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  * [ ] FastAPI FastAPI Table of contents
      + Gold Sponsors
      + Opinions
      + Typer, the FastAPI of CLIs
      + Requirements
      + Installation
      + Example
          o Create it
          o Run it
          o Check it
          o Interactive API docs
          o Alternative API docs
      + Example upgrade
          o Interactive API docs upgrade
          o Alternative API docs upgrade
          o Recap
      + Performance
      + Optional Dependencies
      + License
  * [ ] Languages Languages
      + en
      + es
      + fr
      + it
      + ja
      + ko
      + pt
      + ru
      + sq
      + tr
      + uk
      + zh
  * Features
  * FastAPI People
  * Python Types Intro
  * [ ] Tutorial - User Guide Tutorial - User Guide
      + Tutorial - User Guide - Intro
      + First Steps
      + Path Parameters
      + Query Parameters
      + Request Body
      + Query Parameters and String Validations
      + Path Parameters and Numeric Validations
      + Body - Multiple Parameters
      + Body - Fields
      + Body - Nested Models
      + Schema Extra - Example
      + Extra Data Types
      + Cookie Parameters
      + Header Parameters
      + Response Model
      + Extra Models
      + Response Status Code
      + Form Data
      + Request Files
      + Request Forms and Files
      + Handling Errors
      + Path Operation Configuration
      + JSON Compatible Encoder
      + Body - Updates
      + [ ] Dependencies Dependencies
          o Dependencies - First Steps
          o Classes as Dependencies
          o Sub-dependencies
          o Dependencies in path operation decorators
          o Global Dependencies
          o Dependencies with yield
      + [ ] Security Security
          o Security Intro
          o Security - First Steps
          o Get Current User
          o Simple OAuth2 with Password and Bearer
          o OAuth2 with Password (and hashing), Bearer with JWT
            tokens
      + Middleware
      + CORS (Cross-Origin Resource Sharing)
      + SQL (Relational) Databases
      + Bigger Applications - Multiple Files
      + Background Tasks
      + Metadata and Docs URLs
      + Static Files
      + Testing
      + Debugging
  * [ ] Advanced User Guide Advanced User Guide
      + Advanced User Guide - Intro
      + Path Operation Advanced Configuration
      + Additional Status Codes
      + Return a Response Directly
      + Custom Response - HTML, Stream, File, others
      + Additional Responses in OpenAPI
      + Response Cookies
      + Response Headers
      + Response - Change Status Code
      + Advanced Dependencies
      + [ ] Advanced Security Advanced Security
          o Advanced Security - Intro
          o OAuth2 scopes
          o HTTP Basic Auth
      + Using the Request Directly
      + Advanced Middleware
      + SQL (Relational) Databases with Peewee
      + Async SQL (Relational) Databases
      + NoSQL (Distributed / Big Data) Databases
      + Sub Applications - Mounts
      + Behind a Proxy
      + Templates
      + GraphQL
      + WebSockets
      + Events: startup - shutdown
      + Custom Request and APIRoute class
      + Testing WebSockets
      + Testing Events: startup - shutdown
      + Testing Dependencies with Overrides
      + Testing a Database
      + Async Tests
      + Settings and Environment Variables
      + Conditional OpenAPI
      + Extending OpenAPI
      + OpenAPI Callbacks
      + Including WSGI - Flask, Django, others
  * Concurrency and async / await
  * [ ] Deployment Deployment
      + Deployment - Intro
      + About FastAPI versions
      + About HTTPS
      + Deploy FastAPI on Deta
      + Deploy with Docker
      + Deploy manually
  * Project Generation - Template
  * Alternatives, Inspiration and Comparisons
  * History, Design and Future
  * External Links and Articles
  * Benchmarks
  * Help FastAPI - Get Help
  * Development - Contributing
  * Release Notes

Table of contents

  * Gold Sponsors
  * Opinions
  * Typer, the FastAPI of CLIs
  * Requirements
  * Installation
  * Example
      + Create it
      + Run it
      + Check it
      + Interactive API docs
      + Alternative API docs
  * Example upgrade
      + Interactive API docs upgrade
      + Alternative API docs upgrade
      + Recap
  * Performance
  * Optional Dependencies
  * License

FastAPI

                               FastAPI

  FastAPI framework, high performance, easy to learn, fast to code,
                        ready for production

                    Test Coverage Package version

---------------------------------------------------------------------

Documentation: https://fastapi.tiangolo.com

Source Code: https://github.com/tiangolo/fastapi

---------------------------------------------------------------------

FastAPI is a modern, fast (high-performance), web framework for
building APIs with Python 3.6+ based on standard Python type hints.

The key features are:

  * Fast: Very high performance, on par with NodeJS and Go (thanks to
    Starlette and Pydantic). One of the fastest Python frameworks
    available.

