Setting fixed length to a string

[ahopkins]

• middle version: 0.2.2
• Python version: 3.7.3
• Operating System: Alpine Linux v3.9

Description

Set a length requirement for a str

What I Did

class Foo(middle.Model):
    bar: str = middle.field(min_length=4, max_length=4)

ValueError: The 'min_length' keyword value must not be equal or greater than the 'max_length' keyword value. 

---

This seems like it should be possible. Or, perhaps:

bar: str = middle.field(length=4)

[ahopkins]

bar: str = middle.field(length=4)

This is valid. I did not check before posting this. Perhaps an error message in this case would be helpful?

ValueError: 'min_length' is equal to 'max_length'. Instead, consider using 'length'.

[vltr]

@ahopkins well, length should not be a valid keyword (I think it's derived from attrs), only min_length and max_length, as described in the OpenAPI 3 specs. Perhaps the length=X could be a shorthand for min_length=X, max_length=X as well?

[ahopkins]

I think it should be. Seems like a very useful shorthand. Especially if you are going to drop attrs as a dependency.

[ahopkins]

But... that's just one man's opinion 😉