Abstract: A server computer queries a client device using a test fingerprint that does not correspond to any document stored in the client device, and restricts access by the client device to the server computer if the query result is incorrect. In some implementations, the server selects a set of first fingerprints associated with documents stored in the client device, generates a set of test fingerprints, none of which are associated with any document stored in the client device, and queries the client device using fingerprints from the set of first fingerprints and the set of test fingerprints to produce query results. The server computer restricts access by the client device to the server computer if at least one of the query results is incorrect, and enables the client device to access the server computer if at least a predefined number of the query results are correct and none are incorrect.

Abstract: Before preloading a document to a client device, a server computer gets a client cache map associated with the client device. The client cache map has a matching entry for each document cached by the client device's cache. The server computer first checks if the document to be preloaded is already in the client device's cache by looking up the client cache map. If the document is cached, the server computer then checks whether the cached document's content is still fresh. As a result, the server computer preloads the document to the client device if the document is not cached or if the cached document's content is stale.

Abstract: A server computer identifies a cached document and its associated cache update history in response to a request or in anticipation of a request from a client computer. The server computer analyzes the document's cache update history to determine if the cached document is de facto fresh. If the cached document is de facto fresh, the server computer then transmits the cached document to the client computer. Independently, the server computer also fetches an instance of the document from another source like a web host and updates the document's cache update history using the fetched instance of the document.

Abstract: Caching cookies in a server includes observing cookies in document requests generated from a client and in responses from web hosts and storing them in a data structure based on certain conditions to maintain a path invariance condition. The cookies may be stored in a trie data structure. Upon certain conditions, cookies in the trie may be coalesced if they are equivalent and nodes of the trie may be collapsed. A server may retrieve cookies from the cache for use in a prefetch operation.

Abstract: A server computer identifies a cached document and its associated cache update history in response to a request or in anticipation of a request from a client computer. The server computer analyzes the document's cache update history to determine if the cached document is de facto fresh. If the cached document is de facto fresh, the server computer then transmits the cached document to the client computer. Independently, the server computer also fetches an instance of the document from another source like a web host and updates the document's cache update history using the fetched instance of the document.