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Reorder FastAPI serialization

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Yerassyl Zhanymkanov
2024-06-08 12:44:39 +02:00
parent 9728f53e3d
commit a4c9fc4c1f
1 changed files with 53 additions and 54 deletions
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@@ -21,9 +21,9 @@ Some of them are worth sharing.
- [Prefer `async` dependencies](#prefer-async-dependencies)
- [Miscellaneous](#miscellaneous)
- [Follow the REST](#follow-the-rest)
- [ValueErrors might become Pydantic ValidationError](#valueerrors-might-become-pydantic-validationerror)
- [If you must use sync SDK, then run it in a thread pool.](#if-you-must-use-sync-sdk-then-run-it-in-a-thread-pool)
- [FastAPI response serialization](#fastapi-response-serialization)
- [If you must use sync SDK, then run it in a thread pool.](#if-you-must-use-sync-sdk-then-run-it-in-a-thread-pool)
- [ValueErrors might become Pydantic ValidationError](#valueerrors-might-become-pydantic-validationerror)
- [Docs](#docs)
- [Set DB keys naming conventions](#set-db-keys-naming-conventions)
- [Migrations. Alembic](#migrations-alembic)
@@ -507,6 +507,57 @@ async def get_user_profile_by_id(
return creator_profile
```
### FastAPI response serialization
If you think you can return Pydantic object that matches your route's `response_model` to make some optimizations,
then it's wrong.
FastAPI firstly converts that pydantic object to dict with its `jsonable_encoder`, then validates
data with your `response_model`, and only then serializes your object to JSON.
```python
from fastapi import FastAPI
from pydantic import BaseModel, root_validator
app = FastAPI()
class ProfileResponse(BaseModel):
@model_validator(mode="after")
def debug_usage(self):
print("created pydantic model")
return self
@app.get("/", response_model=ProfileResponse)
async def root():
return ProfileResponse()
```
**Logs Output:**
```
[INFO] [2022-08-28 12:00:00.000000] created pydantic model
[INFO] [2022-08-28 12:00:00.000020] created pydantic model
```
### If you must use sync SDK, then run it in a thread pool.
If you must use a library to interact with external services, and it's not `async`,
then make the HTTP calls in an external worker thread.
We can use the well-known `run_in_threadpool` from starlette.
```python
from fastapi import FastAPI
from fastapi.concurrency import run_in_threadpool
from my_sync_library import SyncAPIClient
app = FastAPI()
@app.get("/")
async def call_my_sync_library():
my_data = await service.get_my_data()
client = SyncAPIClient()
await run_in_threadpool(client.make_request, data=my_data)
```
### ValueErrors might become Pydantic ValidationError
If you raise a `ValueError` in a Pydantic schema that is directly faced by the client, it will return a nice detailed response to users.
@@ -546,58 +597,6 @@ async def get_creator_posts(profile_data: ProfileCreate):
<img src="images/value_error_response.png" width="400" height="auto">
### If you must use sync SDK, then run it in a thread pool.
If you must use a library to interact with external services, and it's not `async`,
then make the HTTP calls in an external worker thread.
We can use the well-known `run_in_threadpool` from starlette.
```python
from fastapi import FastAPI
from fastapi.concurrency import run_in_threadpool
from my_sync_library import SyncAPIClient
app = FastAPI()
@app.get("/")
async def call_my_sync_library():
my_data = await service.get_my_data()
client = SyncAPIClient()
await run_in_threadpool(client.make_request, data=my_data)
```
### FastAPI response serialization
If you think you can return Pydantic object that matches your route's `response_model` to make some optimizations,
then it's wrong.
FastAPI firstly converts that pydantic object to dict with its `jsonable_encoder`, then validates
data with your `response_model`, and only then serializes your object to JSON.
```python
from fastapi import FastAPI
from pydantic import BaseModel, root_validator
app = FastAPI()
class ProfileResponse(BaseModel):
@model_validator(mode="after")
def debug_usage(self):
print("created pydantic model")
return self
@app.get("/", response_model=ProfileResponse)
async def root():
return ProfileResponse()
```
**Logs Output:**
```
[INFO] [2022-08-28 12:00:00.000000] created pydantic model
[INFO] [2022-08-28 12:00:00.000020] created pydantic model
```
### Docs
1. Unless your API is public, hide docs by default. Show it explicitly on the selected envs only.
```python