`hafas-client` documentation

API documentation

Migrating from an old `hafas-client` version

4 → 5 migration guide

Throttling requests

There's opt-in support for throttling requests to the endpoint.

const createClient = require('hafas-client')
const withThrottling = require('hafas-client/throttle')
const dbProfile = require('hafas-client/p/db')

// create a throttled HAFAS client with Deutsche Bahn profile
const client = createClient(withThrottling(dbProfile), 'my-awesome-program')

// Berlin Jungfernheide to München Hbf
await client.journeys('8011167', '8000261', {results: 1})

You can pass custom values for the nr of requests (limit) per interval into withThrottling:

// 2 requests per second
const throttledDbProfile = withThrottling(dbProfile, 2, 1000)
const client = createClient(throttledDbProfile, 'my-awesome-program')

Retrying failed requests

There's opt-in support for retrying failed requests to the endpoint.

const createClient = require('hafas-client')
const withRetrying = require('hafas-client/retry')
const dbProfile = require('hafas-client/p/db')

// create a client with Deutsche Bahn profile that will retry on HAFAS errors
const client = createClient(withRetrying(dbProfile), 'my-awesome-program')

// Berlin Jungfernheide to München Hbf
client.journeys('8011167', '8000261', {results: 1})
.then(console.log)
.catch(console.error)

You can pass custom options into withRetrying. They will be passed into retry.

// retry 2 times, after 10 seconds & 30 seconds
const retryingDbProfile = withRetrying(dbProfile, {
	retries: 2,
	minTimeout: 10 * 1000,
	factor: 3
})
const client = createClient(retryingDbProfile, 'my-awesome-program')

User agent randomization

By default, hafas-client randomizes the client name that you pass into createClient, and sends it as User-Agent in a randomized form:

const createClient('hafas-client')
// …
const client = createClient(someProfile, 'my-awesome-program')

await client.journeys(/* … */)
// User-Agent: my-awee70429some-pre70429ogram
await client.journeys(/* … */)
// User-Agent: my-awesom9bb8e2e-prog9bb8e2ram

You can turn this off by setting profile.randomizeUserAgent to false:

const client = createClient({
	...someProfile,
	randomizeUserAgent: false,
}, 'my-awesome-program')

Logging requests

You can use profile.logRequest and profile.logResponse to process the raw Fetch Request and Response, respectively.

As an example, we can implement a custom logger:

const createClient = require('hafas-client')
const dbProfile = require('hafas-client/p/db')

const logRequest = (ctx, fetchRequest, requestId) => {
	// ctx looks just like with the other profile.* hooks:
	const {profile, opt} = ctx

	console.debug(requestId, fetchRequest.headers, fetchRequest.body + '')
}

const logResponse = (ctx, fetchResponse, body, requestId) => {
	console.debug(requestId, fetchResponse.headers, body + '')
}

// create a client with Deutsche Bahn profile that debug-logs
const client = createClient({
	...dbProfile,
	logRequest,
	logResponse,
}, 'my-awesome-program')

// logRequest output:
'29d0e3' {
	accept: 'application/json',
	'accept-encoding': 'gzip, br, deflate',
	'content-type': 'application/json',
	connection: 'keep-alive',
	'user-agent': 'hafas842c51-clie842c51nt debug C842c51LI'
} {"lang":"de","svcReqL":[{"cfg":{"polyEnc":"GPA"},"meth":"LocMatch",…
// logResponse output:
'29d0e3' {
	'content-encoding': 'gzip',
	'content-length': '1010',
	'content-type': 'application/json; charset=utf-8',
	date: 'Thu, 06 Oct 2022 12:31:09 GMT',
	server: 'Apache',
	vary: 'User-Agent'
} {"ver":"1.45","lang":"deu","id":"sb42zgck4mxtxm4s","err":"OK","graph"…

The default profile.logRequest console.errors the request body, if you have set $DEBUG to hafas-client. Likewise, profile.logResponse console.errors the response body.

Using `hafas-client` from another language

If you want to use hafas-client to access HAFAS APIs but work with non-Node.js environments, you can use hafas-client-rpc to create a JSON-RPC interface that you can send commands to.

Writing a profile

Check the guide.

General documentation for `mgate.exe` APIs

hafas-mgate-api.md

4.7 KiB Raw Blame History

hafas-client documentation

Migrating from an old hafas-client version