OnLAMP: Writing Apache 2.0 Output Filters
"When the filter interface was first designed, it was written for the Apache developers and very little attention was paid to making it easy for other people to write their own filters. Since that time, the developers have looked at the API again and have added a simple layer on top of the original interface. ..."
"... The new API very closely resembles the buffered file I/O API from POSIX. In fact, the developers used that API as the model when redesigning filters. ..." In this article, we will finish discussing output filters. After reading this article, you should be able to write your own Apache filters.