[英]UnhandledPromiseRejectionWarning, Express.js and Node.js
我對Node.js和Express.js完全陌生,並且一直在嘗試通過一些示例將Shippo API集成到我的電子商務Web應用程序中,但是我遇到了一些錯誤,盡管檢查了一下我還是無法解決代碼幾次。
我收到UnhandledPromiseRejectionWarning錯誤,從我在線閱讀的內容中,這意味着我的代碼中某處有一個.then()節,其中不包含“捕獲”或“要做的事情”,這是請求返回的內容一個錯誤。 任何幫助將不勝感激。
這是我的代碼:
var express = require('express') var app = express() var http = require('http'); var Raven = require('raven'); var shippo = require('shippo')('ACCESS_TOKEN'); var engines = require('consolidate'); const bodyParser = require('body-parser'); const path = require('path'); app.use(bodyParser.urlencoded({extended: true})); app.use(bodyParser.json()); app.engine('html', engines.mustache); app.set('view engine', 'html'); //app.use(express.static(path.join(_dirname,'/'))); app.get('/', function (req, res) { res.render('Index.html'); }) app.post('/', function (req, res) { var addressFrom = { "object_purpose":"PURCHASE", "name": "SENDER_NAME", "company":"Shippo", "street1":"215 Clayton St.", "city":"San Francisco", "state":"CA", "zip":"94117", "country":"US", //iso2 country code "phone":"+1 555 341 9393", "email":"SENDER_EMAIL", }; // example address_to object dict var addressTo = { "object_purpose":"PURCHASE", "name": req.body.fnames + ' ' + req.body.lnames, "company": req.body.company, "street1":req.body.street, "city":req.body.city, "state":req.body.state, "zip":req.body.zipcode, "country": req.body.country, //iso2 country code "phone":"+1 555 341 9393", "email":"support@goshippo.com", }; // parcel object dict var parcelOne = { "length":"5", "width":"5", "height":"5", "distance_unit":"in", "weight":"2", "mass_unit":"lb" }; var shipment = { "object_purpose": "PURCHASE", "address_from": addressFrom, "address_to": addressTo, "parcels": [parcelOne], "submission_type": "DROPOFF" }; shippo.transaction.create({ "shipment": shipment, "servicelevel_token": "ups_standard", "carrier_account": 'CARRIER_TOKEN', "label_file_type": "PDF" }) .then(function(transaction) { shippo.transaction.list({ "rate": transaction.rate }) .then(function(mpsTransactions) { mpsTransactions.results.forEach(function(mpsTransaction){ if(mpsTransaction.object_status == "SUCCESS") { console.log("Label URL: %s", mpsTransaction.label_url); console.log("Tracking Number: %s", mpsTransaction.tracking_number); console.log("E-Mail: %s", mpsTransaction.object_owner); console.log(mpsTransaction.object_status); res.status(200).send("Label can be found under: " + mpsTransaction.label_url); } else { // hanlde error transactions console.log("Message: %s", mpsTransactions.messages); } }); }) }, function(err) { // Deal with an error console.log("There was an error creating transaction : %s", err.detail); res.send("something happened :O") }); }) app.post('/successp', function (req, res) { var token = req.body.stripeToken; // Using Express // Charge the user's card: var charge = stripe.charges.create({ amount: 1000, currency: "eur", description: "Example charge", source: token, }, function(err, charge) { // asynchronously called }); res.send('Thanks!') }) app.post('/successp', function (req, res) { var token = req.body.stripeToken; // Using Express // Charge the user's card: var charge = stripe.charges.create({ amount: 1000, currency: "eur", description: "Example charge", source: token, }, function(err, charge) { // asynchronously called }); res.send('Thanks!') }) app.listen(3000, function () { console.log('Example app listening on port 3000!') })
這是我得到的錯誤:
在端口3000上監聽的示例應用程序! (節點:2378)UnhandledPromiseRejectionWarning(節點:2378)UnhandledPromiseRejectionWarning:未處理的承諾拒絕。 引發此錯誤的原因可能是拋出了一個沒有catch塊的異步函數,或者是拒絕了一個.catch()無法處理的承諾。 (拒絕ID:1)(節點:2378)[DEP0018] DeprecationWarning:已棄用未處理的承諾拒絕。 將來,未處理的承諾拒絕將以非零退出代碼終止Node.js進程。
我也不完全確定某些代碼行的用途(再次,我對表示和node.js非常陌生)。 什么是引擎和胡須? 另外,我看到此示例代碼使用APP.POST('/ succesp',function(req,res)...) , '/ succesp'到底是什么? 我需要創建另一個HTML文件嗎? 另外, 開頭的 “ app.use(express.statc([ath.join(_dirnam,'/')));;) ”是什么?
