chocs-middleware-openapi

Chocs-OpenApi

OpenApi middleware for chocs library.

Newest OpenAPI Specification (v.3.x) can be easily integrated into Chocs through application's middleware. Validation is performed via JsonSchema Draft-7.0 specification and all commonly used features are supported.

Features

Open api integration can be used to:

• validate request's body
• validate request's path parameters
• validate request's headers
• validate request's query parameters
• validate request's cookies
• generate dtos from openapi file

Installation

With pip,

pip install chocs-middleware.openapi

or through poetry

poetry add chocs-middleware.openapi

Usage

Using your OpenAPI file

Chocs can read json and yaml files, this example will cover yaml usage although the only difference is the file extension.

import chocs
from chocs_middleware.openapi import OpenApiMiddleware
from os import path

# absolute path to file containing open api documentation; yaml and json files are supported
openapi_filename = path.join(path.dirname(__file__), "/openapi.yml")

# instantiating application and passing open api middleware
app = chocs.Application(OpenApiMiddleware(openapi_filename, validate_body=True, validate_query=True))

# the registered route must correspond to open api route within `path` section.
# if request body is invalid the registered controller will not be invoked
@app.post("/pets")
def create_pet(request: chocs.HttpRequest) -> chocs.HttpResponse:
  ...
  return chocs.HttpResponse(status=200)

Complete integration example can be found here

Keep in mind registered route has to match 1:1 the specified route inside paths section inside your OpenApi documentation

Validating request body

Below is very simple schema to validate request body of a POST /pet request. Request body is required, should be valid json request and contain the following properties:

• name (string)
• tags (array of string)
• id (optional string)

openapi.yml

openapi: "3.0.0"
info:
  version: "1.0.0"
  title: "Pet Store"
paths:
  /pets:
    post:
      description: Creates a new Pet
      requestBody:
        description: Pet
        required: true
        content:
          application/json:
            schema:
              $ref: "#/components/schemas/Pet"
      responses:
        200:
          description: "Success"
components:
  schemas:
    Pet:
      type: object
      required:
        - name
        - tag
      properties:
        id:
          type: integer
        name:
          type: string
        tag:
          type: array
          items:
            type: string

app.py

import chocs
from chocs_middleware.openapi import OpenApiMiddleware
from os import path

openapi_filename = path.join(path.dirname(__file__), "/openapi.yml")
app = chocs.Application(OpenApiMiddleware(openapi_filename, validate_body=True))

@app.post("/pets")
def create_pet(request: chocs.HttpRequest) -> chocs.HttpResponse:
  pet = request.parsed_body # here we will get valid pet
  return chocs.HttpResponse(status=200)

chocs.serve(app)

create_pet controller will be only invoked if request contains valid body. Pet's data can be accessed through request.parsed_body which is a dict-like object.

Json schema support

Chocs uses JSON Schema to validate your open api definitions with full draft-7 support and almost complete 2019-09 standard support. This means you can use almost every feature described on the understanding json schema webpage. The webpage is a great resource full of examples and detailed descriptions around JSON Schema.

There are some caveats around allOf validator:

• all object schemas inside allOf definition are automatically composed into a single object definition
• when combining string validators make sure format validator is the last validator in the pipeline otherwise validation might fail due to string casting