plugins/markdown/markdown.php

   1 <?php
   2
   3 /**
   4  * Plugin Markdown.
   5  *
   6  * Shaare's descriptions are parsed with Markdown.
   7  */
   8
   9 use Shaarli\Config\ConfigManager;
  10
  11 /*
  12  * If this tag is used on a shaare, the description won't be processed by Parsedown.
  13  */
  14 define('NO_MD_TAG', 'nomarkdown');
  15
  16 /**
  17  * Parse linklist descriptions.
  18  *
  19  * @param array         $data linklist data.
  20  * @param ConfigManager $conf instance.
  21  *
  22  * @return mixed linklist data parsed in markdown (and converted to HTML).
  23  */
  24 function hook_markdown_render_linklist($data, $conf)
  25 {
  26     foreach ($data['links'] as &$value) {
  27         if (!empty($value['tags']) && noMarkdownTag($value['tags'])) {
  28             $value = stripNoMarkdownTag($value);
  29             continue;
  30         }
  31         $value['description'] = process_markdown(
  32             $value['description'],
  33             $conf->get('security.markdown_escape', true),
  34             $conf->get('security.allowed_protocols')
  35         );
  36     }
  37     return $data;
  38 }
  39
  40 /**
  41  * Parse feed linklist descriptions.
  42  *
  43  * @param array $data linklist data.
  44  * @param ConfigManager $conf instance.
  45  *
  46  * @return mixed linklist data parsed in markdown (and converted to HTML).
  47  */
  48 function hook_markdown_render_feed($data, $conf)
  49 {
  50     foreach ($data['links'] as &$value) {
  51         if (!empty($value['tags']) && noMarkdownTag($value['tags'])) {
  52             $value = stripNoMarkdownTag($value);
  53             continue;
  54         }
  55         $value['description'] = reverse_feed_permalink($value['description']);
  56         $value['description'] = process_markdown(
  57             $value['description'],
  58             $conf->get('security.markdown_escape', true),
  59             $conf->get('security.allowed_protocols')
  60         );
  61     }
  62
  63     return $data;
  64 }
  65
  66 /**
  67  * Parse daily descriptions.
  68  *
  69  * @param array         $data daily data.
  70  * @param ConfigManager $conf instance.
  71  *
  72  * @return mixed daily data parsed in markdown (and converted to HTML).
  73  */
  74 function hook_markdown_render_daily($data, $conf)
  75 {
  76     //var_dump($data);die;
  77     // Manipulate columns data
  78     foreach ($data['linksToDisplay'] as &$value) {
  79         if (!empty($value['tags']) && noMarkdownTag($value['tags'])) {
  80             $value = stripNoMarkdownTag($value);
  81             continue;
  82         }
  83         $value['formatedDescription'] = process_markdown(
  84             $value['formatedDescription'],
  85             $conf->get('security.markdown_escape', true),
  86             $conf->get('security.allowed_protocols')
  87         );
  88     }
  89
  90     return $data;
  91 }
  92
  93 /**
  94  * Check if noMarkdown is set in tags.
  95  *
  96  * @param string $tags tag list
  97  *
  98  * @return bool true if markdown should be disabled on this link.
  99  */
 100 function noMarkdownTag($tags)
 101 {
 102     return preg_match('/(^|\s)'. NO_MD_TAG .'(\s|$)/', $tags);
 103 }
 104
 105 /**
 106  * Remove the no-markdown meta tag so it won't be displayed.
 107  *
 108  * @param array $link Link data.
 109  *
 110  * @return array Updated link without no markdown tag.
 111  */
 112 function stripNoMarkdownTag($link)
 113 {
 114     if (! empty($link['taglist'])) {
 115         $offset = array_search(NO_MD_TAG, $link['taglist']);
 116         if ($offset !== false) {
 117             unset($link['taglist'][$offset]);
 118         }
 119     }
 120
 121     if (!empty($link['tags'])) {
 122         str_replace(NO_MD_TAG, '', $link['tags']);
 123     }
 124
 125     return $link;
 126 }
 127
 128 /**
 129  * When link list is displayed, include markdown CSS.
 130  *
 131  * @param array $data includes data.
 132  *
 133  * @return mixed - includes data with markdown CSS file added.
 134  */
 135 function hook_markdown_render_includes($data)
 136 {
 137     if ($data['_PAGE_'] == Router::$PAGE_LINKLIST
 138         || $data['_PAGE_'] == Router::$PAGE_DAILY
 139         || $data['_PAGE_'] == Router::$PAGE_EDITLINK
 140     ) {
 141
 142         $data['css_files'][] = PluginManager::$PLUGINS_PATH . '/markdown/markdown.css';
 143     }
 144
 145     return $data;
 146 }
 147
 148 /**
 149  * Hook render_editlink.
 150  * Adds an help link to markdown syntax.
 151  *
 152  * @param array $data data passed to plugin
 153  *
 154  * @return array altered $data.
 155  */
 156 function hook_markdown_render_editlink($data)
 157 {
 158     // Load help HTML into a string
 159     $txt = file_get_contents(PluginManager::$PLUGINS_PATH .'/markdown/help.html');
 160     $translations = [
 161         t('Description will be rendered with'),
 162         t('Markdown syntax documentation'),
 163         t('Markdown syntax'),
 164     ];
 165     $data['edit_link_plugin'][] = vsprintf($txt, $translations);
 166     // Add no markdown 'meta-tag' in tag list if it was never used, for autocompletion.
 167     if (! in_array(NO_MD_TAG, $data['tags'])) {
 168         $data['tags'][NO_MD_TAG] = 0;
 169     }
 170
 171     return $data;
 172 }
 173
 174
 175 /**
 176  * Remove HTML links auto generated by Shaarli core system.
 177  * Keeps HREF attributes.
 178  *
 179  * @param string $description input description text.
 180  *
 181  * @return string $description without HTML links.
 182  */
 183 function reverse_text2clickable($description)
 184 {
 185     $descriptionLines = explode(PHP_EOL, $description);
 186     $descriptionOut = '';
 187     $codeBlockOn = false;
 188     $lineCount = 0;
 189
 190     foreach ($descriptionLines as $descriptionLine) {
 191         // Detect line of code: starting with 4 spaces,
 192         // except lists which can start with +/*/- or `2.` after spaces.
 193         $codeLineOn = preg_match('/^    +(?=[^\+\*\-])(?=(?!\d\.).)/', $descriptionLine) > 0;
 194         // Detect and toggle block of code
 195         if (!$codeBlockOn) {
 196             $codeBlockOn = preg_match('/^```/', $descriptionLine) > 0;
 197         }
 198         elseif (preg_match('/^```/', $descriptionLine) > 0) {
 199             $codeBlockOn = false;
 200         }
 201
 202         $hashtagTitle = ' title="Hashtag [^"]+"';
 203         // Reverse `inline code` hashtags.
 204         $descriptionLine = preg_replace(
 205             '!(`[^`\n]*)<a href="[^ ]*"'. $hashtagTitle .'>([^<]+)</a>([^`\n]*`)!m',
 206             '$1$2$3',
 207             $descriptionLine
 208         );
 209
 210         // Reverse all links in code blocks, only non hashtag elsewhere.
 211         $hashtagFilter = (!$codeBlockOn && !$codeLineOn) ? '(?!'. $hashtagTitle .')': '(?:'. $hashtagTitle .')?';
 212         $descriptionLine = preg_replace(
 213             '#<a href="[^ ]*"'. $hashtagFilter .'>([^<]+)</a>#m',
 214             '$1',
 215             $descriptionLine
 216         );
 217
 218         $descriptionOut .= $descriptionLine;
 219         if ($lineCount++ < count($descriptionLines) - 1) {
 220             $descriptionOut .= PHP_EOL;
 221         }
 222     }
 223     return $descriptionOut;
 224 }
 225
 226 /**
 227  * Remove <br> tag to let markdown handle it.
 228  *
 229  * @param string $description input description text.
 230  *
 231  * @return string $description without <br> tags.
 232  */
 233 function reverse_nl2br($description)
 234 {
 235     return preg_replace('!<br */?>!im', '', $description);
 236 }
 237
 238 /**
 239  * Remove HTML spaces '&nbsp;' auto generated by Shaarli core system.
 240  *
 241  * @param string $description input description text.
 242  *
 243  * @return string $description without HTML links.
 244  */
 245 function reverse_space2nbsp($description)
 246 {
 247     return preg_replace('/(^| )&nbsp;/m', '$1 ', $description);
 248 }
 249
 250 function reverse_feed_permalink($description)
 251 {
 252     return preg_replace('@&#8212; <a href="([^"]+)" title="[^"]+">(\w+)</a>$@im', '&#8212; [$2]($1)', $description);
 253 }
 254
 255 /**
 256  * Replace not whitelisted protocols with http:// in given description.
 257  *
 258  * @param string $description      input description text.
 259  * @param array  $allowedProtocols list of allowed protocols.
 260  *
 261  * @return string $description without malicious link.
 262  */
 263 function filter_protocols($description, $allowedProtocols)
 264 {
 265     return preg_replace_callback(
 266         '#]\((.*?)\)#is',
 267         function ($match) use ($allowedProtocols) {
 268             return ']('. whitelist_protocols($match[1], $allowedProtocols) .')';
 269         },
 270         $description
 271     );
 272 }
 273
 274 /**
 275  * Remove dangerous HTML tags (tags, iframe, etc.).
 276  * Doesn't affect <code> content (already escaped by Parsedown).
 277  *
 278  * @param string $description input description text.
 279  *
 280  * @return string given string escaped.
 281  */
 282 function sanitize_html($description)
 283 {
 284     $escapeTags = array(
 285         'script',
 286         'style',
 287         'link',
 288         'iframe',
 289         'frameset',
 290         'frame',
 291     );
 292     foreach ($escapeTags as $tag) {
 293         $description = preg_replace_callback(
 294             '#<\s*'. $tag .'[^>]*>(.*</\s*'. $tag .'[^>]*>)?#is',
 295             function ($match) { return escape($match[0]); },
 296             $description);
 297     }
 298     $description = preg_replace(
 299         '#(<[^>]+\s)on[a-z]*="?[^ "]*"?#is',
 300         '$1',
 301         $description);
 302     return $description;
 303 }
 304
 305 /**
 306  * Render shaare contents through Markdown parser.
 307  *   1. Remove HTML generated by Shaarli core.
 308  *   2. Reverse the escape function.
 309  *   3. Generate markdown descriptions.
 310  *   4. Sanitize sensible HTML tags for security.
 311  *   5. Wrap description in 'markdown' CSS class.
 312  *
 313  * @param string $description input description text.
 314  * @param bool   $escape      escape HTML entities
 315  *
 316  * @return string HTML processed $description.
 317  */
 318 function process_markdown($description, $escape = true, $allowedProtocols = [])
 319 {
 320     $parsedown = new Parsedown();
 321
 322     $processedDescription = $description;
 323     $processedDescription = reverse_nl2br($processedDescription);
 324     $processedDescription = reverse_space2nbsp($processedDescription);
 325     $processedDescription = reverse_text2clickable($processedDescription);
 326     $processedDescription = filter_protocols($processedDescription, $allowedProtocols);
 327     $processedDescription = unescape($processedDescription);
 328     $processedDescription = $parsedown
 329         ->setMarkupEscaped($escape)
 330         ->setBreaksEnabled(true)
 331         ->text($processedDescription);
 332     $processedDescription = sanitize_html($processedDescription);
 333
 334     if(!empty($processedDescription)){
 335         $processedDescription = '<div class="markdown">'. $processedDescription . '</div>';
 336     }
 337
 338     return $processedDescription;
 339 }
 340
 341 /**
 342  * This function is never called, but contains translation calls for GNU gettext extraction.
 343  */
 344 function markdown_dummy_translation()
 345 {
 346     // meta
 347     t('Render shaare description with Markdown syntax.<br><strong>Warning</strong>:
 348 If your shaared descriptions contained HTML tags before enabling the markdown plugin,
 349 enabling it might break your page.
 350 See the <a href="https://github.com/shaarli/Shaarli/tree/master/plugins/markdown#html-rendering">README</a>.');
 351 }