return Model2(
        ref=Model1(foo="simple_include model foo", bar="simple_include model bar"),
        baz="simple_include model2 baz",
    )


@app.get(
    "/simple_include_dict",
    response_model=Model2,
    response_model_include={"baz": ..., "ref": {"foo"}},
)
def simple_include_dict():
    return {
        "ref": {
            "foo": "simple_include_dict model foo",

from fastapi import FastAPI
from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()


class Model(BaseModel):
    pass


class Model2(BaseModel):
    a: Model


class Model3(BaseModel):
    c: Model
    d: Model2


@app.get("/", response_model=Model3)
def f():
    return {"c": {}, "d": {"a": {}}}


client = TestClient(app)


def test_get_api_route():

# Query Parameter Models

If you have a group of **query parameters** that are related, you can create a **Pydantic model** to declare them.

This would allow you to **re-use the model** in **multiple places** and also to declare validations and metadata for all the parameters at once. 😎

/// note

This is supported since FastAPI version `0.115.0`. 🤓

///

## Query Parameters with a Pydantic Model

    return client


@needs_pydanticv1
def test_filter_sub_model(client: TestClient):
    response = client.get("/model/modelA")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "name": "modelA",
        "description": "model-a-desc",
        "model_b": {"username": "test-user"},
    }


@needs_pydanticv1
def test_validator_is_cloned(client: TestClient):

import peewee

from .database import db


class User(peewee.Model):
    email = peewee.CharField(unique=True, index=True)
    hashed_password = peewee.CharField()
    is_active = peewee.BooleanField(default=True)

    class Meta:
        database = db


class Item(peewee.Model):
    title = peewee.CharField(index=True)
    description = peewee.CharField(index=True)
    owner = peewee.ForeignKeyField(User, backref="items")

    response = client.get("/model/modelA")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "name": "modelA",
        "description": "model-a-desc",
        "foo": {"username": "test-user"},
    }


@needs_pydanticv2
def test_validator_is_cloned(client: TestClient):
    with pytest.raises(ResponseValidationError) as err:
        client.get("/model/modelX")

              <exclude>org.apache.maven.model.composition.DefaultDependencyManagementImporter#importManagement(org.apache.maven.model.Model,java.util.List,org.apache.maven.model.building.ModelBuildingRequest,org.apache.maven.model.building.Mo...

        Model initial = new Model(org.apache.maven.api.model.Model.newBuilder()
                .parent(org.apache.maven.api.model.Parent.newBuilder()
                        .groupId("GROUPID")
                        .artifactId("ARTIFACTID")
                        .build())
                .build());
        Model expected = new Model(org.apache.maven.api.model.Model.newBuilder()

# Extra Models

Continuing with the previous example, it will be common to have more than one related model.

This is especially the case for user models, because:

* The **input model** needs to be able to have a password.
* The **output model** should not have a password.
* The **database model** would probably need to have a hashed password.

/// danger

Never store user's plaintext passwords. Always store a "secure hash" that you can then verify.

     */
    default org.apache.maven.api.model.Model injectProfile(
            org.apache.maven.api.model.Model model,
            org.apache.maven.api.model.Profile profile,
            ModelBuildingRequest request,
            ModelProblemCollector problems) {
        Model m = new Model(model);
        injectProfile(m, profile != null ? new Profile(profile) : null, request, problems);