public static PiczOptions Load()
{
// Defaults
var options = new PiczOptions
{
Route = "picz",
Sizes = new List <int> {
4000, 2500, 1024, 640, 320
},
BackgroundAdjustmentPercent = 10,
CacheDurationHours = 48,
Quality = 90
};
// Mandatory Config
options.CacheRootPath = Config("PiczCachePath");
// Optional Config
var configRoute = Config("PiczRoute");
if (!string.IsNullOrWhiteSpace(configRoute))
{
options.Route = configRoute;
}
var configSizes = Config("PiczSizes");
if (!string.IsNullOrWhiteSpace(configSizes))
{
options.Sizes = configSizes.Split(',').Select(s => int.Parse(s)).ToList();
}
var configBackgroundPercent = Config("PiczBackgroundAdjustmentPercent");
if (!string.IsNullOrWhiteSpace(configBackgroundPercent))
{
options.BackgroundAdjustmentPercent = int.Parse(configBackgroundPercent);
}
var configDuration = Config("PiczCacheDurationHours");
if (!string.IsNullOrWhiteSpace(configDuration))
{
options.CacheDurationHours = int.Parse(configDuration);
}
var configQuality = Config("PiczQuality");
if (!string.IsNullOrWhiteSpace(configQuality))
{
options.Quality = int.Parse(configQuality);
}
return(options);
}
private static int ConstrainSize(int size, PiczOptions options)
{
// Important!
// This prevents random sizes being requested, which would take up infinitely more
// disk space than predicted - this method constrains the size to one of the configured
// values.
if (!options.Sizes.Contains(size))
{
size = options.Sizes.OrderBy(item => Math.Abs(size - item)).First();
}
return(size);
}
private static ISupportedImageFormat GetFormat(ReplacementImage replacement, PiczOptions options)
{
switch (replacement.MimeType)
{
case "image/png":
return(new PngFormat {
Quality = options.Quality
});
case "image/gif":
return(new GifFormat {
Quality = options.Quality
});
default:
return(new JpegFormat {
Quality = options.Quality
});
}
}
private void Resize(int width, ReplacementImage replacement, byte[] photoBytes, PiczOptions options)
{
using (var inStream = new MemoryStream(photoBytes))
using (var fileStream = new FileStream(replacement.Path, FileMode.Create, FileAccess.Write))
using (var imageFactory = new ImageFactory())
{
// No upscaling! No point creating images larger than the original
using (var image = Image.FromStream(inStream))
{
if (image.Width < width)
{
width = image.Width;
}
}
inStream.Position = 0;
var size = new Size(width, 0);
// Load, resize, set the format and quality and save an image.
imageFactory
.Load(inStream)
.Resize(size)
.Format(GetFormat(replacement, options))
.Quality(options.Quality)
.Save(fileStream);
fileStream.Close();
inStream.Close();
}
}
private void Resize(int width, ReplacementImage replacement, string originalPath, PiczOptions options)
{
byte[] photoBytes;
using (var webClient = new WebClient())
{
photoBytes = webClient.DownloadData(originalPath);
}
Resize(width, replacement, photoBytes, options);
}
public ReplacementImage GetReplacementImage(int size, string originalUrl, string hash, Func <byte[]> getImage = null, Func <string> checkHash = null)
{
// Configuration values
var options = PiczOptions.Load();
var hasHash = HasHashCode(hash);
size = ConstrainSize(size, options);
// Create a cache folder that includes the image size
var cacheFolderPath = Path.Combine(options.CacheRootPath, size.ToString());
ReplacementImage replacement = null;
if (hasHash)
{
cacheFolderPath = Path.Combine(cacheFolderPath, "hashvalidated");
replacement = GetSafeNamedImage(hash, originalUrl, cacheFolderPath);
var fileInfo = new FileInfo(replacement.Path);
// Cache Miss - chance the hash has been fiddled so double check it if a validator is supplied
if (!fileInfo.Exists && checkHash != null)
{
var checkedHash = checkHash();
if (checkedHash != hash)
{
// Ah - the hash is not right, so let's try again with the correct one
// this stops us from creating lots of copies of the same image every time
// a robot sends a different hash
hash = checkedHash;
replacement = GetSafeNamedImage(hash, originalUrl, cacheFolderPath);
fileInfo = new FileInfo(replacement.Path);
}
}
if (fileInfo.Exists)
{
return(replacement);
}
}
else
{
replacement = GetSafeNamedImage(hash, originalUrl, cacheFolderPath);
var fileInfo = new FileInfo(replacement.Path);
if (fileInfo.Exists)
{
if (fileInfo.LastWriteTimeUtc.AddHours(options.CacheDurationHours) > DateTime.UtcNow)
{
// If no hash is supplied, check the file is new enough to use
return(replacement);
}
}
}
// Create image
Directory.CreateDirectory(cacheFolderPath);
if (getImage == null)
{
Resize(size, replacement, originalUrl, options);
}
else
{
Resize(size, replacement, getImage(), options);
}
return(replacement);
}
