HPP: HTML Macro-Preprocessing to Support Dynamic Document Caching

A number of techniques are available for reducing latency and bandwidth requirements for resources on the World Wide Web, including caching, compression, and delta-encoding . These approaches are limited: much data on the Web is dynamic, for which traditional caching is of limited use, and delta-encoding requires both a common version base against which to apply a delta and the complete generation of the resource prior to encoding it. In contrast to these approaches, we take an application-specific view, in which we separate the static and dynamic portions of a resource. The static portions (called the template) can then be cached, with (presumably small) dynamic portions obtained on each access. Our HTML extension, which we refer to as HPP (for HTML Pre-Processing) supports resources that contain variable number of static and dynamic elements, such as query responses.

Results with macro-encoding of query response resources from local CGI scripts and two popular search engines indicate that our approach promises a substantial reduction of network traffic, server load, and access latency for dynamic documents. The size of network transfers using HPP are comparable to delta-encoding (factors of 2-8 smaller than the original resource), while the data generated by content providers is simpler, and the load on the end-servers is slightly lower.