Refactor demo (#981)

* Refactor demo code

* Update docs

demos/polls/aiohttpdemo_polls/db.py

@@ -1,3 +1,4 @@
+import aiopg.sa
 import sqlalchemy as sa
 
 
@@ -34,32 +35,43 @@ class RecordNotFound(Exception):
     """Requested record in database was not found"""
 
 
-async def get_question(postgres, question_id):
-    async with postgres.acquire() as conn:
-        cursor = await conn.execute(
-            question.select()
-            .where(question.c.id == question_id))
-        question_record = await cursor.first()
-        if not question_record:
-            msg = "Question with id: {} does not exists"
-            raise RecordNotFound(msg.format(question_id))
-        cursor = await conn.execute(
-            choice.select()
-            .where(choice.c.question_id == question_id)
-            .order_by(choice.c.id))
-        choice_recoreds = await cursor.fetchall()
+async def init_postgres(conf, loop):
+    engine = await aiopg.sa.create_engine(
+        database=conf['database'],
+        user=conf['user'],
+        password=conf['password'],
+        host=conf['host'],
+        port=conf['port'],
+        minsize=conf['minsize'],
+        maxsize=conf['maxsize'],
+        loop=loop)
+    return engine
+
+
+async def get_question(conn, question_id):
+    result = await conn.execute(
+        question.select()
+        .where(question.c.id == question_id))
+    question_record = await result.first()
+    if not question_record:
+        msg = "Question with id: {} does not exists"
+        raise RecordNotFound(msg.format(question_id))
+    result = await conn.execute(
+        choice.select()
+        .where(choice.c.question_id == question_id)
+        .order_by(choice.c.id))
+    choice_recoreds = await result.fetchall()
     return question_record, choice_recoreds
 
 
-async def vote(postgres, question_id, choice_id):
-    async with postgres.acquire() as conn:
-        resp = await conn.execute(
-            choice.update()
-            .returning(*choice.c)
-            .where(choice.c.question_id == question_id)
-            .where(choice.c.id == choice_id)
-            .values(votes=choice.c.votes + 1))
-        record = await resp.fetchone()
-        if not record:
-            msg = "Question with id: {} or choice id: {} does not exists"
-            raise RecordNotFound(msg.format(question_id), choice_id)
+async def vote(conn, question_id, choice_id):
+    result = await conn.execute(
+        choice.update()
+        .returning(*choice.c)
+        .where(choice.c.question_id == question_id)
+        .where(choice.c.id == choice_id)
+        .values(votes=choice.c.votes+1))
+    record = await result.fetchone()
+    if not record:
+        msg = "Question with id: {} or choice id: {} does not exists"
+        raise RecordNotFound(msg.format(question_id), choice_id)

demos/polls/aiohttpdemo_polls/main.py

@@ -15,6 +15,11 @@
 PROJ_ROOT = pathlib.Path(__file__).parent.parent
 
 
+async def close_pg(app):
+    app['db'].close()
+    await app['db'].wait_closed()
+
+
 async def init(loop):
     # setup application and extensions
     app = web.Application(loop=loop)
@@ -24,16 +29,13 @@ async def init(loop):
     conf = load_config(str(PROJ_ROOT / 'config' / 'polls.yaml'))
 
     # create connection to the database
-    pg = await init_postgres(conf['postgres'], loop)
-
-    async def close_pg(app):
-        pg.close()
-        await pg.wait_closed()
+    db = await init_postgres(conf['postgres'], loop)
+    app['db'] = db
 
     app.on_cleanup.append(close_pg)
 
     # setup views and routes
-    handler = SiteHandler(pg)
+    handler = SiteHandler(db)
     setup_routes(app, handler, PROJ_ROOT)
     setup_middlewares(app)
 

demos/polls/aiohttpdemo_polls/routes.py

@@ -1,11 +1,12 @@
+from .views import index, poll, results, vote
 
-def setup_routes(app, handler, project_root):
-    add_route = app.router.add_route
-    add_route('GET', '/', handler.index)
-    add_route('GET', '/poll/{question_id}', handler.poll, name='poll')
-    add_route('GET', '/poll/{question_id}/results',
-              handler.results, name='results')
-    add_route('POST', '/poll/{question_id}/vote', handler.vote, name='vote')
+
+def setup_routes(app, project_root):
+    app.router.add_route('GET', '/', index)
+    app.router.add_route('GET', '/poll/{question_id}', poll, name='poll')
+    app.router.add_route('GET', '/poll/{question_id}/results',
+                         results, name='results')
+    app.router.add_route('POST', '/poll/{question_id}/vote', vote, name='vote')
     app.router.add_static('/static/',
                           path=str(project_root / 'static'),
                           name='static')

demos/polls/aiohttpdemo_polls/utils.py

@@ -1,22 +1,8 @@
 import yaml
-import aiopg.sa
 
 
 def load_config(fname):
     with open(fname, 'rt') as f:
         data = yaml.load(f)
     # TODO: add config validation
     return data
-
-
-async def init_postgres(conf, loop):
-    engine = await aiopg.sa.create_engine(
-        database=conf['database'],
-        user=conf['user'],
-        password=conf['password'],
-        host=conf['host'],
-        port=conf['port'],
-        minsize=conf['minsize'],
-        maxsize=conf['maxsize'],
-        loop=loop)
-    return engine

demos/polls/aiohttpdemo_polls/views.py

@@ -3,24 +3,22 @@
 from . import db
 
 
-class SiteHandler:
+@aiohttp_jinja2.template('index.html')
+async def index(request):
+    async with request['db'].acquire() as conn:
+        cursor = await conn.execute(db.question.select())
+        records = await cursor.fetchall()
 