  * Fast to code: Increase the speed to develop features by about
    200% to 300%. *

  * Fewer bugs: Reduce about 40% of human (developer) induced errors.
    *
  * Intuitive: Great editor support. Completion everywhere. Less time
    debugging.
  * Easy: Designed to be easy to use and learn. Less time reading
    docs.
  * Short: Minimize code duplication. Multiple features from each
    parameter declaration. Fewer bugs.
  * Robust: Get production-ready code. With automatic interactive
    documentation.
  * Standards-based: Based on (and fully compatible with) the open
    standards for APIs: OpenAPI (previously known as Swagger) and
    JSON Schema.

* estimation based on tests on an internal development team, building
production applications.

Gold SponsorsP

[deta] [investsuit] [vimso] [talkpython]

Other sponsors

OpinionsP

"[...] I'm using FastAPI a ton these days. [...] I'm actually
planning to use it for all of my team's ML services at Microsoft.
Some of them are getting integrated into the core Windows product and
some Office products."

Kabir Khan - Microsoft (ref)
---------------------------------------------------------------------

"We adopted the FastAPI library to spawn a REST server that can be
queried to obtain predictions. [for Ludwig]"

Piero Molino, Yaroslav Dudin, and Sai Sumanth Miryala - Uber (ref)
---------------------------------------------------------------------

"Netflix is pleased to announce the open-source release of our crisis
management orchestration framework: Dispatch! [built with FastAPI]"

Kevin Glisson, Marc Vilanova, Forest Monsen - Netflix (ref)
---------------------------------------------------------------------

"I'm over the moon excited about FastAPI. It's so fun!"

Brian Okken - Python Bytes podcast host (ref)
---------------------------------------------------------------------

"Honestly, what you've built looks super solid and polished. In many
ways, it's what I wanted Hug to be - it's really inspiring to see
someone build that."

Timothy Crosley - Hug creator (ref)
---------------------------------------------------------------------

"If you're looking to learn one modern framework for building REST
APIs, check out FastAPI [...] It's fast, easy to use and easy to
learn [...]"

"We've switched over to FastAPI for our APIs [...] I think you'll
like it [...]"

Ines Montani - Matthew Honnibal - Explosion AI founders - spaCy
creators (ref) - (ref)
---------------------------------------------------------------------

Typer, the FastAPI of CLIsP

[logo-margi]

If you are building a CLI app to be used in the terminal instead of a
web API, check out Typer.

Typer is FastAPI's little sibling. And it's intended to be the
FastAPI of CLIs. [?][?] 

RequirementsP

Python 3.6+

FastAPI stands on the shoulders of giants:

  * Starlette for the web parts.
  * Pydantic for the data parts.

InstallationP

$ pip install fastapi

---> 100%

You will also need an ASGI server, for production such as Uvicorn or
Hypercorn.

$ pip install uvicorn[standard]

---> 100%

ExampleP

Create itP

  * Create a file main.py with:

from typing import Optional

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Optional[str] = None):
    return {"item_id": item_id, "q": q}

Or use async def...

If your code uses async / await, use async def:

from typing import Optional

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
async def read_item(item_id: int, q: Optional[str] = None):
    return {"item_id": item_id, "q": q}

Note:

If you don't know, check the "In a hurry?" section about async and
await in the docs.

Run itP

Run the server with:

$ uvicorn main:app --reload

INFO:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
INFO:     Started reloader process [28720]
INFO:     Started server process [28722]
INFO:     Waiting for application startup.
INFO:     Application startup complete.

About the command uvicorn main:app --reload...

The command uvicorn main:app refers to:

  * main: the file main.py (the Python "module").
  * app: the object created inside of main.py with the line app =
    FastAPI().
  * --reload: make the server restart after code changes. Only do
    this for development.

Check itP

Open your browser at http://127.0.0.1:8000/items/5?q=somequery.

You will see the JSON response as:

{"item_id": 5, "q": "somequery"}

You already created an API that:

  * Receives HTTP requests in the paths / and /items/{item_id}.
  * Both paths take GET operations (also known as HTTP methods).
  * The path /items/{item_id} has a path parameter item_id that
    should be an int.
  * The path /items/{item_id} has an optional str query parameter q.

Interactive API docsP

Now go to http://127.0.0.1:8000/docs.

You will see the automatic interactive API documentation (provided by
Swagger UI):

Swagger UI

Alternative API docsP

And now, go to http://127.0.0.1:8000/redoc.

You will see the alternative automatic documentation (provided by
ReDoc):

ReDoc

Example upgradeP

Now modify the file main.py to receive a body from a PUT request.

Declare the body using standard Python types, thanks to Pydantic.

from typing import Optional

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: Optional[bool] = None


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Optional[str] = None):
    return {"item_id": item_id, "q": q}


@app.put("/items/{item_id}")
def update_item(item_id: int, item: Item):
    return {"item_name": item.name, "item_id": item_id}

The server should reload automatically (because you added --reload to
the uvicorn command above).

Interactive API docs upgradeP

Now go to http://127.0.0.1:8000/docs.

