ChatGPT-Next-Web/app/utils/stream.ts

101 lines
3.3 KiB
TypeScript

// using tauri register_uri_scheme_protocol, register `stream:` protocol
// see src-tauri/src/stream.rs, and src-tauri/src/main.rs
// 1. window.fetch(`stream://localhost/${fetchUrl}`), get request_id
// 2. listen event: `stream-response` multi times to get response headers and body
type ResponseEvent = {
id: number;
payload: {
request_id: number;
status?: number;
error?: string;
name?: string;
value?: string;
chunk?: number[];
};
};
export function fetch(url: string, options?: RequestInit): Promise<any> {
if (window.__TAURI__) {
const tauriUri = window.__TAURI__.convertFileSrc(url, "stream");
const { signal, ...rest } = options || {};
return window
.fetch(tauriUri, rest)
.then((r) => r.text())
.then((rid) => parseInt(rid))
.then((request_id: number) => {
// 1. using event to get status and statusText and headers, and resolve it
let resolve: Function | undefined;
let reject: Function | undefined;
let status: number;
let writable: WritableStream | undefined;
let writer: WritableStreamDefaultWriter | undefined;
const headers = new Headers();
let unlisten: Function | undefined;
if (signal) {
signal.addEventListener("abort", () => {
// Reject the promise with the abort reason.
unlisten && unlisten();
reject && reject(signal.reason);
});
}
// @ts-ignore 2. listen response multi times, and write to Response.body
window.__TAURI__.event
.listen("stream-response", (e: ResponseEvent) => {
const { id, payload } = e;
const {
request_id: rid,
status: _status,
name,
value,
error,
chunk,
} = payload;
if (request_id != rid) {
return;
}
/**
* 1. get status code
* 2. get headers
* 3. start get body, then resolve response
* 4. get body chunk
*/
if (error) {
unlisten && unlisten();
return reject && reject(error);
} else if (_status) {
status = _status;
} else if (name && value) {
headers.append(name, value);
} else if (chunk) {
if (resolve) {
const ts = new TransformStream();
writable = ts.writable;
writer = writable.getWriter();
resolve(new Response(ts.readable, { status, headers }));
resolve = undefined;
}
writer &&
writer.ready.then(() => {
writer && writer.write(new Uint8Array(chunk));
});
} else if (_status === 0) {
// end of body
unlisten && unlisten();
writer &&
writer.ready.then(() => {
writer && writer.releaseLock();
writable && writable.close();
});
}
})
.then((u: Function) => (unlisten = u));
return new Promise(
(_resolve, _reject) => ([resolve, reject] = [_resolve, _reject]),
);
});
}
return window.fetch(url, options);
}