增加微信聊天中图片获取能力，较之前的微信图片仅提供缩略图的情况，改善为获取微信聊天中实际图片大小，方便后续 ocr 或者 llm vision 识别聊天图片内容。

pkg/platform/sources/gewechat.py

@@ -28,7 +28,10 @@ from ...utils import image
 
 
 class GewechatMessageConverter(adapter.MessageConverter):
-    
+
+    def __init__(self, config: dict):
+        self.config = config
+
     @staticmethod
     async def yiri2target(
         message_chain: platform_message.MessageChain
@@ -48,8 +51,8 @@ class GewechatMessageConverter(adapter.MessageConverter):
 
         return content_list
 
-    @staticmethod
     async def target2yiri(
+        self,
         message: dict,
         bot_account_id: str
     ) -> platform_message.MessageChain:
@@ -74,10 +77,29 @@ class GewechatMessageConverter(adapter.MessageConverter):
             return platform_message.MessageChain(content_list)
                     
         elif message["Data"]["MsgType"] == 3:
-            image_base64 = message["Data"]["ImgBuf"]["buffer"]
+            image_xml = message["Data"]["Content"]["string"]
-            return platform_message.MessageChain(
+            if not image_xml:
-                [platform_message.Image(base64=f"data:image/jpeg;base64,{image_base64}")]
+                return platform_message.MessageChain([
-            )
+                    platform_message.Plain(text="[图片内容为空]")
+                ])
+
+            try:
+                base64_str, image_format = await image.get_gewechat_image_base64(
+                    gewechat_url=self.config["gewechat_url"],
+                    app_id=self.config["app_id"],
+                    xml_content=image_xml
+                )
+
+                return platform_message.MessageChain([
+                    platform_message.Image(
+                        base64=f"data:image/{image_format};base64,{base64_str}"
+                    )
+                ])
+            except Exception as e:
+                print(f"处理图片消息失败: {str(e)}")
+                return platform_message.MessageChain([
+                    platform_message.Plain(text="[图片处理失败]")
+                ])
 
         elif message["Data"]["MsgType"] == 49:
             # 支持微信聊天记录的消息类型，将 XML 内容转换为 MessageChain 传递
@@ -106,19 +128,26 @@ class GewechatMessageConverter(adapter.MessageConverter):
                 )
 
 class GewechatEventConverter(adapter.EventConverter):
-    
+
+    def __init__(self, config: dict):
+        self.config = config
+        self.message_converter = GewechatMessageConverter(config)
+
     @staticmethod
     async def yiri2target(
         event: platform_events.MessageEvent
     ) -> dict:
         pass
 
-    @staticmethod
     async def target2yiri(
+        self,
         event: dict,
         bot_account_id: str
     ) -> platform_events.MessageEvent:
-        message_chain = await GewechatMessageConverter.target2yiri(copy.deepcopy(event), bot_account_id)
+        message_chain = await self.message_converter.target2yiri(
+            copy.deepcopy(event),
+            bot_account_id
+        )
 
         if not message_chain:
             return None
@@ -172,8 +201,8 @@ class GeWeChatAdapter(adapter.MessagePlatformAdapter):
 
     ap: app.Application
 
-    message_converter: GewechatMessageConverter = GewechatMessageConverter()
+    message_converter: GewechatMessageConverter
-    event_converter: GewechatEventConverter = GewechatEventConverter()
+    event_converter: GewechatEventConverter
 
     listeners: typing.Dict[
         typing.Type[platform_events.Event],
@@ -186,6 +215,9 @@ class GeWeChatAdapter(adapter.MessagePlatformAdapter):
 
         self.quart_app = quart.Quart(__name__)
 
+        self.message_converter = GewechatMessageConverter(config=config)
+        self.event_converter = GewechatEventConverter(config=config)
+
         @self.quart_app.route('/gewechat/callback', methods=['POST'])
         async def gewechat_callback():
             data = await quart.request.json

pkg/utils/image.py

@@ -8,6 +8,60 @@ import aiohttp
 import PIL.Image
 import httpx
 
+
+async def get_gewechat_image_base64(gewechat_url: str, app_id: str, xml_content: str, image_type: int = 2) -> \
+typing.Tuple[str, str]:
+    """从gewechat服务器获取图片并转换为base64格式
+
+    Args:
+        gewechat_url (str): gewechat服务器地址
+        app_id (str): gewechat应用ID
+        xml_content (str): 图片的XML内容
+        image_type (int, optional): 图片类型. Defaults to 2.
+            1: 高清图片
+            2: 常规图片
+            3: 缩略图
+
+    Returns:
+        typing.Tuple[str, str]: (base64编码, 图片格式)
+
+    Raises:
+        Exception: 当图片下载或处理失败时抛出异常
+    """
+    async with aiohttp.ClientSession() as session:
+        # 获取图片下载链接
+        async with session.post(
+                f"{gewechat_url}/v2/api/message/downloadImage",
+                json={
+                    "app_id": app_id,
+                    "type": image_type,
+                    "xml": xml_content
+                }
+        ) as response:
+            if response.status != 200:
+                raise Exception(f"获取gewechat图片下载失败: {await response.text()}")
+
+            resp_data = await response.json()
+            if resp_data.get("ret") != 200:
+                raise Exception(f"获取gewechat图片下载链接失败: {resp_data}")
+
+            image_url = f"{gewechat_url}{resp_data['data']['fileUrl']}"
+
+            # 下载图片内容
+            async with session.get(image_url) as img_response:
+                if img_response.status != 200:
+                    raise Exception(f"下载gewechat图片失败: {await img_response.text()}")
+
+                # 获取图片格式
+                content_type = img_response.headers.get('Content-Type', '')
+                image_format = content_type.split('/')[-1]  # 例如 'image/jpeg' -> 'jpeg'
+
+                # 读取图片数据并转换为base64
+                image_data = await img_response.read()
+                base64_str = base64.b64encode(image_data).decode('utf-8')
+
+                return base64_str, image_format
+
 async def get_wecom_image_base64(pic_url: str) -> tuple[str, str]:
     """
     下载企业微信图片并转换为 base64