Add proxy render

proxy-renderer.js

@@ -10,7 +10,37 @@ const { GenerateScript } = await import('./src/GenerateScript.cjs');
 
 const originalManuScriptPath = path.join(process.cwd(), 'public/original_manuscript.json');
 let cmd = `npm run preview`;
-var childProcess = exec(cmd);
+let childProcess = null;
+
+function startChildProcess() {
+  if (childProcess && !childProcess.killed) {
+    return childProcess;
+  }
+
+  childProcess = exec(cmd);
+
+  childProcess.on('error', (err) => {
+    console.error('Preview child process error:', err);
+  });
+
+  childProcess.on('close', (code, signal) => {
+    console.log('Render studio exited with', code, signal, '. Restarting in 2s...');
+    // clear reference so future callers can recreate
+    childProcess = null;
+    setTimeout(() => {
+      try {
+        startChildProcess();
+      } catch (e) {
+        console.error('Failed to restart preview process', e);
+      }
+    }, 2000);
+  });
+
+  return childProcess;
+}
+
+// start immediately
+startChildProcess();
 export const renderProxy = async (outFile, options) => {
   const ScriptStr = fs.readFileSync(originalManuScriptPath);
   const ScriptInput = JSON.parse(ScriptStr);
@@ -74,33 +104,54 @@ export const renderProxy = async (outFile, options) => {
     axios.post('http://localhost:3000/api/render', renderOptions).then(resp => {
       console.log('Studio started render', resp.data)
 
-      childProcess.stdout.on('data', (data) => {
-        console.log(data)
-        if (data.includes('Cleanup: Closing browser instance')) {
-          try {
-            resolve(outFile)
-          }
-          catch (e) { }
-        }
-      });
-      childProcess.stderr.on('data', (data) => {
-        console.error(data)
+      const proc = startChildProcess();
+
+      let settled = false;
+
+      const cleanupHandlers = () => {
         try {
-          if (data.includes('Failed to render')) {
-          reject(data)
-        }
+          if (proc && proc.stdout && stdoutHandler) proc.stdout.removeListener('data', stdoutHandler);
         } catch (e) { }
-
-      });
-      childProcess.on('close', (code) => {
-        console.log('Render studio exited. Restarting...');
-        setTimeout(() => {
-          childProcess = exec(cmd);
-        }, 2000)
         try {
-          reject(data)
+          if (proc && proc.stderr && stderrHandler) proc.stderr.removeListener('data', stderrHandler);
         } catch (e) { }
-      });
+      };
+
+      const stdoutHandler = (chunk) => {
+        const data = String(chunk);
+        console.log(data);
+        if (data.includes('Cleanup: Closing browser instance')) {
+          if (settled) return;
+          settled = true;
+          cleanupHandlers();
+          resolve(outFile);
+        }
+      };
+
+      const stderrHandler = (chunk) => {
+        const data = String(chunk);
+        console.error(data);
+        if (data.includes('Failed to render')) {
+          if (settled) return;
+          settled = true;
+          cleanupHandlers();
+          reject(new Error(data));
+        }
+      };
+
+      if (proc && proc.stdout) proc.stdout.on('data', stdoutHandler);
+      if (proc && proc.stderr) proc.stderr.on('data', stderrHandler);
+
+      // safety: if proc exits before we resolve, clean up and let the caller retry
+      const onProcClose = () => {
+        if (settled) return;
+        settled = true;
+        cleanupHandlers();
+        reject(new Error('Preview process exited before render finished'));
+      };
+
+      proc.once('close', onProcClose);
+
     }).catch(reject)
   })
 }