vigneshjs · October 8, 2024 04:37 · May 6, 2021 · May 4, 2021 · May 4, 2021
diff --git a/app.py b/app.py
@@ -1,10 +1,10 @@
 """
- FastAPI uses pydantic models to validate API request body and also generate swagger documentation. Since the schema generated
- by pydantic comply to JSON schema specification and not to openAPI specification, swagger documentation generated from pydantic 
- models do not support adding multiple examples for a request body.
+ FastAPI uses pydantic models to validate the API request body and also generate the swagger documentation. Since the schema 
+ generated by pydantic only comply to JSON schema specification and not to openAPI specification, swagger documentation 
+ generated from pydantic models do not support adding multiple examples for a request body.
  Ref: https://fastapi.tiangolo.com/tutorial/schema-extra-example/#technical-details
  
- In the following code I have extended fastAPI openAPI schema to include multiple request body examples.
+ In the following code, I have extended fastAPI openAPI schema to include multiple request body examples.
 """
 
 import json

diff --git a/app.py b/app.py
@@ -0,0 +1,100 @@
+"""
+ FastAPI uses pydantic models to validate API request body and also generate swagger documentation. Since the schema generated
+ by pydantic comply to JSON schema specification and not to openAPI specification, swagger documentation generated from pydantic 
+ models do not support adding multiple examples for a request body.
+ Ref: https://fastapi.tiangolo.com/tutorial/schema-extra-example/#technical-details
+ 
+ In the following code I have extended fastAPI openAPI schema to include multiple request body examples.
+"""
+
+import json
+
+from fastapi import FastAPI, routing, status
+from fastapi.openapi.utils import get_openapi
+from fastapi.responses import Response
+from pydantic import BaseModel
+
+app = FastAPI()
+
+
+# Defining a basic pydantic class that will be used by fastAPI to validate request body and generate swagger
+class Sample(BaseModel):
+    """
+        This is a example pydantic model
+    """
+
+    name: str
+    email: str
+    mobile_number: str
+    password: str
+    otp: str
+
+    class Config:
+        # Follow openAPI 3.0 specification for defining examples. Ref: https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.0.0.md#example-object
+        schema_extra = {
+            "examples": {
+                "Login with otp": {
+                    "description": "Allows to user to login with mobile_number and OTP",
+                    "value": {
+                        "mobile_number": "+9157878787878",
+                        "opt": "123321"
+                    }
+                },
+                "Login with email": {
+                    "description": "Allows to user to login with email and password",
+                    "value": {
+                        "email": "[email protected]",
+                        "password": "userPassword"
+                    }
+                }
+            }
+        }
+
+@app.post("/login", status_code=200)
+async def login(body: Sample):
+    """
+        Login user
+    """
+    return Response({
+        "status": "success"
+    }, status_code=status.HTTP_200_OK)
+
+
+# Extending openapi
+def custom_openapi():
+    if app.openapi_schema:
+        return app.openapi_schema
+    openapi_schema = get_openapi(
+        title="Sample API",
+        version="0.1.0",
+        description="These APIs will be used to manage developer portal and configure applications and permissions",
+        routes=app.routes,
+    )
+
+    # Adding examples present in pydancticModel.schema_extra into openAPI schema
+    for route in app.routes:
+        if isinstance(route, routing.APIRoute):
+            # bodyField refers to the field present in the function that is called when route matches
+            bodyField = route.body_field
+            if bodyField:
+                # Use pydantic schema_json() to get json schema representation (string) of the pydantic model
+                modelSchema = bodyField.type_.schema_json()
+                if modelSchema:
+                    # Parse dict object from json string
+                    jsonModelSchema = json.loads(modelSchema)
+                    if "examples" in jsonModelSchema:
+                        examples = jsonModelSchema['examples']
+                        for method in route.methods:
+                            # We can have requestBody examples only for POST and PUT methods
+                            if method == "POST":
+                                openapi_schema['paths'][route.path]["post"]['requestBody'][
+                                    'content']['application/json']['examples'] = examples
+                            elif method == "PUT":
+                                openapi_schema['paths'][route.path]["put"]['requestBody'][
+                                    'content']['application/json']['examples'] = examples
+
+    app.openapi_schema = openapi_schema
+    return app.openapi_schema
+
+
+app.openapi = custom_openapi