Promise.method（）函数不按我期望的方式工作

Question

我正在编写一些加密两个用户之间的通信通道的代码。 的步骤如下

• 检查中mongoDb
• 存在该频道的密码如果是，取cipher和加密输入数据
• 如果没有，创建一个新的密码，将其保存到mongoDb和加密输入数据

代码使用crypto模块，其在芯中的几个同步库之一的NodeJS

创建加密，并将其返回作为一个承诺使用Promise.method（）

cipher.encryptTextAsPromise = Promise.method((cipher, plainText) => { 
    if (!(typeof plainText === 'string')) { 
    throw new Error("2nd param must be plain text"); 
    let cipherText = ''; 
    cipher.on('readable',() => { 
     var data = cipher.read(); 
     if (data) 
     cipherText += data.toString('hex'); 
    }); 
    cipher.on('end',() => { 
     return cipherText; 
    }); 
    cipher.write(plainText); 
    cipher.end(); 
    } 
}); 

加密数据通过回调函数

cipher.createCipher = Promise.method((pw) => { 
    if (!pw) { 
    throw new Error('Passphrase must be provided'); 
    } 
    return crypto.createCipher('aes192', pw); 
}); 

加密数据。

cipher.encryptText = (cipher, plainText, callback) => { 
    if (!(typeof plainText === 'string')) { 
    throw new Error("2nd param must be plain text"); 
    } 
    try { 
    let cipherText = ''; 
    cipher.on('readable',() => { 
     var data = cipher.read(); 
     if (data) 
     cipherText += data.toString('hex'); 
    }); 
    cipher.on('end',() => { 
     callback(null, cipherText); 
    }); 
    cipher.write(plainText); 
    cipher.end(); 
    } catch (e) { 
    callback(e, null); 
    } 
} 

我无法将这两个链接在一起。我已经是一个可怕的反模式比陷入回调地狱

cipher.createCipher('secretWord') 
    .then((data) => { 
    cipher.encryptTextasPromise(data, 'hello world') 
    .then((data) => { 
     console.log(data); 
    }) 
    .catch((err) => { 
     console.log(err); 
    }) 
    }) 
    .catch((err) => { 
    console.log(err); 
    }) 

mongoDbSearch(username) 
    .then((data) => { 
    if (data) { 
     // Cipher exists, retrieve and encrypt 
    }else { 
     // Create new cipher and save 
     someMongoSave() 
     .then((data) => { 
      // Cipher exists now, retrieve and encrypt 
     }) 
    } 
    }) 
    .catch((mongoErr) => { 
    console.log(mongoErr); 
    }) 

的代码是一个有点不完整，因为我仍然在试图掌握这个概念变得更糟。此外，我试图链接createCipher和encryptTextAsPromise正在返回undefined的数据。我曾试着将这些作为普通回调书写，然后使用Promise.promisfyAll()，这只是另一种反模式。

Answer 1

Promise.method似乎对createCipher有意义，但可能不适用于encryptTextAsPromise。

这里有一个版本，应该指出你正确的方向，蒸馏各种T.J. Crowder's，Jaromanda X's和undefined对这个问题的评论;看到代码的注释更多：

// For this one, `Promise.method` still makes sense (although doing it with 
// your own promise is also perfectly reasonable) 
cipher.createCipher = Promise.method(pw => { 
    if (!pw) { 
    throw new Error('Passphrase must be provided'); 
    } 
    return crypto.createCipher('aes192', pw); 
}); 

// For this one, your own promise makes sense 
cipher.encryptTextAsPromise = (cipher, plainText) => { 
    return new Promise(resolve => { 
    if (!(typeof plainText === 'string')) { 
     // It's fine to throw here (it will get converted into a rejection), 
     // or add `reject` to the arguments list above and call 
     // that and return instead: 
     // reject(new Error("2nd param must be plain text")); 
     // return; 
     throw new Error("2nd param must be plain text"); 
    } 
    let cipherText = ''; 
    cipher.on('readable',() => { 
     var data = cipher.read(); 
     if (data) 
     cipherText += data.toString('hex'); 
    }); 
    cipher.on('end',() => { 
     resolve(cipherText); 
    }); 
    cipher.write(plainText); 
    cipher.end(); 
    }); 
}; 

// Usage: 
cipher.createCipher('secretWord') 
.then(data => cipher.encryptTextAsPromise(data, 'hello world')) 
.then(data => console.log(data)) // See 1 below 
.catch(err => console.log(err)); 

mongoDbSearch(username) 
.then(data => data || someMongoSave(data)) // You pass `data` to `someMongoSave`, presumably? 
.then(data => { 
    // Cipher exists, retrieve and encrypt 
}) 
.catch(mongoErr => { 
    console.log(mongoErr); 
}); 

另外，重新

if (!(typeof plainText === 'string')) { 

有一个JavaScript !==运营商。 Jus'说'。 ; -D