/// <summary>
/// Get ahold of a <see cref="HttpCompressingFilter"/> for the given encoding scheme.
/// If no encoding scheme can be found, it returns null.
/// </summary>
HttpCompressingFilter GetFilterForScheme(string schemes, Stream currentFilterStream)
{
// this makes a copy of the string. i hate making copies.
schemes = schemes.ToLower();
bool foundDeflate = schemes.IndexOf("deflate") >= 0 ? true : false;
bool foundGZip = schemes.IndexOf("gzip") >= 0 ? true : false;
HttpCompressionModuleSettings settings = HttpCompressionModuleSettings.GetSettings();
// if they support the preferred algorithm, use it
if (settings.PreferredAlgorithm == CompressionTypes.Deflate && foundDeflate)
{
return(new DeflateFilter(currentFilterStream, settings.CompressionLevel));
}
if (settings.PreferredAlgorithm == CompressionTypes.GZip && foundGZip)
{
return(new GZipFilter(currentFilterStream));
}
// otherwise, fall back to something they support, which preference to deflate (no reason)
if (foundDeflate)
{
return(new DeflateFilter(currentFilterStream, settings.CompressionLevel));
}
if (foundGZip)
{
return(new GZipFilter(currentFilterStream));
}
// return null. we couldn't find a filter.
return(null);
}
/// <summary>
/// Get the current settings from the xml config file
/// </summary>
public static HttpCompressionModuleSettings GetSettings()
{
HttpCompressionModuleSettings settings = (HttpCompressionModuleSettings)System.Configuration.ConfigurationSettings.GetConfig("blowery.web/httpCompressionModule");
if (settings == null)
{
return(HttpCompressionModuleSettings.DEFAULT);
}
else
{
return(settings);
}
}
/// <summary>
/// Get ahold of a <see cref="HttpCompressingFilter"/> for the given encoding scheme.
/// If no encoding scheme can be found, it returns null.
/// </summary>
HttpCompressingFilter GetFilterForScheme(string[] schemes, Stream currentFilterStream)
{
bool foundDeflate = false;
bool foundGZip = false;
bool foundStar = false;
float deflateQuality = 0;
float gZipQuality = 0;
float starQuality = 0;
bool isAcceptableDeflate;
bool isAcceptableGZip;
bool isAcceptableStar;
for (int i = 0; i < schemes.Length; i++)
{
string acceptEncodingValue = schemes[i].Trim().ToLower();
if (acceptEncodingValue.StartsWith("deflate"))
{
foundDeflate = true;
float newDeflateQuality = GetQuality(acceptEncodingValue);
if (deflateQuality < newDeflateQuality)
{
deflateQuality = newDeflateQuality;
}
}
if (acceptEncodingValue.StartsWith("gzip") || acceptEncodingValue.StartsWith("x-gzip"))
{
foundGZip = true;
float newGZipQuality = GetQuality(acceptEncodingValue);
if (gZipQuality < newGZipQuality)
{
gZipQuality = newGZipQuality;
}
}
if (acceptEncodingValue.StartsWith("*"))
{
foundStar = true;
float newStarQuality = GetQuality(acceptEncodingValue);
if (starQuality < newStarQuality)
{
starQuality = newStarQuality;
}
}
}
isAcceptableStar = foundStar && (starQuality > 0);
isAcceptableDeflate = (foundDeflate && (deflateQuality > 0)) || (!foundDeflate && isAcceptableStar);
isAcceptableGZip = (foundGZip && (gZipQuality > 0)) || (!foundGZip && isAcceptableStar);
if (isAcceptableDeflate && !foundDeflate)
{
deflateQuality = starQuality;
}
if (isAcceptableGZip && !foundGZip)
{
gZipQuality = starQuality;
}
HttpCompressionModuleSettings settings = HttpCompressionModuleSettings.GetSettings();
if (isAcceptableDeflate && (!isAcceptableGZip || (deflateQuality > gZipQuality)))
{
return(new DeflateFilter(currentFilterStream, settings.CompressionLevel));
}
if (isAcceptableGZip && (!isAcceptableDeflate || (deflateQuality < gZipQuality)))
{
return(new GZipFilter(currentFilterStream));
}
// if they support the preferred algorithm, use it
if (isAcceptableDeflate && settings.PreferredAlgorithm == CompressionTypes.Deflate)
{
return(new DeflateFilter(currentFilterStream, settings.CompressionLevel));
}
if (isAcceptableGZip && settings.PreferredAlgorithm == CompressionTypes.GZip)
{
return(new GZipFilter(currentFilterStream));
}
// return null. we couldn't find a filter.
return(null);
}
