introduce brotli compression to build script

build.py

@@ -1,31 +1,84 @@
 #!/usr/bin/env python
 
 import contextlib
-from io import BufferedWriter, FileIO
 import os
 import shutil
+from io import BufferedWriter, FileIO
+
+import brotli
 import git
+import magic
 from jinja2 import Environment, FileSystemLoader
 
 SOURCES_DIR = "src"
 DIST_DIR = "dist"
+BROTLI_THRESHOLD = 1024
+
+# taken from https://caddyserver.com/docs/caddyfile/directives/encode
+BROTLI_MIME_PREFIXES = [
+    "application/atom+xml",
+	"application/eot",
+	"application/font",
+	"application/geo+json",
+	"application/graphql+json",
+	"application/javascript",
+	"application/json",
+	"application/ld+json",
+	"application/manifest+json",
+	"application/opentype",
+	"application/otf",
+	"application/rss+xml",
+	"application/truetype",
+	"application/ttf",
+	"application/vnd.api+json",
+	"application/vnd.ms-fontobject",
+	"application/wasm",
+	"application/x-httpd-cgi",
+	"application/x-javascript",
+	"application/x-opentype",
+	"application/x-otf",
+	"application/x-perl",
+	"application/x-protobuf",
+	"application/x-ttf",
+	"application/xhtml+xml",
+	"application/xml",
+	"font/",
+	"image/svg+xml",
+	"image/vnd.microsoft.icon",
+	"image/x-icon",
+	"multipart/bag",
+	"multipart/mixed",
+	"text/",
+]
+
 
 def latest_git_commit_year() -> int:
     return git.Repo(".").head.commit.authored_datetime.year
 
-def build_template(env: Environment, src_path: str):
+def build_template(env: Environment, src_path: str) -> tuple[str, int]:
     rel_path = os.path.relpath(src_path, SOURCES_DIR)
     dist_path = os.path.splitext(os.path.join(DIST_DIR, rel_path))[0]
 
     template = env.get_template(rel_path)
     rendered_text = template.render(copyright_year = latest_git_commit_year())
 
+    size = 0
     with BufferedWriter(FileIO(dist_path, "wb")) as writer:
         for line in rendered_text.splitlines():
             line = line.strip()
             if len(line) > 0:
-                writer.write(line.encode())
-                writer.write(b"\n")
+                line_b = line.encode()
+                size += len(line_b) + 1
+                _ = writer.write(line.encode())
+                _ = writer.write(b"\n")
+
+    return dist_path, size
+
+def compress(path: str, mode):
+    with open(path, "rb") as reader, open(path + ".br", "wb") as writer:
+        content = reader.read()
+        compressed = brotli.compress(content, mode)
+        writer.write(compressed)
 
 def main():
     with contextlib.suppress(FileNotFoundError):
@@ -36,6 +89,8 @@ def main():
         autoescape=True
     )
 
+    mime = magic.Magic(mime=True)
+
     for root, _, files in os.walk(SOURCES_DIR):
         rel_dir_path = os.path.relpath(root, SOURCES_DIR)
         dist_root = os.path.join(DIST_DIR, rel_dir_path)
@@ -46,11 +101,19 @@ def main():
 
             if src_name.endswith(".jinja"):
                 if not src_name.startswith("_"):
-                    build_template(env, src_path)
-
+                    dist_path, size = build_template(env, src_path)
+                    if size > BROTLI_THRESHOLD:
+                        compress(dist_path, brotli.MODE_TEXT)
             else:
                 dist_path = os.path.join(dist_root, src_name)
                 shutil.copy(src_path, dist_path)
+                if os.path.getsize(dist_path) > BROTLI_THRESHOLD:
+                    mimetype = mime.from_file(dist_path)
+                    if any(mimetype.startswith(prefix) for prefix in BROTLI_MIME_PREFIXES):
+                        mode = brotli.MODE_FONT if mimetype == "font/woff2" else brotli.MODE_GENERIC
+                        compress(dist_path, mode)
+
+
 
 if __name__ == '__main__':
     main()