Improved fetch with retry on all three platforms

ReactNativeClient/lib/shim.js

@@ -30,7 +30,70 @@ shim.isElectron = () => {
     return false;
 }
 
-shim.fetch = typeof fetch !== 'undefined' ? fetch : null;
+// Node requests can go wrong is so many different ways and with so
+// many different error messages... This handler inspects the error
+// and decides whether the request can safely be repeated or not.
+function fetchRequestCanBeRetried(error) {
+    if (!error) return false;
+
+    // Unfortunately the error 'Network request failed' doesn't have a type
+    // or error code, so hopefully that message won't change and is not localized
+    if (error.message == 'Network request failed') return true;
+
+    // request to https://public-ch3302....1fab24cb1bd5f.md failed, reason: socket hang up"
+    if (error.code == 'ECONNRESET') return true;
+
+    // OneDrive (or Node?) sometimes sends back a "not found" error for resources
+    // that definitely exist and in this case repeating the request works.
+    // Error is:
+    // request to https://graph.microsoft.com/v1.0/drive/special/approot failed, reason: getaddrinfo ENOTFOUND graph.microsoft.com graph.microsoft.com:443      
+    if (error.code == 'ENOTFOUND') return true;
+
+    // network timeout at: https://public-ch3302...859f9b0e3ab.md
+    if (error.message && error.message.indexOf('network timeout') === 0) return true;
+
+    // name: 'FetchError',
+    // message: 'request to https://api.ipify.org/?format=json failed, reason: getaddrinfo EAI_AGAIN api.ipify.org:443',
+    // type: 'system',
+    // errno: 'EAI_AGAIN',
+    // code: 'EAI_AGAIN' } } reason: { FetchError: request to https://api.ipify.org/?format=json failed, reason: getaddrinfo EAI_AGAIN api.ipify.org:443
+    //
+    // It's a Microsoft error: "A temporary failure in name resolution occurred."
+    if (error.code == 'EAI_AGAIN') return true;
+
+    // request to https://public-...8fd8bc6bb68e9c4d17a.md failed, reason: connect ETIMEDOUT 204.79.197.213:443
+    // Code: ETIMEDOUT
+    if (error.code === 'ETIMEDOUT') return true;
+
+    return false;
+}
+
+shim.fetchWithRetry = async function(fetchFn, options = null) {
+    const { time } = require('lib/time-utils.js');
+
+    if (!options) options = {};
+    if (!options.timeout) options.timeout = 1000 * 120; // ms
+    if (!('maxRetry' in options)) options.maxRetry = 5;
+
+    let retryCount = 0;
+    while (true) {
+        try {
+            const response = await fetchFn();
+            return response;
+        } catch (error) {
+            if (fetchRequestCanBeRetried(error)) {
+                retryCount++;
+                if (retryCount > options.maxRetry) throw error;
+                await time.sleep(retryCount * 3);
+            } else {
+                throw error;
+            }
+        }
+    }
+}
+
+shim.nativeFetch_ = typeof fetch !== 'undefined' ? fetch : null;
+shim.fetch = () => { throw new Error('Not implemented'); }
 shim.FormData = typeof FormData !== 'undefined' ? FormData : null;
 shim.fs = null;
 shim.FileApiDriverLocal = null;