Fastapi: Regex Amazon ASIN

[tiger360]

I would like to use this regex for the "asin" query.
What's wrong with what I am doing.
None of the test strings here https://regexr.com/3gk2s, are validate with that regex.

@router.post("/product",  tags=["products"])
async def create_product(product: Product, asin: str = Query(None, regex='/(?:[/dp/]|$)([A-Z0-9]{10})/g')):
    """ Create a product   """
    product_dict = product.dict()
    if product.asin:
        product_dict.update({'is_imported': True})
    return product_dict

Thanks

[dbanty]

@tiger360 I think you just don't need the starting "/" and ending "/g". Did you test the regex in Python using the builtin re module?

[dbanty]

Also, generally you want to put regexes in Python in "raw strings" so you can use regex- specific escapes without Python getting mad. You aren't using any escapes it looks like, but it is best practice. Plus some IDEs will give you extra regexy features!

Just add r to the front of the string like r'(?:[/dp/]|$)([A-Z0-9]{10})'.

[tiger360]

yes I tried with python here : https://repl.it/join/xujwnmwd-tiger360
but I still have the error message :

{
  "detail": [
    {
      "loc": [
        "query",
        "a"
      ],
      "msg": "string does not match regex \"(?:[/dp/]|$)([A-Z0-9]{10})\"",
      "type": "value_error.str.regex",
      "ctx": {
        "pattern": "(?:[/dp/]|$)([A-Z0-9]{10})"
      }
    }
  ]
}

with that code with fastapi :

@router.post("/product",  tags=["products"])
async def create_product(a: str = Query(None, regex=r'(?:[/dp/]|$)([A-Z0-9]{10})')):
    """ Create a product   """    
    return a

[dbanty]

I'm pretty sure the regex you provide as a validation needs to match the entire string. Similar to re.fullmatch I believe.

Tweak your regex until it matches the entire URL and you should be all set.

[tiger360]

Ok thanks that's what I did

@router.post("/product",  tags=["products"])
async def create_product(a: str = Query(None, regex=r'.*/?B[\dA-Z]{9}|\d{9}(X|\d)')):
    return a

[tiangolo]

Thanks for the help here @dbanty ! :clap: :bow:

Thanks for reporting back and closing the issue @tiger360 :+1: