mistpark 2.0 infrasturcture lands

1 files changed, 135 insertions, 0 deletions

diff --git a/library/HTMLPurifier/Filter/ExtractStyleBlocks.php b/library/HTMLPurifier/Filter/ExtractStyleBlocks.php
new file mode 100644
index 000000000..bbf78a663
--- /dev/null
+++ b/library/HTMLPurifier/Filter/ExtractStyleBlocks.php
@@ -0,0 +1,135 @@
+<?php
+
+/**
+ * This filter extracts <style> blocks from input HTML, cleans them up
+ * using CSSTidy, and then places them in $purifier->context->get('StyleBlocks')
+ * so they can be used elsewhere in the document.
+ *
+ * @note
+ *      See tests/HTMLPurifier/Filter/ExtractStyleBlocksTest.php for
+ *      sample usage.
+ *
+ * @note
+ *      This filter can also be used on stylesheets not included in the
+ *      document--something purists would probably prefer. Just directly
+ *      call HTMLPurifier_Filter_ExtractStyleBlocks->cleanCSS()
+ */
+class HTMLPurifier_Filter_ExtractStyleBlocks extends HTMLPurifier_Filter
+{
+
+    public $name = 'ExtractStyleBlocks';
+    private $_styleMatches = array();
+    private $_tidy;
+
+    public function __construct() {
+        $this->_tidy = new csstidy();
+    }
+
+    /**
+     * Save the contents of CSS blocks to style matches
+     * @param $matches preg_replace style $matches array
+     */
+    protected function styleCallback($matches) {
+        $this->_styleMatches[] = $matches[1];
+    }
+
+    /**
+     * Removes inline <style> tags from HTML, saves them for later use
+     * @todo Extend to indicate non-text/css style blocks
+     */
+    public function preFilter($html, $config, $context) {
+        $tidy = $config->get('Filter.ExtractStyleBlocks.TidyImpl');
+        if ($tidy !== null) $this->_tidy = $tidy;
+        $html = preg_replace_callback('#<style(?:\s.*)?>(.+)</style>#isU', array($this, 'styleCallback'), $html);
+        $style_blocks = $this->_styleMatches;
+        $this->_styleMatches = array(); // reset
+        $context->register('StyleBlocks', $style_blocks); // $context must not be reused
+        if ($this->_tidy) {
+            foreach ($style_blocks as &$style) {
+                $style = $this->cleanCSS($style, $config, $context);
+            }
+        }
+        return $html;
+    }
+
+    /**
+     * Takes CSS (the stuff found in <style>) and cleans it.
+     * @warning Requires CSSTidy <http://csstidy.sourceforge.net/>
+     * @param $css     CSS styling to clean
+     * @param $config  Instance of HTMLPurifier_Config
+     * @param $context Instance of HTMLPurifier_Context
+     * @return Cleaned CSS
+     */
+    public function cleanCSS($css, $config, $context) {
+        // prepare scope
+        $scope = $config->get('Filter.ExtractStyleBlocks.Scope');
+        if ($scope !== null) {
+            $scopes = array_map('trim', explode(',', $scope));
+        } else {
+            $scopes = array();
+        }
+        // remove comments from CSS
+        $css = trim($css);
+        if (strncmp('<!--', $css, 4) === 0) {
+            $css = substr($css, 4);
+        }
+        if (strlen($css) > 3 && substr($css, -3) == '-->') {
+            $css = substr($css, 0, -3);
+        }
+        $css = trim($css);
+        $this->_tidy->parse($css);
+        $css_definition = $config->getDefinition('CSS');
+        foreach ($this->_tidy->css as $k => $decls) {
+            // $decls are all CSS declarations inside an @ selector
+            $new_decls = array();
+            foreach ($decls as $selector => $style) {
+                $selector = trim($selector);
+                if ($selector === '') continue; // should not happen
+                if ($selector[0] === '+') {
+                    if ($selector !== '' && $selector[0] === '+') continue;
+                }
+                if (!empty($scopes)) {
+                    $new_selector = array(); // because multiple ones are possible
+                    $selectors = array_map('trim', explode(',', $selector));
+                    foreach ($scopes as $s1) {
+                        foreach ($selectors as $s2) {
+                            $new_selector[] = "$s1 $s2";
+                        }
+                    }
+                    $selector = implode(', ', $new_selector); // now it's a string
+                }
+                foreach ($style as $name => $value) {
+                    if (!isset($css_definition->info[$name])) {
+                        unset($style[$name]);
+                        continue;
+                    }
+                    $def = $css_definition->info[$name];
+                    $ret = $def->validate($value, $config, $context);
+                    if ($ret === false) unset($style[$name]);
+                    else $style[$name] = $ret;
+                }
+                $new_decls[$selector] = $style;
+            }
+            $this->_tidy->css[$k] = $new_decls;
+        }
+        // remove stuff that shouldn't be used, could be reenabled
+        // after security risks are analyzed
+        $this->_tidy->import = array();
+        $this->_tidy->charset = null;
+        $this->_tidy->namespace = null;
+        $css = $this->_tidy->print->plain();
+        // we are going to escape any special characters <>& to ensure
+        // that no funny business occurs (i.e. </style> in a font-family prop).
+        if ($config->get('Filter.ExtractStyleBlocks.Escaping')) {
+            $css = str_replace(
+                array('<',    '>',    '&'),
+                array('\3C ', '\3E ', '\26 '),
+                $css
+            );
+        }
+        return $css;
+    }
+
+}
+
+// vim: et sw=4 sts=4