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Better example for Tornado; fix pytest-dev#25; require task context for transaction run; bump version
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‎CHANGELOG.md

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# Changelog
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## 0.5.2
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- Fix #25: starting transaction before connecting raise `AttributeError` exception about `_task_data`
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- **Require** transactions to be run within task context
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## 0.5.1
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- Fix: #23, running not in the context of a task

‎docs/index.rst

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peewee_async/api
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peewee_async/api_older
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peewee_async/tornado
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peewee_async/examples
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Indices and tables

‎docs/peewee_async/examples.rst

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Usage examples
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==============
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Using with Tornado
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------------------
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.. code-block:: python
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import tornado.gen
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import tornado.web
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from tornado.platform.asyncio import AsyncIOMainLoop
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import peewee
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import asyncio
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import peewee_async
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# Set up asincio loop for Tornado
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AsyncIOMainLoop().install()
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loop = asyncio.get_event_loop()
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# Create application
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application = tornado.web.Application(debug=True)
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application.listen(port=8888)
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# Set up database connection
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database = peewee_async.PooledPostgresqlDatabase('test')
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application.db = database
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# Define model, handler and run application:
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class TestNameModel(peewee.Model):
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name = peewee.CharField()
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class Meta:
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database = database
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class TestHandler(tornado.web.RequestHandler):
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@tornado.gen.coroutine
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def post(self):
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name = self.get_argument('name')
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obj = yield from peewee_async.create_object(TestNameModel, name=name)
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self.write({'id': obj.id, 'name': obj.name})
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@tornado.gen.coroutine
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def get(self):
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obj_id = self.get_argument('id')
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try:
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obj = yield from peewee_async.get_object(TestNameModel, TestNameModel.id == obj_id)
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self.write({'id': obj.id, 'name': obj.name})
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except TestNameModel.DoesNotExist:
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raise tornado.web.HTTPError(404, "Object not found!")
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application.add_handlers('', [
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(r"/test", TestHandler)
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])
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# Create database table
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TestNameModel.create_table(True)
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database.close()
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# Set up async connection and run application server
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loop.run_until_complete(application.db.connect_async())
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loop.run_forever()
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More examples
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=============
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**TODO:** update examples to high-level API.
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Using both sync and async calls
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-------------------------------

‎docs/peewee_async/tornado.rst

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Using async peewee with Tornado
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===============================
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`Tornado`_ is a mature and powerful asynchronous web framework. It provides its own event loop, but there's an option to run Tornado on asyncio event loop. And that's exactly what we need!
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.. _Tornado: http://www.tornadoweb.org
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The complete working example is provided below. And here are some general notes:
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1. **Be aware of current asyncio event loop!**
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In the provided example we use the default event loop everywhere, and that's OK. But if you see your application got silently stuck, that's most probably that some task is started on different loop and will never complete as long as that loop is not running.
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2. Tornado request handlers **does not** start asyncio tasks by default.
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The ``CreateHandler`` demostrates that, ``current_task()`` returns ``None`` until taks is run explicitly.
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3. Transactions **must** run within task context.
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All transaction operations have to be done within task. So if you need to run a transaction from Tornado handler, you have to wrap your call into task with ``create_task()`` or ``ensure_future()``.
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**Also note:** if you spawn an extra task during transaction, it will run outside of transaction.
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.. code-block:: python
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import tornado.web
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import logging
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import peewee
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import asyncio
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import peewee_async
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# Set up database and manager
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database = peewee_async.PooledPostgresqlDatabase('test')
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# Define model
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class TestNameModel(peewee.Model):
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name = peewee.CharField()
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class Meta:
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database = database
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def __str__(self):
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return self.name
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# Create table, add some instances
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TestNameModel.create_table(True)
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TestNameModel.get_or_create(id=1, defaults={'name': "TestNameModel id=1"})
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TestNameModel.get_or_create(id=2, defaults={'name': "TestNameModel id=2"})
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TestNameModel.get_or_create(id=3, defaults={'name': "TestNameModel id=3"})
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database.close()
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# Set up Tornado application on asyncio
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from tornado.platform.asyncio import AsyncIOMainLoop
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AsyncIOMainLoop().install()
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app = tornado.web.Application(debug=True)
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app.listen(port=8888)
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app.objects = peewee_async.Manager(database)
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# Add handlers
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class RootHandler(tornado.web.RequestHandler):
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"""Accepts GET and POST methods.
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POST: create new instance, `name` argument is required
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GET: get instance by id, `id` argument is required
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"""
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async def post(self):
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name = self.get_argument('name')
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obj = await self.application.objects.create(TestNameModel, name=name)
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self.write({
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'id': obj.id,
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'name': obj.name
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})
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async def get(self):
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obj_id = self.get_argument('id', None)
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if not obj_id:
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self.write("Please provide the 'id' query argument, i.e. ?id=1")
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return
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try:
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obj = await self.application.objects.get(TestNameModel, id=obj_id)
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self.write({
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'id': obj.id,
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'name': obj.name,
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})
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except TestNameModel.DoesNotExist:
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raise tornado.web.HTTPError(404, "Object not found!")
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class CreateHandler(tornado.web.RequestHandler):
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async def get(self):
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loop = asyncio.get_event_loop()
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task1 = asyncio.Task.current_task()
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task2 = loop.create_task(self.get_or_create())
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obj = await task2
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self.write({
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'task1': task1 and id(task1),
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'task2': task2 and id(task2),
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'obj': str(obj),
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'text': "'task1' should be null, "
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"'task2' should be not null, "
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"'obj' should be newly created object",
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})
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async def get_or_create(self):
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async with self.application.objects.atomic():
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obj, created = await self.application.objects.get_or_create(
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TestNameModel, id=100,
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defaults={'name': "TestNameModel id=100"})
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return obj
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app.add_handlers('', [
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(r"/", RootHandler),
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(r"/create/", CreateHandler),
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])
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# Setup verbose logging
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log = logging.getLogger('')
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log.addHandler(logging.StreamHandler())
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log.setLevel(logging.DEBUG)
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# Run loop
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print("""Run application server http://127.0.0.1:8888
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Try GET urls:
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http://127.0.0.1:8888?id=1
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http://127.0.0.1:8888?id=2
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http://127.0.0.1:8888?id=3
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Try POST with name=<some text> data:
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http://127.0.0.1:8888
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^C to stop server""")
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loop = asyncio.get_event_loop()
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try:
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loop.run_forever()
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except KeyboardInterrupt:
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print(" server stopped")

