Fix relative URLs when serving the specification with a custom baseURL (#1984)

assets/css/fonts/download_google_fonts_css.py

@@ -0,0 +1,134 @@
+#!/usr/bin/env python3
+# Copyright 2021 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This script takes a google fonts CSS URL, downloads the referenced fonts locally
+# and spits out a modified CSS file which now points to those local fonts.
+#
+# Purely for the purposes of converting a website to use local font files instead of
+# making requests to Google Fonts.
+
+import re
+import requests
+import subprocess
+import sys
+
+# Pull the font filename to process and output directory to point at
+if len(sys.argv) < 4:
+    print(f"""
+Error: Not enough arguments.
+
+Usage: {sys.argv[0]} google_fonts_url font_directory css_font_path
+* google fonts url: A URL leading to a google font css file (i.e https://fonts.googleapis.com/css?family=Inter)
+* font directory: The location that font files will be downloaded to (i.e ../../fonts)
+* font path: The directory the resulting CSS will be pointing to, relative to site root (i.e /unstable/css/fonts).
+             This is where the browser will look for fonts.
+""")
+    sys.exit(1)
+
+google_fonts_url = sys.argv[1]
+font_output_dir = sys.argv[2]
+css_font_path = sys.argv[3]
+
+# Get font name
+if google_fonts_url.count(":") > 1:
+    # Account for font weights specified in the URL
+    # (i.e https://fonts.googleapis.com/css?family=Inter:300,300i,400,400i,700,700i)
+    url_match = re.match(r".*family=(.*):", google_fonts_url)
+else:
+    url_match = re.match(r".*family=(.*)", google_fonts_url)
+
+if not url_match:
+    print("Unable to extract font name, invalid google fonts URL:", google_fonts_url)
+    print("URL should look something like: https://fonts.googleapis.com/css?family=Inter...")
+    sys.exit(1)
+
+font_name = url_match.group(1)
+
+# Ensure font paths end with a trailing slash
+if not font_output_dir.endswith("/"):
+    font_output_dir += "/"
+if not css_font_path.endswith("/"):
+    css_font_path += "/"
+
+# Download the css file and split by newline
+resp = requests.get(
+    google_fonts_url,
+    # We need to set a believable user-agent, else google fonts won't give us
+    # all of the font weights we requested for some reason
+    headers={
+        "User-Agent": "User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:86.0) Gecko/20100101 Firefox/86.0"
+    }
+)
+if resp.status_code != 200:
+    print("Failed to download:", google_fonts_url, resp.status_code)
+    sys.exit(1)
+
+original_contents = resp.text.split("\n")
+
+# Download all referenced font files and write out new font file
+new_css_file_lines = []
+
+# Store metadata for helping give friendly names to each font file
+font_lang = None
+font_family = None
+font_style = None
+font_weight = 0
+for line in original_contents:
+    # Check if this line contains a font URL
+    match = re.match(r".*url\((.*)\) format.*", line)
+    if match:
+        # Download the font file
+        font_url = match.group(1)
+        print("Downloading font:", font_url)
+
+        resp = requests.get(font_url)
+        if resp.status_code == 200:
+            # Save the font file
+            filename = "%s-%s-%s-%d.woff2" % (
+                font_family, font_lang, font_style, font_weight
+            )
+            font_filepath = font_output_dir + filename
+            with open(font_filepath, "wb") as f:
+                print("Writing font file:", font_filepath)
+                f.write(resp.content)
+
+            # Replace google URL with local URL
+            line = re.sub(r"url\(.+\)", f"url({css_font_path + filename})", line)
+        else:
+            print("Warning: failed to download font file:", font_url)
+
+    # Check for font metadata. If there is some, we'll note it down and use it to help
+    # name font files when we write them out.
+    # Makes for nicer font filenames than fvQtMwCp50KnMw2boKod... etc.
+    font_lang_match = re.match(r"^/\* (.+) \*/$", line)
+    if font_lang_match:
+        font_lang = font_lang_match.group(1)
+    font_family_match = re.match(r".*font-family: '(.+)';$", line)
+    if font_family_match:
+        font_family = font_family_match.group(1)
+    font_style_match = re.match(r".*font-style: (.+);$", line)
+    if font_style_match:
+        font_style = font_style_match.group(1)
+    font_weight_match = re.match(r".*font-weight: (.+);$", line)
+    if font_weight_match:
+        font_weight = int(font_weight_match.group(1))
+
+    # Append the potentially modified line to the new css file
+    new_css_file_lines.append(line)
+
+# Write out the new font css file
+with open(font_name + ".css", "w") as f:
+    new_css_file_contents = "\n".join(new_css_file_lines)
+    f.write(new_css_file_contents)