I have already read the mod_headers configure document (http://httpd.apache.org/docs/2.4/mod/mod_headers.html).
And I see early requestheader maybe solve my problem.
RequestHeader add|append|edit|edit*|merge|set|unset header [value] [replacement] [early|env=[!]variable]|expr=_expression_]
For my requirement that I need to change a request header before the following operation.
For example, a HTTP request contains a header headerName:headerValue. And now I should convert it to NewHeaderName:NewHeaderValue which NewHeaderValue is depend on the headerValue.
Because early and expr=_expression_ in the requestheader syntax can not use together.
How can I achieve this goal.
Thanks in advance.