Embperl - Building dynamic Websites with Perl Copyright (c) 1997-2008 Gerald Richter / ecos gmbh www.ecos.de Copyright (c) 2008-2015 Gerald Richter Copyright (c) 2015-2023 actevy.io You may distribute under the terms of either the GNU General Public License or the Artistic License, as specified in the Perl README file. THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. OVERVIEW ======== Embperl gives you the power to embed Perl code in your HTML documents and the ability to build your Web site out of small reusable objects in an object-oriented style. You can also take advantage of all the usual Perl modules, (including DBI for database access) use their functionality and easily include their output in your web pages. Additionally Embperl support including XML, XSLT tranformations and a lot of other sources formats. Embperl has several features which are especially useful for creating HTML, including dynamic tables, form field processing and validation, URL escaping/unescaping, session handling, and more. Embperl is a server-side tool, which means that it's browser-independent. It can run in various ways: under mod_perl, as a CGI script, or offline. For database access, there is a module called DBIx::Recordset, which works well together with Embperl and simplifies creating web pages with database content. DOCUMENTATION ============= The following documentation is available within the distribution Detailed list of documenation: perldoc TOC.pod Features of Embperl: perldoc Features.pod Introduction to basic Embperl: perldoc Intro.pod Introduction to Embperl 2 advanced features: perldoc IntroEmbperl2.pod Introduction to EmbperlObject: perldoc IntroEmbperlObject.pod Installation of Embperl: perldoc INSTALL.pod Full documentation: perldoc Config.pod perldoc Embperl.pod perldoc Embperl/Object.pm perldoc Embperl/Mail.pm perldoc Embperl/Inline.pm Tips and Tricks: perldoc TipsAndTricks.pod Changes: perldoc Changes.pod Examples: eg/README Sourcecode encryption: crypto/README Documentation and example for Embperl::Form can be found at: eg/forms All the above and further information can be found at the Embperl website https://perl.apache.org/embperl/ All the above and further information can be found at the german Embperl website https://www.actevy.io/embperl/ FEATURES ======== * Embperl facilitates embedding Perl code into HTML/XML or other text documents. Perl code is evaluated at the server side and the result is sent to the browser. All available Perl modules can be used without any restriction. * Allows one to build Web sites out of small reusable components in an object-oriented way. Components can call and/or embed each other and inherit from other objects. * Standard layout of a web-site site can be defined once and the content can be dynamically generated by these components based on the uri. The documents need only contain the variable portions but not the common items which define the layout like headers/footers or navigation bars which normally form the template. Also these common elements can be overwritten in each sub-directory. * Embperl 2.0 thus facilitates separating code, layout and creating MVC (Model-View-Controller) applications. Control logic can be moved into an application object, which controls further execution of the request, while the actual pages are containing the display code. Simple applications can still embed all the code in the pages. * Source-code for each component can come from a different source, eg. from file, memory or sub-request which allows one to act on the output from another Apache application like PHP, JSP, CGI Script etc. * Each component can be in a different source format (e.g. HTML, WML, XML, POD, ...) and can be transformed to other output formats, say by using via XSLT. * Supports one or more scripting syntax using Embperl, ASP, Text, Perl and others. * Output generation is divided into small steps where each is processed by a plugable provider. The interaction of the providers can be individually configured for each component via recipes. * Supports caching of intermediate results and output. * Embperl encompasses several features that ease the task of dynamic web-site content generation, including dynamic-tables, form-field-processing, escaping/unescaping, etc. * Contains a module for easy form input validation, which is able to validate user input at the server side and on the client side by one definition of rules. * Handles per-user and per-module persistent session requiring only storage and retrieval of the session data from a special hash. * UTF-8 Support (honours Perl's internal UTF-8 flag during in- and