I have no idea when Apache first supported SSI , but personally I never knew it existed until years after PHP became popular.
I would guess , assuming that `Options +Includes` cannot be done by unprincipled users, that this being a disabled-by-default feature it was inaccessible to majority of us.
I have also dug around a bit to find out this one, and the earliest httpd I could get my hands on is 1.3.0 which is hosted on the Apache archive site: https://archive.apache.org/dist/httpd/
"src/modules/standard/mod_include.c" says:
/*
* http_include.c: Handles the server-parsed HTML documents
*
* Original by Rob McCool; substantial fixups by David Robinson;
* incorporated into the Apache module framework by rst.
*
*/
Rob McCool is the author of NCSA HTTPd so it seems there is direct lineage wrt. this feature between the two server implementations.
Archive.org tells me I was using SSI in Jan 1997. I didn’t really understand what I was doing, but including the footer and a visitor counter via an exec one which I presumably copied from somewhere else. At the time I was still on windows and had no real concept of a program being executed as a cgi or ssi, it was all “copy this from Matt’s script archive to your cgi-bin directory”
My shared hosting from claranet supported ssi via a .htaccess configuration.
Technically php was around at that point, but I don’t think it became popular until php3 - certainly my hosting provider didn’t support it until then.
I have no idea when Apache first supported SSI , but personally I never knew it existed until years after PHP became popular.
I would guess , assuming that `Options +Includes` cannot be done by unprincipled users, that this being a disabled-by-default feature it was inaccessible to majority of us.