NAME

    CGI::Compile - Compile .cgi scripts to a code reference like
    ModPerl::Registry

SYNOPSIS

      use CGI::Compile;
      my $sub = CGI::Compile->compile("/path/to/script.cgi");

DESCRIPTION

    CGI::Compile is a utility to compile CGI scripts into a code reference
    that can run many times on its own namespace, as long as the script is
    ready to run on a persistent environment.

    NOTE: for best results, load CGI::Compile before any modules used by
    your CGIs.

RUN ON PSGI

    Combined with CGI::Emulate::PSGI, your CGI script can be turned into a
    persistent PSGI application like:

      use CGI::Emulate::PSGI;
      use CGI::Compile;
    
      my $cgi_script = "/path/to/foo.cgi";
      my $sub = CGI::Compile->compile($cgi_script);
      my $app = CGI::Emulate::PSGI->handler($sub);
    
      # $app is a PSGI application

CAVEATS

    If your CGI script has a subroutine that references the lexical scope
    variable outside the subroutine, you'll see warnings such as:

      Variable "$q" is not available at ...
      Variable "$counter" will not stay shared at ...

    This is due to the way this module compiles the whole script into a big
    sub. To solve this, you have to update your code to pass around the
    lexical variables, or replace my with our. See also
    http://perl.apache.org/docs/1.0/guide/porting.html#The_First_Mystery
    for more details.

METHODS

 new

    Does not need to be called, you only need to call it if you want to set
    your own namespace_root for the generated packages into which the CGIs
    are compiled into.

    Otherwise you can just call "compile" as a class method and the object
    will be instantiated with a namespace_root of CGI::Compile::ROOT.

    You can also set return_exit_val, see "RETURN CODE" for details.

    Example:

        my $compiler = CGI::Compile->new(namespace_root => 'My::CGIs');
        my $cgi      = $compiler->compile('/var/www/cgi-bin/my.cgi');

 compile

    Takes either a path to a perl CGI script or a source code and some
    other optional parameters and wraps it into a coderef for execution.

    Can be called as either a class or instance method, see "new" above.

    Parameters:

      * $cgi_script

      Path to perl CGI script file or a scalar reference that contains the
      source code of CGI script, required.

      * $package

      Optional, package to install the script into, defaults to the path
      parts of the script joined with _, and all special characters
      converted to _%2x, prepended with CGI::Compile::ROOT::.

      E.g.:

          /var/www/cgi-bin/foo.cgi

      becomes:

          CGI::Compile::ROOT::var_www_cgi_2dbin_foo_2ecgi

    Returns:

      * $coderef

      $cgi_script or $$code compiled to coderef.

SCRIPT ENVIRONMENT

 ARGUMENTS

    Things like the query string and form data should generally be in the
    appropriate environment variables that things like CGI expect.

    You can also pass arguments to the generated coderef, they will be
    locally aliased to @_ and @ARGV.

 BEGIN and END blocks

    BEGIN blocks are called once when the script is compiled. END blocks
    are called when the Perl interpreter is unloaded.

    This may cause surprising effects. Suppose, for instance, a script that
    runs in a forking web server and is loaded in the parent process. END
    blocks will be called once for each worker process and another time for
    the parent process while BEGIN blocks are called only by the parent
    process.

 %SIG

    The %SIG hash is preserved meaning the script can change signal
    handlers at will. The next invocation gets a pristine %SIG again.

 exit and exceptions

    Calls to exit are intercepted and converted into exceptions. When the
    script calls exit 19 and exception is thrown and $@ contains a
    reference pointing to the array

        ["EXIT\n", 19]

    Naturally, "$^S" in perlvar (exceptions being caught) is always true
    during script runtime.

    If you really want to exit the process call CORE::exit or set
    $CGI::Compile::USE_REAL_EXIT to true before calling exit:

        $CGI::Compile::USE_REAL_EXIT = 1;
        exit 19;

    Other exceptions are propagated out of the generated coderef. The
    coderef's caller is responsible to catch them or the process will exit.

 Return Code

    The generated coderef's exit value is either the parameter that was
    passed to exit or the value of the last statement of the script. The
    return code is converted into an integer.

    On a 0 exit, the coderef will return 0.

    On an explicit non-zero exit, by default an exception will be thrown of
    the form:

        exited nonzero: <n>

    where n is the exit value.

    This only happens for an actual call to "exit" in perfunc, not if the
    last statement value is non-zero, which will just be returned from the
    coderef.

    If you would prefer that explicit non-zero exit values are returned,
    rather than thrown, pass:

        return_exit_val => 1

    in your call to "new".

    Alternately, you can change this behavior globally by setting:

        $CGI::Compile::RETURN_EXIT_VAL = 1;

 Current Working Directory

    If CGI::Compile->compile was passed a script file, the script's
    directory becomes the current working directory during the runtime of
    the script.

    NOTE: to be able to switch back to the original directory, the compiled
    coderef must establish the current working directory. This operation
    may cause an additional flush operation on file handles.

 STDIN and STDOUT

    These file handles are not touched by CGI::Compile.

 The DATA file handle

    If the script reads from the DATA file handle, it reads the __DATA__
    section provided by the script just as a normal script would do. Note,
    however, that the file handle is a memory handle. So, fileno DATA will
    return -1.

 CGI.pm integration

    If the subroutine CGI::initialize_globals is defined at script runtime,
    it is called first thing by the compiled coderef.

PROTECTED METHODS

    These methods define some of the internal functionality of CGI::Compile
    and may be overloaded if you need to subclass this module.

 _read_source

    Reads the source of a CGI script.

    Parameters:

      * $file_path

      Path to the file the contents of which is to be read.

    Returns:

      * $source

      The contents of the file as a scalar string.

 _build_subname

    Creates a package name and coderef name into which the CGI coderef will
    be compiled into. The package name will be prepended with
    $self-{namespace_root}>.

    Parameters:

      * $file_path

      The path to the CGI script file, the package name is generated based
      on this path.

    Returns:

      * $package

      The generated package name.

      * $subname

      The generated coderef name, based on the file name (without
      directory) of the CGI file path.

 _eval

    Takes the generated perl code, which is the contents of the CGI script
    and some other things we add to make everything work smoother, and
    returns the evaluated coderef.

    Currently this is done by writing out the code to a temp file and
    reading it in with "do" in perlfunc so that there are no issues with
    lexical context or source filters.

    Parameters:

      * $code

      The generated code that will make the coderef for the CGI.

    Returns:

      * $coderef

      The coderef that is the resulting of evaluating the generated perl
      code.

AUTHOR

    Tatsuhiko Miyagawa <miyagawa@bulknews.net>

CONTRIBUTORS

    Rafael Kitover <rkitover@gmail.com>

    Hans Dieter Pearcey <hdp@cpan.org>

    kocoureasy <igor.bujna@post.cz>

    Torsten Förtsch <torsten.foertsch@gmx.net>

    Jörn Reder <jreder@dimedis.de>

    Pavel Mateja <pavel@verotel.cz>

    lestrrat <lestrrat+github@gmail.com>

COPYRIGHT & LICENSE

    Copyright (c) 2020 Tatsuhiko Miyagawa <miyagawa@bulknews.net>

    This library is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself.

SEE ALSO

    ModPerl::RegistryCooker CGI::Emulate::PSGI

