Extension:Gnuplot

require_once('extensions/gnuplot.php');

<?php
/**
 * Parser hook extension adds a <gnuplot> tag and <dataset> tag to wiki markup for rendering gnuplot plots!
 * 
 * 
 * Usage is something like this:
 * <gnuplot>
 * set title "Text"
 * set yrange [0:60]
 * set xtics (0,1,2,3,4,5,6,7,8,9,10)
 * set xrange [0:10]
 * plot <dataset>0 1
 * 2 10
 * 3 15
 * </dataset> using 1:2 title "Burndown" with lines
 * </gnuplot>
 * 
 * Options should be heroicly wide open.. if you can wrap your head around all the possibilities listed in the
 * gnuplot documentation. 
 * 
 **/
 
// Make sure we are being called properly
if( !defined( 'MEDIAWIKI' ) ) {
        echo(" This file is an extension to the MediaWiki software and cannot be used standalone.\n" );
        die( -1 );
}
 
$wgExtensionFunctions[] = "wfGnuplotExtension";
 
/**
 * You should refer to the gnuplot documentation for the different output types
 * Honestly, only image types will work without some other changes
 */
$image_format = "png";
$gnuplot_path   = "/usr/bin/gnuplot";
 
/**
 * The function links its methods as
 * hooks for the Parser
 */
function wfGnuplotExtension() {
        global $wgParser;
        # register the extension with the WikiText parser
        # the first parameter is the name of the new tag.
        # the second parameter is the callback function for
        # processing the text between the tags
        $wgParser->setHook( "dataset", "saveDATA" );
        $wgParser->setHook( "gnuplot", "renderPLOT" );
}
 
 
/**
 * This method setups up the output of the plot script, which 
 * has a few things that we dont want to repeat EVERYTIME someone 
 * wants to make a graph
 *
 * @param String $plot_source - we have to have the full source to wrap
 * @param String $output_filename - we have to tell gnuplot where to output the graph
 * @return the script with output stuff wrapped in it
 */
function wrap_script($plot_source, $output_filename) {
        global $image_format;
        $something  = "set terminal ".$image_format."\n";
        $something .= "set output \"".$output_filename."\"\n";
        $something .= $plot_source;
        return $something;
}
 
/**
 * Caches the command script and calls the gnuplot executable to render the
 * graph image
 *
 * @param String $plot_script
 * @return Nothing.. we assume this all goes correctly.
 */
function renderGnuPlot(&$plot_script) {
        global
        $wgMathDirectory,
        $wgMathPath,
        $wgTmpDirectory,
        $image_format,
        $gnuplot_path;
 
 
        // hash our script
        $script_hash = md5($plot_script);
        // make the output of the command be in the math directory
        $filename = $wgMathDirectory."/plot-".$script_hash.".".$image_format;
 
        //fill in the extras our consumer doesn't care about
        $full_plot_script = wrap_script($plot_script,$filename);
 
        $current_dir = getcwd();
 
        chdir($wgTmpDirectory);
 
        // create temporary file for the plot script
        $winPath = $wgTmpDirectory."/".$script_hash.".plot";
        $fp = fopen($winPath,"a+");
        $w= fputs($fp,$full_plot_script);
        fclose($fp);
 
        // run gnuplot to create our file
        $command = $gnuplot_path." ".$script_hash.".plot ";
        //I had a problem with the status code always being false. so, stopped using it
        $status_code = exec($command);
 
        //delete the plot file
        unlink($wgTmpDirectory."/".$script_hash.".plot");
        chdir($current_dir);
}
 
 
/**
 * Determins if a graph file has already been rendered
 * if not, calls to render one and returns the root host url to the image. 
 *
 * @param String $plot_script
 * @return images/math/plot-.... file reference for the image tag
 */
function getPlotImageURL($plot_script) {
        global
        $wgMathDirectory,
        $wgMathPath,
        $image_format;
 
        //unique our script
        $formula_hash = md5($plot_script);
 
        $filename = 'plot-' . $formula_hash.".".$image_format;
        $full_path_filename = $wgMathDirectory."/".$filename;
 
        if (is_file($full_path_filename)) {
                //nothing to do
                //we've already made this image before
        } else {
                renderGnuPlot($plot_script);
        }
        return $wgMathPath."/".$filename;
}
 
/**
 * The callback function for converting the input text to HTML output
 *
 * @param String $input
 * @param Array<String> $argv
 * @param Parser $parser
 * @return HTML image tag to the graph itself
 */
function renderPLOT( &$input, $argv, &$parser ) {
        //get our parser to finish up its parse and recover the real data-set data (the UNIQ QINU problem)
        $input = $parser->recursiveTagParse( $input );
        $input = $parser->mStripState->unstripBoth($input);
        $url = getPlotImageURL($input);
 
        return "<img src='$url'>";
 
}
 
/**
 * This method takes in the raw tuple input of the dataset, and any arguments, and saves it to a random
 * file on the system. The return is the absolute path to the data file, so that it can be 
 * embedded into the plot command.
 *
 * @param String $input
 * @param Array<String> $argv
 * @param Parser $parser
 * @return unknown
 */
function saveDATA( $input, $argv, &$parser){
        global
        $wgMathDirectory,
        $wgMathPath,
        $wgTmpDirectory;
 
        //make a temp filename with a hash of the input
        $filename = md5($input);
        //we dont wanna create toooo many of these guys either
        if (!is_file($wgTmpDirectory."/".$filename.".dat")) {
                //know where we are
                $current_dir = getcwd();
                //than change it
                chdir($wgTmpDirectory);
 
                // saving this data set as a temporary RANDOM file
                $winPath = $wgTmpDirectory."/".$filename.".dat";
                $fp = fopen($winPath,"a+");
                $w=fputs($fp,$input);
                fclose($fp);
 
                chdir($current_dir);
        }         
        return "\"".$wgTmpDirectory."/".$filename.".dat\"";
}
 
?>