Implement low-level _callAstakos function

This function will handle all requests to Astakos.
On top of this we should build high level wrapper
functions to handle more specific calls/requests
to Astakos. _callAstakos function should log
every single action.

snf-astakos-client/astakosclient/__init__.py

@@ -30,3 +30,77 @@
 # documentation are those of the authors and should not be
 # interpreted as representing official policies, either expressed
 # or implied, of GRNET S.A.
+
+import logging
+import urlparse
+import httplib
+
+import simplejson
+import objpool.http
+
+
+logger = logging.getLogger(__name__)
+
+
+# --------------------------------------------------------------------
+# Private functions
+def _scheme_to_class(scheme):
+    """Return the appropriate httplib class for given scheme"""
+    if scheme == "http":
+        return httplib.HTTPConnection
+    elif scheme == "https":
+        return httplib.HTTPSConnection
+    else:
+        return None
+
+
+def _callAstakos(token, url, headers={}, body=None,
+                 method='GET', use_pool=False):
+    """Make the actual call to astakos service"""
+    logger.debug("Make a %s request to %s with token %s, "
+                 "headers %s and body %s, %s using the pool" %
+                 (method, url, token, headers, body,
+                     "not" if not use_pool else ""))
+
+    # Build request's header and body
+    kwargs = {}
+    kwargs['headers'] = headers
+    kwargs['headers']['X-Auth-Token'] = token
+    if body:
+        kwargs['body'] = body
+        kwargs['headers'].setdefault(
+            'content-type', 'application/octet-stream')
+    kwargs['headers'].setdefault('content-length', len(body) if body else 0)
+
+    # Check for supported scheme
+    p = urlparse.urlparse(url)
+    connection_class = _scheme_to_class(p.scheme)
+    if connection_class is None:
+        m = "Unsupported scheme: %s" % p.scheme
+        logger.error(m)
+        raise ValueError(m)
+
+    # Get connection object
+    if use_pool:
+        conn = objpool.http.get_http_connection(p.netloc, p.scheme)
+    else:
+        conn = connection_class(p.netloc)
+
+    # Send request
+    try:
+        conn.request(method, p.path + '?' + p.query, **kwargs)
+        response = conn.getresponse()
+        length = response.getheader('content-length', None)
+        data = response.read(length)
+        status = int(response.status)
+    except httplib.HTTPException as err:
+        logger.error("Failed to send request: %s" % err)
+        raise
+    finally:
+        conn.close()
+
+    # Return
+    logger.debug("Request returned with status %s" % status)
+    if status < 200 or status >= 300:
+        raise Exception(data, status)
+    return simplejson.loads(unicode(data))

snf-astakos-client/setup.py

@@ -59,7 +59,8 @@ CLASSIFIERS = []
 
 # Package requirements
 INSTALL_REQUIRES = [
-    "objpool"
+    "objpool",
+    "simplejson"
 ]
 
 # Provided as an attribute, so you can append to these instead