fix(MS365): Wait until responding with a throttling response (#142)

postalsys · Sep 13, 2023 · 09bfb3e · 09bfb3e
1 parent 62878e3
commit 09bfb3e
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Showing 4 changed files with 173 additions and 130 deletions.
diff --git a/lib/imap-flow.js b/lib/imap-flow.js
@@ -561,7 +561,28 @@ class ImapFlow extends EventEmitter {
                         err.responseStatus = parsed.command.toUpperCase();
                         if (txt) {
                             err.responseText = txt;
+
+                            // MS365 throttling
+                            // tag BAD Request is throttled. Suggested Backoff Time: 92415 milliseconds
+                            if (/Request is throttled/i.test(txt) && /Backoff Time/i.test(txt)) {
+                                let throttlingMatch = txt.match(/Backoff Time[:=\s]+(\d+)/i);
+                                if (throttlingMatch && throttlingMatch[1] && !isNaN(throttlingMatch[1])) {
+                                    err.code = 'ETHROTTLE';
+                                    err.throttleReset = Number(throttlingMatch[1]);
+
+                                    let delayResponse = err.throttleReset;
+                                    if (delayResponse > 5 * 60 * 1000) {
+                                        // max delay cap
+                                        delayResponse = 5 * 60 * 1000;
+                                    }
+                                    if (delayResponse) {
+                                        this.log.warn({ msg: 'Throttling detected', err, cid: this.id, delayResponse });
+                                        await new Promise(r => setTimeout(r, delayResponse));
+                                    }
+                                }
+                            }
                         }
+
                         request.reject(err);
                         break;
                     }