Files
Multi-Debrid-Downloader/src/main/proxy-segmented-download.ts
T

1065 lines
36 KiB
TypeScript

import fs from "node:fs";
import http from "node:http";
import https from "node:https";
import path from "node:path";
import { randomUUID } from "node:crypto";
import type { IncomingMessage } from "node:http";
import { HttpsProxyAgent } from "https-proxy-agent";
const DEFAULT_CONNECT_TIMEOUT_MS = 15_000;
const DEFAULT_IDLE_TIMEOUT_MS = 45_000;
const DEFAULT_MIN_SEGMENT_BYTES = 8 * 1024 * 1024;
const DEFAULT_MAX_CHUNK_BYTES = 16 * 1024 * 1024;
const DEFAULT_CHUNKS_PER_CONNECTION = 8;
const DEFAULT_PROXY_ATTEMPTS = 3;
const PROXY_PROBE_END = 1;
const MAX_REDIRECTS = 5;
const MAX_SEGMENTS = 4_096;
const MAX_PROXY_FILE_BYTES = 8 * 1024 * 1024;
const DISK_ERROR_CODES = new Set(["ENOSPC", "EDQUOT", "EACCES", "EPERM", "EROFS", "EIO", "ENODEV"]);
export interface ProxyEndpoint {
id: number;
url: string;
authorization: string;
username: string;
password: string;
hostname: string;
port: number;
}
interface CachedProxyFile {
mtimeMs: number;
size: number;
proxies: ProxyEndpoint[];
}
interface ParsedRange {
start: number;
end: number;
total: number;
}
interface RangeResponse {
response: IncomingMessage;
dispose: () => void;
}
interface Segment {
index: number;
start: number;
end: number;
}
export interface ProxySegmentedDownloadOptions {
directUrl: string;
targetPath: string;
proxyListPath: string;
connections: number;
totalConnectionLimit?: number;
downloadId?: string;
reservedProxyIndex?: number;
signal: AbortSignal;
skipTlsVerify?: boolean;
minSegmentBytes?: number;
connectTimeoutMs?: number;
idleTimeoutMs?: number;
proxyAttempts?: number;
waitWhilePaused?: () => Promise<void>;
onTrafficBytes?: (bytes: number) => void;
onProgress?: (deltaBytes: number, downloadedBytes: number, totalBytes: number) => void;
}
export type ProxySegmentedDownloadResult =
| { status: "completed"; totalBytes: number; connections: number }
| { status: "fallback"; reason: ProxyFallbackReason; httpStatus?: number };
export type ProxyFallbackReason =
| "proxy_file_unavailable"
| "no_valid_proxies"
| "range_unsupported"
| "file_too_small"
| "not_enough_proxies"
| "proxy_unavailable"
| "origin_http_error"
| "segment_failed";
const proxyFileCache = new Map<string, CachedProxyFile>();
function proxyEndpointKey(proxy: ProxyEndpoint): string {
return `${proxy.url}\0${proxy.authorization}`;
}
class OriginHttpError extends Error {
public constructor(public readonly statusCode: number) {
super(`origin_http_${statusCode}`);
}
}
interface ProxyLeaseOutcome {
succeeded: boolean;
transferredBytes?: number;
durationMs?: number;
}
interface ProxyLease {
proxy: ProxyEndpoint;
release: (outcome: ProxyLeaseOutcome) => void;
}
interface ProxyLeaseWaiter {
poolKey: string;
groupId: string;
proxies: ProxyEndpoint[];
excluded: ReadonlySet<string>;
signal: AbortSignal;
resolve: (lease: ProxyLease | null) => void;
reject: (error: Error) => void;
}
interface ProxyPerformance {
ewmaBytesPerSecond: number;
failures: number;
samples: number;
}
class SharedProxyCoordinator {
private configuredConnectionLimit = 16;
private adaptiveConnectionLimit = 16;
private activeConnections = 0;
private readonly activeProxies = new Set<string>();
private readonly activeConnectionsByGroup = new Map<string, number>();
private readonly registeredGroups = new Map<string, number>();
private readonly cooldownUntil = new Map<string, number>();
private readonly cursors = new Map<string, number>();
private readonly performance = new Map<string, ProxyPerformance>();
private readonly waiters: ProxyLeaseWaiter[] = [];
private acquisitionCount = 0;
private lastThrottleAt = 0;
private successfulTransfersSinceThrottle = 0;
public setConnectionLimit(limit: number): void {
const normalized = Math.max(2, Math.min(32, Math.floor(limit || 16)));
if (normalized !== this.configuredConnectionLimit) {
this.configuredConnectionLimit = normalized;
this.adaptiveConnectionLimit = normalized;
this.lastThrottleAt = 0;
this.successfulTransfersSinceThrottle = 0;
} else {
