Search Facebook events by location (as a service)

A Express.js-based webservice to get public Facebook events by location and distances, as well as search terms. It can be used as a starting point for an location-based app for example.

Motivation

As Facebook has discontinued the FQL query API for all apps created after 2014-04-30, it has gotten much more complicated to search for public Facebook events by location and distances. This is the reason why this project was created.

Basics

The implementation of facebook-events-by-location-core, which is used for providing the Facebook events search functionality, uses regular Facebook Graph API calls in a three-step approach to get the events:

1. Search for places in the radius of the passed coordinate and distance (/search?type=place&q={query}&center={coordinate}&distance={distance})
2. Use the places to query for their events in parallel (/?ids={id1},{id2},{id3},...)
3. Unify, filter and sort the results from the parallel calls and return them to the client

Known limitations

• The Graph API has some "instabilities" with search results. It's possible that the amount of results returned can vary between calls within seconds
• The /search endpoint "magically" limits the number of results, independent from the distance used (larger distance doesn't guarantee more results)
• Rate limiting will apply, but I experienced no call blocks within a reasonable amount of service requests. Be aware that the way this application works, there are potentially hundreds of (counted) Graph API calls per request to /events.

Installation

As NPM package

First, create a new folder: $ mkdir fb-event-test (where fb-event-test is just an example).

Then change to the newly created directory, and do a quick initialization of your new project with $ cd fb-event-test && npm init --yes.

The application can be installed via $ npm install facebook-events-by-location and started with $ node node_modules/facebook-events-by-location/index.js.

Git

To clone the repository, use

git clone https://github.com/tobilg/facebook-events-by-location.git

and run cd facebook-events-by-location && npm i && npm start to install the dependencies and run the web service.

As Docker microservice

You can build the Docker image via docker build -t <yourTag> . locally if you like. Also, there's an official image (called tobilg/facebook-event-search) in the Docker hub.

The service can be launched via Docker like this:

docker run -d --name fb-event-search -p 3000:3000 tobilg/facebook-event-search

This would expose the app on port 3000 on the Docker host. If you want to specify another port for the app, you can use -e "PORT=10000" together with --net="host" (be aware of the security implications of host networking).

Environment variables

You can use the following environment variables to influence the application:

• FEBL_ACCESS_TOKEN: Used to define a general App Access Token to be used for the requests to the Graph API. This is overridden if the request specifies an accessToken parameter. If it's not specified, every request to /events needs to contain an accessToken parameter.
• FEBL_CORS_WHITELIST: You can pass a comma-separated domain whitelist to enable CORS headers (e.g. http://www.test.com,http://www.test.org). If you don't specify this variable, CORS will be enabled on all origins.
• HOST: The IP address the Express application should bind to. Default is 0.0.0.0 (all available IP addresses).
• PORT: The port on which the application should run. Default is 3000.

API

The basic endpoint is GET /events, but there's also a GET /health endpoint to enable health checks.

Swagger API docs

The Swagger API docs are available at http://tobilg.github.io/facebook-events-by-location/.

Query paramenters

Mandatory parameters are the following:

• lat: The latitude of the position/coordinate the events shall be returned for
• lng: The longitude of the position/coordinate the events shall be returned for

Non-mandatory parameters

• query: The term(s) on which you want to narrow down your location search (this only filters the places, not the events itself!).
• categories: The comma-separated list of place categories that should be searched for. Valid entries are ARTS_ENTERTAINMENT, EDUCATION, FITNESS_RECREATION, FOOD_BEVERAGE, HOTEL_LODGING, MEDICAL_HEALTH, SHOPPING_RETAIL, TRAVEL_TRANSPORTATION. Default is none.
• accessToken: The App Access Token to be used for the requests to the Graph API.
• distance: The distance in meters (it makes sense to use smaller distances, like max. 2500). Default is 100.
• sort: The results can be sorted by time, distance (legacy option, will be removed in future release), venueDistance, eventDistance, venue or popularity. If omitted, the events will be returned in the order they were received from the Graph API.
• version: The version of the Graph API to use. Default is v2.10.
• since: The start of the range to filter results. Format is Unix timestamp or strtotime data value, as accepted by FB Graph API.
• until: The end of the range to filter results.
• showActiveOnly: Whether to show only active (non-draft, non-cancalled Events). Default is true, otherwise false can be passed to show all Events regardless of their state.

