fastapi-code-generator

This code generator creates a FastAPI app from an openapi file.

This project is in experimental phase.

fastapi-code-generator uses datamodel-code-generator to generate pydantic models

Help

See documentation for more details.

Installation

To install fastapi-code-generator:

$ pip install fastapi-code-generator

Usage

The fastapi-code-generator command:

Usage: fastapi-codegen [OPTIONS]
Options:
-i, --input FILENAME [required]
-o, --output PATH [required]
-t, --template-dir PATH
-m, --model-file Specify generated model file path + name, if not default to models.py
-r, --generate-routers Generate modular api with multiple routers using RouterAPI (for bigger applications).
--specify-tags Use along with --generate-routers to generate specific routers from given list of tags.
-c, --custom-visitors PATH - A custom visitor that adds variables to the template.
-d, --output-model-type Specify a Pydantic base model to use (see [datamodel-code-generator](https://github.com/koxudaxi/datamodel-code-generator); default is `pydantic.BaseModel`).
-p, --python-version Specify a Python version to target (default is `3.9`).
--install-completion Install completion for the current shell.
--show-completion Show completion for the current shell, to copy it
or customize the installation.
--help Show this message and exit.

Pydantic 2 support

Specify the Pydantic 2 BaseModel version in the command line, for example:

$ fastapi-codegen --input api.yaml --output app --output-model-type pydantic_v2.BaseModel

Example

OpenAPI

$ fastapi-codegen --input api.yaml --output app

api.yaml


openapi: "3.0.0"
info:
version: 1.0.0
title: Swagger Petstore
license:
name: MIT
servers:
- url: http://petstore.swagger.io/v1
paths:
/pets:
get:
summary: List all pets
operationId: listPets
tags:
- pets
parameters:
- name: limit
in: query
description: How many items to return at one time (max 100)
required: false
schema:
type: integer
format: int32
responses:
'200':
description: A paged array of pets
headers:
x-next:
description: A link to the next page of responses
schema:
type: string
content:
application/json:
schema:
$ref: "#/components/schemas/Pets"
default:
description: unexpected error
content:
application/json:
schema:
$ref: "#/components/schemas/Error"
x-amazon-apigateway-integration:
uri:
Fn::Sub: arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${PythonVersionFunction.Arn}/invocations
passthroughBehavior: when_no_templates
httpMethod: POST
type: aws_proxy
post:
summary: Create a pet
operationId: createPets
tags:
- pets
responses:
'201':
description: Null response
default:
description: unexpected error
content:
application/json:
schema:
$ref: "#/components/schemas/Error"
x-amazon-apigateway-integration:
uri:
Fn::Sub: arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${PythonVersionFunction.Arn}/invocations
passthroughBehavior: when_no_templates
httpMethod: POST
type: aws_proxy
/pets/{petId}:
get:
summary: Info for a specific pet
operationId: showPetById
tags:
- pets
parameters:
- name: petId
in: path
required: true
description: The id of the pet to retrieve
schema:
type: string
responses:
'200':
description: Expected response to a valid request
content:
application/json:
schema:
$ref: "#/components/schemas/Pets"
default:
description: unexpected error
content:
application/json:
schema:
$ref: "#/components/schemas/Error"
x-amazon-apigateway-integration:
uri:
Fn::Sub: arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${PythonVersionFunction.Arn}/invocations
passthroughBehavior: when_no_templates
httpMethod: POST
type: aws_proxy
components:
schemas:
Pet:
required:
- id
- name
properties:
id:
type: integer
format: int64
name:
type: string
tag:
type: string
Pets:
type: array
description: list of pet
items:
$ref: "#/components/schemas/Pet"
Error:
required:
- code
- message
properties:
code:
type: integer
format: int32
message:
type: string

app/main.py:

# generated by fastapi-codegen:# filename: api.yaml# timestamp: 2020-06-14T10:45:22+00:00from __future__ importannotationsfromtypingimportOptionalfromfastapiimportFastAPI, Queryfrom .modelsimportPetsapp=FastAPI(version="1.0.0", title="Swagger Petstore", license="{'name': 'MIT'}",)
@app.get('/pets', response_model=Pets)deflist_pets(limit: Optional[int] =None) ->Pets:
""" List all pets """pass@app.post('/pets', response_model=None)defcreate_pets() ->None:
""" Create a pet """pass@app.get('/pets/{pet_id}', response_model=Pets)defshow_pet_by_id(pet_id: str=Query(..., alias='petId')) ->Pets:
""" Info for a specific pet """pass

app/models.py:

