1f01ce9615
* Updated .py files with Optional tag (up to body_nested_models) * Update optionals * docs_src/ all updates, few I was unsure of * Updated markdown files with Optional param * es: Add Optional typing to index.md * Last of markdown files updated with Optional param * Update highlight lines * it: Add Optional typings * README.md: Update with Optional typings * Update more highlight increments * Update highlights * schema-extra-example.md: Update highlights * updating highlighting on website to reflect .py changes * Update highlighting for query-params & response-directly * Address PR comments * Get rid of unnecessary comment * ⏪ Revert Optional in Chinese docs as it probably also requires changes in text * 🎨 Apply format * ⏪ Revert modified example * ♻️ Simplify example in docs * 📝 Update OpenAPI callback example to use Optional * ✨ Add Optional types to tests * 📝 Update docs about query params, default to using Optional * 🎨 Update code examples line highlighting * 📝 Update nested models docs to use "type parameters" instead of "subtypes" * 📝 Add notes about FastAPI usage of None including: = None and = Query(None) and clarify relationship with Optional[str] * 📝 Add note about response_model_by_alias * ♻️ Simplify query param list example * 🔥 Remove test for removed example * ✅ Update test for updated example Co-authored-by: Christopher Nguyen <chrisngyn99@gmail.com> Co-authored-by: yk396 <yk396@cornell.edu> Co-authored-by: Kai Chen <kaichen120@gmail.com>
2 KiB
Body - Fields
The same way you can declare additional validation and metadata in path operation function parameters with Query, Path and Body, you can declare validation and metadata inside of Pydantic models using Pydantic's Field.
Import Field
First, you have to import it:
{!../../../docs_src/body_fields/tutorial001.py!}
!!! warning
Notice that Field is imported directly from pydantic, not from fastapi as are all the rest (Query, Path, Body, etc).
Declare model attributes
You can then use Field with model attributes:
{!../../../docs_src/body_fields/tutorial001.py!}
Field works the same way as Query, Path and Body, it has all the same parameters, etc.
!!! note "Technical Details"
Actually, Query, Path and others you'll see next create objects of subclasses of a common Param class, which is itself a subclass of Pydantic's FieldInfo class.
And Pydantic's `Field` returns an instance of `FieldInfo` as well.
`Body` also returns objects of a subclass of `FieldInfo` directly. And there are others you will see later that are subclasses of the `Body` class.
Remember that when you import `Query`, `Path`, and others from `fastapi`, those are actually functions that return special classes.
!!! tip
Notice how each model's attribute with a type, default value and Field has the same structure as a path operation function's parameter, with Field instead of Path, Query and Body.
Add extra information
You can declare extra information in Field, Query, Body, etc. And it will be included in the generated JSON Schema.
You will learn more about adding extra information later in the docs, when learning to declare examples.
Recap
You can use Pydantic's Field to declare extra validations and metadata for model attributes.
You can also use the extra keyword arguments to pass additional JSON Schema metadata.