-    def __init__(self, pg):
-        self.postgres = pg
-
-    @aiohttp_jinja2.template('index.html')
-    async def index(self, request):
-        async with self.postgres.acquire() as conn:
-            cursor = await conn.execute(db.question.select())
-            records = await cursor.fetchall()
         questions = [dict(q) for q in records]
         return {'questions': questions}
 
-    @aiohttp_jinja2.template('detail.html')
-    async def poll(self, request):
+
+@aiohttp_jinja2.template('detail.html')
+async def poll(request):
+    async with request['db'].acquire() as conn:
         question_id = request.match_info['question_id']
         try:
-            question, choices = await db.get_question(self.postgres,
+            question, choices = await db.get_question(conn,
                                                       question_id)
         except db.RecordNotFound as e:
             raise web.HTTPNotFound(text=str(e))
@@ -29,12 +27,14 @@ async def poll(self, request):
             'choices': choices
         }
 
-    @aiohttp_jinja2.template('results.html')
-    async def results(self, request):
+
+@aiohttp_jinja2.template('results.html')
+async def results(request):
+    async with request['db'].acquire() as conn:
         question_id = request.match_info['question_id']
 
         try:
-            question, choices = await db.get_question(self.postgres,
+            question, choices = await db.get_question(conn,
                                                       question_id)
         except db.RecordNotFound as e:
             raise web.HTTPNotFound(text=str(e))
@@ -44,7 +44,9 @@ async def results(self, request):
             'choices': choices
         }
 
-    async def vote(self, request):
+
+async def vote(request):
+    async with request['db'].acquire() as conn:
         question_id = int(request.match_info['question_id'])
         data = await request.post()
         try:
@@ -53,7 +55,7 @@ async def vote(self, request):
             raise web.HTTPBadRequest(
                 text='You have not specified choice value') from e
         try:
-            await db.vote(self.postgres, question_id, choice_id)
+            await db.vote(conn, question_id, choice_id)
         except db.RecordNotFound as e:
             raise web.HTTPNotFound(text=str(e))
         router = request.app.router

docs/tutorial.rst

@@ -144,6 +144,10 @@ and second table is choice table:
 | question_id   |
 +---------------+
 
+TBD: aiopg.sa.create_engine and pushing it into app's storage
+
+TBD: graceful cleanup
+
 
 .. _aiohttp-tutorial-views:
 
@@ -156,16 +160,17 @@ next Python code inside file (``polls/aiohttpdemo_polls/views.py``)::
     from aiohttp import web
 
 
-    class SiteHandler:
-        async def index(self, request):
-            return web.Response(text='Hello Aiohttp!')
+    async def index(self, request):
+        return web.Response(text='Hello Aiohttp!')
 
 This is the simplest view possible in Aiohttp. Now we should add ``index`` view
 to ``polls/aiohttpdemo_polls/routes.py``::
 
-    def setup_routes(app, handler, project_root):
-        add_route = app.router.add_route
-        add_route('GET', '/', handler.index)
+    from .views import index
+
+
+    def setup_routes(app, project_root):
+        app.router.add_route('GET', '/', index)
 
 Now if we open browser we can see::
 
@@ -181,17 +186,18 @@ Templates
 Let's add more useful views::
 
    @aiohttp_jinja2.template('detail.html')
-   async def poll(self, request):
-       question_id = request.match_info['question_id']
-       try:
-           question, choices = await db.get_question(self.postgres,
-                                                     question_id)
-       except db.RecordNotFound as e:
-           raise web.HTTPNotFound(text=str(e))
-       return {
-           'question': question,
-           'choices': choices
-       }
+   async def poll(request):
+       async with request['db'].acquire() as conn:
+           question_id = request.match_info['question_id']
+           try:
+               question, choices = await db.get_question(conn,
+                                                         question_id)
+           except db.RecordNotFound as e:
+               raise web.HTTPNotFound(text=str(e))
+           return {
+               'question': question,
+               'choices': choices
+           }
 
 Templates are very convinient way forweb page writing. We return a
 dict with page content, ``aiohttp_jinja2.template`` decorator
@@ -235,3 +241,9 @@ Fortunatelly it can be done easy by single call::
 
 
 where ``project_root`` is the path to root folder.
+
+
+Middlewares
+-----------
+
+TBD