javascript - 使用 Angular JS 获取播放列表中的所有 YouTube 视频

Question

我想要获取指定播放列表中的所有 YouTube 视频。该 API 目前允许您一次提取 50 条记录，但您可以通过传递下一页 token 来提取下一组记录。

我对 Angular 还很陌生，在完成这项任务时遇到了困难。

这是我目前拥有的:

var app = angular.module('ph', []);
        var key = '';

        app.factory('youtubeService', ['$http', function ($http) {

            function getPlaylists(channelId) {
                return $.get("https://www.googleapis.com/youtube/v3/playlists", { part: 'snippet', channelId: channelId, key: key, maxResults: 50 });
            }

            function getPlaylistVideos(playlistId) {

                var items = [];
                var nextPageToken = "";

                $.get('https://www.googleapis.com/youtube/v3/playlistItems', { part: 'snippet', maxResults: 50, playlistId: playlistId, key: key }).then(function (firstResponse) {

                    items = firstResponse.items;
                    var numberOfPages = Math.ceil(firstResponse.pageInfo.totalResults / 50);

                    for (var page = 1; page <= numberOfPages; page++) {
                        $.get('https://www.googleapis.com/youtube/v3/playlistItems', { part: 'snippet', maxResults: 50, pageToken: nextPageToken, playlistId: playlistId, key: key }).then(function(response) {
                            items = items.concat(response.items);
                            nextPageToken = response.nextPageToken;
                        });
                    }
                });

                return items;
            }

            function getVideos(keyword) {
                return $.get('https://www.googleapis.com/youtube/v3/search', { part: 'snippet', q: keyword, key: key, type: 'video' });
            }

            return { getPlaylists: getPlaylists, getPlaylistVideos: getPlaylistVideos, getVideos: getVideos }

        }]);


        app.controller('ctrl', ['$http', '$scope', 'youtubeService', function ($http, $scope, youtubeService) {

            youtubeService.getPlaylists('UC-9-kyTW8ZkZNDHQJ6FgpwQ').then(function (response) {
                $scope.$apply(function () {
                    $scope.playlists = response.items;
                });
            });

            $scope.getPlaylistVideos = function (selection) {
                youtubeService.getPlaylistVideos(selection.id).then(function (response) {
                    $scope.$apply(function () {
                        $scope.playlistvideos = response.items;
                    });
                });
            }

            $scope.getVideos = function (selection) {
                youtubeService.getVideos(selection).then(function (response) {
                    $scope.$apply(function () {
                        $scope.videos = response.items;
                    });
                });
            }
        }]);

我需要对 getPlaylistVideos 函数执行什么操作才能返回播放列表中的所有视频？而不仅仅是 50 个。

这是我之前仅返回第一页的代码:

function getPlaylistVideos(playlistId) {
    return $.get('https://www.googleapis.com/youtube/v3/playlistItems', { part: 'snippet', maxResults: 50, playlistId: playlistId, key: key});
}

示例播放列表 ID 为 PLFPg_IUxqnZNTAbUMEZ76_snWd-ED5en7。

非常感谢任何帮助!

修改后的答案

$scope.getPlaylistVideos = function (selection) {
    // pass the nextPageToken attribute to the getPlaylistVideos method.
    youtubeService.getPlaylistVideos("PLFPg_IUxqnZNTAbUMEZ76_snWd-ED5en7", $scope.nextPageToken).then(function (response) {
        $scope.$apply(function () {
            angular.forEach(response.items, function (item) {
                $scope.playlistvideos.push(item);
            });

            if (typeof response.nextPageToken != 'undefined') {
                $scope.nextPageToken = response.nextPageToken;
                // call the get playlist function again
                $scope.getPlaylistVideos(selection);
            }
        });
    });
}

Answer 1

您需要使用pageToken属性来获取下一页。

根据文档，使用 API 响应中的 nextPageToken 属性。调用 API 一次或多次以检索列表。只要API响应返回一个nextPageToken，还有更多元素需要检索。

在您的 Controller 中，定义一个局部变量 nextPageToken 来检索下一页，并使用 nextPageToken 属性递归调用 getPlaylistVideos，直到所有检索结果。

app.controller('ctrl', ['$http', '$scope', 'youtubeService', function ($http, $scope, youtubeService) {

        // define a local variable pageToken, it is gonna be undefined for the first time and will be initialized with next page token after subsequent responses
        $scope.nextPageToken;
        $scope.playlistVideos = [];

        youtubeService.getPlaylists('UC-9-kyTW8ZkZNDHQJ6FgpwQ').then(function (response) {
            $scope.$apply(function () {
                $scope.playlists = response.items;
            });
        });

        $scope.getPlaylistVideos = function (selection) {
            // pass the nextPageToken attribute to the getPlaylistVideos method.
            youtubeService.getPlaylistVideos(selection.id, $scope.nextPageToken).then(function (response) {
                $scope.$apply(function () {
                    $scope.playlistVideos.push(response.items);

                    if(typeof response.nextPageToken != 'undefined'){
                          $scope.nextPageToken = response.nextPageToken;
                          // call the get playlist function again
                          $scope.getPlaylistVideos(selection);
                    } 
                });
            });
        }

        $scope.getVideos = function (selection) {
            youtubeService.getVideos(selection).then(function (response) {
                $scope.$apply(function () {
                    $scope.videos = response.items;
                });
            });
        }
}]);

在您的服务中，将 pageToken 属性传递给 API 以获取下一页。

function getPlaylistVideos(playlistId, pageToken) {
...
     // pass the page token as a parameter to the API
     $.get('https://www.googleapis.com/youtube/v3/playlistItems', { part: 'snippet', maxResults: 50, playlistId: playlistId, key: key, pageToken: pageToken })
...
}