你需要使用的格式小心一點then(FN, errorFn)
因為如果有內部的錯誤then
,該errorFn不會趕上它。 最好使用then(fn).catch(errorFn)
。 這將允許在任何所有的錯誤then
上面向下篩選到最后catch
處理。
例如,第一個調用正確捕獲了錯誤,而第二個則沒有:
function fn() { return Promise.resolve("good") } fn() .then(r => { throw ("whoops") }) .catch(err => console.log(err)) //<-- catch works here fn() .then(r => { throw ("whoops") }, err => console.log(err) // this can't catch the error above; it will only catch rejections on fn() )
它沒有顯示在代碼段中,但是如果您查看控制台,則會看到未處理的拒絕錯誤。
在您的代碼中,可以通過從shippo.transaction.list
返回承諾來shippo.transaction.list
承諾鏈。 然后,您可以在末尾添加一個catch以處理錯誤。
shippo.transaction.create({
"shipment": shipment,
"servicelevel_token": "ups_standard",
"carrier_account": 'CARRIER_TOKEN',
"label_file_type": "PDF"
})
.then(function(transaction) {
return shippo.transaction.list({ // return this promise
"rate": transaction.rate
})
.then(function(mpsTransactions) { // so this can flatten out
mpsTransactions.results.forEach(function(mpsTransaction){
if(mpsTransaction.object_status == "SUCCESS") {
console.log("Label URL: %s", mpsTransaction.label_url);
console.log("Tracking Number: %s", mpsTransaction.tracking_number);
console.log("E-Mail: %s", mpsTransaction.object_owner);
console.log(mpsTransaction.object_status);
res.status(200).send("Label can be found under: " + mpsTransaction.label_url);
} else {
// hanlde error transactions
console.log("Message: %s", mpsTransactions.messages);
}
});
})
.catch(function(err) { // catch errors
// Deal with an error
console.log("There was an error creating transaction : %s", err.detail);
res.send("something happened :O")
});
})
由於很難在沒有所有內容的情況下在本地運行,因此我對錯誤的來源並res.status(200).send()
,但是看起來您正在循環內發送res.status(200).send()
,這可能會導致如果它被調用兩次,則會出錯。
如果不閱讀完整的代碼,則在使用Promises時不應嘗試使用回調函數捕獲錯誤。 您使用.catch塊捕獲Promises中的錯誤
並且您還應該返回第一個承諾,以便將其傳遞給下一個.then函數(如果您打算將shippo.transaction.list作為mpsTransactions返回)
像這樣:
shippo.transaction.create({
"shipment": shipment,
"servicelevel_token": "ups_standard",
"carrier_account": 'CARRIER_TOKEN',
"label_file_type": "PDF"
})
.then(function(transaction) {
return shippo.transaction.list({
"rate": transaction.rate
})
})
.then(function(mpsTransactions) {
mpsTransactions.results.forEach(function(mpsTransaction){
if(mpsTransaction.object_status == "SUCCESS") {
console.log("Label URL: %s", mpsTransaction.label_url);
console.log("Tracking Number: %s", mpsTransaction.tracking_number);
console.log("E-Mail: %s", mpsTransaction.object_owner);
console.log(mpsTransaction.object_status);
res.status(200).send("Label can be found under: " + mpsTransaction.label_url);
} else {
// hanlde error transactions
console.log("Message: %s", mpsTransactions.messages);
}
});
})
.catch(function (error) {
// Deal with an error
console.log("There was an error creating transaction : %s", err.detail);
res.send("something happened :O")
});
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