Samizdat is a generic RDF-based engine for building collaboration and open publishing Web sites. It provides users with the means to cooperate and coordinate on all kinds of activities, including media activism, resource sharing, education and research, advocacy, and so on. It intends to promote values of freedom, openness, equality, and cooperation.
Graffiti is an RDF store based on dynamic translation of RDF queries into SQL. It allows you to map any relational database schema into RDF semantics and vice-versa, and to store any RDF data in a relational database. Since 2003, this RDF store was used as the primary means of data access in the Samizdat open publishing engine, and now it's released as a stand-alone module ready for use in other applications.
SynCache::Cache stores cached objects in a Hash that is protected by an advanced two-level locking mechanism. Two-level locking ensures that: Multiple threads can add and fetch objects in parallel without stepping on each otherís toes; while one thread is working on a cache entry, other threads can access the rest of the cache with no waiting on the global lock, race conditions, or deadlock or livelock situations; and while one thread is performing a long and resource-intensive operation, other threads that request the same data with #fetch_or_add method will be put on hold, and as soon as the first thread completes the operation, the result will be returned to all threads. Without this feature, a steady stream of requests with less time between them than it takes to complete one request can easily bury a server under an avalanche of threads all wasting resources on the same expensive operation.
The Whitewash module allows Ruby programs to clean up any HTML document or fragment coming from an untrusted source and to remove all dangerous constructs that could be used for cross-site scripting or request forgery. All HTML tags, attribute names and values, and CSS properties are filtered through a whitelist that defines which names and what kinds of values are allowed; everything that doesnít match the whitelist is removed. The whitelist is provided externally, and the default whitelist is loaded from the whitelist.yaml shipped with Whitewash. The default is the most strict (for example, it does not allow cross-site links to images in IMG tags) and can be considered safe for all uses.