Merge lp:~jml/launchpadlib/cred-cache into lp:~launchpad-pqm/launchpadlib/devel

[Jonathan Lange]

[Jonathan Lange (jml)]

This branch is a draft attempt at adding an API to launchpadlib to make it really easy to cache credentials.

Putting it up to get thoughts, happy to revise.

[Jonathan Lange (jml)]

Already implemented in login_with.

review: Disapprove

Unmerged revisions

42. By Jonathan Lange on 2009-05-11

Docstring. Woot.

41. By Jonathan Lange on 2009-05-11

Catch the other kinds of errors that we can get when opening a file.

40. By Jonathan Lange on 2009-05-11

Initial pass at a nicer interface for logging in.

=== modified file 'src/launchpadlib/launchpad.py'
--- src/launchpadlib/launchpad.py	2009-03-23 21:50:35 +0000
+++ src/launchpadlib/launchpad.py	2009-05-11 09:02:22 +0000
@@ -158,6 +158,49 @@
         return cls(credentials, service_root, cache, timeout, proxy_info)
 
     @classmethod
+    def login_from_cache(cls, consumer_name,
+                         service_root=STAGING_SERVICE_ROOT, cache=None,
+                         timeout=None, proxy_info=None):
+        """Use cached credentials if they exist, log in otherwise.
+
+        Looks for cached credentials in a particular file in the 'cache'
+        directory ('creds-<service-host>-<consumer_name>'). If they exist,
+        create a Launchpad instance using those, if not, delegate to
+        `Launchpad.get_token_and_login`.
+
+        Once credentials are established, cache them in the 'cache' in a
+        predictable location, so that this method can acquire them on future
+        invocations.
+
+        :param consumer_name: The consumer name, as appropriate for the
+            `Consumer` constructor
+        :type consumer_name: string
+        :param service_root: The URL to the root of the web service.
+        :type service_root: string
+        :return: The web service root
+        :rtype: `Launchpad`
+        """
+        if cache is None:
+            return cls.get_token_and_login(
+                consumer_name, service_root, cache, timeout, proxy_info)
+        web_root_uri = URI(service_root)
+        credential_name = 'creds-%s-%s' % (web_root_uri.host, consumer_name)
+        credential_path = os.path.join(cache, credential_name)
+        try:
+            credentials = Credentials.load_from_path(credential_path)
+        except (OSError, IOError):
+            launchpad = cls.get_token_and_login(
+                consumer_name, service_root, cache, timeout, proxy_info)
+            launchpad.credentials.save_to_path(credential_path)
+        else:
+            access_key = credentials.access_token.key
+            access_secret = credentials.access_token.secret
+            launchpad = cls.login(
+                consumer_name, access_key, access_secret, service_root,
+                cache, timeout, proxy_info)
+        return launchpad
+
+    @classmethod
     def login_with(cls, consumer_name,
                    service_root=STAGING_SERVICE_ROOT,
                    launchpadlib_dir=None, timeout=None, proxy_info=None):