‎examples/tornado_sample.py

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"""
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Usage example for `peewee-async`_ with `Tornado`_ web framewotk.
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Asynchronous interface for `peewee`_ ORM powered by `asyncio`_:
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https://github.com/05bit/peewee-async
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.. _peewee-async: https://github.com/05bit/peewee-async
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.. _Tornado: http://www.tornadoweb.org
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Licensed under The MIT License (MIT)
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Copyright (c) 2016, Alexey Kinëv <[email protected]>
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"""
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import tornado.web
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import logging
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import peewee
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import asyncio
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import peewee_async
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# Set up database and manager
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database = peewee_async.PooledPostgresqlDatabase('test')
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# Define model
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class TestNameModel(peewee.Model):
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name = peewee.CharField()
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class Meta:
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database = database
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def __str__(self):
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return self.name
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# Create table, add some instances
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TestNameModel.create_table(True)
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TestNameModel.get_or_create(id=1, defaults={'name': "TestNameModel id=1"})
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TestNameModel.get_or_create(id=2, defaults={'name': "TestNameModel id=2"})
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TestNameModel.get_or_create(id=3, defaults={'name': "TestNameModel id=3"})
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database.close()
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# Set up Tornado application on asyncio
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from tornado.platform.asyncio import AsyncIOMainLoop
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AsyncIOMainLoop().install()
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app = tornado.web.Application(debug=True)
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app.listen(port=8888)
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app.objects = peewee_async.Manager(database)
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# Add handlers
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class RootHandler(tornado.web.RequestHandler):
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"""Accepts GET and POST methods.
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POST: create new instance, `name` argument is required
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GET: get instance by id, `id` argument is required
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"""
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async def post(self):
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name = self.get_argument('name')
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obj = await self.application.objects.create(TestNameModel, name=name)
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self.write({
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'id': obj.id,
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'name': obj.name
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})
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async def get(self):
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obj_id = self.get_argument('id', None)
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if not obj_id:
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self.write("Please provide the 'id' query argument, i.e. ?id=1")
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return
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try:
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obj = await self.application.objects.get(TestNameModel, id=obj_id)
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self.write({
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'id': obj.id,
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'name': obj.name,
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})
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except TestNameModel.DoesNotExist:
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raise tornado.web.HTTPError(404, "Object not found!")
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class CreateHandler(tornado.web.RequestHandler):
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async def get(self):
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loop = asyncio.get_event_loop()
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task1 = asyncio.Task.current_task()
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task2 = loop.create_task(self.get_or_create())
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obj = await task2
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self.write({
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'task1': task1 and id(task1),
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'task2': task2 and id(task2),
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'obj': str(obj),
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'text': "'task1' should be null, "
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"'task2' should be not null, "
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"'obj' should be newly created object",
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})
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async def get_or_create(self):
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async with self.application.objects.atomic():
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obj, created = await self.application.objects.get_or_create(
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TestNameModel, id=100,
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defaults={'name': "TestNameModel id=100"})
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return obj
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app.add_handlers('', [
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(r"/", RootHandler),
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(r"/create/", CreateHandler),
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])
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# Setup verbose logging
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log = logging.getLogger('')
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log.addHandler(logging.StreamHandler())
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log.setLevel(logging.DEBUG)
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# Run loop
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print("""Run application server http://127.0.0.1:8888
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Try GET urls:
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http://127.0.0.1:8888?id=1
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http://127.0.0.1:8888?id=2
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http://127.0.0.1:8888?id=3
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Try POST with name=<some text> data:
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http://127.0.0.1:8888
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^C to stop server""")
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loop = asyncio.get_event_loop()
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try:
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loop.run_forever()
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except KeyboardInterrupt:
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print(" server stopped")

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