this.adaptiveConnectionLimit = Math.min(this.adaptiveConnectionLimit, normalized);
}
this.drain();
}
public registerGroup(groupId: string): () => void {
this.registeredGroups.set(groupId, (this.registeredGroups.get(groupId) || 0) + 1);
this.drain();
let released = false;
return () => {
if (released) return;
released = true;
const remaining = Math.max(0, (this.registeredGroups.get(groupId) || 1) - 1);
if (remaining > 0) {
this.registeredGroups.set(groupId, remaining);
} else {
this.registeredGroups.delete(groupId);
}
this.drain();
};
}
public reportOriginStatus(statusCode: number): void {
if (statusCode !== 429 && statusCode !== 503) return;
const now = Date.now();
if (now - this.lastThrottleAt < 1_500) return;
this.lastThrottleAt = now;
this.successfulTransfersSinceThrottle = 0;
this.adaptiveConnectionLimit = Math.max(2, this.adaptiveConnectionLimit - 2);
this.drain();
}
public acquire(
poolKey: string,
groupId: string,
proxies: ProxyEndpoint[],
excluded: ReadonlySet<string>,
signal: AbortSignal
): Promise<ProxyLease | null> {
if (signal.aborted) {
return Promise.reject(abortError());
}
if (!proxies.some((proxy) => !excluded.has(proxyEndpointKey(proxy)))) {
return Promise.resolve(null);
}
return new Promise<ProxyLease | null>((resolve, reject) => {
const waiter: ProxyLeaseWaiter = { poolKey, groupId, proxies, excluded, signal, resolve, reject };
const onAbort = (): void => {
const index = this.waiters.indexOf(waiter);
if (index >= 0) {
this.waiters.splice(index, 1);
reject(abortError());
}
};
signal.addEventListener("abort", onAbort, { once: true });
const resolveWithoutListener = waiter.resolve;
const rejectWithoutListener = waiter.reject;
waiter.resolve = (lease) => {
signal.removeEventListener("abort", onAbort);
resolveWithoutListener(lease);
};
waiter.reject = (error) => {
signal.removeEventListener("abort", onAbort);
rejectWithoutListener(error);
};
this.waiters.push(waiter);
this.drain();
});
}
private selectProxy(waiter: ProxyLeaseWaiter): ProxyEndpoint | null {
if (this.activeConnections >= this.adaptiveConnectionLimit) {
return null;
}
const groupCount = Math.max(1, this.registeredGroups.size);
const groupLimit = Math.max(1, Math.ceil(this.adaptiveConnectionLimit / groupCount));
if ((this.activeConnectionsByGroup.get(waiter.groupId) || 0) >= groupLimit) {
return null;
}
const now = Date.now();
const start = (this.cursors.get(waiter.poolKey) || 0) % waiter.proxies.length;
const select = (allowCooldown: boolean): ProxyEndpoint | null => {
const candidates: Array<{ proxy: ProxyEndpoint; index: number; key: string }> = [];
for (let offset = 0; offset < waiter.proxies.length; offset += 1) {
const index = (start + offset) % waiter.proxies.length;
const proxy = waiter.proxies[index];
const key = proxyEndpointKey(proxy);
if (waiter.excluded.has(key)
|| this.activeProxies.has(key)
|| (!allowCooldown && (this.cooldownUntil.get(key) || 0) > now)) {
continue;
}
candidates.push({ proxy, index, key });
}
if (candidates.length === 0) return null;
this.acquisitionCount += 1;
const unknown = candidates.filter((candidate) => !this.performance.has(candidate.key));
const exploreUnknown = unknown.length > 0 && (unknown.length === candidates.length || this.acquisitionCount % 8 === 0);
let selected = exploreUnknown ? unknown[0] : candidates[0];
if (!exploreUnknown) {
let selectedScore = Number.NEGATIVE_INFINITY;
for (const candidate of candidates) {
const metric = this.performance.get(candidate.key);
const score = metric
? (metric.ewmaBytesPerSecond / (1 + metric.failures)) - (metric.failures * 1024 * 1024)
: 0;
if (score > selectedScore) {
selected = candidate;
selectedScore = score;
}
}
}
this.cursors.set(waiter.poolKey, (selected.index + 1) % waiter.proxies.length);
return selected.proxy;
};
const available = select(false);
if (available) return available;
const poolHasActiveProxy = waiter.proxies.some((proxy) => this.activeProxies.has(proxyEndpointKey(proxy)));
return poolHasActiveProxy ? null : select(true);
}
private createLease(proxy: ProxyEndpoint, groupId: string): ProxyLease {
