mod_dumpio Dumps all I/O to error log as desired. Extension mod_dumpio.c dumpio_module

mod_dumpio allows for the logging of all input received by Apache and/or all output sent by Apache to be logged (dumped) to the error.log file.

The data logging is done right after SSL decoding (for input) and right before SSL encoding (for output). As can be expected, this can produce extreme volumes of data, and should only be used when debugging problems.
Enabling dumpio Support

To enable the module, it should be compiled and loaded in to your running Apache configuration. Logging can then be enabled or disabled separately for input and output via the below directives. Additionally, mod_dumpio needs to be configured to LogLevel trace7:

LogLevel dumpio:trace7
DumpIOInput Dump all input data to the error log DumpIOInput On|Off DumpIOInput Off server config DumpIOInput is only available in Apache 2.1.3 and later.

Enable dumping of all input.

Example DumpIOInput On DumpIOOutput Dump all output data to the error log DumpIOOutput On|Off DumpIOOutput Off server config DumpIOOutput is only available in Apache 2.1.3 and later.

Enable dumping of all output.

Example DumpIOOutput On