Response class¶
You can declare a parameter in a path operation function or dependency to be of type Response and then you can set data for the response like headers or cookies.
You can also use it directly to create an instance of it and return it from your path operations.
Read more about it in the FastAPI docs about returning a custom Response
You can import it directly from fastapi:
fromfastapiimport Response
fastapi.Response ¶
Response(
content=None,
status_code=200,
headers=None,
media_type=None,
background=None,
)
Source code in starlette/responses.py
def__init__(
self,
content: Any = None,
status_code: int = 200,
headers: Mapping[str, str] | None = None,
media_type: str | None = None,
background: BackgroundTask | None = None,
) -> None:
self.status_code = status_code
if media_type is not None:
self.media_type = media_type
self.background = background
self.body = self.render(content)
self.init_headers(headers)
media_type
class-attribute
instance-attribute
¶
media_type = None
charset
class-attribute
instance-attribute
¶
charset = 'utf-8'
status_code
instance-attribute
¶
status_code = status_code
background
instance-attribute
¶
background = background
body
instance-attribute
¶
body = render(content)
headers
property
¶
headers
render ¶
render(content)
Source code in starlette/responses.py
defrender(self, content: Any) -> bytes | memoryview:
if content is None:
return b""
if isinstance(content, bytes | memoryview):
return content
return content.encode(self.charset) # type: ignore
init_headers ¶
init_headers(headers=None)
Source code in starlette/responses.py
definit_headers(self, headers: Mapping[str, str] | None = None) -> None:
if headers is None:
raw_headers: list[tuple[bytes, bytes]] = []
populate_content_length = True
populate_content_type = True
else:
raw_headers = [(k.lower().encode("latin-1"), v.encode("latin-1")) for k, v in headers.items()]
keys = [h[0] for h in raw_headers]
populate_content_length = b"content-length" not in keys
populate_content_type = b"content-type" not in keys
body = getattr(self, "body", None)
if (
body is not None
and populate_content_length
and not (self.status_code < 200 or self.status_code in (204, 304))
):
content_length = str(len(body))
raw_headers.append((b"content-length", content_length.encode("latin-1")))
content_type = self.media_type
if content_type is not None and populate_content_type:
if content_type.startswith("text/") and "charset=" not in content_type.lower():
content_type += "; charset=" + self.charset
raw_headers.append((b"content-type", content_type.encode("latin-1")))
self.raw_headers = raw_headers
set_cookie ¶
set_cookie(
key,
value="",
max_age=None,
expires=None,
path="/",
domain=None,
secure=False,
httponly=False,
samesite="lax",
partitioned=False,
)
Source code in starlette/responses.py
defset_cookie(
self,
key: str,
value: str = "",
max_age: int | None = None,
expires: datetime | str | int | None = None,
path: str | None = "/",
domain: str | None = None,
secure: bool = False,
httponly: bool = False,
samesite: Literal["lax", "strict", "none"] | None = "lax",
partitioned: bool = False,
) -> None:
cookie: http.cookies.BaseCookie[str] = http.cookies.SimpleCookie()
cookie[key] = value
if max_age is not None:
cookie[key]["max-age"] = max_age
if expires is not None:
if isinstance(expires, datetime):
cookie[key]["expires"] = format_datetime(expires, usegmt=True)
else:
cookie[key]["expires"] = expires
if path is not None:
cookie[key]["path"] = path
if domain is not None:
cookie[key]["domain"] = domain
if secure:
cookie[key]["secure"] = True
if httponly:
cookie[key]["httponly"] = True
if samesite is not None:
assert samesite.lower() in [
"strict",
"lax",
"none",
], "samesite must be either 'strict', 'lax' or 'none'"
cookie[key]["samesite"] = samesite
if partitioned:
if sys.version_info < (3, 14):
raise ValueError("Partitioned cookies are only supported in Python 3.14 and above.") # pragma: no cover
cookie[key]["partitioned"] = True # pragma: no cover
cookie_val = cookie.output(header="").strip()
self.raw_headers.append((b"set-cookie", cookie_val.encode("latin-1")))
delete_cookie ¶
delete_cookie(
key,
path="/",
domain=None,
secure=False,
httponly=False,
samesite="lax",
)
Source code in starlette/responses.py
defdelete_cookie(
self,
key: str,
path: str = "/",
domain: str | None = None,
secure: bool = False,
httponly: bool = False,
samesite: Literal["lax", "strict", "none"] | None = "lax",
) -> None:
self.set_cookie(
key,
max_age=0,
expires=0,
path=path,
domain=domain,
secure=secure,
httponly=httponly,
samesite=samesite,
)