const key = proxyEndpointKey(proxy);
this.activeConnections += 1;
this.activeProxies.add(key);
this.activeConnectionsByGroup.set(groupId, (this.activeConnectionsByGroup.get(groupId) || 0) + 1);
let released = false;
return {
proxy,
release: (outcome) => {
if (released) return;
released = true;
this.activeConnections = Math.max(0, this.activeConnections - 1);
this.activeProxies.delete(key);
const groupConnections = Math.max(0, (this.activeConnectionsByGroup.get(groupId) || 1) - 1);
if (groupConnections > 0) {
this.activeConnectionsByGroup.set(groupId, groupConnections);
} else {
this.activeConnectionsByGroup.delete(groupId);
}
if (outcome.succeeded) {
this.cooldownUntil.delete(key);
if ((outcome.transferredBytes || 0) > 0 && (outcome.durationMs || 0) > 0) {
const sample = ((outcome.transferredBytes || 0) * 1_000) / Math.max(1, outcome.durationMs || 1);
const previous = this.performance.get(key);
this.performance.set(key, {
ewmaBytesPerSecond: previous && previous.samples > 0
? (previous.ewmaBytesPerSecond * 0.7) + (sample * 0.3)
: sample,
failures: Math.max(0, (previous?.failures || 0) - 1),
samples: (previous?.samples || 0) + 1
});
this.restoreAdaptiveCapacity();
}
} else {
this.cooldownUntil.set(key, Date.now() + 30_000);
const previous = this.performance.get(key);
this.performance.set(key, {
ewmaBytesPerSecond: (previous?.ewmaBytesPerSecond || 0) * 0.5,
failures: (previous?.failures || 0) + 1,
samples: previous?.samples || 0
});
}
this.drain();
}
};
}
private restoreAdaptiveCapacity(): void {
if (this.adaptiveConnectionLimit >= this.configuredConnectionLimit) return;
this.successfulTransfersSinceThrottle += 1;
if (Date.now() - this.lastThrottleAt < 5_000 || this.successfulTransfersSinceThrottle < 24) return;
this.adaptiveConnectionLimit = Math.min(this.configuredConnectionLimit, this.adaptiveConnectionLimit + 1);
this.successfulTransfersSinceThrottle = 0;
}
private drain(): void {
let granted = true;
while (granted && this.activeConnections < this.adaptiveConnectionLimit) {
granted = false;
for (let index = 0; index < this.waiters.length; index += 1) {
const waiter = this.waiters[index];
if (waiter.signal.aborted) {
this.waiters.splice(index, 1);
waiter.reject(abortError());
granted = true;
break;
}
const proxy = this.selectProxy(waiter);
if (!proxy) {
continue;
}
this.waiters.splice(index, 1);
waiter.resolve(this.createLease(proxy, waiter.groupId));
granted = true;
break;
}
}
}
}
const sharedProxyCoordinator = new SharedProxyCoordinator();
function parseProxyLine(rawLine: string, id: number): ProxyEndpoint | null {
const value = rawLine.trim();
if (!value || value.startsWith("#") || /\s/.test(value)) {
return null;
}
let candidate = value;
if (!/^https?:\/\//i.test(candidate)) {
const parts = candidate.split(":");
if (!candidate.includes("@") && parts.length === 4 && /^\d+$/.test(parts[1])) {
const [host, port, username, password] = parts;
candidate = `http://${encodeURIComponent(username)}:${encodeURIComponent(password)}@${host}:${port}`;
} else if (candidate.includes("@")) {
const separator = candidate.lastIndexOf("@");
const credentials = candidate.slice(0, separator);
const address = candidate.slice(separator + 1);
const credentialSeparator = credentials.indexOf(":");
if (credentialSeparator < 1 || !address) {
return null;
}
candidate = `http://${encodeURIComponent(credentials.slice(0, credentialSeparator))}:${encodeURIComponent(credentials.slice(credentialSeparator + 1))}@${address}`;
} else {
candidate = `http://${candidate}`;
}
}
try {
const parsed = new URL(candidate);
if ((parsed.protocol !== "http:" && parsed.protocol !== "https:") || !parsed.hostname || !parsed.port) {
return null;
}
const port = Number(parsed.port || (parsed.protocol === "https:" ? 443 : 80));
if (!Number.isInteger(port) || port < 1 || port > 65535) {
return null;
}
let authorization = "";
let username = "";
let password = "";
if (parsed.username || parsed.password) {
username = decodeURIComponent(parsed.username);
password = decodeURIComponent(parsed.password);
