From 1d0fb7d260d2ab98ea652e8baed4804d5039bacd Mon Sep 17 00:00:00 2001
From: sunnylqm <sunnylqm@qq.com>
Date: Sat, 18 Jan 2020 23:55:10 +0800
Subject: [PATCH] Backup domains

---
 .prettierrc.js |  1 -
 lib/getHost.js | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++
 lib/index.d.ts |  1 -
 lib/index.js   | 40 +++++++++++++++++++++--------------
 4 files changed, 81 insertions(+), 18 deletions(-)
 create mode 100644 lib/getHost.js

diff --git a/.prettierrc.js b/.prettierrc.js
index e23377f..9166a04 100644
--- a/.prettierrc.js
+++ b/.prettierrc.js
@@ -1,5 +1,4 @@
 module.exports = {
-  printWidth: 120,
   trailingComma: 'all',
   singleQuote: true,
 };
diff --git a/lib/getHost.js b/lib/getHost.js
new file mode 100644
index 0000000..022e071
--- /dev/null
+++ b/lib/getHost.js
@@ -0,0 +1,57 @@
+let availableDomain = 'update.reactnative.cn';
+
+function ping(domain) {
+  return new Promise((resolve, reject) => {
+    const xhr = new XMLHttpRequest();
+    xhr.onreadystatechange = e => {
+      if (xhr.readyState !== 4) {
+        return;
+      }
+      if (xhr.status === 200) {
+        resolve(domain);
+      } else {
+        setTimeout(reject, 5000);
+      }
+    };
+    xhr.open('HEAD', `https://${domain}`);
+    xhr.send();
+    xhr.timeout = 5000;
+    xhr.ontimeout = reject;
+  });
+}
+
+function logger(...args) {
+  // console.warn('pushy', ...args);
+}
+
+export async function tryBackupDomains() {
+  try {
+    await ping(availableDomain);
+    logger('main domain ok');
+    return;
+  } catch (e) {
+    logger('main domain failed');
+  }
+  let backupDomains = [];
+  try {
+    const resp = await fetch(
+      'https://cdn.jsdelivr.net/gh/reactnativecn/react-native-pushy@master/domains.json',
+    );
+    backupDomains = await resp.json();
+    logger('get remote domains:', backupDomains);
+  } catch (e) {
+    logger('get remote domains failed');
+    return;
+  }
+  const fastestDomain = await Promise.race(backupDomains.map(ping));
+  if (typeof fastestDomain === 'string') {
+    logger(`pick domain: ${fastestDomain}`);
+    availableDomain = fastestDomain;
+  } else {
+    logger('all remote domains failed');
+  }
+}
+
+export default function getHost() {
+  return `https://${availableDomain}/api`;
+}
diff --git a/lib/index.d.ts b/lib/index.d.ts
index 9859f16..0f7ff6c 100644
--- a/lib/index.d.ts
+++ b/lib/index.d.ts
@@ -19,7 +19,6 @@ export interface UpdateAvailableResult {
   hash: string;
   description: string;
   metaInfo: string;
-  updateUrl: string;
   pdiffUrl: string;
   diffUrl: string;
 }
diff --git a/lib/index.js b/lib/index.js
index d15513c..ac1ef08 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -1,7 +1,7 @@
+import getHost, { tryBackupDomains } from './getHost';
 import { NativeAppEventEmitter, NativeModules } from 'react-native';
-const Pushy = NativeModules.Pushy || {};
 
-const host = 'https://update.reactnative.cn/api';
+const Pushy = NativeModules.Pushy || {};
 
 export const downloadRootDir = Pushy.downloadRootDir;
 export const packageVersion = Pushy.packageVersion;
@@ -28,7 +28,6 @@ There is available update:
   hash: 'hash',
   description: '添加聊天功能\n修复商城页面BUG',
   metaInfo: '{"silent":true}',
-  updateUrl: 'http://update-packages.reactnative.cn/hash',
   pdiffUrl: 'http://update-packages.reactnative.cn/hash',
   diffUrl: 'http://update-packages.reactnative.cn/hash',
 }
@@ -40,20 +39,29 @@ function assertRelease() {
   }
 }
 
-export async function checkUpdate(APPKEY) {
+export async function checkUpdate(APPKEY, isRetry) {
   assertRelease();
-  const resp = await fetch(`${host}/checkUpdate/${APPKEY}`, {
-    method: 'POST',
-    headers: {
-      Accept: 'application/json',
-      'Content-Type': 'application/json',
-    },
-    body: JSON.stringify({
-      packageVersion,
-      hash: currentVersion,
-      buildTime,
-    }),
-  });
+  let resp;
+  try {
+    resp = await fetch(`${getHost()}/checkUpdate/${APPKEY}`, {
+      method: 'POST',
+      headers: {
+        Accept: 'application/json',
+        'Content-Type': 'application/json',
+      },
+      body: JSON.stringify({
+        packageVersion,
+        hash: currentVersion,
+        buildTime,
+      }),
+    });
+  } catch (e) {
+    if (isRetry) {
+      throw new Error('Could not connect to pushy server');
+    }
+    await tryBackupDomains();
+    return checkUpdate(APPKEY, true);
+  }
 
   if (resp.status !== 200) {
     throw new Error((await resp.json()).message);