Twitter in App Studio Apps

AppStudio.Data\DataProviders\TwitterDataProvider.cs

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Globalization;
using System.Text;
using System.Threading.Tasks;
using Windows.Web.Http;
using Windows.Web.Http.Headers;
using Newtonsoft.Json;

namespace AppStudio.Data
{
    public class TwitterDataProvider
    {
        private readonly string _userName;
        private const string UserAgent = "Mozilla/5.0 (Windows NT 6.3; Trident/7.0; rv:11.0) like Gecko"; 
        private string authString;

        public TwitterDataProvider(string userName, string consumerKey, string consumerSecret)
        {
            _userName = userName;

            authString = Convert.ToBase64String(Encoding.UTF8.GetBytes(
                Uri.EscapeDataString(consumerKey) +
                ":" +
                Uri.EscapeDataString(consumerSecret)
                ));
        }

        public async Task<ObservableCollection<TwitterSchema>> Load()
        {
            var accessToken = await this.GetAccessToken(this.authString);

            var timelineJson = await this.GetTimeline(accessToken, _userName);

            var tweets = JsonConvert.DeserializeObject<List<Dictionary<string, object>>>(timelineJson);

            var result = new ObservableCollection<TwitterSchema>();

            foreach (var tweet in tweets)
            {
                result.Add(new TwitterSchema
                {
                    Id = tweet["id"].ToString(),
                    Content = tweet["text"].ToString(),
                    CreatedDate = DateTimeOffset.ParseExact(tweet["created_at"].ToString(),
                        "ddd MMM dd HH:mm:ss zzz yyyy",
                        CultureInfo.InvariantCulture)
                });
            }

            return result;
        }

        private async Task<string> GetAccessToken(string authData)
        {
            var oauth_url = "https://api.twitter.com/oauth2/token";
            var post_data = "grant_type=client_credentials";

            var client = new Windows.Web.Http.HttpClient();
            client.DefaultRequestHeaders.UserAgent.ParseAdd(UserAgent);

            client.DefaultRequestHeaders.Authorization = new HttpCredentialsHeaderValue("Basic", authData);
            var body = new HttpStringContent(post_data);
            body.Headers.ContentType = new HttpMediaTypeHeaderValue("application/x-www-form-urlencoded;charset=UTF-8");

            var authResp = await client.PostAsync(new Uri(oauth_url), body);

            var authRespStr = await authResp.Content.ReadAsStringAsync();

            var item = JsonConvert.DeserializeObject<Dictionary<string, string>>(authRespStr);

            string access_token = item["access_token"];

            return access_token;
        }

        private async Task<string> GetTimeline(string access_token, string userName)
        {
            var client = new HttpClient();

            client.DefaultRequestHeaders.UserAgent.ParseAdd(UserAgent);

            client.DefaultRequestHeaders.Authorization = new HttpCredentialsHeaderValue("Bearer", access_token);

            var resp = await client.GetAsync(new Uri("https://api.twitter.com/1.1/statuses/user_timeline.json?count=25&trim_user=1&screen_name=" + userName));

            var strResp = await resp.Content.ReadAsStringAsync();

            dynamic tweets = JsonConvert.DeserializeObject(strResp);

            return JsonConvert.SerializeObject(tweets, Formatting.Indented);
        }
    }
}

AppStudio.Data\DataSchemas\TwitterSchema.cs

using System;

namespace AppStudio.Data
{
    public class TwitterSchema : BindableSchemaBase, IEquatable<TwitterSchema>
    {
        private string _content;
        private DateTimeOffset _createdDate;

        public string Content
        {
            get { return _content; }
            set { SetProperty(ref _content, value); }
        }

        public DateTimeOffset CreatedDate
        {
            get { return _createdDate; }
            set { SetProperty(ref _createdDate, value); }
        }

        public string FormattedCreatedDate
        {
            get
            {
                return _createdDate.ToString("h:mmtt").ToLowerInvariant() + _createdDate.ToString(" - d MMM yy");
            }
        }

        public override string DefaultImageUrl
        {
            get
            {
                // We don't have an image for each tweet but the cache requires one
                return string.Empty;
            }
        }