authorization = `Basic ${Buffer.from(`${username}:${password}`).toString("base64")}`;
parsed.username = "";
parsed.password = "";
}
parsed.pathname = "";
parsed.search = "";
parsed.hash = "";
return {
id,
url: parsed.toString(),
authorization,
username,
password,
hostname: parsed.hostname,
port
};
} catch {
return null;
}
}
export function parseProxyList(content: string): number {
return content
.replace(/^\uFEFF/, "")
.split(/\r?\n/)
.reduce((count, line, index) => count + (parseProxyLine(line, index) ? 1 : 0), 0);
}
function parseUniqueProxyEndpoints(content: string): ProxyEndpoint[] {
const seen = new Set<string>();
return content
.replace(/^\uFEFF/, "")
.split(/\r?\n/)
.map((line, index) => parseProxyLine(line, index))
.filter((proxy): proxy is ProxyEndpoint => {
if (!proxy) return false;
const key = `${proxy.url}\0${proxy.authorization}`;
if (seen.has(key)) return false;
seen.add(key);
return true;
});
}
export type FixedProxySelection =
| { status: "ok"; proxy: ProxyEndpoint; selectedIndex: number; proxyCount: number }
| { status: "proxy_file_unavailable" | "no_valid_proxies" | "proxy_index_unavailable" };
export function selectFixedProxy(proxyListPath: string, requestedIndex: number): FixedProxySelection {
const filePath = String(proxyListPath || "").trim();
if (!filePath) return { status: "proxy_file_unavailable" };
try {
const normalizedPath = path.resolve(filePath);
const stat = fs.statSync(normalizedPath);
if (!stat.isFile() || stat.size <= 0 || stat.size > MAX_PROXY_FILE_BYTES) {
return { status: stat.size <= 0 ? "no_valid_proxies" : "proxy_file_unavailable" };
}
const proxies = parseUniqueProxyEndpoints(fs.readFileSync(normalizedPath, "utf8"));
if (proxies.length === 0) return { status: "no_valid_proxies" };
const selectedIndex = Math.max(1, Math.floor(requestedIndex || 1));
const proxy = proxies[selectedIndex - 1];
if (!proxy) return { status: "proxy_index_unavailable" };
return { status: "ok", proxy, selectedIndex, proxyCount: proxies.length };
} catch {
return { status: "proxy_file_unavailable" };
}
}
async function loadProxyFile(filePath: string): Promise<
{ status: "ok"; proxies: ProxyEndpoint[] }
| { status: "unavailable" }
| { status: "empty" }
> {
const normalizedPath = path.resolve(filePath.trim());
try {
const stat = await fs.promises.stat(normalizedPath);
if (!stat.isFile() || stat.size <= 0 || stat.size > MAX_PROXY_FILE_BYTES) {
return { status: stat.size <= 0 ? "empty" : "unavailable" };
}
const cached = proxyFileCache.get(normalizedPath);
if (cached && cached.mtimeMs === stat.mtimeMs && cached.size === stat.size) {
return cached.proxies.length > 0
? { status: "ok", proxies: cached.proxies }
: { status: "empty" };
}
const content = await fs.promises.readFile(normalizedPath, "utf8");
const proxies = parseUniqueProxyEndpoints(content);
proxyFileCache.set(normalizedPath, { mtimeMs: stat.mtimeMs, size: stat.size, proxies });
return proxies.length > 0 ? { status: "ok", proxies } : { status: "empty" };
} catch {
return { status: "unavailable" };
}
}
function parseContentRange(value: string | undefined): ParsedRange | null {
const match = /^bytes\s+(\d+)-(\d+)\/(\d+)$/i.exec(String(value || "").trim());
if (!match) {
return null;
}
const start = Number(match[1]);
const end = Number(match[2]);
const total = Number(match[3]);
if (!Number.isSafeInteger(start) || !Number.isSafeInteger(end) || !Number.isSafeInteger(total)
|| start < 0 || end < start || total <= end) {
return null;
}
return { start, end, total };
}
function abortError(): Error {
return new Error("aborted:proxy_download");
}
function isDiskError(error: unknown): boolean {
const code = error && typeof error === "object" && "code" in error
? String((error as NodeJS.ErrnoException).code || "")
: "";
return DISK_ERROR_CODES.has(code);
}
async function openRangeResponse(
target: URL,
proxy: ProxyEndpoint,
start: number,
end: number,
signal: AbortSignal,
skipTlsVerify: boolean,
connectTimeoutMs: number,
idleTimeoutMs: number,
redirectCount = 0
): Promise<RangeResponse> {
if (signal.aborted) {
throw abortError();
}
const agent = new HttpsProxyAgent(proxy.url, {
