From 3fd96f239e307137c7f42cc00effb8fbffc9be57 Mon Sep 17 00:00:00 2001 From: Roman Mogylatov Date: Wed, 29 Jul 2020 18:26:57 -0400 Subject: [PATCH] Add parts of http tutorial --- docs/tutorials/aiohttp.rst | 688 ++++++++++++++++++++++++++++++++++++- 1 file changed, 687 insertions(+), 1 deletion(-) diff --git a/docs/tutorials/aiohttp.rst b/docs/tutorials/aiohttp.rst index 2406c8b7..0a75e0b8 100644 --- a/docs/tutorials/aiohttp.rst +++ b/docs/tutorials/aiohttp.rst @@ -1,6 +1,692 @@ Aiohttp tutorial ================ -Coming soon... +.. _aiohttp-tutorial: + +This tutorials shows how to build ``Aiohttp`` REST API application following dependency injection +principle. + +Start from the scratch or jump to the section: + +.. contents:: + :local: + :backlinks: none + +You can find complete project on the +`Github `_. + +What are we going to build? +--------------------------- + +.. image:: https://media.giphy.com/media/apvx5lPCPsjN6/source.gif + +We will build a REST API application that searches for funny GIFs on the `Giphy `_. +Let's call it Giphy Navigator. + +How does Giphy Navigator work? + +- Client sends a request specifying the search query and the number of results. +- Giphy Navigator returns a response in json format. +- The response contains: + - the search query + - the limit number + - the list of gif urls + +Example response: + +.. code-block:: json + + { + "query": "Dependency Injector", + "limit": 10, + "gifs": [ + { + "url": "https://giphy.com/gifs/boxes-dependent-swbf2-6Eo7KzABxgJMY" + }, + { + "url": "https://giphy.com/gifs/depends-J56qCcOhk6hKE" + }, + { + "url": "https://giphy.com/gifs/web-series-ccstudios-bro-dependent-1lhU8KAVwmVVu" + }, + { + "url": "https://giphy.com/gifs/TheBoysTV-friends-friend-weneedeachother-XxR9qcIwcf5Jq404Sx" + }, + { + "url": "https://giphy.com/gifs/netflix-a-series-of-unfortunate-events-asoue-9rgeQXbwoK53pcxn7f" + }, + { + "url": "https://giphy.com/gifs/black-and-white-sad-skins-Hs4YzLs2zJuLu" + }, + { + "url": "https://giphy.com/gifs/always-there-for-you-i-am-here-PlayjhCco9jHBYrd9w" + }, + { + "url": "https://giphy.com/gifs/stream-famous-dollar-YT2dvOByEwXCdoYiA1" + }, + { + "url": "https://giphy.com/gifs/i-love-you-there-for-am-1BhGzgpZXYWwWMAGB1" + }, + { + "url": "https://giphy.com/gifs/life-like-twerk-9hlnWxjHqmH28" + } + ] + } + +The task is naive and that's exactly what we need for the tutorial. + +Prepare the environment +----------------------- + +Let's create the environment for the project. + +First we need to create a project folder and the virtual environment: + +.. code-block:: bash + + mkdir giphynav-aiohttp-tutorial + cd giphynav-aiohttp-tutorial + python3 -m venv venv + +Now let's activate the virtual environment: + +.. code-block:: bash + + . venv/bin/activate + +Environment is ready and now we're going to create the layout of the project. + +Project layout +-------------- + +Create next structure in the current directory. All files should be empty. That's ok for now. + +Initial project layout:: + + ./ + ├── giphynavigator/ + │ ├── __init__.py + │ ├── application.py + │ ├── containers.py + │ └── views.py + ├── venv/ + └── requirements.txt + +Install the requirements +------------------------ + +Now it's time to install the project requirements. We will use next packages: + +- ``dependency-injector`` - the dependency injection framework +- ``aiohttp`` - the web framework +- ``aiohttp-devtools`` - the helper library that will provide a development server with live + reloading +- ``pyyaml`` - the YAML files parsing library, used for the reading of the configuration files +- ``pytest-aiohttp``- the helper library for the testing of the ``aiohttp`` application +- ``pytest-cov`` - the helper library for measuring the test coverage + +Put next lines into the ``requirements.txt`` file: + +.. code-block:: bash + + dependency-injector + aiohttp + aiohttp-devtools + pyyaml + pytest-aiohttp + pytest-cov + +and run next in the terminal: + +.. code-block:: bash + + pip install -r requirements.txt + +Let's also install the ``httpie``. It is a user-friendly command-line HTTP client for the API era. +We will