exceeded and we need to reject the attempt
-reject = gcra.update(apiLimitKey, apiRateLimit)
-# Calculate a timestamp that will make OTK expire the
-# unused entry 1 hour in the future
-ts = otk.lifetime(3600)
-otk.set(apiLimitKey,
-tat=gcra.get_tat_as_string(apiLimitKey),
-__timestamp=ts)
-otk.commit()
-limitStatus = gcra.status(apiLimitKey, apiRateLimit)
-if reject:
-for header, value in limitStatus.items():
-self.client.setHeader(header, value)
-# User exceeded limits: tell humans how long to wait
-# Headers above will do the right thing for api
-# aware clients.
-try:
-retry_after = limitStatus['Retry-After']
-except KeyError:
-# handle race condition. If the time between
-# the call to grca.update and grca.status
-# is sufficient to reload the bucket by 1
-# item, Retry-After will be missing from
-# limitStatus. So report a 1 second delay back
-# to the client. We treat update as sole
-# source of truth for exceeded rate limits.
-retry_after = '1'
-self.client.setHeader('Retry-After', retry_after)
-msg = _("Api rate limits exceeded. Please wait: %s seconds.") % retry_after
-output = self.error_obj(429, msg, source="ApiRateLimiter")
-# expose these headers to rest clients. Otherwise they can't
-# respond to:
-#   rate limiting (*RateLimit*, Retry-After)
-#   obsolete API endpoint (Sunset)
-#   options request to discover supported methods (Allow)
-self.client.setHeader(
-"Access-Control-Expose-Headers",
-", ".join([
-"X-RateLimit-Limit",
-"X-RateLimit-Remaining",
-"X-RateLimit-Reset",
-"X-RateLimit-Limit-Period",
-"Retry-After",
-"Sunset",
-"Allow",
-])
-)
-return self.format_dispatch_output(
-self.__default_accept_type,
-output,
-True  # pretty print for this error case as a
-# human may read it
-)
 for header, value in limitStatus.items():
 # Retry-After will be 0 because
 # user still has quota available.
 # Don't put out the header.
 output = self.error_obj(405, msg.args[0])
 self.client.setHeader("Allow", msg.args[1])
 return self.format_dispatch_output(data_type, output, pretty_output)
-def format_dispatch_output(self, accept_mime_type, output, pretty_print):
+def format_dispatch_output(self, accept_mime_type, output,
+pretty_print=True):
 # Format the content type
 if accept_mime_type.lower() == "json":
 self.client.setHeader("Content-Type", "application/json")
 if pretty_print:
 indent = 4

Mercurial > p > roundup > code

comparison roundup/rest.py @ 7605:5b3ecdfd77f7