keepAlive: false,
headers: proxy.authorization ? { "Proxy-Authorization": proxy.authorization } : {}
});
const requestOptions: https.RequestOptions = {
method: "GET",
headers: {
Accept: "*/*",
Range: `bytes=${start}-${end}`,
"User-Agent": "Multi-Debrid-Downloader"
},
agent,
rejectUnauthorized: !skipTlsVerify
};
return new Promise<RangeResponse>((resolve, reject) => {
let settled = false;
let responseRef: IncomingMessage | null = null;
const requestFn: typeof http.request = target.protocol === "https:" ? https.request : http.request;
const request = requestFn(target, requestOptions, (response) => {
responseRef = response;
clearTimeout(connectTimer);
const status = response.statusCode || 0;
const location = response.headers.location;
if (status >= 300 && status < 400 && location) {
settled = true;
response.resume();
response.once("end", () => {
cleanup();
if (redirectCount >= MAX_REDIRECTS) {
reject(new Error("proxy_redirect_limit"));
return;
}
let redirected: URL;
try {
redirected = new URL(location, target);
if (redirected.protocol !== "http:" && redirected.protocol !== "https:") {
reject(new Error("proxy_redirect_invalid"));
return;
}
} catch {
reject(new Error("proxy_redirect_invalid"));
return;
}
openRangeResponse(
redirected,
proxy,
start,
end,
signal,
skipTlsVerify,
connectTimeoutMs,
idleTimeoutMs,
redirectCount + 1
).then(resolve, reject);
});
return;
}
settled = true;
response.setTimeout(idleTimeoutMs, () => response.destroy(new Error("proxy_idle_timeout")));
response.once("close", cleanup);
resolve({
response,
dispose: () => {
cleanup();
response.destroy();
}
});
});
const cleanup = (): void => {
clearTimeout(connectTimer);
signal.removeEventListener("abort", onAbort);
agent.destroy();
};
const onAbort = (): void => {
request.destroy(abortError());
responseRef?.destroy(abortError());
};
const connectTimer = setTimeout(() => request.destroy(new Error("proxy_connect_timeout")), connectTimeoutMs);
signal.addEventListener("abort", onAbort, { once: true });
request.once("error", (error) => {
cleanup();
if (!settled) {
reject(signal.aborted ? abortError() : error);
}
});
request.setTimeout(idleTimeoutMs, () => request.destroy(new Error("proxy_idle_timeout")));
request.end();
});
}
async function consumeProbe(response: IncomingMessage, expectedBytes: number, onTrafficBytes?: (bytes: number) => void): Promise<number> {
let received = 0;
for await (const rawChunk of response) {
const chunk = Buffer.isBuffer(rawChunk) ? rawChunk : Buffer.from(rawChunk);
received += chunk.length;
onTrafficBytes?.(chunk.length);
if (received > expectedBytes) {
throw new Error("proxy_probe_overflow");
}
}
return received;
}
async function probeRangeSupport(
target: URL,
poolKey: string,
groupId: string,
proxies: ProxyEndpoint[],
signal: AbortSignal,
options: Required<Pick<ProxySegmentedDownloadOptions, "skipTlsVerify" | "connectTimeoutMs" | "idleTimeoutMs" | "proxyAttempts">>,
onTrafficBytes?: (bytes: number) => void
): Promise<
{ status: "ok"; totalBytes: number }
| { status: "unsupported" }
| { status: "unavailable" }
| { status: "origin_error"; httpStatus: number }
> {
const attempts = Math.min(proxies.length, options.proxyAttempts);
const excluded = new Set<string>();
let lastHttpStatus = 0;
for (let index = 0; index < attempts; index += 1) {
let opened: RangeResponse | null = null;
let lease: ProxyLease | null = null;
try {
lease = await sharedProxyCoordinator.acquire(poolKey, groupId, proxies, excluded, signal);
if (!lease) break;
excluded.add(proxyEndpointKey(lease.proxy));
opened = await openRangeResponse(
target,
lease.proxy,
0,
PROXY_PROBE_END,
signal,
options.skipTlsVerify,
options.connectTimeoutMs,
options.idleTimeoutMs
);
const status = opened.response.statusCode || 0;
if (status >= 400) {
lastHttpStatus = status;
opened.dispose();
opened = null;
lease.release({ succeeded: true });
lease = null;
continue;
}
if (status === 200) {
opened.dispose();
opened = null;
lease.release({ succeeded: true });
lease = null;
return { status: "unsupported" };
}
