## Streaming de SSE con FastAPI { #stream-sse-with-fastapi }

Para hacer streaming de SSE con FastAPI, usa `yield` en tu path operation function y establece `response_class=EventSourceResponse`.

import `EventSourceResponse` de `fastapi.sse`:

{* ../../docs_src/server_sent_events/tutorial001_py310.py ln[1:25] hl[4,22] *}

Cada ítem producido con `yield` se codifica como JSON y se envía en el campo `data:` de un evento SSE.

OAuth2 specifies that when using the "password flow" (that we are using) the client/user must send a `username` and `password` fields as form data.

And the spec says that the fields have to be named like that. So `user-name` or `email` wouldn't work.

But don't worry, you can show it as you wish to your final users in the frontend.

| `terms_of_service` | `str` | APIの利用規約へのURLです。指定する場合、URLである必要があります。 |

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

app = FastAPI()


class ResponseModel(BaseModel):
    code: int = 200
    message: str = Field(default_factory=lambda: "Successful operation.")


@app.get(
    "/response_model_has_default_factory_return_dict",
    response_model=ResponseModel,
)
async def response_model_has_default_factory_return_dict():

    with runner.isolated_filesystem():
        yield runner


@pytest.fixture(name="root_dir")
def prepare_paths(runner):
    docs_dir = Path("docs")
    en_docs_dir = docs_dir / "en" / "docs"
    lang_docs_dir = docs_dir / "lang" / "docs"
    en_docs_dir.mkdir(parents=True, exist_ok=True)
    lang_docs_dir.mkdir(parents=True, exist_ok=True)
    yield Path.cwd()


@pytest.fixture

package gorm

import "time"

// Model a basic GoLang struct which includes the following fields: ID, CreatedAt, UpdatedAt, DeletedAt
// It may be embedded into your model or you may build your own model without it
//
//	type User struct {
//	  gorm.Model
//	}
type Model struct {
	ID        uint `gorm:"primarykey"`
	CreatedAt time.Time
	UpdatedAt time.Time
	DeletedAt DeletedAt `gorm:"index"`

 * the License.
 */

package com.google.common.collect;

import static java.lang.annotation.ElementType.CONSTRUCTOR;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.ElementType.TYPE;

import java.lang.annotation.Target;

/**

 * the License.
 */

package com.google.common.io;

import static java.lang.annotation.ElementType.CONSTRUCTOR;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.ElementType.TYPE;

import java.lang.annotation.Target;

/**

 * the License.
 */

package com.google.common.base;

import static java.lang.annotation.ElementType.CONSTRUCTOR;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.ElementType.TYPE;

import java.lang.annotation.Target;

/**

from typing import Annotated

import pytest
from fastapi import FastAPI, Query
from fastapi.testclient import TestClient
from inline_snapshot import snapshot
from pydantic import BaseModel, Field

app = FastAPI()

# =====================================================================================
# Without aliases


@app.get("/optional-str")
async def read_optional_str(p: str | None = None):
    return {"p": p}