File size: 7,552 Bytes
c12ef43 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 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 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 | """
Server-sent events support, derived from httpx-sse (https://github.com/florimondmanca/httpx-sse).
```
MIT License
Copyright (c) 2022 Florimond Manca
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
```
"""
from __future__ import annotations
import json as jsonlib
from collections.abc import AsyncIterator, Iterator
from dataclasses import dataclass
from ._config import DEFAULT_MAX_EVENT_SIZE_BYTES
from ._exceptions import TransportError, request_context
from ._models import Response
__all__ = ["EventSource", "SSEError", "ServerSentEvent"]
class SSEError(TransportError):
"""
An error that occurred while connecting to a server-sent events endpoint.
"""
@dataclass(frozen=True)
class ServerSentEvent:
event: str = "message"
data: str = ""
id: str = ""
retry: int | None = None
def json(self) -> object:
return jsonlib.loads(self.data)
class _SSEEventDecoder:
def __init__(self, max_event_size: int | None = None) -> None:
self._max_event_size = max_event_size
self._event = ""
self._data: list[str] = []
self._event_size = 0
self._last_event_id = ""
self._retry: int | None = None
self._pending = False
def decode(self, line: str) -> ServerSentEvent | None:
if not line:
self._event_size = 0
if not self._pending:
return None
sse = ServerSentEvent(
event=self._event or "message",
data="\n".join(self._data),
id=self._last_event_id,
retry=self._retry,
)
self._event = ""
self._data = []
self._retry = None
self._pending = False
return sse
if line.startswith(":"):
return None
self._event_size += len(line.encode("utf-8"))
self._check_size()
fieldname, _, value = line.partition(":")
value = value[1:] if value.startswith(" ") else value
if fieldname == "event":
self._event = value
self._pending = True
elif fieldname == "data":
self._data.append(value)
self._pending = True
elif fieldname == "id":
if "\0" not in value:
self._last_event_id = value
self._pending = True
elif fieldname == "retry":
try:
self._retry = int(value)
self._pending = True
except ValueError:
pass
return None
def check_pending(self, pending_size: int) -> None:
"""
Bound the total bytes buffered for the in-progress event, including
a trailing line that has not been terminated by a newline yet.
"""
self._check_size(pending_size)
def _check_size(self, pending_size: int = 0) -> None:
if self._max_event_size is not None and self._event_size + pending_size > self._max_event_size:
raise SSEError(f"Server-sent event exceeded the {self._max_event_size} byte limit.")
class _SSELineDecoder:
def __init__(self) -> None:
self._parts: list[str] = []
self._pending_size = 0
self._trailing_cr = False
@property
def pending_size(self) -> int:
return self._pending_size
def decode(self, text: str) -> list[str]:
if self._trailing_cr:
text = "\r" + text
self._trailing_cr = False
if text.endswith("\r"):
self._trailing_cr = True
text = text[:-1]
text = text.replace("\r\n", "\n").replace("\r", "\n")
if "\n" not in text:
self._append(text)
return []
lines = text.split("\n")
self._append(lines[0])
lines[0] = self._consume_pending()
self._append(lines.pop())
return lines
def flush(self) -> list[str]:
if self._trailing_cr:
self._append("\n")
self._trailing_cr = False
buffer = self._consume_pending()
if not buffer:
return []
return buffer.split("\n")
def _append(self, text: str) -> None:
if text:
self._parts.append(text)
self._pending_size += len(text.encode("utf-8"))
def _consume_pending(self) -> str:
pending = "".join(self._parts)
self._parts = []
self._pending_size = 0
return pending
class _SSEParser:
def __init__(self, max_event_size: int | None = None) -> None:
self._event_decoder = _SSEEventDecoder(max_event_size)
self._line_decoder = _SSELineDecoder()
def decode(self, text: str) -> Iterator[ServerSentEvent]:
yield from self._decode_lines(self._line_decoder.decode(text))
self._event_decoder.check_pending(self._line_decoder.pending_size)
def flush(self) -> Iterator[ServerSentEvent]:
yield from self._decode_lines(self._line_decoder.flush())
def _decode_lines(self, lines: list[str]) -> Iterator[ServerSentEvent]:
for line in lines:
sse = self._event_decoder.decode(line)
if sse is not None:
yield sse
class EventSource:
def __init__(self, response: Response, max_event_size: int | None = DEFAULT_MAX_EVENT_SIZE_BYTES) -> None:
self._response = response
self._max_event_size = max_event_size
@property
def response(self) -> Response:
return self._response
def _check_content_type(self) -> None:
content_type, _, _ = self._response.headers.get("content-type", "").partition(";")
if content_type.strip().lower() != "text/event-stream":
raise SSEError(f"Expected response with content type 'text/event-stream', got {content_type.strip()!r}.")
def __iter__(self) -> Iterator[ServerSentEvent]:
with request_context(request=self._response.request):
self._check_content_type()
parser = _SSEParser(self._max_event_size)
for chunk in self._response.iter_text():
yield from parser.decode(chunk)
yield from parser.flush()
async def __aiter__(self) -> AsyncIterator[ServerSentEvent]:
with request_context(request=self._response.request):
self._check_content_type()
parser = _SSEParser(self._max_event_size)
async for chunk in self._response.aiter_text():
for sse in parser.decode(chunk):
yield sse
for sse in parser.flush():
yield sse
|