fix: kb add pdf support

backend/app/api/knowledge.py

@@ -50,6 +50,23 @@ def _extract_upload_text(filename: str, content: bytes) -> str:
     if lower.endswith((".xls", ".xlsx")):
         df = pd.read_excel(io.BytesIO(content))
         return df.to_csv(index=False)
+    
+    # 增加对 PDF 的文本提取支持
+    if lower.endswith(".pdf"):
+        try:
+            import PyPDF2
+            pdf_reader = PyPDF2.PdfReader(io.BytesIO(content))
+            text = []
+            for page in pdf_reader.pages:
+                page_text = page.extract_text()
+                if page_text:
+                    text.append(page_text)
+            return "\n".join(text)
+        except ImportError:
+            raise ValueError("PyPDF2 is not installed. Cannot parse PDF files.")
+        except Exception as e:
+            raise ValueError(f"Failed to parse PDF: {str(e)}")
+            
     raise ValueError("Unsupported file type")
 
 
@@ -238,8 +255,9 @@ async def upload_knowledge_documents(
         content = await file.read()
         if not content:
             continue
-        if len(content) > 5 * 1024 * 1024:
+        # 将大小限制从 5MB 放宽到 15MB，以更好地支持带有图片的 PDF 文件
-            raise HTTPException(status_code=400, detail=f"文件过大: {filename}")
+        if len(content) > 15 * 1024 * 1024:
+            raise HTTPException(status_code=400, detail=f"文件过大 (超过 15MB): {filename}")
         try:
             text = _extract_upload_text(filename, content)
         except Exception:

backend/pyproject.toml

@@ -31,6 +31,7 @@ dependencies = [
     "psycopg2-binary>=2.9.11",
     "pydantic>=2.12.0,<3.0.0",
     "pydantic-settings>=2.12.0,<3.0.0",
+    "pypdf2>=3.0.0",
     "python-dotenv>=1.0.1",
     "python-jose[cryptography]>=3.5.0",
     "python-multipart>=0.0.22",

backend/uv.lock

@@ -245,6 +245,7 @@ dependencies = [
     { name = "psycopg2-binary" },
     { name = "pydantic" },
     { name = "pydantic-settings" },
+    { name = "pypdf2" },
     { name = "python-dotenv" },
     { name = "python-jose", extra = ["cryptography"] },
     { name = "python-multipart" },
@@ -293,6 +294,7 @@ requires-dist = [
     { name = "psycopg2-binary", specifier = ">=2.9.11" },
     { name = "pydantic", specifier = ">=2.12.0,<3.0.0" },
     { name = "pydantic-settings", specifier = ">=2.12.0,<3.0.0" },
+    { name = "pypdf2", specifier = ">=3.0.0" },
     { name = "python-dotenv", specifier = ">=1.0.1" },
     { name = "python-jose", extras = ["cryptography"], specifier = ">=3.5.0" },
     { name = "python-multipart", specifier = ">=0.0.22" },
@@ -2660,6 +2662,15 @@ crypto = [
     { name = "cryptography" },
 ]
 
+[[package]]
+name = "pypdf2"
+version = "3.0.1"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/9f/bb/18dc3062d37db6c491392007dfd1a7f524bb95886eb956569ac38a23a784/PyPDF2-3.0.1.tar.gz", hash = "sha256:a74408f69ba6271f71b9352ef4ed03dc53a31aa404d29b5d31f53bfecfee1440", size = 227419, upload-time = "2022-12-31T10:36:13.13Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/8e/5e/c86a5643653825d3c913719e788e41386bee415c2b87b4f955432f2de6b2/pypdf2-3.0.1-py3-none-any.whl", hash = "sha256:d16e4205cfee272fbdc0568b68d82be796540b1537508cef59388f839c191928", size = 232572, upload-time = "2022-12-31T10:36:10.327Z" },
+]
+
 [[package]]
 name = "python-dateutil"
 version = "2.9.0.post0"