/// <summary>
/// This will combine a stylesheet with all of its imports (and any imports within those, and within those, etc..) and minify the resulting content for cases only
/// where all files are in the same folder and no relative or absolute paths are specified in the import declarations. It incorporates caching of the minified
/// content and implements 304 responses for cases where the request came with an If-Modified-Since header indicating that current content already exists on the
/// client. The last-modified-date for the content is determined by retrieving the most recent LastWriteTime for any file in the folder - although this may lead
/// to some false-positives if unrelated files are updated, it does mean that if any file that IS part of the combined stylesheet is updated then the content
/// will be identified as stale and re-generated. The cached content will likewise be invalidated and updated if any files in the folder have changed since the
/// date recorded for the cached data. GZip and Deflate compression of the response are supported where specified in Accept-Encoding request headers.
/// </summary>
private ActionResult Process(
string relativePath,
IRelativePathMapper relativePathMapper,
ICacheThingsWithModifiedDates <TextFileContents> memoryCache,
DateTime?lastModifiedDateFromRequest)
{
if (string.IsNullOrWhiteSpace(relativePath))
{
throw new ArgumentException("Null/blank relativePath specified");
}
if (memoryCache == null)
{
throw new ArgumentNullException(nameof(memoryCache));
}
if (relativePathMapper == null)
{
throw new ArgumentNullException(nameof(relativePathMapper));
}
// Using the SingleFolderLastModifiedDateRetriever means that we can determine whether cached content (either in the ASP.Net cache or in the browser cache)
// is up to date without having to perform the complete import flattening process. It may lead to some unnecessary work if an unrelated file in the folder
// is updated but for the most common cases it should be an efficient approach.
var lastModifiedDateRetriever = new SingleFolderLastModifiedDateRetriever(relativePathMapper, new[] { "css", "less" });
var lastModifiedDate = lastModifiedDateRetriever.GetLastModifiedDate(relativePath);
if ((lastModifiedDateFromRequest != null) && AreDatesApproximatelyEqual(lastModifiedDateFromRequest.Value, lastModifiedDate))
{
Response.StatusCode = 304;
return(Content("Not changed since last request", "text/css"));
}
var cssLoader = (new EnhancedNonCachedLessCssLoaderFactory(
relativePathMapper,
SourceMappingMarkerInjectionOptions.Inject,
ErrorBehaviourOptions.LogAndRaiseException,
new CSSMinifier.Logging.NullLogger()
)).Get();
// Ignore any errors from the DiskCachingTextFileLoader - if the file contents become invalid then allow them to be deleted and rebuilt instead of blowing
// up. The EnhancedNonCachedLessCssLoaderFactory should raise exceptionns since it will indicate invalid source content, which should be flagged up.
var modifiedDateCachingStyleLoader = new CachingTextFileLoader(
new DiskCachingTextFileLoader(
cssLoader,
relativePathRequested => new FileInfo(relativePathMapper.MapPath(relativePathRequested) + ".cache"),
lastModifiedDateRetriever,
DiskCachingTextFileLoader.InvalidContentBehaviourOptions.Delete,
ErrorBehaviourOptions.LogAndContinue,
new CSSMinifier.Logging.NullLogger()
),
lastModifiedDateRetriever,
memoryCache
);
var content = modifiedDateCachingStyleLoader.Load(relativePath);
if (content == null)
{
throw new Exception("Received null response from Css Loader - this should not happen");
}
if ((lastModifiedDateFromRequest != null) && AreDatesApproximatelyEqual(lastModifiedDateFromRequest.Value, lastModifiedDate))
{
Response.StatusCode = 304;
return(Content("Not changed since last request", "text/css"));
}
SetResponseCacheHeadersForSuccess(content.LastModified);
return(Content(content.Content, "text/css"));
}
/// <summary>
/// This will combine a stylesheet with all of its imports (and any imports within those, and within those, etc..) and minify the resulting content for cases only
/// where all files are in the same folder and no relative or absolute paths are specified in the import declarations. It incorporates caching of the minified
/// content and implements 304 responses for cases where the request came with an If-Modified-Since header indicating that current content already exists on the
/// client. The last-modified-date for the content is determined by retrieving the most recent LastWriteTime for any file in the folder - although this may lead
/// to some false-positives if unrelated files are updated, it does mean that if any file that IS part of the combined stylesheet is updated then the content
/// will be identified as stale and re-generated. The cached content will likewise be invalidated and updated if any files in the folder have changed since the
/// date recorded for the cached data. GZip and Deflate compression of the response are supported where specified in Accept-Encoding request headers.
/// </summary>
private ActionResult Process(
string relativePath,
ICacheThingsWithModifiedDates <TextFileContents> memoryCache,
DateTime?lastModifiedDateFromRequest)
{
if (string.IsNullOrWhiteSpace(relativePath))
{
throw new ArgumentException("Null/blank relativePath specified");
}
if (memoryCache == null)
{
throw new ArgumentNullException("memoryCache");
}
// Using the SingleFolderLastModifiedDateRetriever means that we can determine whether cached content (either in the ASP.Net cache or in the browser cache)
// is up to date without having to perform the complete import flattening process. It may lead to some unnecessary work if an unrelated file in the folder
// is updated but for the most common cases it should be an efficient approach.
var lastModifiedDateRetriever = new SingleFolderLastModifiedDateRetriever(new ServerUtilityPathMapper(Server), new[] { "css", "less" });
var lastModifiedDate = lastModifiedDateRetriever.GetLastModifiedDate(relativePath);
if ((lastModifiedDateFromRequest != null) && AreDatesApproximatelyEqual(lastModifiedDateFromRequest.Value, lastModifiedDate))
{
Response.StatusCode = 304;
Response.StatusDescription = "Not Modified";
return(Content("", "text/css"));
}
// In the interests of compatability with this generic example project, we'll use the DefaultNonCachedLessCssLoaderFactory which will enable LESS compilation,
// import-flattening, minification and pseudo-source-mapping but doesn't support the advanced features that the EnhancedNonCachedLessCssLoaderFactory does
// such as media-query-grouping and scope-restricting html-tag stripping (see comments in the EnhancedNonCachedLessCssLoaderFactory for more information)
var cssLoader = (new DefaultNonCachedLessCssLoaderFactory(Server)).Get();
// Layers of caching are added to persist the processed content in memory and on disk (last-modified-date checking is incorporated so that cache entries are
// expired if the source files have changed since the cached data was stored)
var diskCachingCssLoader = new DiskCachingTextFileLoader(
cssLoader,
relativePathRequested => new FileInfo(Server.MapPath(relativePathRequested) + ".cache"),
lastModifiedDateRetriever,
DiskCachingTextFileLoader.InvalidContentBehaviourOptions.Delete,
ErrorBehaviourOptions.LogAndRaiseException,
new NullLogger()
);
var memoryAndDiskCachingCssLoader = new CachingTextFileLoader(
diskCachingCssLoader,
lastModifiedDateRetriever,
memoryCache
);
var content = memoryAndDiskCachingCssLoader.Load(relativePath);
if (content == null)
{
throw new Exception("Received null response from Css Loader - this should not happen");
}
if ((lastModifiedDateFromRequest != null) && AreDatesApproximatelyEqual(lastModifiedDateFromRequest.Value, lastModifiedDate))
{
Response.StatusCode = 304;
Response.StatusDescription = "Not Modified";
return(Content("", "text/css"));
}
SetResponseCacheHeadersForSuccess(content.LastModified);
return(Content(content.Content, "text/css"));
}
