Tags: plugin Edition: performance Tagline: Disk cache output images. Makes dynamic image processing as responsive and scalable as static images. Required for websites with significant traffic. Aliases: /plugins/diskcache
Output caching for output images. Each result is stored on disk as a single file, and can be served as a static file for cache hits. Does not affect SEO.
Improves latency and scalability. Suggested for all production sites. Used by nearly all ImageResizer users.
Works well with all plugins.
This plugin only applies to the URL API, not the managed API. It currently integrates with native ASP.NET and IIS static file serving to provide optimal performance.
When disabling DiskCache on a site that hosts non-public images, it is best to use <diskcache enabled="false" /> instead of removing <add name="DiskCache" />. The existing /imagecache/ folder will otherwise become publicly accessible when the plugin is removed. Keep this in mind with sub-applications as well.
All images are cached by default. Specify &cache=no to prevent caching of a result. The disk cache can be (roughly) constrained by image count using subfolders=x and autoClean=true. Evicting items from disk is expensive, so we don't enable this by default, nor suggest it unless monitoring proves it necessary.
Either run Install-Package ImageResizer.Plugins.DiskCache in the NuGet package manager, or:
- Add a reference to ImageResizer.Plugins.DiskCache.dll file in your project.
- In the plugins section, insert
<add name="DiskCache" />.
You're done. If you want to configure the cache directory, you can set <diskcache dir="~/app-relative-path-here" />.
The DiskCache assembly includes 3 additional caching plugins
Caches up to 10MB of original image files in memory. Files not accessed for more than 10 minutes are removed from the cache.
Improves performance for real-time image editing (such as via StudioJS or jCrop).
Only images with &scache=mem are cached.
Install by adding <add name="SourceMemCache" />.
Caches up to 10MB of output image files in memory. Files not accessed for more than 10 minutes are removed from the cache.
Useful for few-time-use image processing, such as a live camera feed.
Only images with &mcache=true are cached.
Install by adding <add name="MemCache" />.
Like DiskCache, but for source files. Not advisable if your source image collection is larger than available local storage.
Only images with &scache=disk are cached.
Install by adding <add name="SourceDiskCache" />.
Default cache folder is ~/cache/sourceimages. No configuration options available through XML installation - only through code installation.
The defaults are good - you don't actually need to specify any configuration.
The following is what the default settings look like. Only specify what you need to change.
Where to store the images. This can specify an IIS virtual directory if you want to cache images outside the site folder.
Should be in virtual path form, like /vdir/cache or ~/imagecache.
When true, will keep a background thread running to 'clean' unused items from the disk cache. This background thread uses smart 'activity sensing' to avoid doing cleanup work when the site is busy. Defaults to false, since the cleanup system is still in beta.
true by default. False disables the plugin completely, but prevents public access to ~/imagecache, which would become possible if you simply uninstalled the plugin.
Controls how many subfolders to use for disk caching. Rounded to the next power of two.
NTFS does not handle more than 8,000 files per folder well. Larger folders also make cleanup more resource-intensive.
Defaults to 8192, which combined with the default setting of 400 images per folder, allows for scalability to ~1 million actively used image versions.
For example, given a desired cache size of 100,000 items, this should be set to 256.
Defaults to 15 seconds. How long to wait for a file lock to become available before giving up on the request.
When true, writing to the disk cache will occur on separate threads, permitting the request to complete faster in the case of a cache miss. This adds a bit more overhead on the server, but makes the client experience more responsive. Very helpful on slow or overwhelmed I/O systems.
The number of bytes to allowed to be used for the async write queue. Defaults to 10MB (10485760). This is the maximum amount of RAM that will be used for the write cache. If this value would be exceeded, the disk cache switches to synchronous mode until the queue has emptied enough to permit another job to be added without exceeding the maximum.
Controls how the background thread determines which files to 'clean up'. Not used unless autoClean='true'
Changing the 'cleanupStrategy' settings may void your warranty - it's tricky business.
Times are parsed in the following format: { s | d.hh:mm[:ss[.ff]] | hh:mm[:ss[.ff]] }. If you just enter a number, it's considered seconds.