lib/request: use async/await, simplify error handling

lib/errors.js

@@ -207,23 +207,10 @@ const byErrorCode = Object.assign(Object.create(null), {
 	}
 })
 
-const addErrorInfo = (err, errorCode, errorText, responseId) => {
-	if (byErrorCode[errorCode]) {
-		Object.assign(err, byErrorCode[errorCode])
-		if (errorCode) err.hafasErrorCode = errorCode
-		if (errorText) err.hafasErrorMessage = errorText
-	} else {
-		err.code = errorCode || null
-		err.message = errorText || errorCode || null
-		err.responseId = responseId || null
-	}
-}
-
 module.exports = {
 	ACCESS_DENIED,
 	INVALID_REQUEST,
 	NOT_FOUND,
 	SERVER_ERROR,
 	byErrorCode,
-	addErrorInfo,
 }

lib/request.js

@@ -1,7 +1,5 @@
 'use strict'
 
-const DEV = process.env.NODE_ENV === 'dev'
-
 const ProxyAgent = require('https-proxy-agent')
 const {isIP} = require('net')
 const {Agent: HttpsAgent} = require('https')
@@ -9,12 +7,11 @@ const roundRobin = require('@derhuerst/round-robin-scheduler')
 const {randomBytes} = require('crypto')
 const createHash = require('create-hash')
 const pick = require('lodash/pick')
-const captureStackTrace = DEV ? require('capture-stack-trace') : () => {}
 const {stringify} = require('qs')
 const Promise = require('pinkie-promise')
 const {Request, fetch} = require('fetch-ponyfill')({Promise})
 const {parse: parseContentType} = require('content-type')
-const {addErrorInfo} = require('./errors')
+const {byErrorCode} = require('./errors')
 
 const proxyAddress = process.env.HTTPS_PROXY || process.env.HTTP_PROXY || null
 const localAddresses = process.env.LOCAL_ADDRESS || null
@@ -66,16 +63,16 @@ const randomizeUserAgent = (userAgent) => {
 
 const md5 = input => createHash('md5').update(input).digest()
 
-const request = (ctx, userAgent, reqData) => {
+const request = async (ctx, userAgent, reqData) => {
 	const {profile, opt} = ctx
 
-	const body = profile.transformReqBody(ctx, {
+	const rawReqBody = profile.transformReqBody(ctx, {
 		// todo: is it `eng` actually?
 		// RSAG has `deu` instead of `de`
 		lang: opt.language || profile.defaultLanguage || 'en',
 		svcReqL: [reqData]
 	})
-	Object.assign(body, pick(profile, [
+	Object.assign(rawReqBody, pick(profile, [
 		'client', // client identification
 		'ext', // ?
 		'ver', // HAFAS protocol version
@@ -86,7 +83,7 @@ const request = (ctx, userAgent, reqData) => {
 		agent: getAgent(),
 		method: 'post',
 		// todo: CORS? referrer policy?
-		body: JSON.stringify(body),
+		body: JSON.stringify(rawReqBody),
 		headers: {
 			'Content-Type': 'application/json',
 			'Accept-Encoding': 'gzip, br, deflate',
@@ -129,56 +126,66 @@ const request = (ctx, userAgent, reqData) => {
 	const fetchReq = new Request(url, req)
 	profile.logRequest(ctx, fetchReq, reqId)
 
-	// Async stack traces are not supported everywhere yet, so we create our own.
-	const err = new Error()
-	err.isHafasError = true // todo: rename to `isHafasClientError`
-	err.request = req.body // todo: commit as bugfix
-	err.url = url
-	captureStackTrace(err)
+	const res = await fetch(url, req)
 
-	return fetch(fetchReq)
-	.then((res) => {
-		err.statusCode = res.status
-		if (!res.ok) {
-			err.message = res.statusText
+	// Async stack traces are not supported everywhere yet, so we create our own.
+	const errProps = {
+		isHafasError: true, // todo: rename to `isHafasClientError`
+		statusCode: res.status,
+		request: req.body, // todo [breaking]: change to fetchReq
+		url: url,
+	}
+
+	if (!res.ok) {
+		const err = new Error(res.statusText)
+		Object.assign(err, errProps)
+		throw err
+	}
+
+	let cType = res.headers.get('content-type')
+	if (cType) {
+		const {type} = parseContentType(cType)
+		if (type !== 'application/json') {
+			const err = new Error('invalid response content-type: ' + cType)
+			err.response = res
 			throw err
 		}
+	}
 
-		let cType = res.headers.get('content-type')
-		if (cType) {
-			const {type} = parseContentType(cType)
-			if (type !== 'application/json') {
-				const err = new Error('invalid response content-type: ' + cType)
-				err.response = res
-				throw err
-			}
+	const body = await res.text()
+	profile.logResponse(ctx, res, body, reqId)
+
+	const b = JSON.parse(body)
+	if (b.err) errProps.hafasErrorCode = b.err
+	if (b.errTxt) errProps.hafasErrorMessage = b.errTxt
+	if (b.id) errProps.responseId = b.id
+	if (b.err && b.err !== 'OK') {
+		const err = new Error(b.errTxt || b.err)
+		Object.assign(err, errProps)
+		if (b.err in byErrorCode) {
+			Object.assign(err, byErrorCode[b.err])
 		}
+		throw err
+	}
+	if (!b.svcResL || !b.svcResL[0]) {
+		const err = new Error('invalid/unsupported response structure')
+		Object.assign(err, errProps)
+		throw err
+	}
+	if (b.svcResL[0].err !== 'OK') {
+		const err = new Error(b.svcResL[0].errTxt || b.svcResL[0].err)
+		Object.assign(err, errProps)
+		if (b.svcResL[0].err in byErrorCode) {
+			Object.assign(err, byErrorCode[b.svcResL[0].err])
+		}
+		throw err
+	}
 
-		return res.text()
-		.then((body) => {
-			profile.logResponse(ctx, res, body, reqId)
-			const b = JSON.parse(body)
-
-			if (b.err && b.err !== 'OK') {
-				addErrorInfo(err, b.err, b.errTxt, b.id)
-				throw err
-			}
-			if (!b.svcResL || !b.svcResL[0]) {
-				err.message = 'invalid response'
-				throw err
-			}
-			if (b.svcResL[0].err !== 'OK') {
-				addErrorInfo(err, b.svcResL[0].err, b.svcResL[0].errTxt, b.id)
-				throw err
-			}
-
-			const svcRes = b.svcResL[0].res
-			return {
-				res: svcRes,
-				common: profile.parseCommon({...ctx, res: svcRes}),
-			}
-		})
-	})
+	const svcRes = b.svcResL[0].res
+	return {
+		res: svcRes,
+		common: profile.parseCommon({...ctx, res: svcRes}),
+	}
 }
 
 module.exports = request

package.json

@@ -46,7 +46,6 @@
 	"dependencies": {
 		"@derhuerst/br2nl": "^1.0.0",
 		"@derhuerst/round-robin-scheduler": "^1.0.4",
-		"capture-stack-trace": "^1.0.0",
 		"content-type": "^1.0.4",
 		"create-hash": "^1.2.0",
 		"fetch-ponyfill": "^7.0.0",