feat(renderer): improve error handling with fallback images for missing resources (#525)

Author: fllesser

src/nonebot_plugin_parser/renders/common.py

@@ -387,15 +387,12 @@ async def _load_cover(self) -> PILImage | None:
         if self.result.video is None:
             return None
 
-        cover_task = self.result.video.cover
+        cover_path = None
+        if cover_task := self.result.video.cover:
+            cover_path = await cover_task.safe_get()
 
-        if cover_task is None:
-            return None
-
-        cover_path = await cover_task.safe_get()
-
-        if cover_path is None or not cover_path.exists():
-            return None
+        if cover_path is None:
+            return Image.open(resources.random_fallback_pic())
 
         with Image.open(cover_path) as img:
             if img.mode != "RGBA":
@@ -473,7 +470,7 @@ async def _render_image_grid(self) -> None:
         for content in display_contents:
             path = await content.safe_get()
             if path is None or not path.exists():
-                continue
+                path = resources.random_fallback_pic()
             if img := self._load_grid_image(path, len(display_contents)):
                 images.append(img)
 
@@ -578,7 +575,7 @@ async def _render_img_in_graphics(self, image_content: ImageContent) -> None:
         """渲染图片"""
         path = await image_content.path_task.safe_get()
         if path is None or not path.exists():
-            return
+            path = resources.random_fallback_pic()
 
         with Image.open(path) as img:
             if img.width > self.content_width:

src/nonebot_plugin_parser/renders/htmlrender.py

@@ -1,4 +1,3 @@
-import random
 from typing_extensions import override
 
 from nonebot import require
@@ -23,18 +22,15 @@ async def render_image(self) -> bytes:
         font = pconfig.custom_font or resources.DEFAULT_FONT_PATH
         font = font.as_uri() if font.exists() else None
 
-        fallback_pics = list(resources.FAILED_PIC_DIR.glob("*.jpg"))
-        fallback_pic = random.choice(fallback_pics).as_uri() if fallback_pics else None
-
         return await template_to_pic(
             template_path=str(self.templates_dir),
             template_name="card.html.jinja2",
             templates={
                 "logo": logo,
                 "font": font,
                 "result": self.result,
-                "fallback_pic": fallback_pic,
                 "font_weight": pconfig.custom_font_weight,
+                "fallback_pic": resources.random_fallback_pic().as_uri(),
                 "play_button": resources.DEFAULT_VIDEO_BUTTON_PATH.as_uri(),
                 "default_avatar": resources.DEFAULT_AVATAR_PATH.as_uri(),
             },

src/nonebot_plugin_parser/renders/resources/__init__.py

@@ -1,3 +1,4 @@
+import random
 from pathlib import Path
 
 RESOURCES_DIR = Path(__file__).parent
@@ -8,5 +9,9 @@
 """默认头像文件路径"""
 DEFAULT_VIDEO_BUTTON_PATH = RESOURCES_DIR / "play.png"
 """默认视频播放按钮文件路径"""
-FAILED_PIC_DIR = RESOURCES_DIR / "failed_pic"
+FALLBACK_PIC_DIR = RESOURCES_DIR / "fallback_pic"
 """下载失败显示的图片文件路径"""
+
+
+def random_fallback_pic() -> Path:
+    return FALLBACK_PIC_DIR / f"{random.randint(1, 9)}.jpg"