How do I use the new HttpClient from Windows.Web.Http to download an image?

Question

Using Windows.Web.Http.HttpClient how can I download an image? I would like use this HttpClient because it is available to use in portable class libraries.

Answer 1

This is what I eventually came up with. There is not much documentation around Windows.Web.Http.HttpClient and a lot of the examples online use old mechanisms like ReadAllBytesAsync which are not available with this HttpClient.

I should note that this question from MSDN helped me out a lot, so thanks to that person. As the comment over there states, this guy must be the only person in the world who knows about Windows.Web.Http !

using System;
using System.Diagnostics;
using System.IO;
using System.Net;
using System.Threading.Tasks;
using System.Windows.Media.Imaging;
using Windows.Storage.Streams;
using Windows.Web.Http;

public class ImageLoader
{
    public async static Task<BitmapImage> LoadImage(Uri uri)
    {
        BitmapImage bitmapImage = new BitmapImage();

        try
        {
            using (HttpClient client = new HttpClient())
            {
                using (var response = await client.GetAsync(uri))
                {
                    response.EnsureSuccessStatusCode();

                    using (IInputStream inputStream = await response.Content.ReadAsInputStreamAsync())
                    {
                        bitmapImage.SetSource(inputStream.AsStreamForRead());
                    }
                }
            }
            return bitmapImage;
        }
        catch (Exception ex)
        {
            Debug.WriteLine("Failed to load the image: {0}", ex.Message);
        }

        return null;
    }
}

Answer 2

public async void downLoadImage(string url)
{
        using (var client = new HttpClient())
        {
            var response = client.GetAsync(url).Result;
            BitmapImage bitmap = new BitmapImage();
            if (response != null && response.StatusCode == HttpStatusCode.OK)
            {
                using (var stream = await response.Content.ReadAsStreamAsync())
                {
                    using (var memStream = new MemoryStream())
                    {
                        await stream.CopyToAsync(memStream);
                        memStream.Position = 0;
                        bitmap.SetSource(memStream.AsRandomAccessStream());
                    }
                }
                HardcodedValues.profilePic = bitmap;
            }
        }
}

Answer 3

In .net core web api you can use the below code

[Route("getProductImage/v1")]
    [HttpGet]
    public async Task<IActionResult> getProductImage(GetProductImageQueryParam parammodel)
    {
        using (HttpClient client = new HttpClient())
        {
            MNimg_URL = MNimg_URL + parammodel.modelname;
            HttpResponseMessage response = await client.GetAsync(MNimg_URL);
            byte[] content = await response.Content.ReadAsByteArrayAsync();
            //return "data:image/png;base64," + Convert.ToBase64String(content);
            return File(content, "image/png", parammodel.modelname);
        }
    }

here GetProductImageQueryParam is a class with input parameters

Answer 4

Most answers here are correct but if you need something simple:

HttpClient http = new HttpClient();

var res = await http.GetAsync(linktojpg);

byte[] bytes = await res.Content.ReadAsByteArrayAsync();

using (Image image = Image.FromStream(new MemoryStream(bytes)))
{
    image.Save(path/name.jpg);  // Or Png
}

Answer 5

Updated for 8.1 - 10.

    public async static Task<BitmapImage> LoadImage(Uri uri)
    {
        BitmapImage bitmapImage = new BitmapImage();

        try
        {
            using (Windows.Web.Http.HttpClient client = new Windows.Web.Http.HttpClient())
            {
                using (var response = await client.GetAsync(uri))
                {
                    response.EnsureSuccessStatusCode();

                    using (MemoryStream inputStream = new MemoryStream())
                    {
                        await inputStream.CopyToAsync(inputStream);
                        bitmapImage.SetSource(inputStream.AsRandomAccessStream());
                    }
                }
            }
            return bitmapImage;
        }
        catch (Exception ex)
        {
            Debug.WriteLine("Failed to load the image: {0}", ex.Message);
        }

        return null;
    }

Answer 6

Made a demo UWP application for downloading an image file. Just paste the image URL link and press the download button.

MainPage.xaml

<Page
    x:Class="HttpDownloader.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:HttpDownloader"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">

    <Grid>
        <StackPanel>
            <TextBox x:Name="uriInput"
                     Header="URI:" PlaceholderText="Please provide an uri"
                     Width="300"
                     HorizontalAlignment="Center"/>
            <Button Content="Dowload"
                    HorizontalAlignment="Center"
                    Click="Button_Click"/>
        </StackPanel>
    </Grid>
</Page>

MainPage.xaml.xs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net.Http;
using System.Runtime.InteropServices.WindowsRuntime;
using System.Threading.Tasks;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;
using System.Net.Http;
using System.Net;
using Windows.Storage.Streams;
using Windows.Storage.Pickers;
using Windows.Storage;
using Windows.Graphics.Imaging;
using System.Threading;

// The Blank Page item template is documented at https://go.microsoft.com/fwlink/?LinkId=402352&clcid=0x409

namespace HttpDownloader
{
    /// <summary>
    /// An empty page that can be used on its own or navigated to within a Frame.
    /// </summary>
    public sealed partial class MainPage : Page
    {
        public MainPage()
        {
            this.InitializeComponent();
        }

        private async void Button_Click(object sender, RoutedEventArgs e)
        {
            HttpClient client = new HttpClient();
            string imageUrl = uriInput.Text;
            try
            {
                using (var cancellationTokenSource = new CancellationTokenSource(50000))
                {
                    var uri = new Uri(WebUtility.HtmlDecode(imageUrl));
                    using (var response = await client.GetAsync(uri, cancellationTokenSource.Token))
                    {
                        response.EnsureSuccessStatusCode();
                        var mediaType = response.Content.Headers.ContentType.MediaType;
                        string fileName = DateTime.Now.ToString("yyyyMMddhhmmss");
                        if (mediaType.IndexOf("jpg", StringComparison.OrdinalIgnoreCase) >= 0
                            || mediaType.IndexOf("jpeg", StringComparison.OrdinalIgnoreCase) >= 0)
                        {
                            fileName += ".jpg";
                        }
                        else if (mediaType.IndexOf("png", StringComparison.OrdinalIgnoreCase) >= 0)
                        {
                            fileName += ".png";
                        }
                        else if (mediaType.IndexOf("gif", StringComparison.OrdinalIgnoreCase) >= 0)
                        {
                            fileName += ".gif";
                        }
                        else if (mediaType.IndexOf("bmp", StringComparison.OrdinalIgnoreCase) >= 0)
                        {
                            fileName += ".bmp";
                        }
                        else
                        {
                            fileName += ".png";
                        }

                        // Get the app's local folder.
                        StorageFolder localFolder = Windows.Storage.ApplicationData.Current.LocalFolder;

                        // Create a new subfolder in the current folder.
                        // Replace the folder if already exists.
                        string desiredName = "Images";
                        StorageFolder newFolder = await localFolder.CreateFolderAsync(desiredName, CreationCollisionOption.ReplaceExisting);
                        StorageFile newFile = await newFolder.CreateFileAsync(fileName, CreationCollisionOption.ReplaceExisting);

                        using (Stream streamStream = await response.Content.ReadAsStreamAsync())
                        {
                            using (Stream streamToWriteTo = File.Open(newFile.Path, FileMode.Create))
                            {
                                await streamStream.CopyToAsync(streamToWriteTo);
                            }
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine("Exception occur");
                Console.WriteLine(ex.ToString());
            }
        }
    }
}

You will find the image in this folder.

Users/[current user name]/AppData/Local/Packages/[Application package name]/LocalState/Images