Pydantic errors

Pydantic has been a game-changer in defining and using data types. It makes the code way more readable and robust while feeling like a natural extension to the language.

First, let’s create a standard pydantic model and use the default validators to validate and normalize our data. A pydantic model is simply a class that inherits from the BaseModel of pydantic. The properties of the model are declared with type annotations which will be used for data validation and conversion. Note that you need to install pydantic with pip first.

Is it possible to return a list of validation errors for a specific field, without having separate validators for the same field? It would be nice to get all errors back in 1 shot for the field, instead of having to get separate responses back for each failed validation.

However, "msg" comes as a string list. Can we get that as a list?

If you check out the class delcaration ValidationError In the repository for pydantic, you see how the msg prop is generated using the method error_dict

In some cases, a ForwardRef won’t be able to be resolved during model creation. For example, this happens whenever a model references itself as a field type. When this happens, you’ll need to call update_forward_refs after the model has been created before it can be used.

A few things to note on validators:

• validators are “class methods”, so the first argument value they receive is the UserModel class, not an instance of UserModel.
• the second argument is always the field value to validate; it can be named as you please.

The problem with implementing schema.org in pydantic is that there are a lot of (circular) references. Importing the all the models in the package’s init.py is a solution makes the package initial import very slow..

I merged your suggestion in the library. It was indeed importing the ISO8601Date from the wrong directory.

This client could be a browser with a frontend, a code from someone else, an IoT device, etc.

You could need to tell the client that:

• The client doesn’t have enough privileges for that operation.
• The client doesn’t have access to that resource.
• The item the client was trying to access doesn’t exist.
• etc.

It is an easy-to-use tool that helps developers validate and parse data based on given definitions, all fully integrated with Python’s type hints. The principal use cases include reading application configurations, checking API requests, and creating any data structure one might need as an internal building block.

I believe this should now be without quotes since you declared the reference.
class User(pydantic.BaseModel):
in_projects: List[Project] = []