Add html-extract-stupid

html-extract-stupid

@@ -0,0 +1,43 @@
+#!/bin/bash
+# Reads HTML from stdin, extracts links and page requisites with simple string splitting and regexes.
+# Usage cannot be recommended against enough.
+# Produces lines of 'TAG URL', e.g. 'a https://example.org/'.
+{
+	# Reformat so each line is one tag
+	# Yes, this may break attribute values if they contain CR, LF, or <, but that's rare enough.
+	tr '\r\n' '  ' | tr '<' '\n' |
+
+	# Extract tags of interest
+	grep -i '^\(a\|base\|img\|link\|script\)\s' |
+
+	# Fix scripty backslash nonsense
+	perl -pe 's,\\,,g' |
+
+	# Split img tags with src and srcset
+	perl -pe "s,^img(?=\s(?:(?:[^>'\"]|\"[^\"]*\"|'[^']*')*\s)?src\s*=\s*([^>'\"\s]*|\"[^\"]*\"|'[^']*')(?:\s|>))\s(?:(?:[^>'\"]|\"[^\"]*\"|'[^']*')*\s)?srcset\s*=\s*([^>'\"\s]*|\"[^\"]*\"|'[^']*')(\s|>).*,img src=\1\nimg srcset=\2," |
+
+	# Extract interesting tags/attributes
+	perl -pe "s,^(a|base)\s(?:(?:[^>'\"]|\"[^\"]*\"|'[^']*')*\s)?href\s*=\s*([^>'\"\s]*|\"[^\"]*\"|'[^']*')(\$|\s|>).*,+\1 \2,i;
+	          s,^(img|script)\s(?:(?:[^>'\"]|\"[^\"]*\"|'[^']*')*\s)?src\s*=\s*([^>'\"\s]*|\"[^\"]*\"|'[^']*')(\$|\s|>).*,+\1 \2,i;
+	          s,^(link)\s(?=(?:(?:[^>'\"]|\"[^\"]*\"|'[^']*')*\s)?rel\s*=\s*(?:stylesheet|\"(?:[^\"]*\s)?stylesheet(?:\s[^\"]*)?\"|'(?:[^']*\s)?stylesheet(?:\s[^']*)?')(?:\$|\s|>))(?:(?:[^>'\"]|\"[^\"]*\"|'[^']*')*\s)?href\s*=\s*([^>'\"\s]*|\"[^\"]*\"|'[^']*')(\$|\s|>).*,+\1 \2,i;
+	          s,^(img)\s(?:(?:[^>'\"]|\"[^\"]*\"|'[^']*')*\s)?(srcset)\s*=\s*([^>'\"\s]*|\"[^\"]*\"|'[^']*')(\$|\s|>).*,+\1\2 \3,i;
+	          # Ensure that there's a LF at the end of each line since \s might match it.
+	          s,\s*$,\n,;
+	         " |
+
+	# Filter out unprocessed lines
+	grep '^+' | sed 's,^+,,' |
+
+	# Remove quotes from attribute values
+	perl -pe "s,^([a-zA-Z]+) (['\"])(.*)\2$,\1 \3," |
+
+	# img srcset splitting
+	python3 -c 'import re, sys'$'\n''for l in map(str.strip, sys.stdin):'$'\n'' tag, value = l.split(" ", 1)'$'\n'' if tag != "imgsrcset":'$'\n''  print(l); continue'$'\n'' for url in re.split(r"\s+\d+[wx]\s*(?:,\s*|$)|,\s+", value.strip()):'$'\n''  if url: print(f"img {url}")' |
+
+	# Decode HTML references
+	python3 -c 'import html, sys'$'\n''for l in sys.stdin:'$'\n'' try: print(html.unescape(l.strip()))'$'\n'' except BrokenPipeError: break' |
+
+	# Combine base and values to get absolute URLs
+	# If multiple base tags are present, they all get respected. This violates the HTML specs.
+	python3 -c 'import sys, urllib.parse; base = None'$'\n''for l in map(str.strip, sys.stdin):'$'\n'' tag, value = l.split(" ", 1)'$'\n'' tag = tag.lower()'$'\n'' if base:'$'\n''  value = urllib.parse.urljoin(base, value)'$'\n'' if tag == "base":'$'\n''  base = value'$'\n''  continue'$'\n'' try: print(f"{tag} {value}")'$'\n'' except BrokenPipeError: break'
+}