feat: support http(s) image URLs in training metadata

diffsynth/core/data/operators.py

@@ -1,9 +1,27 @@
 import math, warnings
 import torch, torchvision, imageio, os
 import imageio.v3 as iio
+import urllib.request
+from io import BytesIO
 from PIL import Image
 
 
+def _is_url(path):
+    return isinstance(path, str) and path.startswith(("http://", "https://"))
+
+
+def _load_image_from_url(url, timeout=30):
+    # A custom User-Agent avoids the 403 that many CDNs / image hosts return for the default urllib agent.
+    request = urllib.request.Request(url, headers={"User-Agent": "Mozilla/5.0 (compatible; DiffSynth-Studio)"})
+    try:
+        with urllib.request.urlopen(request, timeout=timeout) as response:
+            image = Image.open(BytesIO(response.read()))
+            image.load()  # force a full decode while the byte buffer is still in scope
+        return image
+    except Exception as e:
+        raise RuntimeError(f"Failed to load image from URL '{url}': {e}") from e
+
+
 class DataProcessingPipeline:
     def __init__(self, operators=None):
         self.operators: list[DataProcessingOperator] = [] if operators is None else operators
@@ -54,12 +72,16 @@ def __call__(self, data):
 
 
 class LoadImage(DataProcessingOperator):
-    def __init__(self, convert_RGB=True, convert_RGBA=False):
+    def __init__(self, convert_RGB=True, convert_RGBA=False, timeout=30):
         self.convert_RGB = convert_RGB
         self.convert_RGBA = convert_RGBA
-
+        self.timeout = timeout
+
     def __call__(self, data: str):
-        image = Image.open(data)
+        if _is_url(data):
+            image = _load_image_from_url(data, timeout=self.timeout)
+        else:
+            image = Image.open(data)
         if self.convert_RGB: image = image.convert("RGB")
         if self.convert_RGBA: image = image.convert("RGBA")
         return image
@@ -241,6 +263,9 @@ def __init__(self, base_path=""):
         self.base_path = base_path
 
     def __call__(self, data):
+        # A remote URL is already absolute; joining it with base_path would corrupt it.
+        if _is_url(data):
+            return data
         return os.path.join(self.base_path, data)