REST: Add key lookup

E.g. /data/status/open or /data/status/name=open
Also update documentation and tests

Author: schlatterbeck

doc/rest.txt

@@ -97,6 +97,17 @@ link for the file or message. If @verbose is >= 3, the content property
 is shown in json as a (possibly very long) string. Currently the json
 serializer cannot handle files not properly utf-8 encoded, so specifying
 @verbose=3 for files is currently discouraged.
+Note that if the class has a key attribute (like e.g., the 'status'
+class in the classic tracker), you can get an individual status by
+specifying the key-attribute e.g. ``/data/status/name=closed``. Note
+that ``name`` in this example must be the key-attribute of the class.
+A short-form (which might no longer be supported in future version of
+the API) is to specify only the value, e.g. ``/data/status/closed``.
+This short-form only works when you're sure that the key of the class is
+not numeric.
+The long-form (with ``=``) is different from a query-parameter like
+``/data/status?@name=closed`` which would find all stati that have
+``closed`` as a substring.
 
 A ``GET`` method on a property (e.g. ``/data/issue/42/title``) returns the
 link, an ``@etag``, the type of the property (e.g. "<type str>") the id

roundup/rest.py

@@ -605,6 +605,8 @@ def get_element(self, class_name, item_id, input):
         Args:
             class_name (string): class name of the resource (Ex: issue, msg)
             item_id (string): id of the resource (Ex: 12, 15)
+                or (if the class has a key property) this can also be
+                the key name, e.g. class_name = status, item_id = 'open'
             input (list): the submitted form of the user
 
         Returns:
@@ -617,16 +619,37 @@ def get_element(self, class_name, item_id, input):
         """
         if class_name not in self.db.classes:
             raise NotFound('Class %s not found' % class_name)
+        class_obj = self.db.getclass(class_name)
+        uid = self.db.getuid()
+        # If it's not numeric it is a key
+        if item_id.isdigit():
+            id = item_id
+        else:
+            keyprop = class_obj.getkey()
+            try:
+                k, v = item_id.split('=', 1)
+                if k != keyprop:
+                    raise UsageError ("Not key property")
+            except ValueError:
+                v = item_id
+                pass
+            if not self.db.security.hasPermission(
+                'View', uid, class_name, itemid=item_id, property=keyprop
+            ):
+                raise Unauthorised(
+                    'Permission to view %s%s.%s denied'
+                    % (class_name, item_id, keyprop)
+                )
+            id = class_obj.lookup(v)
         if not self.db.security.hasPermission(
-            'View', self.db.getuid(), class_name, itemid=item_id
+            'View', uid, class_name, itemid=id
         ):
             raise Unauthorised(
-                'Permission to view %s%s denied' % (class_name, item_id)
+                'Permission to view %s%s denied' % (class_name, id)
             )
 
-        class_obj = self.db.getclass(class_name)
-        node = class_obj.getnode(item_id)
-        etag = calculate_etag(node, class_name, item_id)
+        node = class_obj.getnode(id)
+        etag = calculate_etag(node, class_name, id)
         props = None
         protected=False
         verbose=1
@@ -651,7 +674,7 @@ def get_element(self, class_name, item_id, input):
             for pn in sorted(props):
                 prop = props[pn]
                 if not self.db.security.hasPermission(
-                    'View', uid, class_name, pn, item_id
+                    'View', uid, class_name, pn, id
                 ):
                     continue
                 v = getattr(node, pn)
@@ -690,7 +713,7 @@ def get_element(self, class_name, item_id, input):
         except KeyError as msg:
             raise UsageError("%s field not valid" % msg)
         result = {
-            'id': item_id,
+            'id': id,
             'type': class_name,
             'link': '%s/%s/%s' % (self.data_path, class_name, item_id),
             'attributes': dict(result),

test/rest_common.py

@@ -116,6 +116,21 @@ def testGet(self):
         self.assertEqual(results['attributes']['username'], 'joe')
         self.assertEqual(results['attributes']['realname'], 'Joe Random')
 
+        # Obtain data for 'joe' via username lookup.
+        results = self.server.get_element('user', 'joe', self.empty_form)
+        results = results['data']
+        self.assertEqual(self.dummy_client.response_code, 200)
+        self.assertEqual(results['attributes']['username'], 'joe')
+        self.assertEqual(results['attributes']['realname'], 'Joe Random')
+
+        # Obtain data for 'joe' via username lookup (long form).
+        key = 'username=joe'
+        results = self.server.get_element('user', key, self.empty_form)
+        results = results['data']
+        self.assertEqual(self.dummy_client.response_code, 200)
+        self.assertEqual(results['attributes']['username'], 'joe')
+        self.assertEqual(results['attributes']['realname'], 'Joe Random')
+
         # Obtain data for 'joe'.
         results = self.server.get_attribute(
             'user', self.joeid, 'username', self.empty_form