# generated by datamodel-codegen:# filename: api.yaml# timestamp: 2020-06-14T10:45:22+00:00fromtypingimportList, OptionalfrompydanticimportBaseModel, FieldclassPet(BaseModel):
id: intname: strtag: Optional[str] =NoneclassPets(BaseModel):
__root__: List[Pet] =Field(..., description='list of pet')
classError(BaseModel):
code: intmessage: str

Custom Template

If you want to generate custom *.py files then you can give a custom template directory to fastapi-code-generator with -t or --template-dir options of the command.

fastapi-code-generator will search for jinja2 template files in given template directory, for example some_jinja_templates/list_pets.py.

fastapi-code-generator --template-dir some_jinja_templates --output app --input api.yaml

These files will be rendered and written to the output directory. Also, the generated file names will be created with the template name and extension of *.py, for example app/list_pets.py will be a separate file generated from the jinja template alongside the default app/main.py

Variables

You can use the following variables in the jinja2 templates

imports all imports statements
info all info statements
operationsoperations is list of operation
- operation.type HTTP METHOD
- operation.path Path
- operation.snake_case_path Snake-cased Path
- operation.response response object
- operation.function_name function name is created operationId or METHOD + Path
- operation.snake_case_arguments Snake-cased function arguments
- operation.securitySecurity
- operation.summary a summary
- operation.tagsTags

default template

main.jinja2

from __future__ import annotations
from fastapi import FastAPI
{{imports}}
app = FastAPI(
{%ifinfo%}{%forkey,valueininfo.items() %}
{{ key }} = "{{ value }}",
{%endfor%}{%endif%}
)
{%foroperationinoperations%}
@app.{{operation.type}}('{{operation.snake_case_path}}', response_model={{operation.response}})
def {{operation.function_name}}({{operation.snake_case_arguments}}) -> {{operation.response}}:
{%- ifoperation.summary%}
"""
{{ operation.summary }}
"""
{%- endif%}
pass
{%endfor%}

modular template

modular_template/main.jinja2:

from __future__ import annotations
from fastapi import FastAPI
from .routers import {{ routers | join(", ") }}
app = FastAPI(
{%ifinfo%}{%forkey,valueininfo.items() %}{%setinfo_value= value.__repr__() %}
{{ key }} = {{info_value}},
{%endfor%}{%endif%}
)
{%forrouterinrouters -%}
app.include_router({{router}}.router)
{%endfor -%}
@app.get("/")
async def root():
return {"message": "Gateway of the App"}

modular_template/routers.jinja2:

from __future__ import annotations
from fastapi import APIRouter
from fastapi import FastAPI
from ..dependencies import *
router = APIRouter(
tags=['{{tag}}']
)
{%foroperationinoperations%}{%ifoperation.tags[0] == tag%}
@router.{{operation.type}}('{{operation.snake_case_path}}', response_model={{operation.response}}
{%ifoperation.additional_responses%}
, responses={
{%forstatus_code, modelsinoperation.additional_responses.items() %}
'{{ status_code }}': {
{%forkey, modelinmodels.items() %}
'{{ key }}': {{ model }}{%ifnotloop.last%},{%endif%}{%endfor%}
}{%ifnotloop.last%},{%endif%}{%endfor%}
}
{%endif%}{%ifoperation.tags%}
, tags={{operation.tags}}
{%endif%})
def {{operation.function_name}}({{operation.snake_case_arguments}}) -> {{operation.return_type}}:
{%- ifoperation.summary%}
"""
{{ operation.summary }}
"""
{%- endif%}
pass
{%endif%}{%endfor%}

modular_template/dependencies.jinja2:

{{imports}}

Custom Visitors

Custom visitors allow you to pass custom variables to your custom templates.

E.g.

custom template

custom-template.jinja2

#{ % custom_header %}
from __future__ import annotations
from fastapi import FastAPI
...

custom visitor

custom-visitor.py

fromtypingimportDict, Optionalfromfastapi_code_generator.parserimportOpenAPIParserfromfastapi_code_generator.visitorimportVisitordefcustom_visitor(parser: OpenAPIParser, model_path: Path) ->Dict[str, object]:
return {'custom_header': 'My header'}
visit: Visitor=custom_visitor

Multiple Files using APIRouter (For Bigger Applications)

├── app # "app" is a Root directory │ ├── main.py # "main" module
│ ├── models.py # "models" of the application
│ ├── dependencies.py # "dependencies" module, e.g. import app.dependencies
│ └── routers # "routers" is a "app subpackage"
│ ├── fat_cats.py # "fat_cats" submodule, e.g. import app.routers.fat_cats
│ ├── slim_dogs.py # "slim_dogs" submodule, e.g. import app.routers.slim_dogs
│ └── wild_boars.py # "wild_boars" submodule, e.g. import app.routers.wild_boars

See documentation of APIRouter OpenAPI for more details.

