request-promise未处理的拒绝RequestError：错误：ETIMEDOUT

嗨，我尝试编写一些下载function的承诺要求，但如果我有一个超时，我不能处理这个错误，我尝试一些例子，但仍然有这个错误

Unhandled rejection RequestError: Error: ETIMEDOUT at new RequestError (/home/parse/node_modules/request-promise-core/lib/errors.js:14:15) at Request.plumbing.callback (/home/parse/node_modules/request-promise-core/lib/plumbing.js:87:29) at Request.RP$callback [as _callback] (/home/parse/node_modules/request-promise-core/lib/plumbing.js:46:31) at self.callback (/home/parse/node_modules/request/request.js:186:22) at emitOne (events.js:101:20) at Request.emit (events.js:191:7) at Timeout._onTimeout (/home/parse/node_modules/request/request.js:816:16) at ontimeout (timers.js:380:14) at tryOnTimeout (timers.js:244:5) at Timer.listOnTimeout (timers.js:214:5) 

我的代码

function下载：

 function downloadPhoto(url,uploadUrl,name){ return new Promise(function(resolve, reject){ rp(url,{timeout:15000},function(e){if(e) reject(e);}).on('error', function(e){return reject(e);}).pipe(fs.createWriteStream(name+'.jpg')).on('finish', () => { //console.log('done Download photo'); return resolve(); }); }); } 

调用这个函数

 function sndPht(url,uploadUrl){ return new Promise(function(resolve, reject){ return downloadPhoto(url,uploadUrl,name).then(function(){ ..... some logic ..... }).catch(function(err){ return reject(err); }); } 

对于蓝鸟js地图调用函数的许多文件：

 Promise.map(photos, function(photo) { if(photo.type === 'photo'){ return sndPht(photo,uploadUrl); } },{concurrency: 1}); 

我做错了什么？

Answer 1

您可以使用Promise.race来使用parsing或拒绝的第一个承诺中的值。

使用这种技术，如果下载时间过长，我们可能会出现一段时间后会超时的错误。 downloadPhoto Promise仍然会解决，但不会被处理

 const images = [ { url: 'www.foo.com', uploadUrl: '/foo', name: 'foo' } , { url: 'www.bar.com', uploadUrl: '/bar', name: 'bar' } , { url: 'www.baz.com', uploadUrl: '/baz', name: 'baz' } ] const promiseTimeout = (delay, promise) => Promise.race([ new Promise((resolve, reject) => setTimeout(resolve, delay, { status: 'error', msg: 'took too long!' }) ), promise ]) const downloadPhoto = ({ url, uploadUrl, name }) => promiseTimeout( 1000, new Promise((resolve, reject) => { setTimeout(resolve, 3000, { status: 'success', msg: `this will never resolve ${url}` }) }) ) // map images array [...image] into [...Promise(image)] const imagePromises = images.map(downloadPhoto) // resolve all promises Promise.all(imagePromises) // called once all promises are resolved with array of results .then(images => { // map over the resolved images and do further processing images.map(console.log.bind(console, 'Image resolved')) }) // promises no longer reject, you will need to look at the status .catch(console.log.bind(console, 'Error: ')) 

Answer 2

我有一个解决scheme，如果你使用一个请求 – 承诺你喊创造诺言，并返回他，并赶上免除，它不工作与pipe在我的情况下，所以我们需要改变function下载像

 function downloadPhoto(url){ var options = { uri:url, timeout:10000, encoding: 'binary' }; return rp(options); } 

然后我们可以使用它

 return downloadPhoto(url).then(function(file){ fs.writeFileSync(name+'.jpg', file, 'binary'); }).catch(function(err){ console.log(err); }); 

我们可以使用地图

 Promise.map(photos, function(photo) { if(photo.type === 'photo'){ return sndPht(photo,uploadUrl); } },{concurrency: 1}); 

但如果您需要下载大文件，则需要使用calback的请求