Add disk cache

.gitignore

@@ -1,3 +1,5 @@
+cache
+
 node_modules
 /frontend/dist
 

Dockerfile

@@ -41,7 +41,9 @@ RUN apk add --no-cache --virtual .deps \
 
 COPY --from=frontend /usr/src/app/frontend/dist/ frontend/dist
 
-COPY [^frontend]* ./
+COPY *.py ./
+
+VOLUME ["/usr/src/app/cache/"]
 
 ENTRYPOINT ["gunicorn", "mangareader:app", "--bind", "0.0.0.0:8000", "--chdir", "/library"]
 

backend.py

@@ -1,4 +1,5 @@
 from PIL import Image
+from disk_cache import DiskCache
 from io import BytesIO
 from mimetypes import types_map as mimetypes
 from zipfile import ZipFile
@@ -10,6 +11,10 @@ import werkzeug.exceptions as exceptions
 
 mimetypes['.webp'] = 'image/webp'
 
+if os.environ.get('DISK_CACHE', '1') == '0':
+    disk_cache = DiskCache(enabled=False)
+else:
+    disk_cache = DiskCache()
 thumbnail_cache = {}
 
 
@@ -231,12 +236,18 @@ class CalibreDB:
             if self.webp is True and mimetype != 'image/webp':
                 mimetype = 'image/webp'
 
+                try:
+                    page_data = disk_cache.get(f'{volume_id}-{page_number}')
+                except FileNotFoundError:
                     with volume.open(page_filename) as orig_page_data:
                         image = Image.open(orig_page_data)
                         image.thumbnail((self.webp_size, self.webp_size))
                         image = image.convert('RGB')
                         image = webp.WebPPicture.from_pil(image)
                         page_data = BytesIO(image.encode(self.webp_config).buffer())
+
+                        disk_cache.set(f'{volume_id}-{page_number}', page_data)
+                        page_data.seek(0)
             else:
                 page_data = BytesIO()
                 page_data.write(volume.read(page_filename))

disk_cache.py

@@ -0,0 +1,33 @@
+from io import BytesIO
+import os
+
+
+class DiskCache:
+    def __init__(self, path=None, enabled=True):
+        if path is None:
+            self.path = os.path.join(os.path.dirname(__file__), 'cache')
+        else:
+            self.path = path
+
+        self.enabled = enabled
+        if self.enabled is False:
+            return
+
+        os.makedirs(self.path, exist_ok=True)
+
+    def set(self, identifier, buf):
+        if self.enabled is False:
+            return
+
+        with open(self._build_path(identifier), 'wb') as f:
+            f.write(buf.read())
+
+    def get(self, identifier):
+        if self.enabled is False:
+            raise FileNotFoundError
+
+        with open(self._build_path(identifier), 'rb') as f:
+            return BytesIO(f.read())
+
+    def _build_path(self, identifier):
+        return os.path.join(self.path, identifier)