Generate main aside with all of its routers:

$ fastapi-codegen --input swagger.yaml --output app --generate-routers

Regenerate specific routers:

$ fastapi-codegen --input swagger.yaml --output app --generate-routers --specify-tags "Wild Boars, Fat Cats"

swagger.yaml


openapi: "3.0.0"
info:
version: 1.0.0
title: Swagger Petstore
license:
name: MIT
servers:
- url: /
- url: http://petstore.swagger.io/v1
- url: http://localhost:8080/
paths:
/boars:
get:
summary: List All Wild Boars
operationId: listWildBoars
tags:
- Wild Boars
parameters:
- name: limit
in: query
description: How many items to return at one time (max 100)
required: false
schema:
type: integer
responses:
'200':
description: An array of wild boars
content:
application/json:
schema:
$ref: "#/components/schemas/WildBoars"
post:
summary: Create a Wild Boar
operationId: createWildBoars
tags:
- Wild Boars
responses:
'201':
description: Null response
/boars/{boarId}:
get:
summary: Info For a Specific Boar
operationId: showBoarById
tags:
- Wild Boars
parameters:
- name: boarId
in: path
required: true
description: The id of the boar to retrieve
schema:
type: string
responses:
'200':
description: Expected response to a valid request
content:
application/json:
schema:
$ref: "#/components/schemas/Pet"
/cats:
get:
summary: List All Fat Cats
operationId: listFatCats
tags:
- Fat Cats
parameters:
- name: limit
in: query
description: How many items to return at one time (max 100)
required: false
schema:
type: integer
responses:
'200':
description: An array of fat cats
content:
application/json:
schema:
$ref: "#/components/schemas/FatCats"
post:
summary: Create a Fat Cat
operationId: createFatCats
tags:
- Fat Cats
responses:
'201':
description: Null response
/cats/{catId}:
get:
summary: Info For a Specific Cat
operationId: showCatById
tags:
- Fat Cats
parameters:
- name: catId
in: path
required: true
description: The id of the cat to retrieve
schema:
type: string
responses:
'200':
description: Expected response to a valid request
content:
application/json:
schema:
$ref: "#/components/schemas/Pet"
/dogs:
get:
summary: List All Slim Dogs
operationId: listSlimDogs
tags:
- Slim Dogs
parameters:
- name: limit
in: query
description: How many items to return at one time (max 100)
required: false
schema:
type: integer
responses:
'200':
description: An array of slim dogs
content:
application/json:
schema:
$ref: "#/components/schemas/SlimDogs"
post:
summary: Create a Slim Dog
operationId: createSlimDogs
tags:
- Slim Dogs
responses:
'201':
description: Null response
/dogs/{dogId}:
get:
summary: Info For a Specific Dog
operationId: showDogById
tags:
- Slim Dogs
parameters:
- name: dogId
in: path
required: true
description: The id of the dog to retrieve
schema:
type: string
responses:
'200':
description: Expected response to a valid request
content:
application/json:
schema:
$ref: "#/components/schemas/Pet"
components:
schemas:
Pet:
required:
- id
- name
properties:
id:
type: integer
name:
type: string
tag:
type: string
FatCats:
type: array
description: list of fat cats
items:
$ref: "#/components/schemas/Pet"
SlimDogs:
type: array
description: list of slim dogs
items:
$ref: "#/components/schemas/Pet"
WildBoars:
type: array
description: list of wild boars
items:
$ref: "#/components/schemas/Pet"

app/main.py:

# generated by fastapi-codegen:# filename: swagger.yaml# timestamp: 2023-04-04T12:06:16+00:00from __future__ importannotationsfromfastapiimportFastAPIfrom .routersimportfat_cats, slim_dogs, wild_boarsapp=FastAPI(
version='1.0.0',
title='Swagger Petstore',
license={'name': 'MIT'},
servers=[
{'url': '/'},
{'url': 'http://petstore.swagger.io/v1'},
{'url': 'http://localhost:8080/'},
],
)
app.include_router(fat_cats.router)
app.include_router(slim_dogs.router)
app.include_router(wild_boars.router)
@app.get("/")asyncdefroot():
return {"message": "Gateway of the App"}

app/models.py:

