Add basic updates handler support.

mefyl · mefyl · commit 636338714152 · 2015-08-12T13:16:52.000+02:00
diff --git a/couchdb/tests/view.py b/couchdb/tests/view.py
@@ -102,6 +102,57 @@ def test_reduce_empty(self):
         self.assertEqual(output.getvalue(),
                          b'[true, [0]]\n')
 
+    def test_update(self):
+        import json
+        commands = [
+            [
+                'ddoc',
+                'new',
+                '_design/test_update',
+                {
+                    '_id': '_design/test_update',
+                    '_rev': '8-d7379de23a751dc2a19e5638a7bbc5cc',
+                    'language': 'python',
+                    'updates': {
+                        'inc': {
+                            'map': '''\
+def fun(obj, req):
+    if obj is not None:
+        obj['field'] += 1
+    return [obj, {"body": "."}]
+''',
+                        }
+                    }
+                },
+            ],
+            [
+                'ddoc',
+                '_design/test_update',
+                ['updates', 'inc'],
+                [None, {}]
+            ],
+            [
+                'ddoc',
+                '_design/test_update',
+                ['updates', 'inc'],
+                [{'field': 41, 'other_field': 'x'}, {}]
+            ],
+        ]
+        input = StringIO(b'\n'.join(json.dumps(c).encode('utf-8')
+                                    for c in commands))
+        output = StringIO()
+        view.run(input=input, output=output)
+        results = [
+            json.loads(l.decode('utf-8'))
+            for l in output.getvalue().strip().split(b'\n')
+        ]
+        self.assertEqual(len(results), 3)
+        self.assertEqual(results[0], True)
+        self.assertEqual(results[1], ['up', None, {'body': '.'}])
+        self.assertEqual(
+            results[2],
+            ['up', {'field': 42, 'other_field': 'x'}, {'body': '.'}])
+
 
 def suite():
     suite = unittest.TestSuite()
diff --git a/couchdb/view.py b/couchdb/view.py
@@ -23,6 +23,7 @@
 
 log = logging.getLogger('couchdb.view')
 
+ddocs = {}
 
 def run(input=sys.stdin, output=sys.stdout):
     r"""CouchDB view function handler implementation for Python.
@@ -135,8 +136,33 @@ def rereduce(*cmd):
         # Note: weird kwargs is for Python 2.5 compat
         return reduce(*cmd, **{'rereduce': True})
 
-    handlers = {'reset': reset, 'add_fun': add_fun, 'map_doc': map_doc,
-                'reduce': reduce, 'rereduce': rereduce}
+    def ddoc(*cmd):
+        if cmd[0] == 'new':
+            ddoc = cmd[2]
+            ddoc['updates'] = dict(
+                (name, {'map': compile_fun(value['map'])})
+                for name, value in ddoc['updates'].items())
+            ddocs[cmd[1]] = ddoc
+            return True
+        else:
+            ddoc = ddocs[cmd[0]]
+            action = cmd[1]
+            if action[0] == 'updates':
+                fun = ddoc['updates'][action[1]]['map']
+                doc, body = fun(*cmd[2])
+                res = ['up', doc, body]
+                sys.stderr.flush()
+                return res
+
+
+    handlers = {
+        'add_fun': add_fun,
+        'ddoc': ddoc,
+        'map_doc': map_doc,
+        'reduce': reduce,
+        'rereduce': rereduce,
+        'reset': reset,
+    }
 
     try:
         while True:
diff --git a/doc/views.rst b/doc/views.rst
@@ -1,10 +1,11 @@
 Writing views in Python
 =======================
 
-The couchdb-python package comes with a view server to allow you to write
-views in Python instead of JavaScript. When couchdb-python is installed, it
-will install a script called couchpy that runs the view server. To enable
-this for your CouchDB server, add the following section to local.ini::
+The couchdb-python package comes with a query server to allow you to
+write views or update handlers in Python instead of JavaScript. When
+couchdb-python is installed, it will install a script called couchpy
+that runs the view server. To enable this for your CouchDB server, add
+the following section to local.ini::
 
     [query_servers]
     python=/usr/bin/couchpy
@@ -18,3 +19,15 @@ the language pull-down menu. Here's some sample view code to get you started::
 
 Note that the ``map`` function uses the Python ``yield`` keyword to emit
 values, where JavaScript views use an ``emit()`` function.
+
+Here's an example update handler code that will increment the
+``field`` member of an existing document. The name of the ``field`` to
+increment is passed in the query string::
+
+    def fun(obj, req):
+        field = req.query['field']
+        if obj is not None and field in obj:
+            obj[field] += 1
+            return [obj, {"body": "incremented"}]
+        else:
+            return [None, {"body": "no such document or field"}]
