How was my script launched?

Chosen Typist has asked for the wisdom of the Perl Monks concerning the following question:

Replies are listed 'Best First'.
Re: How was my script launched? by gaal (Parson) on Jul 20, 2008 at 17:25 UTC
It's not the socket that invokes your script, it's a web server or some other server process. Perhaps you can configure them to pass a command line argument. In the case of CGI, you typically have cgi environment variables set up for you that you might try to detect. In many cases, you can replace "`use`" with runtime "`require Foo; Foo->import(ARGS)`", which you can of course predicate on the method you detected you were called with. Best.pm also has some goodies for conditional module loading that may suit your needs.	[reply] [d/l] [select]
Re: How was my script launched? by pc88mxer (Vicar) on Jul 20, 2008 at 18:48 UTC
How about using the `-S` and `-p` operators on `STDIN`? If your program was invoked by a TCP server (like `inetd`), then `-S STDIN` should be true. If it was invoked by a web server then `-p STDIN` is likely to be true (check this). And if it is taking input from a user then `-t STDIN` (or perhaps `-c STDIN`) should be true. You can also check for environment variables to help decide how you were invoked. For instance, if you are being invoked as a CGI script, the web server will set up a lot of variables that won't be set if you are handling the connection yourself. Same for an interactive session.	[reply] [d/l] [select]
Re: How was my script launched? by Perlbotics (Archbishop) on Jul 20, 2008 at 18:54 UTC
Additionally, you might get some further clues from inspecting the filename (`$0`) or the command line arguments (`@ARGV`). If your OS supports symbolic links, than aliasing your script by symlinking it might be another alternative to identify launch circumstances. E.g., if you symlink `yourscript.pl` to `alt_name.pl` and then call the latter, `$0 =~ m{/alt_name\.pl$}` will render true, at least under *NIX.	[reply] [d/l] [select]