节点child_process等待结果

Question

face_detection我有一个进行命令行调用的异步函数。否则一切正常，但我无法等待回复。这是我的功能：

async uploadedFile(@UploadedFile() file) {
    let isThereFace: boolean;
    const foo: child.ChildProcess = child.exec(
      `face_detection ${file.path}`,
      (error: child.ExecException, stdout: string, stderr: string) => {
        console.log(stdout.length);

        if (stdout.length > 0) {
          isThereFace = true;
        } else {
          isThereFace = false;
        }
        console.log(isThereFace);

        return isThereFace;
      },
    );

    console.log(file);

    const response = {
      filepath: file.path,
      filename: file.filename,
      isFaces: isThereFace,
    };
    console.log(response);

    return response;
  }

isThereFace在我的响应中，我返回始终是undefined因为响应是在响应face_detection准备好之前发送给客户端的。我怎样才能做到这一点？

Answer 1

您可以使用该child_process.execSync调用，该调用将等待 exec 完成。但不鼓励执行同步调用......

或者你可以child_process.exec用一个承诺来包装

const result = await new Promise((resolve, reject) => {
   child.exec(
      `face_detection ${file.path}`,
      (error: child.ExecException, stdout: string, stderr: string) => {
        if (error) {
          reject(error);
        } else {
          resolve(stdout); 
        }
      });
});