# generated by fastapi-codegen:# filename: swagger.yaml# timestamp: 2023-04-04T12:06:16+00:00from __future__ importannotationsfromtypingimportList, OptionalfrompydanticimportBaseModel, FieldclassPet(BaseModel):
id: intname: strtag: Optional[str] =NoneclassFatCats(BaseModel):
__root__: List[Pet] =Field(..., description='list of fat cats')
classSlimDogs(BaseModel):
__root__: List[Pet] =Field(..., description='list of slim dogs')
classWildBoars(BaseModel):
__root__: List[Pet] =Field(..., description='list of wild boars')

app/routers/fat_cats.py:

# generated by fastapi-codegen:# filename: swagger.yaml# timestamp: 2023-04-04T12:06:16+00:00from __future__ importannotationsfromfastapiimportAPIRouterfrom ..dependenciesimport*router=APIRouter(tags=['Fat Cats'])
@router.get('/cats', response_model=FatCats, tags=['Fat Cats'])deflist_fat_cats(limit: Optional[int] =None) ->FatCats:
""" List All Fat Cats """pass@router.post('/cats', response_model=None, tags=['Fat Cats'])defcreate_fat_cats() ->None:
""" Create a Fat Cat """pass@router.get('/cats/{cat_id}', response_model=Pet, tags=['Fat Cats'])defshow_cat_by_id(cat_id: str=Path(..., alias='catId')) ->Pet:
""" Info For a Specific Cat """pass

app/routers/slim_dogs.py:

# generated by fastapi-codegen:# filename: swagger.yaml# timestamp: 2023-04-04T12:06:16+00:00from __future__ importannotationsfromfastapiimportAPIRouterfrom ..dependenciesimport*router=APIRouter(tags=['Slim Dogs'])
@router.get('/dogs', response_model=SlimDogs, tags=['Slim Dogs'])deflist_slim_dogs(limit: Optional[int] =None) ->SlimDogs:
""" List All Slim Dogs """pass@router.post('/dogs', response_model=None, tags=['Slim Dogs'])defcreate_slim_dogs() ->None:
""" Create a Slim Dog """pass@router.get('/dogs/{dog_id}', response_model=Pet, tags=['Slim Dogs'])defshow_dog_by_id(dog_id: str=Path(..., alias='dogId')) ->Pet:
""" Info For a Specific Dog """pass

app/routers/wild_boars.py:

# generated by fastapi-codegen:# filename: swagger.yaml# timestamp: 2023-04-04T12:06:16+00:00from __future__ importannotationsfromfastapiimportAPIRouterfrom ..dependenciesimport*router=APIRouter(tags=['Wild Boars'])
@router.get('/boars', response_model=WildBoars, tags=['Wild Boars'])deflist_wild_boars(limit: Optional[int] =None) ->WildBoars:
""" List All Wild Boars """pass@router.post('/boars', response_model=None, tags=['Wild Boars'])defcreate_wild_boars() ->None:
""" Create a Wild Boar """pass@router.get('/boars/{boar_id}', response_model=Pet, tags=['Wild Boars'])defshow_boar_by_id(boar_id: str=Path(..., alias='boarId')) ->Pet:
""" Info For a Specific Boar """pass

app/dependencies.py:

# generated by fastapi-codegen:# filename: swagger.yaml# timestamp: 2023-04-04T12:06:16+00:00from __future__ importannotationsfromtypingimportOptionalfromfastapiimportPathfrom .modelsimportFatCats, Pet, SlimDogs, WildBoars

PyPi

https://pypi.org/project/fastapi-code-generator

License

fastapi-code-generator is released under the MIT License. http://www.opensource.org/licenses/mit-license

Name		Name	Last commit message	Last commit date
Latest commit History 557 Commits
.github		.github
docs		docs
fastapi_code_generator		fastapi_code_generator
scripts		scripts
tests		tests
.gitignore		.gitignore
.pre-commit-config.yaml		.pre-commit-config.yaml
LICENSE		LICENSE
README.md		README.md
mkdocs.yml		mkdocs.yml
mypy.ini		mypy.ini
poetry.lock		poetry.lock
pyproject.toml		pyproject.toml
swagger.yaml		swagger.yaml

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fastapi-code-generator

This project is in experimental phase.

Help

Installation

Usage

Pydantic 2 support

Example

OpenAPI

Custom Template

Variables

default template

modular template

Custom Visitors

custom template

custom visitor

Multiple Files using APIRouter (For Bigger Applications)

PyPi

License

About

Releases

Packages

Contributors

Languages

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Repository files navigation

fastapi-code-generator

This project is in experimental phase.

Help

Installation

Usage

Pydantic 2 support

Example

OpenAPI

Custom Template

Variables

default template

modular template

Custom Visitors

custom template

custom visitor

Multiple Files using APIRouter (For Bigger Applications)

PyPi

License

About

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Stars

Watchers

Forks

Releases

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Contributors

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