GNU Web

The GNU Web project is an enhancement to autoconf and automake. This is a collection of M4 macros and Perl utilities to automatically produce Makefile for software packages of non-native run-times:

The current release 0.2.0 supports:

• PHP runtime
• W3C complaint object such as javascripts, stylesheet, etc.

Introduction

The autotools is well-know tools for producing shell scripts that automatically configure, build, and install software. These tools has build-in support for various native and non-native run-times such as C, C++, Erlang, Fortran, and many other. However, its do not support run-times mostly used for Web applications development. The support of additional run-time within the Autotools could be enabled through additional macros and Makefile rules.

The collection macroses provided by GNU Web project is an extension to autoconf and automake. You have to simply use macros within configure.ac and Makefile.am as the result your configure and build software through GNU Build System

   ./configure
   make
   make install

In addition to use cases supported by Autotools, this project supports:

• Check for programs required to build sources of non-native runtime.
• Check for libraries and other dependencies required to build and run non-native application.
• Write Makefile rules to enable runtime support via GNU Build System.
• Convert config.h into runtime complaint syntax.
• Defines additional directory variables.
• Supported VPATH enables parallel builds for development, staging and production environments.
• Rolling-out binaries as tarballs.

Writing configure.ac

A configure script for a software package is generated from configure.ac (See autoconf manual). Tedious coding of configure script becomes straight forward with help of GNU Web project, you have to just reference M4 macros following standard configure.ac layout:

Example: configure.ac

   AC_INIT([package], [version], [bug-report])
   AM_INIT_AUTOMAKE
   #
   # check for programs
   ACX_PREFIX
   ACX_PHP
   #
   # check for libraries
   ACX_CHECK_PHP_LIB([libxyz.php])
   #
   # check for optional features
   ACX_FEATURE([fea]) 
   #
   # define Makefile rules
   AMX_PHP
   #
   # output configuration
   AM_CONFIG_HEADER(config.h)
   AC_OUTPUT(\
      Makefile \
      src/Makefile \
   )
   ACX_DONE

Note: M4 macros provided by GNU Web project utilizes following prefixes:

• ACX_XXX expanded into sequence of shell operation used within configure script.
• AMX_XXX outputs Makefile rules

Check for programs (configure runtime)

The project defines a single macro to encapsulate sequence of actions, required to configure a runtime.

Macro: ACX_PHP

Checks for php, php-cgi programs and set corresponding variables; defines directory variables: libphpdir, wwwdir and staticdir.

Macro: ACX_W3C

Checks for either yuicompressor or jsmin; define directory variables: libjsdir.

Check for libraries (manage dependencies)

The following macros check for the precence of non-native runtime libraries and defines variable into config.h and Makefile.

Macro: ACX_CHECK_PHP_LIB(library, [action-if-found], [action-if-not-found])

Checks if library exists in default PHP path, libphpdir or nested packages. Defines Makefile and config.h variable HAVE_library

Macro: ACX_CHECK_JS_LIB(library, [action-if-found], [action-if-not-found], [link-to-dir])

Checks if library exists in libjsdir; defines Makefile and config.h variable HAVE_library; creates a symbolic link into link-to-dir (usefull feature for widget developers).

Define Makefile rules

The following macros encapsulate Makefile rules and outputs them into aminclude.am during software configuration. Later on aminclude.am referenced from Makefile via include directive.

Macro: AMX_PHP

defines rules to validate syntax of php files; index.php creation for web application; converts config.h into php syntax and assembles multiple files into php library.

Macro: AMX_W3C

defines rules to minify javascript and stylesheet files; converts config.h into javascript syntax and assembles multiple javascript/stylesheet files into single library.

Macro: AMX_TARBALL

define a new make target make tarball. In contrast to make dist, it creates a package-version-bin.tgz from all installable objects. The created package is usable for further installation across cluster nodes by single command tar -C / -xzvf package-version-bin.tgz

Helper macros

Macro: ACX_PREFIX

copies ${ac_default_prefix} into ${ac_prefix} if --prefix options is not defined.

Macro: ACX_FEATURE

defines a optional feature configurable via command-line options of ./configure --enable-feature. The macros performs routine to defines command line arguments, validates user input, define a Makefile and config.h variables.

Macro: ACX_ROOT_PACKAGE

helper script for nested package management

Macro: ACX_PACKAGE

helper script for nested package management

Output variable

Directory variables

We extends default folders hierarchy for software installation, that is denoted by GNU Coding Standards. The following variables specified the directory for non-native runtime packages installation. The default value of directory variables could be altered from command line arguments of configure script.

   ./configure --libdir=/var/local/lib wwwdir=/var/www/html
   
   Note: 
      In contrast with default directory variables front dash symbols are skipped. 
      Runtime dir variables are implemented via environment variables. 

The directory variables could be referenced in make and automake scripts:

   #Makefile.am
   www_DATA = index.html
   
   #Makefile
   copy: index.html
      cp $^ $(wwwdir)

PHP

Variable: libphpdir

The directory for installing PHP code libraries (default $libdir/php).

Variable: wwwdir

The directory for installing dynamic objects, accessible via web server (default $prefix/var/www)

Variable: staticdir

The directory for installing static objects, accessible via web server (default $wwwdir/static)..

W3C

Variable: libjsdir

The directory for installing Javascript code libraries (default of $libdir/js).

Other variable

Variable: have_xxx

automatically defined into Makefile and config.h for each configurable feature, library or nested package.

Configuration Header File

Source code pre-processor available in C allows conditional compilation to adapt they code depending on system configuration. Non-native runtime extends these possibility to perform code adaptation at runtime. GNU Build System scans system configuration and outputs result into config.h. GNU Web project has built-in mechanism to convert config.h file into format acceptable by non-native runtime.

PHP

Converts config.h into PHP class, where each #define macro is translated into static public variable:

   <?php
   class libxyz
   {
        static public $PACKAGE_URL = "";
        static public $PACKAGE = "xyz";
        static public $PACKAGE_BUGREPORT = "...";
        static public $PACKAGE_STRING = "xyz 1.0";
        static public $VERSION = "1.0";
        static public $PACKAGE_VERSION = "1.0";
        static public $PACKAGE_TARNAME = "xyz";
        static public $PACKAGE_NAME = "xyz";
        ...
        static public $HAVE_FEA_XYZ = 1;
   }
   ?>

It enables a runtime check for desired configuration

   if(libxyz::$HAVE_FEA_XYZ)
      print "Feature XYZ is on";
   else
      print "Feature XYZ is off";

W3C

Converts config.h into javascript class, where each #define macro is translated into static public variable:

   var libxyz = {
        PACKAGE_URL : "",
        PACKAGE : "xyz",
        PACKAGE_STRING : "xyz 1.0",
        PACKAGE_VERSION : "1.0",
        PACKAGE_TARNAME : "xyz",
        PACKAGE_BUGREPORT : "...",
        VERSION : "1.0",
        PACKAGE_NAME : "xyz",
        ...
        HAVE_FEA_XYZ : 1
   }

It enables a runtime check for desired configuration

   if(libxyz.HAVE_FEA_XYZ)
      alert("Feature XYZ is on");
   else
      alert("Feature XYZ is off");

See also

1. GNUWeb HowTo
2. autoconf manual
3. automake manual