const range = parseContentRange(opened.response.headers["content-range"]);
const expectedEnd = range ? Math.min(PROXY_PROBE_END, range.total - 1) : -1;
const expectedBytes = expectedEnd + 1;
const contentLength = Number(opened.response.headers["content-length"] || 0);
if (status !== 206
|| !range
|| range.start !== 0
|| range.end !== expectedEnd
|| (contentLength > 0 && contentLength !== expectedBytes)) {
opened.dispose();
opened = null;
lease.release({ succeeded: false });
lease = null;
continue;
}
const received = await consumeProbe(opened.response, expectedBytes, onTrafficBytes);
opened.dispose();
opened = null;
if (received === expectedBytes) {
lease.release({ succeeded: true });
lease = null;
return { status: "ok", totalBytes: range.total };
}
} catch (error) {
opened?.dispose();
opened = null;
lease?.release({ succeeded: signal.aborted });
lease = null;
if (signal.aborted) {
throw abortError();
}
if (isDiskError(error)) {
throw error;
}
} finally {
opened?.dispose();
lease?.release({ succeeded: false });
}
}
if (lastHttpStatus > 0) {
sharedProxyCoordinator.reportOriginStatus(lastHttpStatus);
return { status: "origin_error", httpStatus: lastHttpStatus };
}
return { status: "unavailable" };
}
function buildSegments(totalBytes: number, connections: number, minSegmentBytes: number): Segment[] {
const preferredChunkBytes = Math.max(
minSegmentBytes,
Math.min(DEFAULT_MAX_CHUNK_BYTES, Math.ceil(totalBytes / Math.max(1, connections * DEFAULT_CHUNKS_PER_CONNECTION)))
);
const chunkBytes = Math.max(preferredChunkBytes, Math.ceil(totalBytes / MAX_SEGMENTS));
const count = Math.ceil(totalBytes / chunkBytes);
let start = 0;
return Array.from({ length: count }, (_, index) => {
const end = Math.min(totalBytes - 1, start + chunkBytes - 1);
const segment = { index, start, end };
start = end + 1;
return segment;
});
}
async function writeBufferAt(handle: fs.promises.FileHandle, buffer: Buffer, position: number): Promise<void> {
let offset = 0;
while (offset < buffer.length) {
const result = await handle.write(buffer, offset, buffer.length - offset, position + offset);
if (result.bytesWritten <= 0) {
throw new Error("proxy_disk_write_zero");
}
offset += result.bytesWritten;
}
}
async function downloadSegmentOnce(
target: URL,
tempPath: string,
segment: Segment,
proxy: ProxyEndpoint,
signal: AbortSignal,
options: Required<Pick<ProxySegmentedDownloadOptions, "skipTlsVerify" | "connectTimeoutMs" | "idleTimeoutMs">>,
callbacks: Pick<ProxySegmentedDownloadOptions, "waitWhilePaused" | "onTrafficBytes" | "onProgress">,
totalBytes: number,
currentProgress: () => number
): Promise<number> {
const opened = await openRangeResponse(
target,
proxy,
segment.start,
segment.end,
signal,
options.skipTlsVerify,
options.connectTimeoutMs,
options.idleTimeoutMs
);
const response = opened.response;
const status = response.statusCode || 0;
if (status >= 400) {
opened.dispose();
throw new OriginHttpError(status);
}
const expectedBytes = segment.end - segment.start + 1;
const range = parseContentRange(response.headers["content-range"]);
const contentLength = Number(response.headers["content-length"] || 0);
if (status !== 206
|| !range
|| range.start !== segment.start
|| range.end !== segment.end
|| range.total !== totalBytes
|| (contentLength > 0 && contentLength !== expectedBytes)) {
opened.dispose();
throw new Error("proxy_range_mismatch");
}
let handle: fs.promises.FileHandle;
try {
handle = await fs.promises.open(tempPath, "r+");
} catch (error) {
opened.dispose();
throw error;
}
let received = 0;
try {
for await (const rawChunk of response) {
if (signal.aborted) {
throw abortError();
}
const chunk = Buffer.isBuffer(rawChunk) ? rawChunk : Buffer.from(rawChunk);
callbacks.onTrafficBytes?.(chunk.length);
if (received + chunk.length > expectedBytes) {
throw new Error("proxy_segment_overflow");
}
if (callbacks.waitWhilePaused) {
response.setTimeout(0);
await callbacks.waitWhilePaused();
response.setTimeout(options.idleTimeoutMs);
}
await writeBufferAt(handle, chunk, segment.start + received);
received += chunk.length;
