FastAPI post request and input data validation.

Author: Dattatraya Tembare

README.md

@@ -1,2 +1,15 @@
 # python-fastapi
 Python FastAPI examples
+
+**Pydantic:**
+
+Data validation and settings management using python type annotations.
+
+pydantic enforces type hints at runtime, and provides user friendly errors when data is invalid.
+
+Define how data should be in pure, canonical python; validate it with pydantic.
+
+**OpenAPI/Swagger UI:**
+
+A document (or set of documents) that defines or describes an API. An OpenAPI definition uses and conforms 
+to the OpenAPI Specification.

data_validation_query_path.py

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+import uvicorn
+from fastapi import FastAPI, Query, Path
+
+app = FastAPI(debug=True)
+item_id: str
+
+
+@app.get("/items/")
+async def read_items(item_id: str = Query(..., min_length=2, max_length=10, regex="^Item\d{1,6}")):
+    """
+    Validate query string parameter values
+    :param item_id:
+    :return:
+    """
+    results = {"items": [{"item_id": "Pen"}, {"item_id": "Pencil"}]}
+    results.update({"New Item": item_id})
+    return {"item": item_id}
+
+
+@app.get("/items/{item_id}")
+async def get_items(item_id: int = Path(..., le=10, ge=2, title="Item Id")):
+    """
+    Validate Path parameter values.
+    :param item_id:
+    :return:
+    """
+    return {"item_id": item_id}
+
+
+if __name__ == "__main__":
+    uvicorn.run(app, host="127.0.0.1", port=8000)

post_request_example.py

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+import uvicorn
+from fastapi import FastAPI
+from pydantic import BaseModel
+
+app = FastAPI(debug=True)
+
+
+class Item(BaseModel):
+    name: str
+    description: str = None
+    price: float
+    tax: float = None
+
+
+@app.post("/items/")
+async def create_item(item: Item):
+    item_dict = item.dict()
+    if item.tax:
+        total = item.price + item.tax
+        item_dict.update({"TotalAmount": total})
+    return item_dict
+
+
+if __name__ == "__main__":
+    uvicorn.run(app, host="127.0.0.1", port=8000)