        public override string DefaultContent
        {
            get { return Content; }
        }

        override public string GetValue(string fieldName)
        {
            if (!String.IsNullOrEmpty(fieldName))
            {
                switch (fieldName.ToLower())
                {
                    case "id":
                        return String.Format("{0}", Id);
                    case "content":
                        return String.Format("{0}", Content);
                    case "createdDate":
                        return String.Format("{0}", CreatedDate);
                    case "defaulttitle":
                        return String.Format("{0}", DefaultTitle);
                    case "defaultsummary":
                        return String.Format("{0}", DefaultSummary);
                    case "defaultimageurl":
                        return String.Format("{0}", DefaultImageUrl);
                    default:
                        break;
                }
            }
            return String.Empty;
        }

        public override string DefaultTitle
        {
            get { return this.Content; }
        }

        public override string DefaultSummary
        {
            get { return this.Content; }
        }

        public bool Equals(TwitterSchema other)
        {
            if (other == null)
            {
                return false;
            }
            return this.Id == other.Id;
        }
    }
}

AppStudio.Data\DataSources\TwitterDataSource.cs

using System;
using System.Collections.Generic;
using System.Threading.Tasks;

namespace AppStudio.Data
{
    public class TwitterDataSource : DataSourceBase<TwitterSchema>
    {
        // TODO: update these values as appropriate
        private const string _username = "mrlacey";
        private const string _consumerKey = "CONSUMER_KEY";
        private const string _consumerSecret = "CONSUMER_SECRET";

        protected override string CacheKey
        {
            get { return "TwitterDataSource"; }
        }

        public override bool HasStaticData
        {
            get { return false; }
        }

        public static string UserName { get { return _username; } }

        public async override Task<IEnumerable<TwitterSchema>> LoadDataAsync()
        {
            try
            {
                var twitterDataProvider = new TwitterDataProvider(_username, _consumerKey, _consumerSecret);
                return await twitterDataProvider.Load();
            }
            catch (Exception ex)
            {
                AppLogs.WriteError("TwitterDataSourceDataSource.LoadData", ex.ToString());
                return new TwitterSchema[0];
            }
        }
    }
}

AppStudio.Shared\App.xaml

        <!-- add this ResourceDictionary -->
        <ResourceDictionary Source="Views/DataTemplates/TwitterViews.xaml"/>

AppStudio.Shared\ViewModels\MainViewModel.cs

        // add this field
        private TwitterViewModel _twitterModel;

        // add this property
        public TwitterViewModel TwitterModel
        {
            get { return _twitterModel ?? (_twitterModel = new TwitterViewModel()); }
        }
        
        // Add this to the method SetViewType
        TwitterModel.ViewType = viewType;
        
        // add this to the Task array in the method LoadDataAsync
        TwitterModel.LoadItemsAsync(forceRefresh),        

AppStudio.Shared\Views\TwitterViewModel.cs

using System;
using Windows.System;
using Windows.UI.Xaml;
using AppStudio.Data;

namespace AppStudio.ViewModels
{
    public class TwitterViewModel : ViewModelBase<TwitterSchema>
    {
        private RelayCommandEx<TwitterSchema> itemClickCommand;

        public RelayCommandEx<TwitterSchema> ItemClickCommand
        {
            get
            {
                if (itemClickCommand == null)
                {
                    itemClickCommand = new RelayCommandEx<TwitterSchema>(
                        async (item) =>
                        {
                            await Launcher.LaunchUriAsync(new Uri(string.Format("https://twitter.com/{0}/status/{1}", TwitterDataSource.UserName, item.Id)));
                        });
                }

                return itemClickCommand;
            }
        }

        override protected DataSourceBase<TwitterSchema> CreateDataSource()
        {
            return new TwitterDataSource();
        }

        override public Visibility GoToSourceVisibility
        {
            get { return ViewType == ViewTypes.Detail ? Visibility.Visible : Visibility.Collapsed; }
        }

        override protected void GoToSource()
        {
            base.GoToSource("{FeedUrl}");
        }

        override public Visibility RefreshVisibility
        {
            get { return ViewType == ViewTypes.List ? Visibility.Visible : Visibility.Collapsed; }
        }

        public override bool HasMoreItems
        {
            get { return false; }
        }

        override public void NavigateToSectionList()
        {
            throw new NotImplementedException();
        }

        override protected void NavigateToSelectedItem()
        {
            throw new NotImplementedException();
        }
    }
}

