@lobehub/chat
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Lobe Chat - an open-source, high-performance chatbot framework that supports speech synthesis, multimodal, and extensible Function Call plugin system. Supports one-click free deployment of your private ChatGPT/LLM web application.
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text/typescript
//@ts-nocheck
/* eslint-disable unicorn/no-abusive-eslint-disable */
/* eslint-disable */
/**
* Represents a message sent in an event stream
* https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events/Using_server-sent_events#Event_stream_format
*/
export interface EventSourceMessage {
/** The event ID to set the EventSource object's last event ID value. */
id: string;
/** A string identifying the type of event described. */
event: string;
/** The event data */
data: string;
/** The reconnection interval (in milliseconds) to wait before retrying the connection */
retry?: number;
}
/**
* Converts a ReadableStream into a callback pattern.
* @param stream The input ReadableStream.
* @param onChunk A function that will be called on each new byte chunk in the stream.
* @returns {Promise<void>} A promise that will be resolved when the stream closes.
*/
export async function getBytes(
stream: ReadableStream<Uint8Array>,
onChunk: (arr: Uint8Array) => void,
) {
const reader = stream.getReader();
let result: ReadableStreamDefaultReadResult<Uint8Array>;
while (!(result = await reader.read()).done) {
onChunk(result.value);
}
}
const enum ControlChars {
NewLine = 10,
CarriageReturn = 13,
Space = 32,
Colon = 58,
}
/**
* Parses arbitary byte chunks into EventSource line buffers.
* Each line should be of the format "field: value" and ends with \r, \n, or \r\n.
* @param onLine A function that will be called on each new EventSource line.
* @returns A function that should be called for each incoming byte chunk.
*/
export function getLines(onLine: (line: Uint8Array, fieldLength: number) => void) {
let buffer: Uint8Array | undefined;
let position: number; // current read position
let fieldLength: number; // length of the `field` portion of the line
let discardTrailingNewline = false;
// return a function that can process each incoming byte chunk:
return function onChunk(arr: Uint8Array) {
if (buffer === undefined) {
buffer = arr;
position = 0;
fieldLength = -1;
} else {
// we're still parsing the old line. Append the new bytes into buffer:
buffer = concat(buffer, arr);
}
const bufLength = buffer.length;
let lineStart = 0; // index where the current line starts
while (position < bufLength) {
if (discardTrailingNewline) {
if (buffer[position] === ControlChars.NewLine) {
lineStart = ++position; // skip to next char
}
discardTrailingNewline = false;
}
// start looking forward till the end of line:
let lineEnd = -1; // index of the \r or \n char
for (; position < bufLength && lineEnd === -1; ++position) {
switch (buffer[position]) {
case ControlChars.Colon:
if (fieldLength === -1) {
// first colon in line
fieldLength = position - lineStart;
}
break;
// @ts-ignore:7029 \r case below should fallthrough to \n:
case ControlChars.CarriageReturn:
discardTrailingNewline = true;
case ControlChars.NewLine:
lineEnd = position;
break;
}
}
if (lineEnd === -1) {
// We reached the end of the buffer but the line hasn't ended.
// Wait for the next arr and then continue parsing:
break;
}
// we've reached the line end, send it out:
onLine(buffer.subarray(lineStart, lineEnd), fieldLength);
lineStart = position; // we're now on the next line
fieldLength = -1;
}
if (lineStart === bufLength) {
buffer = undefined; // we've finished reading it
} else if (lineStart !== 0) {
// Create a new view into buffer beginning at lineStart so we don't
// need to copy over the previous lines when we get the new arr:
buffer = buffer.subarray(lineStart);
position -= lineStart;
}
};
}
/**
* Parses line buffers into EventSourceMessages.
* @param onId A function that will be called on each `id` field.
* @param onRetry A function that will be called on each `retry` field.
* @param onMessage A function that will be called on each message.
* @returns A function that should be called for each incoming line buffer.
*/
export function getMessages(
onId: (id: string) => void,
onMessage?: (msg: EventSourceMessage) => void,
) {
let message = newMessage();
const decoder = new TextDecoder();
// return a function that can process each incoming line buffer:
return function onLine(line: Uint8Array, fieldLength: number) {
if (line.length === 0) {
// empty line denotes end of message. Trigger the callback and start a new message:
onMessage?.(message);
message = newMessage();
} else if (fieldLength > 0) {
// exclude comments and lines with no values
// line is of format "<field>:<value>" or "<field>: <value>"
// https://html.spec.whatwg.org/multipage/server-sent-events.html#event-stream-interpretation
const field = decoder.decode(line.subarray(0, fieldLength));
const valueOffset = fieldLength + (line[fieldLength + 1] === ControlChars.Space ? 2 : 1);
const value = decoder.decode(line.subarray(valueOffset));
switch (field) {
case 'data':
// if this message already has data, append the new value to the old.
// otherwise, just set to the new value:
message.data = message.data ? message.data + '\n' + value : value; // otherwise,
break;
case 'event':
message.event = value;
break;
case 'id':
onId((message.id = value));
break;
}
}
};
}
function concat(a: Uint8Array, b: Uint8Array) {
const res = new Uint8Array(a.length + b.length);
res.set(a);
res.set(b, a.length);
return res;
}
function newMessage(): EventSourceMessage {
// data, event, and id must be initialized to empty strings:
// https://html.spec.whatwg.org/multipage/server-sent-events.html#event-stream-interpretation
// retry should be initialized to undefined so we return a consistent shape
// to the js engine all the time: https://mathiasbynens.be/notes/shapes-ics#takeaways
return {
data: '',
event: '',
id: '',
retry: undefined,
};
}