FastAPI integration example

Author: Andrew Brookins

docs/fastapi_integration.md

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+# FastAPI Integration
+
+## Introduction
+
+This section includes a complete example showing how to integrate Redis OM with FastAPI.
+
+Good news: Redis OM was **specifically designed to integrate with FastAPI**!
+
+## Concepts
+
+### Every Redis OM Model is also a Pydantic model
+
+Every Redis OM model is also a Pydantic model, so you can define a model and then pass the model class into any location that FastAPI expects a Pydantic model.
+
+This means a couple of things:
+
+1. A Redis OM model can be used for request body validation
+2. Redis OM models show up in the auto-generated API documentation
+
+### Cache vs. Data
+
+Redis works well as either a durable data store or a cache, but the optiomal Redis configuration is often different between these two use cases.
+
+You almost always want to use a Redis instance tuned for caching when you're caching and a separate Redis instance tuned for data durability for storing application state.
+
+This example shows how to manage these two uses of Redis within the same application. The app uses a FastAPI caching framework and dedicated caching instance of Redis for caching, and a separate Redis instance tuned for durability for Redis OM models.
+
+
+## Example app code
+
+This is a complete example that you can run as-is:
+
+```python
+import datetime
+from typing import Optional
+
+import aioredis
+
+from fastapi import FastAPI, HTTPException
+from starlette.requests import Request
+from starlette.responses import Response
+
+from fastapi_cache import FastAPICache
+from fastapi_cache.backends.redis import RedisBackend
+from fastapi_cache.decorator import cache
+
+from pydantic import EmailStr
+
+from redis_om.model import HashModel, NotFoundError
+from redis_om.connections import get_redis_connection
+
+# This Redis instance is tuned for durability.
+REDIS_DATA_URL = "redis://localhost:6380"
+
+# This Redis instance is tuned for cache performance.
+REDIS_CACHE_URL = "redis://localhost:6381"
+
+
+class Customer(HashModel):
+    first_name: str
+    last_name: str
+    email: EmailStr
+    join_date: datetime.date
+    age: int
+    bio: Optional[str]
+
+
+app = FastAPI()
+
+
+@app.post("/customer")
+async def save_customer(customer: Customer):
+    # We can save the model to Redis by calling `save()`:
+    return customer.save()
+
+
+@app.get("/customers")
+async def list_customers(request: Request, response: Response):
+    # To retrieve this customer with its primary key, we use `Customer.get()`:
+    return {"customers": Customer.all_pks()}
+
+
+@app.get("/customer/{pk}")
+@cache(expire=10)
+async def get_customer(pk: str, request: Request, response: Response):
+    # To retrieve this customer with its primary key, we use `Customer.get()`:
+    try:
+        return Customer.get(pk)
+    except NotFoundError:
+        raise HTTPException(status_code=404, detail="Customer not found")
+
+
+@app.on_event("startup")
+async def startup():
+    r =  aioredis.from_url(REDIS_CACHE_URL, encoding="utf8", decode_responses=True)
+    FastAPICache.init(RedisBackend(r), prefix="fastapi-cache")
+
+    # You can set the Redis OM URL using the REDIS_OM_URL environment
+    # variable, or by manually creating the connection using your model's
+    # Meta object.
+    Customer.Meta.database = get_redis_connection(url=REDIS_DATA_URL, decode_responses=True)
+```
+
+## Testing the app
+
+You should install the app's dependencies first. This app uses Poetry, so you'll want to make sure you have that installed first:
+
+    $ pip install poetry
+
+Then install the dependencies:
+
+    $ poetry install
+
+Next, start the server:
+
+    $ poetry run uvicorn --reload main:test
+
+Then, in another shell, create a customer:
+
+    $ curl -X POST -H 'Content-Length: 0' "http://localhost:8000/customer"
+    $ curl -X POST  "http://localhost:8000/customer" -H 'Content-Type: application/json' -d '{"first_name":"Andrew","last_name":"Brookins","email":"[email protected]","age":"38","join_date":"2020
+-01-02"}'
+    {"pk":"01FM2G8EP38AVMH7PMTAJ123TA","first_name":"Andrew","last_name":"Brookins","email":"[email protected]","join_date":"2020-01-02","age":38,"bio":""}
+
+Get a copy of the value for "pk" and make another request to get that customer:
+
+    $ curl "http://localhost:8000/customer/01FM2G8EP38AVMH7PMTAJ123TA"
+    {"pk":"01FM2G8EP38AVMH7PMTAJ123TA","first_name":"Andrew","last_name":"Brookins","email":"[email protected]","join_date":"2020-01-02","age":38,"bio":""}
+
+You can also get a list of all customer PKs:
+
+    $ curl "http://localhost:8000/customers"
+    {"customers":["01FM2G8EP38AVMH7PMTAJ123TA"]}