  * The interactive API documentation will be automatically updated,
    including the new body:

Swagger UI

  * Click on the button "Try it out", it allows you to fill the
    parameters and directly interact with the API:

Swagger UI interaction

  * Then click on the "Execute" button, the user interface will
    communicate with your API, send the parameters, get the results
    and show them on the screen:

Swagger UI interaction

Alternative API docs upgradeP

And now, go to http://127.0.0.1:8000/redoc.

  * The alternative documentation will also reflect the new query
    parameter and body:

ReDoc

RecapP

In summary, you declare once the types of parameters, body, etc. as
function parameters.

You do that with standard modern Python types.

You don't have to learn a new syntax, the methods or classes of a
specific library, etc.

Just standard Python 3.6+.

For example, for an int:

item_id: int

or for a more complex Item model:

item: Item

...and with that single declaration you get:

  * Editor support, including:
      + Completion.
      + Type checks.
  * Validation of data:
      + Automatic and clear errors when the data is invalid.
      + Validation even for deeply nested JSON objects.
  * Conversion of input data: coming from the network to Python data
    and types. Reading from:
      + JSON.
      + Path parameters.
      + Query parameters.
      + Cookies.
      + Headers.
      + Forms.
      + Files.
  * Conversion of output data: converting from Python data and types
    to network data (as JSON):
      + Convert Python types (str, int, float, bool, list, etc).
      + datetime objects.
      + UUID objects.
      + Database models.
      + ...and many more.
  * Automatic interactive API documentation, including 2 alternative
    user interfaces:
      + Swagger UI.
      + ReDoc.

---------------------------------------------------------------------

Coming back to the previous code example, FastAPI will:

  * Validate that there is an item_id in the path for GET and PUT
    requests.
  * Validate that the item_id is of type int for GET and PUT
    requests.
      + If it is not, the client will see a useful, clear error.
  * Check if there is an optional query parameter named q (as in
    http://127.0.0.1:8000/items/foo?q=somequery) for GET requests.
      + As the q parameter is declared with = None, it is optional.
      + Without the None it would be required (as is the body in the
        case with PUT).
  * For PUT requests to /items/{item_id}, Read the body as JSON:
      + Check that it has a required attribute name that should be a
        str.
      + Check that it has a required attribute price that has to be a
        float.
      + Check that it has an optional attribute is_offer, that should
        be a bool, if present.
      + All this would also work for deeply nested JSON objects.
  * Convert from and to JSON automatically.
  * Document everything with OpenAPI, that can be used by:
      + Interactive documentation systems.
      + Automatic client code generation systems, for many languages.
  * Provide 2 interactive documentation web interfaces directly.

---------------------------------------------------------------------

We just scratched the surface, but you already get the idea of how it
all works.

Try changing the line with:

    return {"item_name": item.name, "item_id": item_id}

...from:

        ... "item_name": item.name ...

...to:

        ... "item_price": item.price ...

...and see how your editor will auto-complete the attributes and know
their types:

editor support

For a more complete example including more features, see the Tutorial
- User Guide.

Spoiler alert: the tutorial - user guide includes:

  * Declaration of parameters from other different places as: headers
    , cookies, form fields and files.
  * How to set validation constraints as maximum_length or regex.
  * A very powerful and easy to use Dependency Injection system.
  * Security and authentication, including support for OAuth2 with
    JWT tokens and HTTP Basic auth.
  * More advanced (but equally easy) techniques for declaring deeply
    nested JSON models (thanks to Pydantic).
  * Many extra features (thanks to Starlette) as:
      + WebSockets
      + GraphQL
      + extremely easy tests based on requests and pytest
      + CORS
      + Cookie Sessions
      + ...and more.

PerformanceP

Independent TechEmpower benchmarks show FastAPI applications running
under Uvicorn as one of the fastest Python frameworks available, only
below Starlette and Uvicorn themselves (used internally by FastAPI).
(*)

To understand more about it, see the section Benchmarks.

Optional DependenciesP

Used by Pydantic:

  * ujson - for faster JSON "parsing".
  * email_validator - for email validation.

Used by Starlette:

  * requests - Required if you want to use the TestClient.
  * aiofiles - Required if you want to use FileResponse or
    StaticFiles.
  * jinja2 - Required if you want to use the default template
    configuration.
  * python-multipart - Required if you want to support form "parsing"
    , with request.form().
  * itsdangerous - Required for SessionMiddleware support.
  * pyyaml - Required for Starlette's SchemaGenerator support (you
    probably don't need it with FastAPI).
  * graphene - Required for GraphQLApp support.
  * ujson - Required if you want to use UJSONResponse.

Used by FastAPI / Starlette:

  * uvicorn - for the server that loads and serves your application.
  * orjson - Required if you want to use ORJSONResponse.

You can install all of these with pip install fastapi[all].

LicenseP

This project is licensed under the terms of the MIT license.

 
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