Add custom endpoints

lib/endpoint.js

@@ -0,0 +1,82 @@
+let currentEndpoint = 'https://update.reactnative.cn/api';
+
+function ping(url, rejectImmediate) {
+  return new Promise((resolve, reject) => {
+    const xhr = new XMLHttpRequest();
+    xhr.onreadystatechange = (e) => {
+      if (xhr.readyState !== 4) {
+        return;
+      }
+      if (xhr.status === 200) {
+        resolve(url);
+      } else {
+        rejectImmediate ? reject() : setTimeout(reject, 5000);
+      }
+    };
+    xhr.open('HEAD', url);
+    xhr.send();
+    xhr.timeout = 5000;
+    xhr.ontimeout = reject;
+  });
+}
+
+function logger(...args) {
+  // console.warn('pushy', ...args);
+}
+
+let backupEndpoints = [];
+let backupEndpointsQueryUrl =
+  'https://cdn.jsdelivr.net/gh/reactnativecn/react-native-pushy@master/endpoints.json';
+
+export async function tryBackupEndpoints() {
+  try {
+    await ping(getStatusUrl(), true);
+    logger('current endpoint ok');
+    return;
+  } catch (e) {
+    logger('current endpoint failed');
+  }
+  if (!backupEndpoints.length && backupEndpointsQueryUrl) {
+    try {
+      const resp = await fetch(backupEndpointsQueryUrl);
+      backupEndpoints = await resp.json();
+      logger('get remote endpoints:', backupEndpoints);
+    } catch (e) {
+      logger('get remote endpoints failed');
+      return;
+    }
+  }
+  await pickFatestAvailableEndpoint();
+}
+
+async function pickFatestAvailableEndpoint(endpoints = backupEndpoints) {
+  const fastestEndpoint = await Promise.race(
+    endpoints.map(pingAndReturnEndpoint),
+  );
+  if (typeof fastestEndpoint === 'string') {
+    logger(`pick endpoint: ${fastestEndpoint}`);
+    currentEndpoint = fastestEndpoint;
+  } else {
+    logger('all remote endpoints failed');
+  }
+}
+
+async function pingAndReturnEndpoint(endpoint = currentEndpoint) {
+  return ping(getStatusUrl(endpoint)).then(() => endpoint);
+}
+
+function getStatusUrl(endpoint = currentEndpoint) {
+  return `${endpoint}/status`;
+}
+
+export function getCheckUrl(APPKEY, endpoint = currentEndpoint) {
+  return `${endpoint}/checkUpdate/${APPKEY}`;
+}
+
+export function setCustomEndpoints(mainEndpoint, backups) {
+  currentEndpoint = mainEndpoint;
+  if (Array.isArray(backups) && backups.length > 0) {
+    backupEndpoints = backups;
+    pickFatestAvailableEndpoint();
+  }
+}