Querystring Validation¶
The querystring is an optional part of the URL that allows for parameters to be specified. It makes sense to check that they’ve sent it in a format you understand. This is done by validating them against a schema you define. Quart-Schema allows validation via decorating the route handler, as so,
from dataclasses import dataclass
from quart_schema import validate_querystring
@dataclass
class Query:
count_le: Optional[int] = None
count_gt: Optional[int] = None
@app.route("/")
@validate_querystring(Query)
async def index(query_args: Query):
...
this will allow the client to add a count_le, count_gt, or
both parameters to the URL e,g. /?count_le=2&count_gt=0.
If the client doesn’t supply correctly structured data they will
receive a 400 (bad request) response without your route handler
running. If the client does supploy correctly structured data it will
be passed into your route handler as the query_args argument.
Note
Querystring parameters must be optional defaulting to
None (as querystrings are optional).
Handling validation errors¶
By default if the client sends a body that doesn’t satisfy the schema a 400 bad request response will be sent. You can alter this by adding an error handler, for example for a JSON error response,
from quart_schema import RequestSchemaValidationError
@app.errorhandler(RequestSchemaValidationError)
async def handle_request_validation_error():
return {"error": "VALIDATION"}, 400