public static bool DeleteCachedImage(string screenName, string userId, ImageCacheType cacheType)
{
string fileName = $"{screenName}_{userId}-{cacheType.ToString().ToLower()}";
string fullPath = Path.Combine(ApplicationData.Instance.GetImageCacheFolderAbsolutePath(), fileName);
if (File.Exists(fullPath))
{
File.Delete(fullPath);
if (!File.Exists(fullPath))
{
return(true);
}
}
return(false);
}
public static BitmapImage LoadCachedImage(string screenName, long userId, ImageCacheType cacheType)
{
string fileName = $"{screenName}_{userId}-{cacheType.ToString().ToLower()}";
string fullPath = Path.Combine(ApplicationData.Instance.GetImageCacheFolderAbsolutePath(), fileName);
if (File.Exists(fullPath) && (new FileInfo(fileName)).Length > 0)
{
var image = new BitmapImage(new Uri(fullPath));
if (image != null && (image.Width > 0 && image.Height > 0))
{
return(image);
}
}
return(null);
}
/// <summary>
/// Caches a SNS account's image from URL.
/// </summary>
/// <param name="url">Absolute image URL to be downloaded from.</param>
/// <param name="screenName">ScreenName of the account.</param>
/// <param name="userId">User ID of the account.</param>
/// <param name="cacheType">Specifies the type of image.</param>
/// <param name="overwrite">Whether to overwrite existing cached image.</param>
/// <returns>`true` if the cache process has done successfully, `false` if not.</returns>
///
/// <exception cref="InvalidOperationException" />
public static bool Cache(string url, string screenName, long userId, ImageCacheType cacheType, bool overwrite = true)
{
#region 1. Download file from `url`
string tempFilePath = Path.GetTempFileName();
WebClient client = new WebClient();
client.DownloadFile(url, tempFilePath);
if (!File.Exists(tempFilePath))
{
return(false);
}
#endregion
#region 2. Determine image type for downloaded file
var header = new byte[8];
ImageHeaderInfo.ImageType determinedType = ImageHeaderInfo.ImageType.UNKNOWN;
using (var fileStream = new FileStream(tempFilePath, FileMode.Open, FileAccess.Read, FileShare.None)) {
if (fileStream.Length > 0)
{
fileStream.Read(header, 0, header.Length);
}
}
var headerHexString = string.Concat(header.Select(v => v.ToString("X2")).ToArray());
foreach (var type in ImageHeaderInfo.StringHexOfTypes)
{
if (headerHexString.StartsWith(type.Value))
{
determinedType = type.Key;
break;
}
}
if (determinedType == ImageHeaderInfo.ImageType.UNKNOWN)
{
return(false); // If the process has failed or not supported format
}
#endregion
#region 3. Move/Overwrite downloaded temp image file into QuiqCompose cache folder
string destinationFileName = $"{screenName}_{userId}-{cacheType.ToString().ToLower()}";
string destinationFullPath = Path.Combine(ApplicationData.Instance.GetImageCacheFolderAbsolutePath(), destinationFileName);
if (!Directory.Exists(ApplicationData.Instance.GetImageCacheFolderAbsolutePath()))
{
Directory.CreateDirectory(ApplicationData.Instance.GetImageCacheFolderAbsolutePath());
}
if (overwrite && File.Exists(destinationFullPath))
{
File.Delete(destinationFullPath);
}
else if (!overwrite && File.Exists(destinationFullPath))
{
throw new InvalidOperationException("Cached file already exists and overwriting is not permitted.");
}
File.Move(tempFilePath, destinationFullPath);
if (!File.Exists(destinationFullPath))
{
return(false);
}
#endregion
#region 4. Check if cached image can be loaded into BitmapImage
try {
var testImage = new BitmapImage(new Uri(destinationFullPath));
if (testImage != null && testImage.Height > 0 && testImage.Width > 0)
{
return(true);
}
} catch (Exception) {
return(false);
}
#endregion
return(false);
}
