Remove delay before recording starts (#12)

Sources/ApertureCLI/main.swift

@@ -14,6 +14,8 @@ struct Options: Decodable {
 }
 
 func record() throws {
+  setbuf(__stdoutp, nil)
+
   let options: Options = try CLI.arguments.first!.jsonDecoded()
 
   let recorder = try Aperture(
@@ -28,7 +30,7 @@ func record() throws {
   )
 
   recorder.onStart = {
-    print("R")
+    print("FR")
   }
 
   recorder.onFinish = {
@@ -48,7 +50,9 @@ func record() throws {
 
   recorder.start()
 
-  setbuf(__stdoutp, nil)
+  // Inform the Node.js code that the recording has started.
+  print("R")
+
   RunLoop.main.run()
 }
 

example.js

@@ -10,6 +10,8 @@ async function main() {
   console.log('Preparing to record for 5 seconds');
   await recorder.startRecording();
   console.log('Recording started');
+  await recorder.isFileReady;
+  console.log('File is ready');
   await delay(5000);
   const fp = await recorder.stopRecording();
   fs.renameSync(fp, 'recording.mp4');

index.js

@@ -118,14 +118,25 @@ class Aperture {
         reject(error);
       });
 
+      this.isFileReady = new Promise(resolve => {
+        this._fileReadyResolve = resolve;
+      });
+
       this.recorder.stdout.setEncoding('utf8');
       this.recorder.stdout.on('data', data => {
         debuglog(data);
 
-        if (data.trim() === 'R') {
-          // `R` is printed by Swift when the recording **actually** starts
+        const trimmed = data.trim();
+
+        if (trimmed === 'R') {
+          // `R` is printed by Swift about a second before the recording **actually** starts
           clearTimeout(timeout);
-          resolve(this.tmpPath);
+          setTimeout(resolve, 1000);
+        } else if (trimmed === 'FR') {
+          // `FR` is printed by Swift when the the recording file is ready
+          if (this._fileReadyResolve) {
+            this._fileReadyResolve(this.tmpPath);
+          }
         }
       });
     });
@@ -139,6 +150,8 @@ class Aperture {
     this.recorder.kill();
     await this.recorder;
     delete this.recorder;
+    delete this._fileReadyResolve;
+    delete this.isFileReady;
 
     return this.tmpPath;
   }

readme.md

@@ -86,9 +86,15 @@ Map {
 
 #### recorder.startRecording([[options]](#options))
 
-Returns a `Promise` for the path to the screen recording file.
+Returns a `Promise` that fullfills when the recording starts or rejects if the recording didn't start after 5 seconds.
+
+#### recorder.isFileReady
+
+`Promise` that fullfills with the path to the screen recording file when it's ready. This will never reject.
+
+Only available while a recording is happening, `undefined` otherwise.
 
-Fullfills when the recording starts or rejects if the recording didn't start after 5 seconds.
+Usually, this resolves around 1 second before the recording starts, but that's not guaranteed.
 
 #### recorder.stopRecording()
 

test.js

@@ -25,7 +25,8 @@ test('returns available video codecs', t => {
 
 test('records screen', async t => {
   const recorder = aperture();
-  t.true(fs.existsSync(await recorder.startRecording()));
+  await recorder.startRecording();
+  t.true(fs.existsSync(await recorder.isFileReady));
   await delay(1000);
   const videoPath = await recorder.stopRecording();
   t.true(fs.existsSync(videoPath));