move checksum calculation to lib/request

lib/default-profile.js

@@ -26,6 +26,9 @@ const filters = require('../format/filters')
 const id = x => x
 
 const defaultProfile = {
+	salt: null,
+	addChecksum: false,
+
 	transformReqBody: id,
 	transformReq: id,
 

lib/request.js

@@ -1,5 +1,6 @@
 'use strict'
 
+const crypto = require('crypto')
 const Promise = require('pinkie-promise')
 const {fetch} = require('fetch-ponyfill')({Promise})
 const {stringify} = require('query-string')
@@ -9,6 +10,8 @@ const hafasError = (err) => {
 	return err
 }
 
+const md5 = input => crypto.createHash('md5').update(input).digest()
+
 const request = (profile, data) => {
 	const body = profile.transformReqBody({lang: 'en', svcReqL: [data]})
 	const req = profile.transformReq({
@@ -20,10 +23,21 @@ const request = (profile, data) => {
 			'Accept-Encoding': 'gzip, deflate',
 			'user-agent': 'https://github.com/derhuerst/hafas-client'
 		},
-		query: null
+		query: {}
 	})
-	const url = profile.endpoint + (req.query ? '?' + stringify(req.query) : '')
 
+	if (profile.addChecksum) {
+		if (!Buffer.isBuffer(profile.salt)) {
+			throw new Error('profile.salt must be a Buffer.')
+		}
+		const checksum = md5(Buffer.concat([
+			Buffer.from(req.body, 'utf8'),
+			profile.salt
+		]))
+		req.query.checksum = checksum.toString('hex')
+	}
+
+	const url = profile.endpoint +'?' + stringify(req.query)
 	return fetch(url, req)
 	.then((res) => {
 		if (!res.ok) {

p/db/index.js

@@ -1,7 +1,5 @@
 'use strict'
 
-const crypto = require('crypto')
-
 const _createParseLine = require('../../parse/line')
 const _createParseJourney = require('../../parse/journey')
 const _formatStation = require('../../format/station')
@@ -23,17 +21,6 @@ const transformReqBody = (body) => {
 	return body
 }
 
-const salt = 'bdI8UVj40K5fvxwf'
-const transformReq = (req) => {
-	const hash = crypto.createHash('md5')
-	hash.update(req.body + salt)
-
-	if (!req.query) req.query = {}
-	req.query.checksum = hash.digest('hex')
-
-	return req
-}
-
 const transformJourneysQuery = (query, opt) => {
 	const filters = query.jnyFltrL
 	if (opt.bike) filters.push(bike)
@@ -142,8 +129,11 @@ const dbProfile = {
 	locale: 'de-DE',
 	timezone: 'Europe/Berlin',
 	endpoint: 'https://reiseauskunft.bahn.de/bin/mgate.exe',
+
+	salt: Buffer.from('bdI8UVj40K5fvxwf', 'utf8'),
+	addChecksum: true,
+
 	transformReqBody,
-	transformReq,
 	transformJourneysQuery,
 
 	products: modes.allProducts,