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Add basic markdown html sanitizer (#116)
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|---|---|---|
| @@ -0,0 +1,234 @@ | ||
| module html | ||
|
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||
| import maps | ||
| import net.html as net_html | ||
| import net.urllib | ||
|
|
||
| const allowed_tags = [ | ||
| 'h1', | ||
| 'h2', | ||
| 'h3', | ||
| 'h4', | ||
| 'h5', | ||
| 'h6', | ||
| 'h7', | ||
| 'h8', | ||
| 'br', | ||
| 'b', | ||
| 'i', | ||
| 'strong', | ||
| 'em', | ||
| 'a', | ||
| 'pre', | ||
| 'code', | ||
| 'img', | ||
| 'tt', | ||
| 'div', | ||
| 'ins', | ||
| 'del', | ||
| 'sup', | ||
| 'sub', | ||
| 'p', | ||
| 'ol', | ||
| 'ul', | ||
| 'text', | ||
| 'table', | ||
| 'thead', | ||
| 'tbody', | ||
| 'tfoot', | ||
| 'blockquote', | ||
| 'dl', | ||
| 'dt', | ||
| 'dd', | ||
| 'kbd', | ||
| 'q', | ||
| 'samp', | ||
| 'var', | ||
| 'hr', | ||
| 'ruby', | ||
| 'rt', | ||
| 'rp', | ||
| 'li', | ||
| 'tr', | ||
| 'td', | ||
| 'th', | ||
| 's', | ||
| 'strike', | ||
| 'summary', | ||
| 'details', | ||
| ]! | ||
|
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| const allowed_attributes = [ | ||
| 'abbr', | ||
| 'accept', | ||
| 'accept-charset', | ||
| 'accesskey', | ||
| 'action', | ||
| 'align', | ||
| 'alt', | ||
| 'axis', | ||
| 'border', | ||
| 'class', | ||
| 'cellpadding', | ||
| 'cellspacing', | ||
| 'char', | ||
| 'charoff', | ||
| 'charset', | ||
| 'checked', | ||
| 'clear', | ||
| 'cols', | ||
| 'colspan', | ||
| 'color', | ||
| 'compact', | ||
| 'coords', | ||
| 'datetime', | ||
| 'dir', | ||
| 'disabled', | ||
| 'enctype', | ||
| 'for', | ||
| 'frame', | ||
| 'headers', | ||
| 'height', | ||
| 'hreflang', | ||
| 'hspace', | ||
| 'ismap', | ||
| 'label', | ||
| 'lang', | ||
| 'maxlength', | ||
| 'media', | ||
| 'method', | ||
| 'multiple', | ||
| 'name', | ||
| 'nohref', | ||
| 'noshade', | ||
| 'nowrap', | ||
| 'open', | ||
| 'prompt', | ||
| 'readonly', | ||
| 'rel', | ||
| 'rev', | ||
| 'rows', | ||
| 'rowspan', | ||
| 'rules', | ||
| 'scope', | ||
| 'selected', | ||
| 'shape', | ||
| 'size', | ||
| 'span', | ||
| 'start', | ||
| 'summary', | ||
| 'tabindex', | ||
| 'target', | ||
| 'title', | ||
| 'type', | ||
| 'usemap', | ||
| 'valign', | ||
| 'value', | ||
| 'vspace', | ||
| 'width', | ||
| 'itemprop', | ||
| ]! | ||
|
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| pub fn sanitize(text string) string { | ||
| dom := net_html.parse(text) | ||
|
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| mut root := dom.get_root() | ||
| if root == unsafe { nil } { | ||
| return '' | ||
| } | ||
|
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| for t in root.children { | ||
| traverse_and_sanitize(&t) | ||
| } | ||
|
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| unsafe { | ||
| root.children = root.children.filter(it != nil) | ||
| } | ||
| return root.str() | ||
| } | ||
|
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| fn traverse_and_sanitize(tag &&net_html.Tag) { | ||
| if tag.name == 'br' { | ||
| unsafe { | ||
| tag.close_type = .in_name | ||
| } | ||
| } | ||
|
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| // Filter allowed tags | ||
| if tag.name !in html.allowed_tags { | ||
| match true { | ||
| tag.name == 'input' && tag.attributes['type'] == 'checkbox' {} | ||
| else { | ||
| println('met ${tag.name} EXTERMINATE') | ||
| unsafe { | ||
| *tag = nil | ||
| } | ||
| return | ||
| } | ||
| } | ||
| } | ||
|
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||
| // Filter allowed attributes | ||
| unsafe { | ||
| match true { | ||
| // Filter protocols for a with href | ||
| tag.name == 'a' { | ||
| mut attributes := map[string]string{} | ||
| for k, v in tag.attributes { | ||
| if k == 'href' { | ||
| url := urllib.parse(v) or { urllib.URL{} } | ||
| if url.scheme in ['http', 'https', 'mailto', 'github-windows', 'github-mac', | ||
| 'x-github-client']! { | ||
| attributes['href'] = v | ||
| } | ||
| } else if k in html.allowed_attributes { | ||
| attributes[k] = v | ||
| } | ||
| } | ||
| tag.attributes = attributes.move() | ||
| } | ||
| // Filter protocols for specific tags | ||
| tag.name in ['blockquote', 'del', 'ins', 'q']! { | ||
| mut attributes := map[string]string{} | ||
| for k, v in tag.attributes { | ||
| if k == 'cite' { | ||
| url := urllib.parse(v) or { urllib.URL{} } | ||
| if url.scheme in ['http', 'https']! { | ||
| attributes['cite'] = v | ||
| } | ||
| } else if k in html.allowed_attributes { | ||
| attributes[k] = v | ||
| } | ||
| } | ||
| tag.attributes = attributes.move() | ||
| } | ||
| // Filter protocols for img with src | ||
| tag.name == 'img' { | ||
| mut attributes := map[string]string{} | ||
| for k, v in tag.attributes { | ||
| if k in ['src', 'longdesc']! { | ||
| url := urllib.parse(v) or { urllib.URL{} } | ||
| if url.scheme in ['http', 'https']! { | ||
| attributes[k] = v | ||
| } | ||
| } else if k in html.allowed_attributes { | ||
| attributes[k] = v | ||
| } | ||
| } | ||
| tag.attributes = attributes.move() | ||
| } | ||
| else { | ||
| tag.attributes = maps.filter(tag.attributes, fn (k string, v string) bool { | ||
| return k in html.allowed_attributes | ||
| }) | ||
| } | ||
| } | ||
| } | ||
| for i := 0; i < tag.children.len; i++ { | ||
| traverse_and_sanitize(&tag.children[i]) | ||
| } | ||
|
|
||
| unsafe { | ||
| tag.children = tag.children.filter(it != nil) | ||
| } | ||
| } |
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