api queue

services/ApiQueueService.js

@@ -0,0 +1,82 @@
+const MAX_QUERY_PER_SECOND = 4;
+
+class ApiQueueService {
+  constructor() {
+    this.queue = [];
+    this.executeHistory = [];
+    this.isRun = false;
+  }
+
+  executeInQueue(method, ...data) {
+    return new Promise((resolve, reject) => {
+      this.addToQueue(method, data, ({ err, data }) => {
+        if (err) {
+          return reject(err);
+        }
+        return resolve(data);
+      });
+    });
+  }
+
+  addToQueue(method, data, cb) {
+    this.queue.push({ method, data, cb });
+    this.run();
+  }
+
+  run(force = false) {
+    if (this.isRun && !force) {
+      return;
+    }
+    this.isRun = true;
+    if (this.isBusy()) {
+      const timer = setTimeout(() => {
+        clearTimeout(timer);
+        this.run(true);
+      }, 100);
+      return;
+    }
+    const q = this.getFirst();
+    if (!q) {
+      this.isRun = false;
+      return;
+    }
+    this.execute(q).finally(() => {
+      this.removeFirst();
+      if (this.queue.length === 0) {
+        this.isRun = false;
+        return;
+      }
+      this.run(true);
+    });
+  }
+
+  getFirst() {
+    return this.queue && this.queue[0];
+  }
+
+  removeFirst() {
+    this.queue.splice(0, 1);
+  }
+
+  isBusy() {
+    return this.getCountQueryInLastSecond() >= MAX_QUERY_PER_SECOND;
+  }
+
+  getCountQueryInLastSecond() {
+    const currentTime = +new Date();
+    this.executeHistory = this.executeHistory.filter((d) => d.time > (currentTime - 1000));
+    return this.executeHistory.length;
+  }
+
+  execute(q) {
+    this.executeHistory.push({ time: +new Date() });
+    return q.method(...(q.data || [])).then((data) => {
+      q.cb({ data });
+    }).catch((err) => {
+      q.cb({ err });
+    });
+
+  }
+}
+
+module.exports = new ApiQueueService();