问题:

Is it possible to crawl check-in data from foursquare in a greedy way? (even if I don't have friendship with all the users) Just like crawling publicly available twitter messages. If you have any experience or suggestions, please share. Thanks.

回答1:

If you have publicly available tweets containing links to foursquare, you can resolve the foursquare short links (4sq.com/XXXXXX) by making a HEAD request. The head request will return a URL with a check-in ID and a signature. You can use those two values to retrieve a check-in object via the foursquare API /checkins/ endpoint. You're only allowed to access 500 of these per hour.

You must abide by both the Twitter and foursquare terms of service -- in fourquare's case, you may not display this information to anyone, nor may you retain any user information for more than 3 hours (since the user has not authorized your application).

回答2:

You can only get the check-in data for a location if the manager of the location gives you OAuth access to your application. If you have that, you can use the real-time API defined here: https://developer.foursquare.com/docs/realtime.html