fix: 占位符替换 - 新增 selected_text 字段彻底解决位置偏移问题

- 新增 generation_points.selected_text 字段存储用户实际选中的文本
- 生成任务优先使用 selected_text 直改 docx，不再依赖脆弱的位置偏移
- 前端创建生成点时同时传递选中文本内容
- 原始 docx 直改方案完美保留所有样式(加粗/标题/表格)
- 端到端验证: {{ placeholder }} → AI 内容替换成功，样式不变

backend/alembic/versions/011bde04d871_add_selected_text_to_generation_points.py

@@ -0,0 +1,27 @@
+"""Add selected_text to generation_points
+
+Revision ID: 011bde04d871
+Revises: 857f5a3874dd
+Create Date: 2026-07-06 18:19:15.771438
+"""
+from typing import Sequence, Union
+from alembic import op
+import sqlalchemy as sa
+
+
+revision: str = '011bde04d871'
+down_revision: Union[str, None] = '857f5a3874dd'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.add_column('generation_points', sa.Column('selected_text', sa.Text(), nullable=True))
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_column('generation_points', 'selected_text')
+    # ### end Alembic commands ###

backend/app/api/generation_points.py

@@ -25,6 +25,7 @@ async def create_generation_point(
     prompt: str = Form(...),
     model_id: uuid.UUID | None = Form(None),
     order: int = Form(0),
+    selected_text: str | None = Form(None),
     ref_file: UploadFile | None = File(None),
     db: AsyncSession = Depends(get_db),
 ):
@@ -51,6 +52,7 @@ async def create_generation_point(
         model_id=model_id,
         order=order,
         ref_file_path=ref_file_path,
+        selected_text=selected_text,
     )
     db.add(point)
     await db.flush()

backend/app/models/generation_point.py

@@ -19,6 +19,7 @@ class GenerationPoint(Base, UUIDMixin, TimestampMixin):
     )
     ref_file_path: Mapped[str | None] = mapped_column(String(500), nullable=True)
     order: Mapped[int] = mapped_column(Integer, default=0, nullable=False)
+    selected_text: Mapped[str | None] = mapped_column(Text, nullable=True)
 
     template = relationship("Template")
     model = relationship("AIModel")

backend/app/schemas/generation_point.py

@@ -9,6 +9,7 @@ class GenerationPointCreate(BaseModel):
     prompt: str
     model_id: uuid.UUID | None = None
     order: int = 0
+    selected_text: str | None = None
 
 
 class GenerationPointUpdate(BaseModel):
@@ -16,6 +17,7 @@ class GenerationPointUpdate(BaseModel):
     prompt: str | None = None
     model_id: uuid.UUID | None = None
     order: int | None = None
+    selected_text: str | None = None
 
 
 class GenerationPointResponse(BaseModel):
@@ -26,6 +28,7 @@ class GenerationPointResponse(BaseModel):
     model_id: uuid.UUID | None = None
     ref_file_path: str | None = None
     order: int
+    selected_text: str | None = None
     created_at: datetime
     updated_at: datetime
 

backend/app/tasks/generate.py

@@ -26,23 +26,28 @@ def _create_db_session() -> async_sessionmaker[AsyncSession]:
     return async_sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)
 
 
+def _strip_html(html: str) -> str:
+    from html.parser import HTMLParser
+
+    class Stripper(HTMLParser):
+        def __init__(self):
+            super().__init__()
+            self.text = ""
+        def handle_data(self, data):
+            self.text += data
+
+    s = Stripper()
+    s.feed(html)
+    return s.text
+
+
 def _get_selected_text(html_content: str, position: dict) -> str:
     start = position.get("start", 0)
     end = position.get("end", 0)
-    if 0 <= start < end <= len(html_content):
-        from html.parser import HTMLParser
 
-        class TextStripper(HTMLParser):
-            def __init__(self):
-                super().__init__()
-                self.text = ""
-
-            def handle_data(self, data):
-                self.text += data
-
-        stripper = TextStripper()
-        stripper.feed(html_content[start:end])
-        return stripper.text.strip()
+    plain_text = _strip_html(html_content)
+    if 0 <= start < end <= len(plain_text):
+        return plain_text[start:end].strip()
 
     return ""
 
@@ -141,7 +146,7 @@ async def _generate_document(task_id: str) -> None:
 
         try:
             for point in points:
-                selected_text = _get_selected_text(html_content, point.position)
+                selected_text = point.selected_text or _get_selected_text(html_content, point.position)
                 if not selected_text:
                     continue
 

web/src/api/generationPoints.ts

@@ -14,6 +14,7 @@ export async function createGenerationPoint(body: {
   prompt: string;
   model_id?: string;
   order?: number;
+  selected_text?: string;
   ref_file?: File;
 }) {
   const formData = new FormData();
@@ -22,6 +23,7 @@ export async function createGenerationPoint(body: {
   formData.append("prompt", body.prompt);
   if (body.model_id) formData.append("model_id", body.model_id);
   if (body.order !== undefined) formData.append("order", String(body.order));
+  if (body.selected_text) formData.append("selected_text", body.selected_text);
   if (body.ref_file) formData.append("ref_file", body.ref_file);
   const { data } = await request.post<GenerationPoint>("/generation-points", formData);
   return data;

web/src/pages/TemplateEditor.tsx

@@ -155,6 +155,7 @@ export default function TemplateEditor() {
           prompt: values.prompt,
           model_id: values.model_id,
           order: points.length,
+          selected_text: selectionRef.current?.text,
           ref_file: refFile,
         });
         message.success("创建成功");