将多个API请求与NodeJS连接

Question

I'm messing with SteamAPI in order to learn some NodeJS. Right now I'm trying to get games's info after an initial request to get the player's profile, once I have the games IDs stored in an array. The point is that I don't know how to "return" an array AFTER the whole ID array is iterated and all results has come from the server.

function getThumbs(game) {
    return rq(
        'http://store.steampowered.com/api/appdetails?appids=' + game,
        {json: true},
        function (error, response, bd) {
            if(response.statusCode === 200 && bd[game].data) {
                return bd[game].data.screenshots;
            }
        });
}

function getGamesThumbnails(games) {
    var deferred = $q.defer(),
        queue = [];

    for (var y = 0; y < games.length; y++) {
        var game = games[y];
        var thumbs = getThumbs(game);

        queue.push(thumbs);
    }

    $q.all(queue).then(
        function (data) {
            deferred.resolve(data);
        },
        function (err) {
            deferred.reject(err)
        }
    );

    return deferred.promise;
}

    app.get('/blog',function(client_req,client_res){

    rq('http://api.steampowered.com/IPlayerService/GetOwnedGames/v0001/?key=' + key + '&steamid=blablabla&format=json', function (error, response, body) {
        var data = JSON.parse(body);
        var games = data.response.games.map(function (game) {
            return game.appid;
        });

        getGamesThumbnails(games).then(function (data) {
            console.log(data)
        })

    });
});

Answer 1

Your getThumbs() function does not return a promise. $q.all only works on an array containing promises, whereas rq uses callbacks.

Try this:

function getThumbs(game) {
  var deferred = $q.defer(),
  rq(
      'http://store.steampowered.com/api/appdetails?appids=' + game,
      {json: true},
      function (error, response, bd) {
          if(response.statusCode === 200 && bd[game].data) {
              deferred.resolve(bd[game].data.screenshots);
          }
      });

  return deferred.promise;
}

Answer 2

Basically, you should use a callback, because like you are doing in getThumbs you are returning the object, while you should return the value bd[game].data.screenshots;

function getThumbs(game, cb) {
    return rq(
        'http://store.steampowered.com/api/appdetails?appids=' + game,
        {json: true},
        function (error, response, bd) {
            if(response.statusCode === 200 && bd[game].data) {
                cb(null, bd[game].data.screenshots);
            }
        });
}

function getGamesThumbnails(games) {
    var deferred = $q.defer(),
        queue = [];

    for (var y = 0; y < games.length; y++) {
        var game = games[y];
        getThumbs(game, function(err, value) {
            queue.push(value);
        });


    }

    $q.all(queue).then(
        function (data) {
            deferred.resolve(data);
        },
        function (err) {
            deferred.reject(err)
        }
    );

    return deferred.promise;
}

And plust to return the response to the client you have to use the client_res.send(VALUE)

so the bottom part would become like this:

app.get('/blog',function(client_req,client_res){

    rq('http://api.steampowered.com/IPlayerService/GetOwnedGames/v0001/?key=' + key + '&steamid=blablabla&format=json', function (error, response, body) {
        var data = JSON.parse(body);
        var games = data.response.games.map(function (game) {
            return game.appid;
        });

        getGamesThumbnails(games).then(function (data) {
            client_res.send(data);
            console.log(data)
        })

    });
});

Answer 3

Thank you both! I tried Yuri's approach, but $q.all it doesn't seem to resolve the array of promises (nothing happens after the last request from getThumbs())

  for (var y = 0; y < games.length; y++) {
    var game = games[y];
    var thumbs = getThumbs(game);

    queue.push(thumbs);
  }

$q.all(queue).then(
    function (data) {
        console.log(data)
        deferred.resolve(data);
    },
    function (err) {
        deferred.reject(err)
    }
);