output) * Offers flexible configuration options to suite individual tastes and needs. * Fully integrated into Apache and mod_perl to acheive the best performance. Can also run as a free standing CGI-script, off-line or can be called from another Perl program. * The Perl module DBIx::Recordset offers high level, easy to use database access for Embperl. * Embperl::Mail enables redirecting the result output to a mail-recipient. * Embperl::Inline allows one to embedd Embperl code in normal Perl code * Embperl::Form is a sophisticated library for building HTML forms COMPATIBILITY ============= I have tested Embperl successfully on different linux distributions. Embperl does work on Windows, but is not fully tested there. See perldoc INSTALL.pod for installation instructions. Hints for using Embperl 2.x and higher -------------------------------------- Embperl 2 is totaly rewritten. Most of the Perl code is moved into C to speed up processing. The core is totaly redesigned to give a lot of new possibilities. The Embperl core now works in a totaly different way. The processing of the source towards the output is done by providers. Every provider takes a small step. Which providers are used is defined by a recipe. The standard Embperl recipe contains the following providers: 1 reading the source 2 parsing 3 compiling 4 executing 5 outputing The providers work in a similar way as Unix shell programs which are processing a single source in a pipeline towards the output. In Embperl is is not only a smimple pipeline, but a tree structure, so multiple sources can be incorpoarted in one result. Recipes descripes how providers are executed. Rearrangeing the provideres or writing and useing new ones gives flexibility and power. Addtional to the standard Embperl providers Embperl ships with XML parser and XSLT processor providers. The new execution scheme is also faster, because html tags and metacommands are parsed only once (Perl code was also (and is still) cached in 1.x) My first benchmarks show 50%-100% faster execution under mod_perl compared to Embperl 1.x. Another new feature is that the syntax of the Embperl parser is defined within the module Embperl::Syntax and can be modified as nessecary. Embperl comes with a set of syntax definitons which can be modified by the user. So far there are syntax definitions for SSI, Text only, Perl only, ASP, POD, RTF and a Mail taglib. You can tell Embperl which syntax to use either in the configuration via EMBPERL_SYNTAX, or with the syntax parameter of Execute, or you can change the syntax dynamically inside the page via the [$syntax $] command. You also could specify more then one syntax at the same time, e.g. [$syntax Embperl SSI $] to mix Embperl tags and SSI tags in the same page. If you'd like to create your own syntax read: perldoc Embperl::Syntax and look at the files under Embperl/Syntax/ for examples on how to do it. Also new is the ability to cache (parts of) the output. See the new configuration directives below. Starting with 2.0b6 Embperl provides a set of new object, which allows to access Embperl internals and manipulate the processing. Basicly there are three major objects: - Application - Request - Component The application object is responsible for a set of pages that forms an application. It is used to configure things like session handling and logging which should be unique across these pages. More important it can be overriden and the overriden object can contain the application logic, to create a proper separation of logic and presentation. The request object holds everything which spans a whole (HTTP-)request. The component object is responsible for a single component, inside the desired output. It holds things like sourcefile etc. All three objects have a subobject which holds the configuration and a subobject for it's current parameters. Debugging --------- Starting with 2.0b2 Embperl files can debugged via the interactive debugger. The debugger shows the Embperl page source along with the correct linenumbers. You can do anything you can do inside a normal Perl program via the debugger, e.g. show variables, modify variables, single step, set breakpoints etc. You can use the Perl interacive command line debugger via perl -d embpexec.pl file.epl or if you prefer a graphical debugger, try ddd (https://www.gnu.org/software/ddd/) it's a great tool, also for debugging any other perl script: ddd --debugger 'perl -d embpexec.pl file.epl' NOTE: embpexec.pl could be found in the Embperl source directory If you want to debug your pages, while running under mod_perl, Apache::DB is the right thing. Apache::DB is available from CPAN. The