private async Task ResizeSourceImage(byte[] sourceBytes, UrlParserResult urlParserResult)
{
string preProcessedFile = null;
string postProcessorCommand = GetPostProcessorCommand(urlParserResult);
if (!string.IsNullOrEmpty(postProcessorCommand))
{
preProcessedFile = Regex.Replace(urlParserResult.Destination, @"\.(gif|jpe?g|png)$", new MatchEvaluator((match) => { return(".tmp" + match.Value); }), RegexOptions.IgnoreCase);
}
ImageFit.IEncoder encoder = GetEncoder(urlParserResult);
Action <byte[], string, int, int, ImageFit.IEncoder> action;
ResizeMethod resizeMethod = urlParserResult.ResizeMethod ?? ResizeMethod.ScaleDown;
switch (resizeMethod)
{
case ResizeMethod.Contain: action = ImageFit.Image.Contain; break;
case ResizeMethod.Cover: action = ImageFit.Image.Cover; break;
case ResizeMethod.Fill: action = ImageFit.Image.Fill; break;
case ResizeMethod.ScaleDown: action = ImageFit.Image.ScaleDown; break;
default: throw new NotSupportedException();
}
action(sourceBytes, preProcessedFile ?? urlParserResult.Destination, urlParserResult.Width, urlParserResult.Height, encoder);
if (!string.IsNullOrEmpty(postProcessorCommand))
{
string command = postProcessorCommand
.Replace("{inputfile}", preProcessedFile)
.Replace("{outputfile}", urlParserResult.Destination);
SimpleShell.ICommandResult commandResult = await SimpleShell.Command.Run(command);
File.Delete(preProcessedFile);
File.Delete(urlParserResult.Destination + ".bak"); // OptiPng likes creating .bak files...
if (!string.IsNullOrEmpty(commandResult.StandardOutput))
{
_logger.LogInfo(commandResult.StandardOutput);
}
if (!string.IsNullOrEmpty(commandResult.StandardError))
{
_logger.LogInfo(commandResult.StandardError);
}
if (commandResult.ErrorType != SimpleShell.CommandErrorType.None)
{
File.Delete(urlParserResult.Destination);
throw new Exception($"Error running post-processor command: {postProcessorCommand}");
}
}
}
public async Task <IRequestHandlerResult> HandleRequest(Uri url, string ipAddress)
{
if (_rateLimiter.IsBlacklisted(ipAddress))
{
_logger.LogInfo($"Denied request from blacklisted ip: {ipAddress}");
return(new RequestHandlerResult(ResultStatus.Forbidden));
}
if (_rateLimiter.IsLimitExceeded(ipAddress))
{
_logger.LogInfo($"Denied request because limit was exceeded for ip: {ipAddress}");
return(new RequestHandlerResult(ResultStatus.TooManyRequests));
}
try
{
UrlParserResult urlParserResult = _urlParser.Parse(url);
byte[] sourceBytes = await GetSourceImage(urlParserResult.Source);
_rateLimiter.RegisterRequest(ipAddress, sourceBytes.LongLength);
await FileAccessor.RunAction(urlParserResult.Destination, () => ResizeSourceImage(sourceBytes, urlParserResult));
_logger.LogInfo($"Created image at: {urlParserResult.Destination}");
string contentType = "image/" + urlParserResult.ImageType.ToString().ToLower();
FileInfo fileInfo = new FileInfo(urlParserResult.Destination);
return(new RequestHandlerResult(ResultStatus.OK, new ImageInfo(fileInfo.Length, contentType, urlParserResult.Destination)));
}
catch (UrlParserException)
{
_logger.LogWarning($"Could not parse url: {url}");
return(new RequestHandlerResult(ResultStatus.BadRequest));
}
catch (FileNotFoundException e)
{
_logger.LogWarning($"Could not find source: {e.FileName}");
return(new RequestHandlerResult(ResultStatus.FileNotFound));
}
catch (HttpRequestException e)
{
_logger.LogError($"Exception was thrown trying to fetch remote source: {e.ToString()}");
return(new RequestHandlerResult(ResultStatus.BadGateway));