AppStudio.Windows\Views\DataTemplates\TwitterViews.xaml

<ResourceDictionary
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:commands="using:AppStudio.Commands">

    <DataTemplate x:Key="TwitterList">
        <Grid>
            <ListView
                ItemsSource="{Binding Items}"
                SelectionMode="None"
                IsSwipeEnabled="False"
                IsItemClickEnabled="True"
                commands:ItemClickCommand.Command="{Binding ItemClickCommand}"
                ScrollViewer.VerticalScrollBarVisibility="Auto"
                ItemTemplate="{StaticResource TwitterItem}" />
            <ProgressBar Width="480" Height="40" Foreground="White" VerticalAlignment="Top" IsIndeterminate="True" Visibility="{Binding ProgressBarVisibility}" />
        </Grid>
    </DataTemplate>

    <DataTemplate x:Key="TwitterItem">
        <StackPanel MaxWidth="480" Margin="0,0,0,15">
            <TextBlock Style="{StaticResource ItemHeaderWrapText}"
                       FontWeight="Normal"
                       VerticalAlignment="Top"
                       Text="{Binding Content, Converter={StaticResource TextPlainConverter}, ConverterParameter=140}" />
            <TextBlock Style="{StaticResource ItemSubheaderText}"
                       VerticalAlignment="Top"
                       Text="{Binding FormattedCreatedDate}" />
        </StackPanel>
    </DataTemplate>
</ResourceDictionary>

AppStudio.Windows\Views\MainPage.xaml

    
    // add this to your hub
    <HubSection x:Name="TwitterSection"
                Header="Twitter"
                DataContext="{Binding MainViewModel.TwitterModel}"
                ContentTemplate="{StaticResource TwitterList}"
                IsHeaderInteractive="{Binding HasMoreItems}"
                Style="{StaticResource AppHubSectionStyle}" />

AppStudio.WindowsPhone\Views\DataTemplates\TwitterViews.xaml

<ResourceDictionary
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:controls="using:AppStudio.Controls"
    xmlns:html2xaml="using:AppStudio.Controls.Html2Xaml"
    xmlns:commands="using:AppStudio.Commands">

    <DataTemplate x:Key="TwitterList">
        <Grid>
            <ListView
                ItemsSource="{Binding Items}"
                SelectionMode="None"
                IsSwipeEnabled="False"
                IsItemClickEnabled="True"
                commands:ItemClickCommand.Command="{Binding ItemClickCommand}"
                ScrollViewer.VerticalScrollBarVisibility="Hidden"
                ItemTemplate="{StaticResource TwitterItem}" />
            <ProgressBar Width="380" Height="40" Foreground="White" VerticalAlignment="Top" IsIndeterminate="True" Visibility="{Binding ProgressBarVisibility}" />
        </Grid>
    </DataTemplate>

    <DataTemplate x:Key="TwitterItem">
        <StackPanel MaxWidth="380" Margin="0,0,0,15">
            <TextBlock Style="{StaticResource ItemHeaderWrapText}"
                       FontWeight="Normal"
                       VerticalAlignment="Top"
                       Text="{Binding Content, Converter={StaticResource TextPlainConverter}, ConverterParameter=140}" />
            <TextBlock Style="{StaticResource ItemSubheaderText}"
                       VerticalAlignment="Top"
                       Text="{Binding FormattedCreatedDate}" />
        </StackPanel>
    </DataTemplate>
</ResourceDictionary>

AppStudio.WindowsPhone\Views\MainPage.xaml

    
    // add this to your hub
    <HubSection HeaderTemplate="{StaticResource HubHeader}"
                Width="360"
                Header="Twitter" 
                DataContext="{Binding MainViewModel.TwitterModel}"
                ContentTemplate="{StaticResource TwitterList}"
                IsHeaderInteractive="{Binding HasMoreItems}" />