callbacks.onProgress?.(chunk.length, currentProgress() + chunk.length, totalBytes);
}
if (received !== expectedBytes) {
throw new Error("proxy_segment_underflow");
}
return received;
} finally {
opened.dispose();
await handle.close();
}
}
export async function downloadWithProxySegments(options: ProxySegmentedDownloadOptions): Promise<ProxySegmentedDownloadResult> {
const proxyPath = String(options.proxyListPath || "").trim();
if (!proxyPath) {
return { status: "fallback", reason: "proxy_file_unavailable" };
}
const loaded = await loadProxyFile(proxyPath);
if (loaded.status === "unavailable") {
return { status: "fallback", reason: "proxy_file_unavailable" };
}
if (loaded.status === "empty") {
return { status: "fallback", reason: "no_valid_proxies" };
}
const poolKey = path.resolve(proxyPath);
const requestedConnections = Math.max(2, Math.min(32, Math.floor(options.connections || 16)));
const totalConnectionLimit = Math.max(2, Math.min(32, Math.floor(options.totalConnectionLimit ?? requestedConnections)));
sharedProxyCoordinator.setConnectionLimit(totalConnectionLimit);
const reservedProxyIndex = Math.max(0, Math.floor(options.reservedProxyIndex || 0));
const reservedProxy = reservedProxyIndex > 0 ? loaded.proxies[reservedProxyIndex - 1] : null;
const reservedProxyKey = reservedProxy ? proxyEndpointKey(reservedProxy) : "";
const segmentProxies = reservedProxyKey
? loaded.proxies.filter((proxy) => proxyEndpointKey(proxy) !== reservedProxyKey)
: loaded.proxies;
let target: URL;
try {
target = new URL(options.directUrl);
if (target.protocol !== "http:" && target.protocol !== "https:") {
return { status: "fallback", reason: "proxy_unavailable" };
}
} catch {
return { status: "fallback", reason: "proxy_unavailable" };
}
const groupId = String(options.downloadId || options.targetPath || randomUUID());
const unregisterGroup = sharedProxyCoordinator.registerGroup(groupId);
try {
const normalized = {
skipTlsVerify: Boolean(options.skipTlsVerify),
connectTimeoutMs: Math.max(1_000, Math.floor(options.connectTimeoutMs ?? DEFAULT_CONNECT_TIMEOUT_MS)),
idleTimeoutMs: Math.max(2_000, Math.floor(options.idleTimeoutMs ?? DEFAULT_IDLE_TIMEOUT_MS)),
proxyAttempts: Math.max(1, Math.min(10, Math.floor(options.proxyAttempts ?? DEFAULT_PROXY_ATTEMPTS)))
};
const probe = await probeRangeSupport(target, poolKey, groupId, segmentProxies, options.signal, normalized, options.onTrafficBytes);
if (probe.status === "unsupported") {
return { status: "fallback", reason: "range_unsupported" };
}
if (probe.status === "unavailable") {
return { status: "fallback", reason: "proxy_unavailable" };
}
if (probe.status === "origin_error") {
return { status: "fallback", reason: "origin_http_error", httpStatus: probe.httpStatus };
}
const minSegmentBytes = Math.max(1, Math.floor(options.minSegmentBytes ?? DEFAULT_MIN_SEGMENT_BYTES));
const connections = Math.min(requestedConnections, segmentProxies.length, Math.floor(probe.totalBytes / minSegmentBytes));
if (connections < 2) {
return {
status: "fallback",
reason: segmentProxies.length < 2 ? "not_enough_proxies" : "file_too_small"
};
}
await fs.promises.mkdir(path.dirname(options.targetPath), { recursive: true });
try {
const targetStat = await fs.promises.stat(options.targetPath);
if (targetStat.size > 0) {
return { status: "fallback", reason: "segment_failed" };
}
await fs.promises.rm(options.targetPath, { force: true });
} catch (error) {
const code = error && typeof error === "object" && "code" in error
? String((error as NodeJS.ErrnoException).code || "")
: "";
if (code !== "ENOENT") {
throw error;
}
}
const tempPath = `${options.targetPath}.proxy-${process.pid}-${randomUUID()}.part`;
let committedProgress = 0;
let tempCreated = false;
const updateProgress = (deltaBytes: number, _downloadedBytes: number, totalBytes: number): void => {
committedProgress = Math.max(0, Math.min(totalBytes, committedProgress + deltaBytes));
options.onProgress?.(deltaBytes, committedProgress, totalBytes);
};
try {
const initialHandle = await fs.promises.open(tempPath, "wx");
tempCreated = true;
