tweetbed.erl

-module(tweetbed).
-author("Harish Mallipeddi <harish.mallipeddi@gmail.com>").
 
-behaviour(mattress).
 
-export([map/0, reduce/2]).
 
-define(TWITTER_BASE_URL, "http://twitter.com").
-define(TWITTER_USER, "INSERT TWITTER USERID HERE").
-define(TWITTER_PASS, "INSERT PASSWORD HERE").
 
map() ->
    twitter_client:start(),
    twitter_client:add_session(?TWITTER_USER, ?TWITTER_PASS),
    {Followers,_} = iter_while(
        fun ({Followers, Page}) -> 
            More = twitter_client:call(?TWITTER_USER, user_followers, [{"page", integer_to_list(Page)}]),
            ShouldContinue = if 
                    length(More) > 0 -> true;
                    true -> false
            end,
            {ShouldContinue, {lists:flatten(Followers, More), Page+1}}
        end, {[],1}),
    lists:map(fun(F) -> {element(4, F), F} end, Followers).
 
reduce(reduce, KeyValues) ->
    lists:foldl(
        fun ({_Username, Follower}, CountsByLoc) -> 
            Loc = element(21, Follower),
            dict:update_counter(Loc, 1, CountsByLoc)
        end, dict:new(), KeyValues);
reduce(rereduce, Reds) ->
    lists:foldl(
        fun (CountsByLoc, FinalCounts) ->
            dict:merge(
                fun (_Key, Value1, Value2) -> Value1+Value2 end, 
                CountsByLoc, FinalCounts)
        end, dict:new(), Reds).
 
iter_while(Fun, Acc) ->
    {Continue, Acc1} = Fun(Acc),
    case Continue of
        true -> iter_while(Fun, Acc1);
        false -> Acc1
    end.