X-Git-Url: https://git.kaliko.me/?a=blobdiff_plain;f=sima%2Flib%2Fhttp.py;h=0c1b3968d90ce31bfcb13fbadd4c948c22d2289a;hb=7d24f8a6f0bb74de07c3e6d333a2948d9186be1b;hp=1040c2a98f949daae3a9e15261136b3e77a0df6a;hpb=71500abd7ef16784d027a8a20aa28b06e8a13a4f;p=mpd-sima.git

diff --git a/sima/lib/http.py b/sima/lib/http.py
index 1040c2a..0c1b396 100644
--- a/sima/lib/http.py
+++ b/sima/lib/http.py
@@ -26,6 +26,10 @@ import time
 
 import email.utils
 
+from requests import Session, Request, Timeout, ConnectionError
+
+from sima import SOCKET_TIMEOUT, WAIT_BETWEEN_REQUESTS
+from sima.utils.utils import WSError, WSTimeout, WSHTTPError, Throttle
 from .cache import DictCache
 
 
@@ -88,11 +92,11 @@ class CacheController(object):
             retval = dict(parts_with_args + parts_wo_args)
         return retval
 
-    def cached_request(self, url, headers):
+    def cached_request(self, request):
         """Return the cached resquest if available and fresh
         """
-        cache_url = self.cache_url(url)
-        cc = self.parse_cache_control(headers)
+        cache_url = self.cache_url(request.url)
+        cc = self.parse_cache_control(request.headers)
 
         # non-caching states
         no_cache = True if 'no-cache' in cc else False
@@ -125,7 +129,7 @@ class CacheController(object):
             for header in varied_headers:
                 # If our headers don't match for the headers listed in
                 # the vary header, then don't use the cached response
-                if headers.get(header, None) != original_headers.get(header):
+                if request.headers.get(header, None) != original_headers.get(header):
                     return False
 
         now = time.time()
@@ -173,11 +177,25 @@ class CacheController(object):
             resp.from_cache = True
             return resp
 
-        # we're not fresh.
-        self.cache.delete(cache_url)
+        # we're not fresh. If we don't have an Etag, clear it out
+        if 'etag' not in resp.headers:
+            self.cache.delete(cache_url)
+
+        if 'etag' in resp.headers:
+            request.headers['If-None-Match'] = resp.headers['ETag']
+
+        if 'last-modified' in resp.headers:
+            request.headers['If-Modified-Since'] = resp.headers['Last-Modified']
+
         # return the original handler
         return False
 
+    def add_headers(self, url):
+        resp = self.cache.get(url)
+        if resp and 'etag' in resp.headers:
+            return {'If-None-Match': resp.headers['etag']}
+        return {}
+
     def cache_response(self, request, resp):
         """
         Algorithm for caching requests.
@@ -199,10 +217,14 @@ class CacheController(object):
         if no_store and self.cache.get(cache_url):
             self.cache.delete(cache_url)
 
+        # If we've been given an etag, then keep the response
+        if self.cache_etags and 'etag' in resp.headers:
+            self.cache.set(cache_url, resp)
+
         # Add to the cache if the response headers demand it. If there
         # is no date header then we can't do anything about expiring
         # the cache.
-        if 'date' in resp.headers:
+        elif 'date' in resp.headers:
             # cache when there is a max-age > 0
             if cc_resp and cc_resp.get('max-age'):
                 if int(cc_resp['max-age']) > 0:
@@ -213,3 +235,84 @@ class CacheController(object):
             elif 'expires' in resp.headers:
                 if resp.headers['expires']:
                     self.cache.set(cache_url, resp)
+
+    def update_cached_response(self, request, response):
+        """On a 304 we will get a new set of headers that we want to
+        update our cached value with, assuming we have one.
+
+        This should only ever be called when we've sent an ETag and
+        gotten a 304 as the response.
+        """
+        cache_url = self.cache_url(request.url)
+
+        resp = self.cache.get(cache_url)
+
+        if not resp:
+            # we didn't have a cached response
+            return response
+
+        # did so lets update our headers
+        resp.headers.update(response.headers)
+
+        # we want a 200 b/c we have content via the cache
+        request.status_code = 200
+
+        # update the request as it has the if-none-match header + any
+        # other headers that the server might have updated (ie Date,
+        # Cache-Control, Expires, etc.)
+        resp.request = request
+
+        # update our cache
+        self.cache.set(cache_url, resp)
+
+        # Let everyone know this was from the cache.
+        resp.from_cache = True
+
+        return resp
+
+
+class HttpClient:
+    def __init__(self, cache=None, stats=None):
+        """
+        Prepare http request
+        Use cached elements or proceed http request
+        """
+        self.stats = stats
+        self.controller = CacheController(cache)
+
+    def __call__(self, ress, payload):
+        req = Request('GET', ress, params=payload,).prepare()
+        if self.stats:
+            self.stats.update(total=self.stats.get('total')+1)
+        cached_response = self.controller.cached_request(req)
+        if cached_response:
+            if self.stats:
+                self.stats.update(ccontrol=self.stats.get('ccontrol')+1)
+            return cached_response
+        try:
+            return self.fetch_ws(req)
+        except Timeout:
+            raise WSTimeout('Failed to reach server within {0}s'.format(
+                SOCKET_TIMEOUT))
+        except ConnectionError as err:
+            raise WSError(err)
+
+    @Throttle(WAIT_BETWEEN_REQUESTS)
+    def fetch_ws(self, prepreq):
+        """fetch from web service"""
+        sess = Session()
+        resp = sess.send(prepreq, timeout=SOCKET_TIMEOUT)
+        if resp.status_code == 304:
+            self.stats.update(etag=self.stats.get('etag')+1)
+            resp = self.controller.update_cached_response(prepreq, resp)
+        elif resp.status_code != 200:
+            raise WSHTTPError('{0.status_code}: {0.reason}'.format(resp))
+        ratelimit = resp.headers.get('x-ratelimit-remaining', None)
+        if ratelimit and self.stats:
+            minrl = min(int(ratelimit), self.stats.get('minrl'))
+            self.stats.update(minrl=minrl)
+        self.controller.cache_response(resp.request, resp)
+        return resp
+
+# VIM MODLINE
+# vim: ai ts=4 sw=4 sts=4 expandtab