try {
await initialHandle.truncate(probe.totalBytes);
} finally {
await initialHandle.close();
}
const segments = buildSegments(probe.totalBytes, connections, minSegmentBytes);
const segmentController = new AbortController();
const cascadeAbort = (): void => segmentController.abort("parent_abort");
options.signal.addEventListener("abort", cascadeAbort, { once: true });
const signal = AbortSignal.any([options.signal, segmentController.signal]);
const downloadSegment = async (segment: Segment): Promise<number> => {
const excluded = new Set<string>();
let lastError: unknown = null;
for (let attempt = 0; attempt < normalized.proxyAttempts; attempt += 1) {
if (signal.aborted) {
throw abortError();
}
const lease = await sharedProxyCoordinator.acquire(poolKey, groupId, segmentProxies, excluded, signal);
if (!lease) {
break;
}
excluded.add(proxyEndpointKey(lease.proxy));
let attemptProgress = 0;
const startedAt = Date.now();
try {
const bytes = await downloadSegmentOnce(
target,
tempPath,
segment,
lease.proxy,
signal,
normalized,
{
waitWhilePaused: options.waitWhilePaused,
onTrafficBytes: options.onTrafficBytes,
onProgress: (deltaBytes, downloadedBytes, totalBytes) => {
attemptProgress += deltaBytes;
updateProgress(deltaBytes, downloadedBytes, totalBytes);
}
},
probe.totalBytes,
() => committedProgress
);
lease.release({
succeeded: true,
transferredBytes: bytes,
durationMs: Math.max(1, Date.now() - startedAt)
});
return bytes;
} catch (error) {
const originError = error instanceof OriginHttpError;
lease.release({ succeeded: originError || signal.aborted });
if (originError) {
sharedProxyCoordinator.reportOriginStatus(error.statusCode);
}
if (attemptProgress > 0) {
updateProgress(-attemptProgress, committedProgress - attemptProgress, probe.totalBytes);
}
if (options.signal.aborted || isDiskError(error)) {
throw error;
}
lastError = error;
}
}
throw lastError || new Error("proxy_segment_failed");
};
let nextSegmentIndex = 0;
const tasks = Array.from({ length: Math.min(connections, segments.length) }, async () => {
let downloadedBytes = 0;
while (!signal.aborted) {
const segmentIndex = nextSegmentIndex;
nextSegmentIndex += 1;
const segment = segments[segmentIndex];
if (!segment) break;
downloadedBytes += await downloadSegment(segment);
}
return downloadedBytes;
});
const guardedTasks = tasks.map((task) => task.catch((error) => {
segmentController.abort("segment_failed");
throw error;
}));
const settled = await Promise.allSettled(guardedTasks);
options.signal.removeEventListener("abort", cascadeAbort);
const failed = settled.find((result): result is PromiseRejectedResult => result.status === "rejected");
if (failed) {
if (options.signal.aborted) {
throw abortError();
}
if (isDiskError(failed.reason)) {
throw failed.reason;
}
const originFailure = settled.find((result): result is PromiseRejectedResult => (
result.status === "rejected" && result.reason instanceof OriginHttpError
));
if (originFailure) {
return {
status: "fallback",
reason: "origin_http_error",
httpStatus: (originFailure.reason as OriginHttpError).statusCode
};
}
return { status: "fallback", reason: "segment_failed" };
}
const finalizedHandle = await fs.promises.open(tempPath, "r+");
try {
await finalizedHandle.datasync();
} finally {
await finalizedHandle.close();
}
const finalStat = await fs.promises.stat(tempPath);
if (finalStat.size !== probe.totalBytes) {
return { status: "fallback", reason: "segment_failed" };
}
await fs.promises.rename(tempPath, options.targetPath);
tempCreated = false;
return { status: "completed", totalBytes: probe.totalBytes, connections };
} catch (error) {
if (options.signal.aborted || String(error).includes("aborted:proxy_download")) {
throw abortError();
}
if (isDiskError(error)) {
throw error;
}
return { status: "fallback", reason: "segment_failed" };
} finally {
if (tempCreated) {
try {
await fs.promises.rm(tempPath, { force: true });
} catch {
}
}
if (committedProgress > 0 && tempCreated) {
updateProgress(-committedProgress, 0, probe.totalBytes);
}
}
} finally {
unregisterGroup();
}
}