Bỏ qua

Custom Response Classes - File, HTML, Redirect, Streaming, etc.

There are several custom response classes you can use to create an instance and return them directly from your path operations.

Read more about it in the FastAPI docs for Custom Response - HTML, Stream, File, others.

You can import them directly from fastapi.responses:

from fastapi.responses import (
    FileResponse,
    HTMLResponse,
    JSONResponse,
    ORJSONResponse,
    PlainTextResponse,
    RedirectResponse,
    Response,
    StreamingResponse,
    UJSONResponse,
)

FastAPI Responses

There are a couple of custom FastAPI response classes, you can use them to optimize JSON performance.

fastapi.responses.UJSONResponse 

UJSONResponse(
    content,
    status_code=200,
    headers=None,
    media_type=None,
    background=None,
)

Bases: JSONResponse

JSON response using the high-performance ujson library to serialize data to JSON.

Read more about it in the FastAPI docs for Custom Response - HTML, Stream, File, others.

Source code in starlette/responses.py 
182
183
184
185
186
187
188
189
190
def __init__(
    self,
    content: Any,
    status_code: int = 200,
    headers: Mapping[str, str] | None = None,
    media_type: str | None = None,
    background: BackgroundTask | None = None,
) -> None:
    super().__init__(content, status_code, headers, media_type, background)

charset class-attribute instance-attribute 

charset = 'utf-8'

status_code instance-attribute 

status_code = status_code

media_type class-attribute instance-attribute 

media_type = 'application/json'

body instance-attribute 

body = render(content)

background instance-attribute 

background = background

headers property 

headers

render 

render(content)
Source code in fastapi/responses.py 
31
32
33
def render(self, content: Any) -> bytes:
    assert ujson is not None, "ujson must be installed to use UJSONResponse"
    return ujson.dumps(content, ensure_ascii=False).encode("utf-8")

init_headers 

init_headers(headers=None)
Source code in starlette/responses.py 
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
def init_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(
    key,
    value="",
    max_age=None,
    expires=None,
    path="/",
    domain=None,
    secure=False,
    httponly=False,
    samesite="lax",
    partitioned=False,
)
Source code in starlette/responses.py 
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
def set_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(
    key,
    path="/",
    domain=None,
    secure=False,
    httponly=False,
    samesite="lax",
)
Source code in starlette/responses.py 
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
def delete_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,
    )

fastapi.responses.ORJSONResponse 

ORJSONResponse(
    content,
    status_code=200,
    headers=None,
    media_type=None,
    background=None,
)

Bases: JSONResponse

JSON response using the high-performance orjson library to serialize data to JSON.

Read more about it in the FastAPI docs for Custom Response - HTML, Stream, File, others.

Source code in starlette/responses.py 
182
183
184
185
186
187
188
189
190
def __init__(
    self,
    content: Any,
    status_code: int = 200,
    headers: Mapping[str, str] | None = None,
    media_type: str | None = None,
    background: BackgroundTask | None = None,
) -> None:
    super().__init__(content, status_code, headers, media_type, background)

charset class-attribute instance-attribute 

charset = 'utf-8'

status_code instance-attribute 

status_code = status_code

media_type class-attribute instance-attribute 

media_type = 'application/json'

body instance-attribute 

body = render(content)

background instance-attribute 

background = background

headers property 

headers

render 

render(content)
Source code in fastapi/responses.py 
44
45
46
47
48
def render(self, content: Any) -> bytes:
    assert orjson is not None, "orjson must be installed to use ORJSONResponse"
    return orjson.dumps(
        content, option=orjson.OPT_NON_STR_KEYS | orjson.OPT_SERIALIZE_NUMPY
    )

init_headers 

init_headers(headers=None)
Source code in starlette/responses.py 
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
def init_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(
    key,
    value="",
    max_age=None,
    expires=None,
    path="/",
    domain=None,
    secure=False,
    httponly=False,
    samesite="lax",
    partitioned=False,
)
Source code in starlette/responses.py 
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
def set_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(
    key,
    path="/",
    domain=None,
    secure=False,
    httponly=False,
    samesite="lax",
)
Source code in starlette/responses.py 
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
def delete_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,
    )

Starlette Responses

fastapi.responses.FileResponse 

FileResponse(
    path,
    status_code=200,
    headers=None,
    media_type=None,
    background=None,
    filename=None,
    stat_result=None,
    method=None,
    content_disposition_type="attachment",
)

