Cache a fixed amount of image in case of connectivity loss

.gitignore

@@ -1,2 +1,3 @@
 keys.py
 *.pyc
+.image-cache/

image_convert.py

@@ -42,6 +42,7 @@ class ImageShrink:
         image = self.shrink(image)
         image = self.convert_to_reduced_colors(image)
         # image.save("test.png")
+        return image
 
 
     def shrink(self, image: Image) -> Image:

image_get.py

@@ -1,7 +1,8 @@
 import httpx as h
 import json
 import random
-
+from pathlib import Path
+import uuid
 import keys
 
 
@@ -15,29 +16,43 @@ class ImageGetter:
     }
 
     def __init__(self):
+        self.cached_num = 10
+        self.cached_path = Path("./.image-cache/")
         pass
 
 
     def get_random_image(self) -> bytearray:
-        id = self.get_random_image_id()
+        try:
-        bytes = self.get_image_file(id)
+            ids = self.get_random_image_ids(num=self.cached_num + 1)
+            bytes = self.get_image_file(ids[0])
+            self.save_cached_files(ids[1:])
+        except (h.ConnectError, h.HTTPStatusError, h.NetworkError, h.RequestError, h.DecodingError, h.TransportError, ImageGetException):
+            print("Loading image from cache")
+            bytes = self.load_cached_file()
+
         return bytes
     
 
-    def get_random_image_id(self) -> str:
+    def get_random_image_ids(self, num=1) -> str:
         url = keys.immich_api_root_url + "album/" + keys.immich_album_id
         headers = self.headers | {"Accept": "application/json"}
         
         response = h.request("GET", url, headers=headers, data={})
+        # raises an htppx exception if anything goes wrong
         if response.status_code == 200:
             response = json.loads(response.text)
         else:
             raise ImageGetException("Error in step get_random_image_id: " + str(response.status_code))
 
         images = response['assets']
-        print(f"Picking random image out of {len(images)} album images")
+
+        print(f"Picking {num} random id(s) out of {len(images)} album images")
+        ids = []
+        for i in range(num):
             image = random.choice(images)
-        return image["id"]
+            ids.append(image["id"])
+
+        return ids
 
 
     def get_image_file(self, image_id: str) -> bytearray:
@@ -49,3 +64,28 @@ class ImageGetter:
             raise ImageGetException("Error in step get_image_file: " + str(response.status_code))
             
         return response.content
+
+
+    def save_cached_files(self, image_ids: list[str]) -> None:
+        """Ensures self.cached_num files are at self.cached_path at any time"""
+        if not self.cached_path.exists():
+            self.cached_path.mkdir()
+
+        present_count = len(list(self.cached_path.glob("*")))
+        for i in range(self.cached_num -  present_count):
+            print(f"Caching image {i + 1}")
+            new_cache = self.cached_path / f"{uuid.uuid4()}"
+            new_cache.write_bytes(self.get_image_file(image_ids[i]))
+
+
+    def load_cached_file(self) -> bytearray:
+        """Returns a random file from self.cached_path"""
+        files = list(self.cached_path.glob("*"))
+
+        if len(files) == 0:
+            raise ImageGetException("Could not load cached file: directory empty")
+
+        file = random.choice(files)
+        bytes  = file.read_bytes()
+        file.unlink()
+        return bytes

image_show.py

@@ -27,7 +27,7 @@ class ImageShow:
         if image.size != (self.epd.width, self.epd.height):
             raise ImageShowError("Image does not match screen size")
 
-        # self.__init__()
+        self.__init__()
         # possibly include a blank image to clear screen
 
         self.epd.display(self.epd.getbuffer(image))

main.py

@@ -1,8 +1,12 @@
 from image_convert import ImageShrink
 from image_get import ImageGetter
+# from image_show import ImageShow
 
 get = ImageGetter()
 convert = ImageShrink()
+# show = ImageShow()
 
 image = get.get_random_image()
-convert.convert(image)
+image = convert.convert(image)
+
+# show.show_image(image)