✨ 实现 Post.content 相关扩展协议 (#553)

* ✨ `post` 新增 `get_content()` 方法

* 🚨 make linter happy

* 💄 auto fix by pre-commit hooks

* 🐛 fix: 调整函数使用

* 💄 auto fix by pre-commit hooks

* ✨ 转用函数处理文本

* 💄 auto fix by pre-commit hooks

* 🔨 使用`Dict`存储`content_handlers`

* 💄 auto fix by pre-commit hooks

* 🎨 fix

* :arts: 简化函数使用

* 🐛 移除`Theme`的过时参数

* 🗑️ 复用 `self.plain_content`

* 💄 auto fix by pre-commit hooks

* ✨ 注册式装饰器写法

* 💄 auto fix by pre-commit hooks

* 🐛 fix

* 💄 auto fix by pre-commit hooks

* :feat: 通用纯文本处理函数

* 💄 auto fix by pre-commit hooks

* :downgrade: 复用`==`处理标题

* 🎨 简化（？）写法

* ✅ 测试修复

* ♻️ via ContentSupport extensions

* 🐛 fix test

* 💄 auto fix by pre-commit hooks

* 🐛 for clean text

* 🐛 fix

* 💄 auto fix by pre-commit hooks

* fix: for xml

* 💄 auto fix by pre-commit hooks

* chore: art

* 💄 auto fix by pre-commit hooks

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

nonebot_bison/theme/themes/ht2i/build.py

@@ -5,6 +5,7 @@ from typing import TYPE_CHECKING, Literal
 from nonebot_plugin_saa import Text, Image, MessageSegmentFactory
 
 from nonebot_bison.theme import Theme, ThemeRenderError
+from nonebot_bison.post.protocol import HTMLContentSupport
 from nonebot_bison.utils import pic_merge, is_pics_mergable
 
 if TYPE_CHECKING:
@@ -30,16 +31,28 @@ class Ht2iTheme(Theme):
             raise ThemeRenderError(f"渲染文本失败: {e}")
 
     async def render(self, post: "Post"):
+
         md_text = ""
 
         md_text += f"## {post.title}\n\n" if post.title else ""
 
-        md_text += post.content if len(post.content) < 500 else f"{post.content[:500]}..."
+        if isinstance(post, HTMLContentSupport):
+            content = await post.get_html_content()
+        else:
+            content = await post.get_content()
+        md_text += content if len(content) < 500 else f"{content[:500]}..."
         md_text += "\n\n"
         if rp := post.repost:
             md_text += f"> 转发自 {f'**{rp.nickname}**' if rp.nickname else ''}:  \n"
             md_text += f"> {rp.title}  \n" if rp.title else ""
-            md_text += ">  \n> " + rp.content if len(rp.content) < 500 else f"{rp.content[:500]}..." + "  \n"
+            if isinstance(rp, HTMLContentSupport):
+                rp_content = await rp.get_html_content()
+            else:
+                rp_content = await rp.get_content()
+
+            md_text += (
+                ">  \n> " + rp_content if len(rp_content) < 500 else f"{rp_content[:500]}..." + "  \n"  # noqa: E501
+            )  # noqa: E501
         md_text += "\n\n"
 
         md_text += f"###### 来源: {post.platform.name} {post.nickname or ''}\n"