NAME PLP - Perl in HTML pages MODULE INSTALLATION perl Makefile.PL make make install SYNOPSIS mod_perl installation * httpd.conf (for mod_perl setup) SetHandler perl-script PerlHandler PLP PerlSendHeader On PerlSetVar PLPcache On # Who said CGI was easier to set up? :) CGI installation * /foo/bar/plp.cgi (local filesystem address) #!/usr/bin/perl use PLP; PLP::everything(); * httpd.conf (for CGI setup) ScriptAlias /foo/bar/ /PLP_COMMON/ AllowOverride None Options +ExecCGI Order allow,deny Allow from all AddHandler plp-document plp Action plp-document /PLP_COMMON/plp.cgi Test script (test.plp) <: print "Hurrah, it works!
" for 1..10; :> DESCRIPTION PLP is yet another Perl embedder, primarily for HTML documents. Unlike with other Perl embedders, there is no need to learn a meta-syntax or object model: one can just use the normal Perl constructs. PLP runs under mod_perl for speeds comparable to those of PHP, but can also be run as a CGI script. PLP Syntax "<: perl_code(); :>" With "<:" and ":>", you can add Perl code to your document. This is what PLP is all about. All code outside of these tags is printed. It is possible to mix perl language constructs with normal HTML parts of the document: <: unless ($ENV{REMOTE_USER}) { :> You are not logged in. <: } :> ":>" always stops a code block, even when it is found in a string literal. "<:= $expression :>" Includes a dynamic expression in your document. The expression is evaluated in list context. Please note that the expression should not end a statement: avoid semi-colons. No whitespace may be between "<:" and the equal sign. "foo <:= $bar :> $baz" is like "<: print 'foo ', $bar, ' baz'; :>". "<(filename)>" Includes another file before the PLP code is executed. The file is included literally, so it shares lexical variables. Because this is a compile-time tag, it's fast, but you can't use a variable as the filename. You can create recursive includes, so beware! (PLP will catch simple recursion: the maximum depth is 128.) Whitespace in the filename is not ignored so "<( foo.txt)>" includes the file named " foo.txt", including the space in its name. A compile-time alternative is include(), which is described in PLP::Functions. PLP Functions These are described in PLP::Functions. PLP Variables $ENV{PLP_NAME} The URI of the PLP document, without the query string. (Example: "/foo.plp") $ENV{PLP_FILENAME} The filename of the PLP document. (Example: "/var/www/index.plp") $PLP::VERSION The version of PLP. $PLP::DEBUG Controls debugging output, and should be treated as a bitmask. The least significant bit (1) controls if run-time error messages are reported to the browser, the second bit (2) controls if headers are sent twice, so they get displayed in the browser. A value of 3 means both features are enabled. The default value is 1. $PLP::ERROR Contains a reference to the code that is used to report run-time errors. You can override this to have it in your own design, and you could even make it report errors by e-mail. The sub reference gets two arguments: the error message as plain text and the error message with special characters encoded with HTML entities. %header, %cookie, %get, %post, %fields These are described in PLP::Fields. (mod_perl only) PerlSetVar configuration directives PLPcache Sets caching On/Off. When caching, PLP saves your script in memory and doesn't re-read and re-parse it if it hasn't changed. PLP will use more memory, but will also run 50% faster. On is default, anything that isn't =~ /^off$/i is considered On. Things that you should know about Not only syntax is important, you should also be aware of some other important features. Your script runs inside the package "PLP::Script" and shouldn't leave it. This is because when your script ends, all global variables in the "PLP::Script" package are destroyed, which is very important if you run under mod_perl (they would retain their values if they weren't explicitly destroyed). Until your first output, you are printing to a tied filehandle "PLPOUT". On first output, headers are sent to the browser and "STDOUT" is selected for efficiency. To set headers, you must assign to $header{ $header_name} before any output. This means the opening "<:" have to be the first characters in your document, without any whitespace in front of them. If you start output and try to set headers later, an error message will appear telling you on which line your output started. Because the interpreter that mod_perl uses never ends, "END { }" blocks won't work properly. You should use "PLP_END { };" instead. Note that this is a not a built-in construct, so it needs proper termination with a semi-colon (as do and ). Under mod_perl, modules are loaded only once. A good modular design can improve performance because of this, but you will have to reload the modules yourself when there are newer versions. The special hashes are tied hashes and do not always behave the way you expect, especially when mixed with modules that expect normal CGI environments, like Read PLP::Fields for information more about this. FAQ A lot of questions are asked often, so before asking yours, please read the FAQ at PLP::FAQ. NO WARRANTY No warranty, no guarantees. Use PLP at your own risk, as I disclaim all responsibility. AUTHOR Juerd Waalboer SEE ALSO PLP::Functions, PLP::Fields, PLP::FAQ