# aiohttp-valera-validator
[](https://codecov.io/gh/tsv1/aiohttp-valera-validator)
[](https://pypi.python.org/pypi/aiohttp-valera-validator/)
[](https://pypi.python.org/pypi/aiohttp-valera-validator/)
[](https://pypi.python.org/pypi/aiohttp-valera-validator/)
Request validation for [aiohttp](https://docs.aiohttp.org/en/stable/) (via [valera](https://github.com/tsv1/valera))
## Installation
```shell
$ pip3 install aiohttp-valera-validator
```
## Usage
```python
from aiohttp.web import Application, json_response, route, run_app
from district42 import schema
from aiohttp_valera_validator import validate
ParamsSchema = schema.dict({
"q": schema.str.len(1, ...)
})
@validate(params=ParamsSchema)
async def handler(request):
q = request.query["q"]
return json_response({"q": q})
app = Application()
app.add_routes([route("GET", "/users", handler)])
run_app(app)
```
```javascript
// http /users?q=Bob
{
"q": "Bob"
}
```
```javascript
// http /users
{
"errors": [
"Value <class 'str'> at _['q'] must have at least 1 element, but it has 0 elements"
]
}
```
## Docs
### Query params validation
```python
from district42 import schema
from aiohttp_valera_validator import validate
# schema.dict is strict by default (all keys must be present)
ParamsSchema = schema.dict({
"q": schema.str.len(1, ...)
})
@routes.get("/users")
@validate(params=ParamsSchema)
async def handler(request):
q = request.query["q"]
return json_response({"q": q})
```
### Headers validation
```python
from district42 import schema
from aiohttp_valera_validator import validate
from multidict import istr
# "..." means that there can be any other keys
# headers are case-insensitive, so we use istr for
HeadersSchema = schema.dict({
istr("User-Agent"): schema.str.len(1, ...),
...: ...
})
@routes.get("/users")
@validate(headers=HeadersSchema)
async def handler(request):
user_agent = request.headers["User-Agent"]
return json_response({"user_agent": user_agent})
```
### JSON body validation
```python
from district42 import schema
from aiohttp_valera_validator import validate
BodySchema = schema.dict({
"id": schema.int.min(1),
"name": schema.str.len(1, ...),
})
@routes.post("/users")
@validate(json=BodySchema)
async def handler(request):
payload = await request.json()
return json_response({
"id": payload["id"],
"name": payload["name"]
})
```
### URL segments validation
Segments — is a variable part of URL path (aiohttp [uses](https://docs.aiohttp.org/en/stable/web_quickstart.html#variable-resources) `match_info` for it)
```python
from district42 import schema
from aiohttp_valera_validator import validate
SegmentsSchema = schema.dict({
"user_id": schema.str.regex(r"[1-9][0-9]*"),
})
@routes.get("/users/{user_id}")
@validate(segments=SegmentsSchema)
async def handler(request):
user_id = int(request.match_info["user_id"])
return json_response({"user_id": user_id})
```
### Custom response
```python
from http import HTTPStatus
from aiohttp.web import Request, Response
from aiohttp_valera_validator import validate as validate_orig
class validate(validate_orig):
def create_error_response(self, request: Request, errors: List[str]) -> Response:
status = HTTPStatus.UNPROCESSABLE_ENTITY
body = "<ul>" + "".join(f"<li>{error}</li>" for error in errors) + "</ul>"
return Response(status=status, text=body, headers={"Content-Type": "text/html"})
```
—
Fore more information read [valera docs](https://github.com/tsv1/valera)