From 1fd13607b1e0a2163440a21b51857dd3f60a5600 Mon Sep 17 00:00:00 2001 From: DarkSun Date: Tue, 2 Jun 2020 01:04:40 +0800 Subject: [PATCH] =?UTF-8?q?=E9=80=89=E9=A2=98:=2020200601=20Use=20FastAPI?= =?UTF-8?q?=20to=20build=20web=20services=20in=20Python?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit sources/tech/20200601 Use FastAPI to build web services in Python.md --- ...FastAPI to build web services in Python.md | 193 ++++++++++++++++++ 1 file changed, 193 insertions(+) create mode 100644 sources/tech/20200601 Use FastAPI to build web services in Python.md diff --git a/sources/tech/20200601 Use FastAPI to build web services in Python.md b/sources/tech/20200601 Use FastAPI to build web services in Python.md new file mode 100644 index 0000000000..d1b42bb6dd --- /dev/null +++ b/sources/tech/20200601 Use FastAPI to build web services in Python.md @@ -0,0 +1,193 @@ +[#]: collector: (lujun9972) +[#]: translator: ( ) +[#]: reviewer: ( ) +[#]: publisher: ( ) +[#]: url: ( ) +[#]: subject: (Use FastAPI to build web services in Python) +[#]: via: (https://fedoramagazine.org/use-fastapi-to-build-web-services-in-python/) +[#]: author: (Clément Verna https://fedoramagazine.org/author/cverna/) + +Use FastAPI to build web services in Python +====== + +![][1] + +_[FastAPI][2]_ is a modern Python web framework that leverage the latest Python improvement in asyncio. In this article you will see how to set up a container based development environment and implement a small web service with FastAPI. + +### Getting Started + +The development environment can be set up using the Fedora container image. The following Dockerfile prepares the container image with FastAPI, [Uvicorn][3] and [aiofiles][4]. + +``` +FROM fedora:32 +RUN dnf install -y python-pip \ + && dnf clean all \ + && pip install fastapi uvicorn aiofiles +WORKDIR /srv +CMD ["uvicorn", "main:app", "--reload"] +``` + +After saving this Dockerfile in your working directory, build the container image using podman. + +``` +$ podman build -t fastapi . +$ podman images +REPOSITORY TAG IMAGE ID CREATED SIZE +localhost/fastapi latest 01e974cabe8b 18 seconds ago 326 MB +``` + +Now let’s create a basic FastAPI program and run it using that container image. + +``` +from fastapi import FastAPI + +app = FastAPI() + +@app.get("/") +async def root(): + return {"message": "Hello Fedora Magazine!"} +``` + +Save that source code in a _main.py_ file and then run the following command to execute it: + +``` +$ podman run --rm -v $PWD:/srv:z -p 8000:8000 --name fastapi -d fastapi +$ curl http://127.0.0.1:8000 +{"message":"Hello Fedora Magazine!" +``` + +You now have a running web service using FastAPI. Any changes to _main.py_ will be automatically reloaded. For example, try changing the “Hello Fedora Magazine!” message. + +To stop the application, run the following command. + +``` +$ podman stop fastapi +``` + +### Building a small web service + +To really see the benefits of FastAPI and the performance improvement it brings ([see comparison][5] with other Python web frameworks), let’s build an application that manipulates some I/O. You can use the output of the _dnf history_ command as data for that application. + +First, save the output of that command in a file. + +``` +$ dnf history | tail --lines=+3 > history.txt +``` + +The command is using _tail_ to remove the headers of _dnf history_ which are not needed by the application. Each dnf transaction can be represented with the following information: + + * id : number of the transaction (increments every time a new transaction is run) + * command : the dnf command run during the transaction + * date: the date and time the transaction happened + + + +Next, modify the _main.py_ file to add that data structure to the application. + +``` +from fastapi import FastAPI +from pydantic import BaseModel + +app = FastAPI() + +class DnfTransaction(BaseModel): + id: int + command: str + date: str +``` + +FastAPI comes with the [pydantic][6] library which allow you to easily build data classes and benefit from type annotation to validate your data. + +Now, continue building the application by adding a function that will read the data from the _history.txt_ file. + +``` +import aiofiles + +from fastapi import FastAPI +from pydantic import BaseModel + +app = FastAPI() + +class DnfTransaction(BaseModel): + id: int + command: str + date: str + + +async def read_history(): + transactions = [] + async with aiofiles.open("history.txt") as f: + async for line in f: + transactions.append(DnfTransaction( + id=line.split("|")[0].strip(" "), + command=line.split("|")[1].strip(" "), + date=line.split("|")[2].strip(" "))) + return transactions +``` + +This function makes use of the _[aiofiles][4]_ library which provides an asyncio API to manipulate files in Python. This means that opening and reading the file will not block other requests made to the server. + +Finally, change the root function to return the data stored in the transactions list. + +``` +@app.get("/") +async def read_root(): + return await read_history() +``` + +To see the output of the application, run the following command + +``` +$ curl http://127.0.0.1:8000 | python -m json.tool +[ +{ +"id": 103, +"command": "update", +"date": "2020-05-25 08:35" +}, +{ +"id": 102, +"command": "update", +"date": "2020-05-23 15:46" +}, +{ +"id": 101, +"command": "update", +"date": "2020-05-22 11:32" +}, +.... +] +``` + +### Conclusion + +_FastAPI_ is gaining a lot a popularity in the Python web framework ecosystem because it offers a simple way to build web services using asyncio. You can find more information about _FastAPI_ in the [documentation][2]. + +The code of this article is available in [this GitHub repository][7]. + +* * * + +_Photo by [Jan Kubita][8] on [Unsplash][9]._ + +-------------------------------------------------------------------------------- + +via: https://fedoramagazine.org/use-fastapi-to-build-web-services-in-python/ + +作者：[Clément Verna][a] +选题：[lujun9972][b] +译者：[译者ID](https://github.com/译者ID) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://fedoramagazine.org/author/cverna/ +[b]: https://github.com/lujun9972 +[1]: https://fedoramagazine.org/wp-content/uploads/2020/05/fastapi-python-816x345.jpg +[2]: https://fastapi.tiangolo.com/ +[3]: https://www.uvicorn.org/ +[4]: https://github.com/Tinche/aiofiles +[5]: https://www.techempower.com/benchmarks/#section=test&runid=7464e520-0dc2-473d-bd34-dbdfd7e85911&hw=ph&test=composite&l=z8kflr-v&a=2&f=jz8cg-0-3s-0-3k-6bo-0-0-18y74-8s5c-0 +[6]: https://pydantic-docs.helpmanual.io/ +[7]: https://github.com/cverna/fastapi_app +[8]: https://unsplash.com/@jankubita?utm_source=unsplash&utm_medium=referral&utm_content=creditCopyText +[9]: https://unsplash.com/s/photos/fast-snake?utm_source=unsplash&utm_medium=referral&utm_content=creditCopyText