Query results

The response will be application/json and contain an events property containing the array of event objects, as well as a metadata property with some stats. See below for an example.

Location/Place data in the query result

There are two types of locations in the resulting event JSON objects:

• place: This is the consolidated Place object from the Venue (which is actually the Page object which was returned from the Place search), and the Event's place data. The latter will supersede the Place page data.
• venue.location: This is the location data of the Page object.

As the Facebook Graph API can only be queried for Places via coordinate/distance, and Events can have their own, "real" location, it's possible that the place data which is found in place can be outside the boundaries of the original query.

Consequences:

• If you want consistency regarding query vs. results, you should use venue.location.
• If you want accuracy regarding the real event location, you should use place.

Sample call

http://localhost:3000/events?lat=40.710803&lng=-73.964040&distance=100&sort=venue&accessToken=YOUR_APP_ACCESS_TOKEN (make sure you replace YOUR_APP_ACCESS_TOKEN with a real access token!)

Sample output (shortened)

{
  "events": [{
    "id": "836655879846811",
    "name": "U.S. Girls at Baby's All Right",
    "type": "public",
    "coverPicture": "https://scontent.xx.fbcdn.net/v/t31.0-8/s720x720/24883312_1521878931228093_3223523563973203944_o.jpg?oh=9bc3e5c5d45e39c542b057b92df95243&oe=5AC0353F",
    "profilePicture": "https://scontent.xx.fbcdn.net/v/t1.0-0/c0.0.200.200/p200x200/24862268_1521878931228093_3223523563973203944_n.jpg?oh=23ec7dc943402ec7e0137f2d17f27719&oe=5AC246F8",
    "description": "Friday, April 13th @ Baby's All Right\n\nAdHoc Presents\n\nU.S. Girls\n\nTickets:  http://ticketf.ly/2j7AegO\n\n| Baby's All Right |\n146 Broadway @ Bedford Ave | Williamsburg, Brooklyn \nJMZ-Marcy, L-Bedford, G-Broadway | 8pm | $12 | 21+\n\nCheck out our calendar and sign up for our mailing list http://adhocpresents.com/",
    "distance": 89,
    "startTime": "2018-04-13T20:00:00-0400",
    "endTime": null,
    "timeFromNow": 9982924,
    "isCancelled": false,
    "category": "MUSIC_EVENT",
    "ticketing": {
      "ticket_uri": "http://ticketf.ly/2j7AegO"
    },
    "place": {
      "id": "460616340718401",
      "name": "Baby's All Right",
      "location": {
        "city": "Brooklyn",
        "country": "United States",
        "latitude": 40.71012,
        "longitude": -73.96348,
        "state": "NY",
        "street": "146 Broadway",
        "zip": "11211"
      }
    },
    "stats": {
      "attending": 20,
      "declined": 0,
      "maybe": 77,
      "noreply": 6
    },
    "distances": {
      "venue": 89,
      "event": 89
    },
    "venue": {
      "id": "460616340718401",
      "name": "Baby's All Right",
      "about": "[email protected]",
      "emails": ["[email protected]"],
      "coverPicture": "https://scontent.xx.fbcdn.net/v/t31.0-8/s720x720/20507438_1418517768261582_7945740169309872258_o.jpg?oh=24280a4732605e140c227db955c8d5e0&oe=5AC6B878",
      "profilePicture": "https://scontent.xx.fbcdn.net/v/t1.0-1/p200x200/1480734_642185745894792_5820988503650852577_n.png?oh=c6e72b8a5645644e7dd3eb3d2161329f&oe=5AC0CD2D",
      "category": "Bar",
      "categoryList": ["Bar", "Breakfast & Brunch Restaurant", "Dance & Night Club"],
      "location": {
        "city": "Brooklyn",
        "country": "United States",
        "latitude": 40.71012,
        "longitude": -73.96348,
        "state": "NY",
        "street": "146 Broadway",
        "zip": "11211"
      }
    }
  }],
  "metadata": {
    "venues": 100,
    "venuesWithEvents": 2,
    "events": 25
  }
}