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I have an endpoint in in which the main body parameter was defined as follows:

@router.post("/myendpoint")
async def delete_objectss(param: DeleteItemParams = DeleteItemParamsMetadata, 
                          .....)

Reason behind this is that I needed:

DeleteItemParamsMetadata = Body(None, description="my verbose description  " \
" that will appear on swaggerui under the schema of this parameter")

Now I have a need for performing some custom checks when I receive this parameter, in order to have that dependency sorted, I could replace my param definition within /myendpoint as follows:

@router.post("/myendpoint")
async def delete_objectss(param: DeleteItemParams = Depends(validate_param), 
                          .....)

or course where I have somewhere a definition

def validate_param(param: DeleteItemParams):
 if bla_bla: # lenghty and complex condition
    raise HTTPException(status_code=422, detail="Invalid item")
 
 param = possibly_alter_param_in_some_way(param)

 return param

The problem I have now, is that as far as I know Depends does not support a description field, so I now lost my verbose description that would have appeared on swaggerui.

Does anyone know of a way so I can have the best of both worlds and have the dependency pulled AND the description processed?

Thank you to anyone who has any input!

Chris
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Fabri Ba
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  • Any reason why you don't define `DeleteItemParams` as `= Body(None, description="my verbose description that will appear on swaggerui under the schema of this parameter")` in your dependency? You can also move the validation to your Pydantic model instead and thus get it out of your dependency - if it is relevant for all instances of `DeleteItemParams` (and if not, it might be worth separating it into a specific domain model instead, where one has that specific validation and other doesn't). – MatsLindh Nov 24 '22 at 12:11
  • Thank you!!! So simple, I didn't think of it! --- ```def validate_param(param: DeleteItemParams = DeleteItemParamsMetadata):``` worked. Can you suggest it as an answer I'll give you credit for that? – Fabri Ba Nov 24 '22 at 13:47

1 Answers1

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A parameter in a dependency can have a Body reference (or any other type) and it will be resolved correctly. Since you removed that metadata reference in your example it won't show up. You can fix that by adding it back:

DeleteItemParamsMetadata = Body(None, description="my verbose description  " \
" that will appear on swaggerui under the schema of this parameter")

def validate_param(param: DeleteItemParams = DeleteItemParamsMetadata):

or directly inline:

def validate_param(param: DeleteItemParams = Body(None, description="my verbose description that will appear on swaggerui under the schema of this parameter")):
MatsLindh
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