}
catch (Exception e)
{
_logger.LogError($"An unhandled exception occurred: {e.ToString()}");
return(new RequestHandlerResult(ResultStatus.ServerError));
}
}
private string GetPostProcessorCommand(UrlParserResult urlParserResult)
{
bool forcedOn = urlParserResult.PostProcess.HasValue && urlParserResult.PostProcess.Value == true;
bool forcedOff = urlParserResult.PostProcess.HasValue && urlParserResult.PostProcess.Value == false;
Func <IPostProcessorSettings, string> GetCommand = (settings) =>
{
string cmd = string.Empty;
if (forcedOn || (settings.PostProcessorEnabled && !forcedOff))
{
cmd = settings.PostProcessorCommand;
if (string.IsNullOrEmpty(cmd))
{
_logger.LogWarning($"Post-processing requested but no post-processor command specified.");
}
}
return(cmd);
};
string command = string.Empty;
if (!forcedOff)
{
switch (urlParserResult.ImageType)
{
case ImageType.Gif:
command = GetCommand(_settings.GifSettings);
break;
case ImageType.Jpeg:
command = GetCommand(_settings.JpegSettings);
break;
case ImageType.Png:
command = GetCommand(_settings.PngSettings);
break;
}
}
return(command);
}
private ImageFit.IEncoder GetEncoder(UrlParserResult urlParserResult)
{
switch (urlParserResult.ImageType)
{
case ImageType.Gif:
return(new ImageFit.GifEncoder());
case ImageType.Jpeg:
int quality = urlParserResult.Quality.HasValue ? urlParserResult.Quality.Value : _settings.JpegSettings.Quality;
return(new ImageFit.JpegEncoder(quality));
case ImageType.Png:
int compressionLevel = urlParserResult.Compression.HasValue ? urlParserResult.Compression.Value : _settings.PngSettings.CompressionLevel;
return(new ImageFit.PngEncoder(compressionLevel));
default:
throw new NotSupportedException();
}
}
public UrlParserResult Parse(Uri url)
{
string pattern = @"^
(?<location>.*)
/
(?<modifier>
(?<width>\d+)x(?<height>\d+)
(
-(?<resize>contain|cover|fill|scaledown)
|
-(q(?<quality>\d+))
|
-(c(?<compression>\d+))
|
-(?<postprocess>n?pp)
)*
)
/
(?<file>[^/]+\.(?<extension>gif|jpe?g|png))
$";
Match match = Regex.Match(url.GetLeftPart(UriPartial.Path), pattern, RegexOptions.IgnoreCase | RegexOptions.IgnorePatternWhitespace);
if (!match.Success)
{
throw new UrlParserException($"The URL {url.GetLeftPart(UriPartial.Path)} is not a valid.");
}
string location = match.Groups["location"].Value;
string modifier = match.Groups["modifier"].Value;
string file = match.Groups["file"].Value;
string extension = match.Groups["extension"].Value;
string root = _destinationRoot.AbsoluteUrl.OriginalString;
string dirs = string.Empty;
if (location.StartsWith(root, StringComparison.InvariantCultureIgnoreCase))
{
dirs = location.Replace(root, "").Trim('/');
}
else
{
throw new UrlParserException($"The requested location {location} is not below the root location {root}.");
}
UrlParserResult result = new UrlParserResult()
{
Source = GetSource(dirs, file),
Destination = GetDestination(dirs, modifier, file),
ImageType = GetImageType(extension),
Width = Convert.ToInt32(match.Groups["width"].Value),
Height = Convert.ToInt32(match.Groups["height"].Value),
ResizeMethod = GetValueOrNull <ResizeMethod>(match.Groups["resize"].Value),
Quality = GetValueOrNull <int>(match.Groups["quality"].Value),
Compression = GetValueOrNull <int>(match.Groups["compression"].Value)
};
string postProcessValue = match.Groups["postprocess"].Value;
if (!string.IsNullOrEmpty(postProcessValue))
{
result.PostProcess = postProcessValue == "pp";
}
return(result);
}
