implemented jit-optimization for images

scripts/wizard.sh

@@ -185,13 +185,21 @@ function wizard_create_config() {
     )
   fi
 
-  if whiptail --title "$TITLE - gzip" --yesno "Whether to gzip the content. Reduces the response-size and thus loading time of text-based responses on cost of CPU-Time.
+  if whiptail --title "$TITLE - Server" --yesno "Whether to gzip the content. Reduces the response-size and thus loading time of text-based responses on cost of CPU-Time.
 note: Should be done by the Proxy-Server if possible. Otherwise, this is the option." 20 60; then
     GZIP="yes"
   else
     GZIP="no"
   fi
 
+  if whiptail --title "$TITLE - Server" --yesno "Allow media optimization.
+Enabling this option allows for faster downloads as supported media is just-in-time optimized.
+Important: only use this option for a very small userbase as it can take up lots of system-resources." 20 60; then
+    OPTIMIZE=true
+  else
+    OPTIMIZE=false
+  fi
+
   if whiptail --title "$TITLE - Auth" --yesno "Do you want to require authentication?" 20 60; then
     USERNAME=$(
       whiptail --title "$TITLE - Auth" --inputbox "Username:" 20 60 3>&2 2>&1 1>&3
@@ -243,6 +251,9 @@ Blacklist: directories or files are disabled/hidden" --yes-button "Whitelist" --
       echo "    username: \"$USERNAME\""
       echo "    password: \"$PASSWORD\""
     fi
+    if [ $OPTIMIZE = true ]; then
+      echo "  optimize: yes"
+    fi
     echo "ignore:"
     if [ $WHITELIST = true ]; then
       echo "  - \"/*\""
@@ -281,10 +292,10 @@ function wizard_main() {
 }
 
 case $1 in
-#install)
-#  wizard_install ;;
-#uninstall)
-#  wizard_uninstall ;;
+install)
+  wizard_install ;;
+uninstall)
+  wizard_uninstall ;;
 "")  # no command
   wizard_main "${@:2}" ;;
 -h | --help)

src/jarklin/_commands/web/__init__.py

@@ -53,6 +53,8 @@ def make_session_permanent() -> None:
     app.config['SESSION_REFRESH_EACH_REQUEST'] = \
         config.getbool('web', 'session', 'refresh_each_request', fallback=False)
 
+    app.config['JIT_OPTIMIZATION'] = config.getbool('web', 'optimize', fallback=False)
+
     if config.getbool('web', 'gzip', fallback=True):
         from flask_compress import Compress  # no need to load unless required
         Compress(app)

src/jarklin/web/__init__.py

@@ -2,12 +2,15 @@
 r"""
 
 """
+import io
 import os
 import os.path as p
+import mimetypes
 from http import HTTPStatus
 import flask
+from PIL import Image
 from werkzeug.exceptions import Unauthorized as HTTPUnauthorized, BadRequest as HTTPBadRequest, NotFound as HTTPNotFound
-from .utility import requires_authenticated, validate_user
+from .utility import requires_authenticated, validate_user, to_bool
 
 
 WEB_UI = p.join(p.dirname(__file__), 'web-ui')
@@ -16,11 +19,46 @@
 
 @app.get("/files/<path:resource>")
 @requires_authenticated
-def files(resource: str, download: bool = False):
-    fp = p.join(os.getcwd(), resource)
+def files(resource: str):
+    optimize = flask.request.args.get("optimize", default=False, type=to_bool)
+    download = flask.request.args.get("download", default=False, type=to_bool)
+
+    root = p.abspath(os.getcwd())
+    fp = p.join(root, resource)
     if fp in app.config['EXCLUDE']:
         raise HTTPNotFound()
-    return flask.send_from_directory(os.getcwd(), resource, as_attachment=download)
+    if p.commonpath([root, fp]) != root:
+        raise HTTPNotFound(f"{fp!s}")
+
+    file = fp
+
+    if optimize and flask.current_app.config['JIT_OPTIMIZATION']:
+        mimetype, _ = mimetypes.guess_type(fp)
+        if mimetype and mimetype.startswith("image/"):
+            with Image.open(fp) as image:
+                # we don't support animated images
+                if not getattr(image, 'is_animated', False):
+                    # support for giant image commonly found in comics or mangas
+                    boundary = (2000, 2000)
+                    if image.width > 2 * image.height or image.height > image.width * 2:
+                        boundary = (4000, 4000)
+
+                    image.thumbnail(boundary, resample=Image.Resampling.BICUBIC)  # resize but keep aspect
+
+                    buffer = io.BytesIO()
+                    image.save(buffer, format='WEBP')  # WebP should be better than JPEG or PNG
+                    buffer.seek(0)
+                    file = buffer
+
+                # ensure image gets closed
+                image.close()
+                del image
+
+            if isinstance(file, io.BytesIO):
+                return flask.send_file(file, "image/webp", as_attachment=download,
+                                       download_name="optimized.webp", conditional=False, etag=False)
+
+    return flask.send_file(file, as_attachment=download)
 
 
 @app.get("/auth/username")

src/jarklin/web/utility.py

@@ -34,3 +34,8 @@ def wrapper(*args, **kwargs):
         return fn(*args, **kwargs)
 
     return wrapper
+
+
+def to_bool(value: str) -> bool:
+    # important: this evaluates empty strings to true (/resource?download)
+    return value.lower() in {"true", "yes", "1", ""}