我有一个分析网站的服务,压缩他们的来源,如CSS文档,图像等。我有2个函数,一个是具有异步回调函数的Socket.IO socket.on()
方法。另一个是服务的主要功能。
socket.on('run', async options => {
debug(`${options.target} Adresine Bir Kullanıcı İstek Yaptı!`);
let user = null;
console.log(options);
if(options.token) {
user = await User.findById(jwt.verify(options.token, config.get('jwtPrivateKey'))._id);
options.userId = user._id.toString();
} else if(options.visitor) {
user = await Visitor.findById(options.visitor._id);
if(user.report) {
return socket.emit('error', new Error('You have exceeded your report limit'));
} else {
options.userId = user._id.toString();
}
}
if(options.userId) {
let userType = await UserType.find({ name: user.type });
if(userType.length > 0 && ((user.type == 'Visitor' && user.report == undefined) || (user.reports.length < userType[0].rights.reportsLimit.limit || userType[0].rights.reportsLimit.unlimited))) {
options.rights = userType[0].rights;
let { error, data } = await wrapper(runService(options.target, options, socket));
if(error) {
console.log('Here', error);
return socket.emit('error', error);
}
.
.
.
}
.
.
.
}
});
在上面的功能中,
let { error, data } = await wrapper(runService(options.target, options, socket));
if(error) {
console.log('Here', error);
return socket.emit('error', error);
}
这部分很重要,因为我用我的async函数包装函数调用我的主要异步服务函数runService
,该函数名为wrapper
。包装函数就是这个;
const wrapper = promise => (
promise
.then(data => ({ data, error: null }))
.catch(error => ({ error, data: null }))
);
在我的主要异步服务函数中,我只抛出一个错误;
async function runService(target, options, socket) {
throw new Error('any error');
}
但预期产量与实际产量大不相同。这是此代码的输出;
Here Error: any error
at startService (C:\Projeler\OpDetect\Background-Service\lib\app.js:404:11)
at Socket.socket.on (C:\Projeler\OpDetect\Background-Service\app.js:73:57)
at process._tickCallback (internal/process/next_tick.js:68:7)
(node:16600) UnhandledPromiseRejectionWarning: Error: any error
at startService (C:\Projeler\OpDetect\Background-Service\lib\app.js:404:11)
at Socket.socket.on (C:\Projeler\OpDetect\Background-Service\app.js:73:57)
at process._tickCallback (internal/process/next_tick.js:68:7)
(node:16600) UnhandledPromiseRejectionWarning: Unhandled promise rejection.
This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 2)
(node:16600) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate
Node.js进程使用非零退出代码。
我对输出的期望是这样的;
Here Error: any error
at startService (C:\Projeler\OpDetect\Background-Service\lib\app.js:404:11)
at Socket.socket.on (C:\Projeler\OpDetect\Background-Service\app.js:73:57)
at process._tickCallback (internal/process/next_tick.js:68:7)
因为我已经使用我的包装函数处理了承诺拒绝并获得了拒绝,为什么在拒绝时还有2个UnhandledPromiseRejectionWarning
错误?
这条线,
return socket.emit('error', error);
不是没有理由的。它应该在if
陈述时被称为truthy。为什么不调用这个socket.emit
函数?
最佳做法是使用try {} catch(){}
和async / await。
对于前者
userUtils.signUp = async (userName) => {
try {
const callFunction = await userUtils.checkExistancy(userName);
if (!callFunction.isExist) {
...
} else {
...
}
} catch (err) {
console.log(err);
throw err;
}
};
在你的情况下,它会像
socket.on('run', async options => {
try {
user = await User.findById(jwt.verify(options.token, config.get('jwtPrivateKey'))._id);
options.userId = user._id.toString();
return true;
} catch (err) {
throw err;
}});