Add API to provide descriptions as Minetest hypertext markup

app/utils/minetest_hypertext.py

@@ -0,0 +1,177 @@
+from html.parser import HTMLParser
+import re
+import sys
+
+
+def normalize_whitespace(x):
+	return re.sub(r"\s+", " ", x)
+
+
+assert normalize_whitespace(" one  three\nfour\n\n") == " one three four "
+
+
+# Styles and custom tags
+HEAD = normalize_whitespace("""
+	<tag name=code color=#7bf font=mono>
+	<tag name=action color=#77f hovercolor=#aaf>
+""").strip()
+
+
+def get_attributes(attrs):
+	retval = {}
+	for attr in attrs:
+		retval[attr[0]] = attr[1]
+	return retval
+
+
+class MinetestHTMLParser(HTMLParser):
+	def __init__(self, include_images):
+		super().__init__()
+		self.include_images = include_images
+
+		self.text_buffer = ""
+		self.has_line_started = False
+		self.links = {}
+		self.images = {}
+		self.image_tooltips = {}
+		self.is_preserving = False
+		self.remove_until = None
+
+	def handle_starttag(self, tag, attrs):
+		if self.is_preserving or self.remove_until:
+			return
+
+		print("OPEN", tag, file=sys.stderr)
+
+		self.has_line_started = True
+		if tag == "p":
+			self.has_line_started = False
+		elif tag == "pre":
+			self.text_buffer += "<code>"
+			self.is_preserving = True
+			self.has_line_started = False
+		elif tag == "table":
+			# Tables are currently unsupported and removed
+			self.remove_until = "table"
+			self.text_buffer += "<i>(table removed)</i>\n"
+		elif tag == "br":
+			self.text_buffer += "\n"
+			self.has_line_started = False
+		elif tag == "h1" or tag == "h2":
+			self.text_buffer += "\n<big>"
+		elif tag == "h3" or tag == "h4" or tag == "h5":
+			self.text_buffer += "\n<b>"
+		elif tag == "a":
+			for attr in attrs:
+				if attr[0] == "href":
+					name = f"link_{len(self.links)}"
+					self.links[name] = attr[1]
+					self.text_buffer += f"<action name={name}><u>"
+					break
+			else:
+				self.text_buffer += "<action><u>"
+		elif tag == "img":
+			attr_by_value = get_attributes(attrs)
+			if "src" in attr_by_value and self.include_images:
+				name = f"image_{len(self.images)}"
+				self.images[name] = attr_by_value["src"]
+				width = attr_by_value.get("width", 128)
+				height = attr_by_value.get("height", 128)
+				self.text_buffer += f"<img name={name} width={width} height={height}>"
+
+				if "alt" in attr_by_value:
+					self.image_tooltips[name] = attr_by_value["alt"]
+		elif tag == "b" or tag == "strong":
+			self.text_buffer += "<b>"
+		elif tag == "i" or tag == "em":
+			self.text_buffer += "<i>"
+		elif tag == "u":
+			self.text_buffer += "<u>"
+		elif tag == "li":
+			self.has_line_started = False
+			self.text_buffer += "• "
+		elif tag == "code":
+			self.text_buffer += "<code>"
+		elif tag == "span" or tag == "ul":
+			pass
+		else:
+			print("UNKNOWN TAG ", tag, attrs, file=sys.stderr)
+
+	def handle_endtag(self, tag):
+		if self.remove_until:
+			if self.remove_until == tag:
+				self.remove_until = None
+			return
+
+		print("CLOSE", tag, file=sys.stderr)
+
+		if tag == "pre":
+			self.text_buffer = self.text_buffer.rstrip()
+			self.text_buffer += "</code>\n"
+			self.is_preserving = False
+			self.has_line_started = False
+		elif self.is_preserving:
+			return
+		elif tag == "p":
+			self.text_buffer = self.text_buffer.rstrip()
+			self.text_buffer += "\n"
+			self.has_line_started = False
+		elif tag == "h1" or tag == "h2":
+			self.text_buffer += "</big>\n"
+			self.has_line_started = False
+		elif tag == "h3" or tag == "h4" or tag == "h5":
+			self.text_buffer += "</b>\n"
+			self.has_line_started = False
+		elif tag == "a":
+			self.text_buffer += "</u></action>"
+		elif tag == "code":
+			self.text_buffer += "</code>"
+		elif tag == "b" or tag == "strong":
+			self.text_buffer += "</b>"
+		elif tag == "i" or tag == "em":
+			self.text_buffer += "</i>"
+		elif tag == "u":
+			self.text_buffer += "</u>"
+		elif tag == "li":
+			self.text_buffer += "\n"
+		# else:
+		# 	print("END", tag, file=sys.stderr)
+
+	def handle_data(self, data):
+		print(f"DATA \"{data}\"", file=sys.stderr)
+		if self.remove_until:
+			return
+
+		if not self.is_preserving:
+			data = normalize_whitespace(data)
+			if not self.has_line_started:
+				data = data.lstrip()
+
+		self.text_buffer += data
+		self.has_line_started = True
+
+	def handle_entityref(self, name):
+		to_value = {
+			"lt": "\\<",
+			"gr": "\\>",
+			"amp": "&",
+			"quot": "\"",
+			"apos": "'",
+		}
+
+		if name in to_value:
+			self.text_buffer += to_value[name]
+		else:
+			self.text_buffer += f"&{name};"
+
+
+def html_to_minetest(html, formspec_version=6, include_images=True):
+	parser = MinetestHTMLParser(include_images)
+	parser.feed(html)
+	return {
+		"head": HEAD,
+		"body": parser.text_buffer.strip() + "\n\n",
+		"links": parser.links,
+		"images":  parser.images,
+		"image_tooltips": parser.image_tooltips,
+	}