following differences to Embperl 1.x apply: ------------------------------------------------------ - When running under mod_perl you _must_ load Embperl at server startup time. Either with a PerlModule Embperl in your httpd.conf or a use Embperl ; inside of a startup script. You can use the Embperl configuration directives now directly, (without PerlSetEnv/SetEnv). If you still want to use environment varibales to configure Embperl, write Embperl_UseEnv on - Embperl now supports Apache 2 / mod_perl 2, but you need a additional configuration line in your httpd.conf: LoadModule embperl_module /path/to/perl/site/lib/Embperl/Embperl.so - For every container in your httpd.conf (e.g. VirtualHost,Directory,Location) where you want to define any application level configuration directives (see below under tAppConfig for a list), you need to set a unique value for EMBPERL_APPNAME. This is for example necessary for all Embperl::Object parameters. Example: EMBPERL_APPNAME my_embperl_app EMBPERL_OBJECT_BASE base.epl - The following options can currently only be set from httpd.conf: optKeepSpaces - The option optRawInput is replaced by EMBPERL_INPUT_ESCMODE, which is off by default (same as when optRawInput was set in 1.x) - The following options are currently not supported: optRedirectStdout optDisableHtmlScan, optDisableTableScan, optDisableInputScan, optDisableMetaScan optDisableHtmlScan can be replaced by switching the syntax, e.g. [$syntax EmbperlBlocks $] # same as [- $optDisableHtmlScan = 1 -] (here goes your code - Embperl will not interpret any html tags here) [$syntax Embperl $] # same as [- $optDisableHtmlScan = 0 -] - Nesting must be done properly. I.e. you cannot put a tag (for a dynamic table) inside an 'if' and the
inside another 'if'. (That still works for static tables) - optUndefToEmptyValue is always set and cannot be disabled. - [$ foreach $x (@x) $] now requires the brackets around the array (like Perl) - [+ +] blocks must now contain a valid Perl expression. Embperl 1.x allows you to put multiple statements into such a block. For performance reasons this is not possible anymore. Also the expression must _not_ be terminated with a semicolon. To let old code work, just wrap it into a 'do' e.g. [+ do { my $a = $b + 5 ; $a } +] - EMBPERL_INPUT_FUNC and EMBPERL_OUTPUT_FUNC are not supported anymore You can the same result and much more by writing custom provider. - Embperl doesn't change the current working directory anymore to the directory of the source file. This is done for performance reasons and because it won't reliable work with threads under mod_perl 2.0. You can use $req -> component -> cwd to get the directory of the sourcefile (where $req is Embperl request object, which is the first parameter passed to the page i.e. $_[0]) - safe namespaces are not supported anymore, since are are not really safe anyway - errors can be mailed to an administrator - Parameters of SetupSession, CleanupSession and SetSessionCookie have changed. Embperl 1.x compatibility flag ------------------------------ The compatibility flag isn't available anymore in 2.0b6. Since now Embperl 2.0 lives in his own namespace, you can install Embperl 1.x and 2.x on the same machine without conflicts. exit ---- B will override the normal Perl exit in every Embperl document. Calling exit will immediately stop any further processing of that file and send the already-done work to the output/browser. B If you are inside of an Execute, Embperl will only exit this Execute, but the file which called the file containing the exit with Execute will continue. If you want to exit the whole request, call exit with an argument e.g. exit (200) B If you write a module which should work with Embperl under mod_perl, you must use Embperl::exit instead of the normal Perl exit. (In 1.3.x it was Apache::Exit) FEEDBACK and BUG REPORTS ======================== Please let me know if you use or test this module. Bugs, questions, suggestions for things you would find useful, etc., are discussed on the Embperl mailing list. The Embperl mailing list (embperl@perl.apache.org) is available for Embperl users and developers to share ideas, solve problems and discuss things related to Embperl To subscribe to this list, send mail to embperl-subscribe@perl.apache.org. To unsubscribe send email to embperl-unsubscribe@perl.apache.org . There is an archive for the Embperl mailing list at https://mail-archives.apache.org/mod_mbox/perl-embperl For mod_perl related questions you may search the mod_perl mailing list archive at https://mail-archives.apache.org/mod_mbox/perl-modperl AUTHOR ====== G. Richter (richter at embperl dot org)