Bases: Response

Source code in starlette/responses.py 
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
def __init__(
    self,
    path: str | os.PathLike[str],
    status_code: int = 200,
    headers: Mapping[str, str] | None = None,
    media_type: str | None = None,
    background: BackgroundTask | None = None,
    filename: str | None = None,
    stat_result: os.stat_result | None = None,
    method: str | None = None,
    content_disposition_type: str = "attachment",
) -> None:
    self.path = path
    self.status_code = status_code
    self.filename = filename
    if method is not None:
        warnings.warn(
            "The 'method' parameter is not used, and it will be removed.",
            DeprecationWarning,
        )
    if media_type is None:
        media_type = guess_type(filename or path)[0] or "text/plain"
    self.media_type = media_type
    self.background = background
    self.init_headers(headers)
    self.headers.setdefault("accept-ranges", "bytes")
    if self.filename is not None:
        content_disposition_filename = quote(self.filename)
        if content_disposition_filename != self.filename:
            content_disposition = f"{content_disposition_type}; filename*=utf-8''{content_disposition_filename}"
        else:
            content_disposition = f'{content_disposition_type}; filename="{self.filename}"'
        self.headers.setdefault("content-disposition", content_disposition)
    self.stat_result = stat_result
    if stat_result is not None:
        self.set_stat_headers(stat_result)

chunk_size class-attribute instance-attribute 

chunk_size = 64 * 1024

charset class-attribute instance-attribute 

charset = 'utf-8'

status_code instance-attribute 

status_code = status_code

media_type instance-attribute 

media_type = media_type

body instance-attribute 

body = render(content)

background instance-attribute 

background = background

headers property 

headers

render 

render(content)
Source code in starlette/responses.py 
50
51
52
53
54
55
def render(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 
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
def init_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(
    key,
    value="",
    max_age=None,
    expires=None,
    path="/",
    domain=None,
    secure=False,
    httponly=False,
    samesite="lax",
    partitioned=False,
)
Source code in starlette/responses.py 
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
def set_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(
    key,
    path="/",
    domain=None,
    secure=False,
    httponly=False,
    samesite="lax",
)
Source code in starlette/responses.py 
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
def delete_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,
    )

fastapi.responses.HTMLResponse 

HTMLResponse(
    content=None,
    status_code=200,
    headers=None,
    media_type=None,
    background=None,
)

Bases: Response

Source code in starlette/responses.py 
35
36
37
38
39
40
41
42
43
44
45
46
47
48
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)

charset class-attribute instance-attribute 

charset = 'utf-8'

status_code instance-attribute 

status_code = status_code

media_type class-attribute instance-attribute 

media_type = 'text/html'

body instance-attribute 

body = render(content)

background instance-attribute 

background = background

headers property 

headers

render 

render(content)
Source code in starlette/responses.py 
50
51
52
53
54
55
def render(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 
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
def init_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(
    key,
    value="",
    max_age=None,
    expires=None,
    path="/",
    domain=None,
    secure=False,
    httponly=False,
    samesite="lax",
    partitioned=False,
)
Source code in starlette/responses.py 
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
def set_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(
    key,
    path="/",
    domain=None,
    secure=False,
    httponly=False,
    samesite="lax",
)
Source code in starlette/responses.py 
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
def delete_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,
    )

fastapi.responses.JSONResponse 

JSONResponse(
    content,
    status_code=200,
    headers=None,
    media_type=None,
    background=None,
)

Bases: Response

Source code in starlette/responses.py 
182
183
184
185
186
187
188
189
190
def __init__(
    self,
    content: Any,
    status_code: int = 200,
    headers: Mapping[str, str] | None = None,
    media_type: str | None = None,
    background: BackgroundTask | None = None,
) -> None:
    super().__init__(content, status_code, headers, media_type, background)

charset class-attribute instance-attribute 

charset = 'utf-8'

status_code instance-attribute 

status_code = status_code

media_type class-attribute instance-attribute 

media_type = 'application/json'

body instance-attribute 

body = render(content)

background instance-attribute 

background = background

headers property 

headers

render 

render(content)
Source code in starlette/responses.py 
192
193
194
195
196
197
198
199
def render(self, content: Any) -> bytes:
    return json.dumps(
        content,
        ensure_ascii=False,
        allow_nan=False,
        indent=None,
        separators=(",", ":"),
    ).encode("utf-8")

init_headers 

init_headers(headers=None)
Source code in starlette/responses.py 
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
def init_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(
    key,
    value="",
    max_age=None,
    expires=None,
    path="/",
    domain=None,
    secure=False,
    httponly=False,
    samesite="lax",
    partitioned=False,
)
Source code in starlette/responses.py 
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
def set_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(
    key,
    path="/",
    domain=None,
    secure=False,
    httponly=False,
    samesite="lax",
)
Source code in starlette/responses.py 
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
def delete_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,
    )

fastapi.responses.PlainTextResponse 

PlainTextResponse(
    content=None,
    status_code=200,
    headers=None,
    media_type=None,
    background=None,
)