use it for the manual testing. + +Run the command in the terminal: + +.. code-block:: bash + + pip install httpie + +The requirements are setup. Now we will build a minimal application. + +Minimal application +------------------- + +In this section we will build a minimal application. It will have an endpoint that we can call. +The endpoint will answer in the right format and will have no data. + +Edit ``views.py``: + +.. code-block:: python + + """Views module.""" + + from aiohttp import web + + + async def index(request: web.Request) -> web.Response: + query = request.query.get('query', 'Dependency Injector') + limit = int(request.query.get('limit', 10)) + + gifs = [] + + return web.json_response( + { + 'query': query, + 'limit': limit, + 'gifs': gifs, + }, + ) + +Now let's create the main part of our application - the container. Container will keep all of the +application components and their dependencies. First two providers we need to add are +the ``aiohttp`` application provider and the view provider. + +Put next into the ``containers.py``: + +.. code-block:: python + + """Application containers module.""" + + from dependency_injector import containers + from dependency_injector.ext import aiohttp + from aiohttp import web + + from . import views + + + class ApplicationContainer(containers.DeclarativeContainer): + """Application container.""" + + app = aiohttp.Application(web.Application) + + index_view = aiohttp.View(views.index) + +At the last we need to create the ``aiohttp`` application factory. It is traditionally called +``create_app()``. It will create the container. Then it will use the container to create +the ``aiohttp`` application. Last step is to configure the routing - we will assign +``index_view`` from the container to handle the requests to the root ``/`` of our REST API server. + +Put next into the ``application.py``: + +.. code-block:: python + + """Application module.""" + + from aiohttp import web + + from .containers import ApplicationContainer + + + def create_app(): + """Create and return Flask application.""" + container = ApplicationContainer() + + app: web.Application = container.app() + app.container = container + + app.add_routes([ + web.get('/', container.index_view.as_view()), + ]) + + return app + +.. note:: + + Container is the first object in the application. + + The container is used to create all other objects. + +Now we're ready to run our application + +Do next in the terminal: + +.. code-block:: bash + + adev runserver giphynavigator/application.py --livereload + +The output should be something like: + +.. code-block:: bash + + [18:52:59] Starting aux server at http://localhost:8001 ◆ + [18:52:59] Starting dev server at http://localhost:8000 ● + +Let's use ``httpie`` to check that it works: + +.. code-block:: bash + + http http://127.0.0.1:8000/ + +You should see: + +.. code-block:: json + + HTTP/1.1 200 OK + Content-Length: 844 + Content-Type: application/json; charset=utf-8 + Date: Wed, 29 Jul 2020 21:01:50 GMT + Server: Python/3.8 aiohttp/3.6.2 + + { + "gifs": [], + "limit": 10, + "query": "Dependency Injector" + } + +Minimal application is ready. Let's connect our application with the Giphy API. + +Giphy API client +---------------- + +In this section we will integrate our application with the Giphy API. + +We will create our own API client using ``aiohttp`` client. + +Create ``giphy.py`` module in the ``giphynavigator`` package: + +.. code-block:: bash + :emphasize-lines: 6 + + ./ + ├── giphynavigator/ + │ ├── __init__.py + │ ├── application.py + │ ├── containers.py + │ ├── giphy.py + │ └── views.py + ├── venv/ + └── requirements.txt + +and put next into it: + +.. code-block:: python + + """Giphy client module.""" + + from aiohttp import ClientSession, ClientTimeout + + + class GiphyClient: + + API_URL = 'http://api.giphy.com/v1' + + def __init__(self, api_key, timeout): + self._api_key = api_key + self._timeout = ClientTimeout(timeout) + + async def search(self, query, limit): + """Make search API call and return result.""" + if not query: + return [] + + url = f'{self.API_URL}/gifs/search' + params = { + 'q': query, + 'api_key': self._api_key, + 'limit': limit, + } + async with ClientSession(timeout=self._timeout) as session: + async with session.get(url, params=params) as response: + if response.status != 200: + response.raise_for_status() + return await response.json() + +Now we need to add ``GiphyClient`` into the container. The ``GiphyClient`` has two dependencies +that have to be injected: the API key and the request timeout. We will need to use two more +providers from the ``dependency_injector.providers`` module: + +- ``Factory`` provider that will create the ``GiphyClient`` client. +- ``Configuration`` provider that will provide the API key and the request timeout. + +Edit ``containers.py``: + +.. code-block:: python + :emphasize-lines: 3,7,15,17-21 + + """Application containers module.""" + + from dependency_injector import containers, providers + from dependency_injector.ext import aiohttp + from aiohttp import web + + from . import giphy, views + + + class ApplicationContainer(containers.DeclarativeContainer): + """Application container.""" + + app = aiohttp.Application(web.Application) + + config = providers.Configuration() + + giphy_client = providers.Factory( + giphy.GiphyClient, + api_key=config.giphy.api_key, + timeout=config.giphy.request_timeout, + ) + + index_view = aiohttp.View(views.index) + +.. note:: + + We have used the configuration value before it was defined. That's the principle how the + ``Configuration`` provider works. + + Use first, define later. + +Now let's add the configuration file. + +We will use YAML. + +Create an empty file ``config.yml`` in the root root of the project: + +.. code-block:: bash + :emphasize-lines: 9 + + ./ + ├── giphynavigator/ + │ ├── __init__.py + │ ├── application.py + │ ├── containers.py + │ ├── giphy.py + │ └── views.py + ├── venv/ + ├── config.yml + └── requirements.txt + +and put next into it: + +.. code-block:: yaml + + giphy: + request_timeout: 10 + +We will use an environment variable ``GIPHY_API_KEY`` to provide the API key. + +Now we need to edit ``create_app()`` to make two things when application starts: + +- Load the configuration file the ``config.yml``. +- Load the API key from the ``GIPHY_API_KEY`` environment variable. + +Edit ``application.py``: + +.. code-block:: python + :emphasize-lines: 11-12 + + """Application module.""" + + from aiohttp import web + + from .containers import ApplicationContainer + + + def create_app(): + """Create and return Flask application.""" + container = ApplicationContainer() + container.config.from_yaml('config.yml') + container.config.giphy.api_key.from_env('GIPHY_API_KEY') + + app: web.Application = container.app() + app.container = container + + app.add_routes([ + web.get('/', container.index_view.as_view()), + ]) + + return app + +Now we need to create an API key and set it to the environment variable. + +As for now, don’t worry, just take this one: + +.. code-block:: bash + + export GIPHY_API_KEY=wBJ2wZG7SRqfrU9nPgPiWvORmloDyuL0 + +.. note:: + + To create your own Giphy API key follow this + `guide `_. + +The Giphy API client and the configuration setup is done. Let's proceed to the search service. + +Search service +-------------- + +Now it's time to add the ``SearchService``. It will: + +- Perform the search. +- Format result data. + +``SearchService`` will use ``GiphyClient``. + +Create ``services.py`` module in the ``giphynavigator`` package: + +.. code-block:: bash + :emphasize-lines: 7 + + ./ + ├── giphynavigator/ + │ ├── __init__.py + │ ├── application.py + │ ├── containers.py + │ ├── giphy.py + │ ├── services.py + │ └── views.py + ├── venv/ + └── requirements.txt + +and put next into it: + +.. code-block:: python + + """Services module.""" + + from .giphy import GiphyClient + + + class SearchService: + + def __init__(self, giphy_client: GiphyClient): + self._giphy_client = giphy_client + + async def search(self, query, limit): + """Search for gifs and return formatted data.""" + if not query: + return [] + + result = await self._giphy_client.search(query, limit) + + return [{'url': gif['url']} for gif in result['data']] + +The ``SearchService`` has a dependency on the ``GiphyClient``. This dependency will be injected. +Let's add ``SearchService`` to the container. + +Edit ``containers.py``: + +.. code-block:: python + :emphasize-lines: 7,23-26 + + """Application containers module.""" + + from dependency_injector import containers, providers + from dependency_injector.ext import aiohttp + from aiohttp import web + + from . import giphy, services, views + + + class ApplicationContainer(containers.DeclarativeContainer): + """Application container.""" + + app = aiohttp.Application(web.Application) + + config = providers.Configuration() + + giphy_client = providers.Factory( + giphy.GiphyClient, + api_key=config.giphy.api_key, + timeout=config.giphy.request_timeout, + ) + + search_service = providers.Factory( + services.SearchService, + giphy_client=giphy_client, + ) + + index_view = aiohttp.View(views.index) + + +The search service is ready. In the next section we're going to make it work. + +Make the search work +-------------------- + +Now we are ready to make the search work. Let's use the ``SearchService`` in the ``index`` view. + +Edit ``views.py``: + +.. code-block:: python + :emphasize-lines: 5,8-11,15 + + """Views module.""" + + from aiohttp import web + + from .services import SearchService + + + async def index( + request: web.Request, + search_service: SearchService, + ) -> web.Response: + query = request.query.get('query', 'Dependency Injector') + limit = int(request.query.get('limit', 10)) + + gifs = await search_service.search(query, limit) + + return web.json_response( + { + 'query': query, + 'limit': limit, + 'gifs': gifs, + }, + ) + +Now let's inject the ``SearchService`` dependency into the ``index`` view. + +Edit ``containers.py``: + +.. code-block:: python + :emphasize-lines: 28-31 + + """Application containers module.""" + + from dependency_injector import containers, providers + from dependency_injector.ext import aiohttp + from aiohttp import web + + from . import giphy, services, views + + + class ApplicationContainer(containers.DeclarativeContainer): + """Application container.""" + + app = aiohttp.Application(web.Application) + + config = providers.Configuration() + + giphy_client = providers.Factory( + giphy.GiphyClient, + api_key=config.giphy.api_key, + timeout=config.giphy.request_timeout, + ) + + search_service = providers.Factory( + services.SearchService, + giphy_client=giphy_client, + ) + + index_view = aiohttp.View( + views.index, + search_service=search_service, + ) + +Make sure the app is running or use: + +.. code-block:: bash + + adev runserver giphynavigator/application.py --livereload + +and make a request to the API in the terminal: + +.. code-block:: bash + + http http://localhost:8000/ query=="wow,it works" + +You should see: + +.. code-block:: json + + HTTP/1.1 200 OK + Content-Length: 850 + Content-Type: application/json; charset=utf-8 + Date: Wed, 29 Jul 2020 22:22:55 GMT + Server: Python/3.8 aiohttp/3.6.2 + + { + "gifs": [ + { + "url": "https://giphy.com/gifs/discoverychannel-nugget-gold-rush-rick-ness-KGGPIlnC4hr4u2s3pY" + }, + { + "url": "https://giphy.com/gifs/primevideoin-ll1hyBS2IrUPLE0E71" + }, + { + "url": "https://giphy.com/gifs/jackman-works-jackmanworks-l4pTgQoCrmXq8Txlu" + }, + { + "url": "https://giphy.com/gifs/cat-massage-at-work-l46CzMaOlJXAFuO3u" + }, + { + "url": "https://giphy.com/gifs/everwhatproductions-fun-christmas-3oxHQCI8tKXoeW4IBq" + }, + { + "url": "https://giphy.com/gifs/spacestationgaming-love-wow-team-YST1F1J5g2yyLLvMJc" + }, + { + "url": "https://giphy.com/gifs/dollyparton-3xIVVMnZfG3KQ9v4Ye" + }, + { + "url": "https://giphy.com/gifs/greatbigstory-wow-omg-BLGlU7OWvFAFMoNjsM" + }, + { + "url": "https://giphy.com/gifs/soulpancake-wow-work-xUe4HVXTPi0wQ2OAJC" + }, + { + "url": "https://giphy.com/gifs/nickelodeon-nick-pull-ups-casagrandes-eK136cynbxuOVk0qzJ" + } + ], + "limit": 10, + "query": "wow,it works" + } + +.. image:: https://media.giphy.com/media/3oxHQCI8tKXoeW4IBq/source.gif + +The search works! + +Make some refactoring +--------------------- + +Tests +----- + +Conclusion +---------- .. disqus::