130 lines
4.1 KiB
JavaScript
130 lines
4.1 KiB
JavaScript
const rateLimit = require('express-rate-limit');
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const log = require('../../log')
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const NOMINATIM_URL = 'https://nominatim.openstreetmap.org/search'
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const PHOTON_URL = 'https://photon.komoot.io/api/'
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const axios = require('axios')
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const { version } = require('../../../package.json')
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const cache = require('memory-cache');
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let d = 0 // departure time
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let h = 0 // hit geocoding provider time (aka Latency)
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const geolocationController = {
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/**
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* TODO: replace/merge with a general 'instance rate-limiter' or 'instance api-related rate-limiter' when this will be defined
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*/
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instanceApiRateLimiter: rateLimit({
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windowMs: 15 * 60 * 1000, // 15 minutes
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max: 100, // Limit each IP to 100 requests per `window` (here, per 15 minutes)
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standardHeaders: true, // Return rate limit info in the `RateLimit-*` headers
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legacyHeaders: false, // Disable the `X-RateLimit-*` headers
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}),
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/**
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* Limit api usage
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* From https://operations.osmfoundation.org/policies/nominatim/
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* [Requirements] No heavy uses (an absolute maximum of 1 request per second).
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* [Websites and Apps]
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* - Note that the usage limits above apply per website/application: the sum of traffic by all your users should not exceed the limits.
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* - If at all possible, set up a proxy and also enable caching of requests.
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*/
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providerRateLimit (req, res, next) {
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let a = Date.now(); // arrival time
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let dprev = d
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d = dprev + 1000 + h
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console.log('a: ' + a)
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console.log('dprev: ' + dprev)
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console.log('d: ' + d)
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// if the same request was already cached skip the delay mechanism
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if (cache.get(req.params.place_details)) {
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if (a < d) {
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log.warn('More than 1 request per second to geolocation api. This from ' + req.ip + ' . The response data is served from memory-cache')
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}
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// reset departure time because there is no need to ask provider
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d = dprev
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return next()
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}
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if (d === 0 || a > d) {
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// no-queue or old-queue
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console.log('No queue or Old queue')
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// arrival time + 10ms estimated computing time
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d = a + 10
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next()
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} else {
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// fresh queue
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console.log('Fresh queue')
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let wait = d - a
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console.log('Waiting '+ wait)
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log.warn('More than 1 request per second to geolocation api. This from ' + req.ip + ' . Applying ToS padding before asking to provider. The response data is now cached.')
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setTimeout(() => {
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next()
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}, wait)
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}
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},
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async _nominatim (req, res) {
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const details = req.params.place_details
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const countrycodes = res.locals.settings.geocoding_countrycodes || []
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const geocoding_provider = res.locals.settings.geocoding_provider || NOMINATIM_URL
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// ?limit=3&format=json&namedetails=1&addressdetails=1&q=
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const ret = await axios.get(`${geocoding_provider}`, {
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params: {
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countrycodes: countrycodes.join(','),
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q: details,
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limit: 3,
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format: 'json',
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addressdetails: 1,
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namedetails: 1,
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},
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headers: { 'User-Agent': `gancio ${version}` }
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})
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return res.json(ret.data)
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},
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async _photon (req, res) {
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const details = req.params.place_details
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const geocoding_provider = res.locals.settings.geocoding_provider || PHOTON_URL
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if (cache.get(details)) {
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console.log('Retrieving data from cache')
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const ret = {
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data: await cache.get(details)
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}
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return res.json(ret.data)
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} else {
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let RTTstart = Date.now()
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console.log('Asking Provider: ' + RTTstart)
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const ret = await axios.get(`${geocoding_provider}`, {
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params: {
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q: details,
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limit: 3,
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},
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headers: { 'User-Agent': `gancio ${version}` }
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})
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if (ret) {
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let RTTend = Date.now()
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console.log('Response arrived: ' + RTTend)
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// Save the hit time (aka Latency)
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h = (RTTend - RTTstart) / 2
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console.log('Saving latency h: ' + h)
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}
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console.log('Caching results')
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cache.put(details, ret.data);
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return res.json(ret.data)
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}
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},
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}
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module.exports = geolocationController |