Bases: Response

Source code in starlette/responses.py 
35
36
37
38
39
40
41
42
43
44
45
46
47
48
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)

charset class-attribute instance-attribute 

charset = 'utf-8'

status_code instance-attribute 

status_code = status_code

media_type class-attribute instance-attribute 

media_type = 'text/plain'

body instance-attribute 

body = render(content)

background instance-attribute 

background = background

headers property 

headers

render 

render(content)
Source code in starlette/responses.py 
50
51
52
53
54
55
def render(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 
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
def init_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(
    key,
    value="",
    max_age=None,
    expires=None,
    path="/",
    domain=None,
    secure=False,
    httponly=False,
    samesite="lax",
    partitioned=False,
)
Source code in starlette/responses.py 
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
def set_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(
    key,
    path="/",
    domain=None,
    secure=False,
    httponly=False,
    samesite="lax",
)
Source code in starlette/responses.py 
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
def delete_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,
    )

fastapi.responses.RedirectResponse 

RedirectResponse(
    url, status_code=307, headers=None, background=None
)

Bases: Response

Source code in starlette/responses.py 
203
204
205
206
207
208
209
210
211
def __init__(
    self,
    url: str | URL,
    status_code: int = 307,
    headers: Mapping[str, str] | None = None,
    background: BackgroundTask | None = None,
) -> None:
    super().__init__(content=b"", status_code=status_code, headers=headers, background=background)
    self.headers["location"] = quote(str(url), safe=":/%#?=@[]!$&'()*+,;")

charset class-attribute instance-attribute 

charset = 'utf-8'

status_code instance-attribute 

status_code = status_code

media_type class-attribute instance-attribute 

media_type = None

body instance-attribute 

body = render(content)

background instance-attribute 

background = background

headers property 

headers

render 

render(content)
Source code in starlette/responses.py 
50
51
52
53
54
55
def render(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 
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
def init_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(
    key,
    value="",
    max_age=None,
    expires=None,
    path="/",
    domain=None,
    secure=False,
    httponly=False,
    samesite="lax",
    partitioned=False,
)
Source code in starlette/responses.py 
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
def set_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(
    key,
    path="/",
    domain=None,
    secure=False,
    httponly=False,
    samesite="lax",
)
Source code in starlette/responses.py 
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
def delete_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,
    )

fastapi.responses.Response 

Response(
    content=None,
    status_code=200,
    headers=None,
    media_type=None,
    background=None,
)
Source code in starlette/responses.py 
35
36
37
38
39
40
41
42
43
44
45
46
47
48
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)

charset class-attribute instance-attribute 

charset = 'utf-8'

status_code instance-attribute 

status_code = status_code

media_type class-attribute instance-attribute 

media_type = None

body instance-attribute 

body = render(content)

background instance-attribute 

background = background

headers property 

headers

render 

render(content)
Source code in starlette/responses.py 
50
51
52
53
54
55
def render(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 
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
def init_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(
    key,
    value="",
    max_age=None,
    expires=None,
    path="/",
    domain=None,
    secure=False,
    httponly=False,
    samesite="lax",
    partitioned=False,
)
Source code in starlette/responses.py 
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
def set_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(
    key,
    path="/",
    domain=None,
    secure=False,
    httponly=False,
    samesite="lax",
)
Source code in starlette/responses.py 
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
def delete_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,
    )

fastapi.responses.StreamingResponse 

StreamingResponse(
    content,
    status_code=200,
    headers=None,
    media_type=None,
    background=None,
)

Bases: Response

Source code in starlette/responses.py 
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
def __init__(
    self,
    content: ContentStream,
    status_code: int = 200,
    headers: Mapping[str, str] | None = None,
    media_type: str | None = None,
    background: BackgroundTask | None = None,
) -> None:
    if isinstance(content, AsyncIterable):
        self.body_iterator = content
    else:
        self.body_iterator = iterate_in_threadpool(content)
    self.status_code = status_code
    self.media_type = self.media_type if media_type is None else media_type
    self.background = background
    self.init_headers(headers)

body_iterator instance-attribute 

body_iterator

charset class-attribute instance-attribute 

charset = 'utf-8'

status_code instance-attribute 

status_code = status_code

media_type instance-attribute 

media_type = (
    media_type if media_type is None else media_type
)

body instance-attribute 

body = render(content)

background instance-attribute 

background = background

headers property 

headers

render 

render(content)
Source code in starlette/responses.py 
50
51
52
53
54
55
def render(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 
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
def init_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(
    key,
    value="",
    max_age=None,
    expires=None,
    path="/",
    domain=None,
    secure=False,
    httponly=False,
    samesite="lax",
    partitioned=False,
)
Source code in starlette/responses.py 
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
def set_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(
    key,
    path="/",
    domain=None,
    secure=False,
    httponly=False,
    samesite="lax",
)
Source code in starlette/responses.py 
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
def delete_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,
    )