feat: 增加sqlite 数据库支持

backend/__init__.py

@@ -1,9 +1,10 @@
 import os
+from pathlib import Path
+
 import yaml
 from flask import Flask
-from flask_sqlalchemy import SQLAlchemy
 from flask_cors import CORS
-from pathlib import Path
+from flask_sqlalchemy import SQLAlchemy
 
 # Initialize db BEFORE importing models/routes that depend on it
 db = SQLAlchemy()
@@ -15,15 +16,40 @@ def load_config():
         return yaml.safe_load(f)
 
 
+def _get_database_uri(cfg: dict) -> str:
+    """Build database URI based on database type."""
+    db_type = cfg.get("db_type", "mysql").lower()
+
+    if db_type == "sqlite":
+        # SQLite: sqlite:///path/to/database.db
+        db_file = cfg.get("db_sqlite_file", "app.db")
+        # Store in instance folder for better organization
+        instance_path = Path(__file__).parent.parent / "instance"
+        instance_path.mkdir(exist_ok=True)
+        db_path = instance_path / db_file
+        return f"sqlite:///{db_path}"
+
+    elif db_type == "postgresql":
+        # PostgreSQL: postgresql://user:password@host:port/database
+        return (
+            f"postgresql://{cfg['db_user']}:{cfg['db_password']}"
+            f"@{cfg.get('db_host', 'localhost')}:{cfg.get('db_port', 5432)}/{cfg['db_name']}"
+        )
+
+    else:  # mysql (default)
+        # MySQL: mysql+pymysql://user:password@host:port/database?charset=utf8mb4
+        return (
+            f"mysql+pymysql://{cfg['db_user']}:{cfg['db_password']}"
+            f"@{cfg.get('db_host', 'localhost')}:{cfg.get('db_port', 3306)}/{cfg['db_name']}"
+            f"?charset=utf8mb4"
+        )
+
+
 def create_app():
     cfg = load_config()
 
     app = Flask(__name__)
-    app.config["SQLALCHEMY_DATABASE_URI"] = (
-        f"mysql+pymysql://{cfg['db_user']}:{cfg['db_password']}"
-        f"@{cfg.get('db_host', 'localhost')}:{cfg.get('db_port', 3306)}/{cfg['db_name']}"
-        f"?charset=utf8mb4"
-    )
+    app.config["SQLALCHEMY_DATABASE_URI"] = _get_database_uri(cfg)
     app.config["SQLALCHEMY_TRACK_MODIFICATIONS"] = False
 
     # Enable CORS for all routes

backend/models.py

@@ -1,12 +1,35 @@
-from datetime import datetime, timezone
-from sqlalchemy.dialects.mysql import LONGTEXT
 from backend import db
+from datetime import datetime, timezone
+from flask import current_app
+from sqlalchemy import Text
+from sqlalchemy.dialects.mysql import LONGTEXT as MYSQL_LONGTEXT
+
+
+
+def get_longtext_type():
+    """Get appropriate text type for long content based on database dialect."""
+    db_uri = current_app.config.get("SQLALCHEMY_DATABASE_URI", "")
+    if db_uri.startswith("mysql"):
+        return MYSQL_LONGTEXT
+    return Text  # SQLite and PostgreSQL use Text
+
+
+# For model definitions, we'll use a callable that returns the right type
+class LongText(db.TypeDecorator):
+    """Cross-database LONGTEXT type that works with MySQL, SQLite, and PostgreSQL."""
+    impl = Text
+    cache_ok = True
+
+    def load_dialect_impl(self, dialect):
+        if dialect.name == "mysql":
+            return dialect.type_descriptor(MYSQL_LONGTEXT)
+        return dialect.type_descriptor(Text)
 
 
 class User(db.Model):
     __tablename__ = "users"
 
-    id = db.Column(db.BigInteger, primary_key=True, autoincrement=True)
+    id = db.Column(db.Integer, primary_key=True, autoincrement=True)
     username = db.Column(db.String(50), unique=True, nullable=False)
     password = db.Column(db.String(255), nullable=True)  # Allow NULL for third-party login
     phone = db.Column(db.String(20))
@@ -20,7 +43,7 @@ class Conversation(db.Model):
     __tablename__ = "conversations"
 
     id = db.Column(db.String(64), primary_key=True)
-    user_id = db.Column(db.BigInteger, db.ForeignKey("users.id"), nullable=False, index=True)
+    user_id = db.Column(db.Integer, db.ForeignKey("users.id"), nullable=False, index=True)
     title = db.Column(db.String(255), nullable=False, default="")
     model = db.Column(db.String(64), nullable=False, default="glm-5")
     system_prompt = db.Column(db.Text, default="")
@@ -43,9 +66,9 @@ class Message(db.Model):
     conversation_id = db.Column(db.String(64), db.ForeignKey("conversations.id"), 
                                 nullable=False, index=True)
     role = db.Column(db.String(16), nullable=False)  # user, assistant, system, tool
-    content = db.Column(LONGTEXT, default="")  # LONGTEXT for long conversations
+    content = db.Column(LongText, default="")  # LongText for long conversations
     token_count = db.Column(db.Integer, default=0)
-    thinking_content = db.Column(LONGTEXT, default="")
+    thinking_content = db.Column(LongText, default="")
     created_at = db.Column(db.DateTime, default=lambda: datetime.now(timezone.utc), index=True)
 
     # Tool call support - relation to ToolCall table
@@ -58,14 +81,14 @@ class ToolCall(db.Model):
     """Tool call record - separate table, follows database normalization"""
     __tablename__ = "tool_calls"
 
-    id = db.Column(db.BigInteger, primary_key=True, autoincrement=True)
+    id = db.Column(db.Integer, primary_key=True, autoincrement=True)
     message_id = db.Column(db.String(64), db.ForeignKey("messages.id"), 
                            nullable=False, index=True)
     call_id = db.Column(db.String(64), nullable=False)  # Tool call ID
     call_index = db.Column(db.Integer, nullable=False, default=0)  # Call order
     tool_name = db.Column(db.String(64), nullable=False)  # Tool name
-    arguments = db.Column(LONGTEXT, nullable=False)  # Call arguments JSON
-    result = db.Column(LONGTEXT)  # Execution result JSON
+    arguments = db.Column(LongText, nullable=False)  # Call arguments JSON
+    result = db.Column(LongText)  # Execution result JSON
     execution_time = db.Column(db.Float, default=0)  # Execution time (seconds)
     created_at = db.Column(db.DateTime, default=lambda: datetime.now(timezone.utc))
 
@@ -77,8 +100,8 @@ class ToolCall(db.Model):
 class TokenUsage(db.Model):
     __tablename__ = "token_usage"
 
-    id = db.Column(db.BigInteger, primary_key=True, autoincrement=True)
-    user_id = db.Column(db.BigInteger, db.ForeignKey("users.id"), 
+    id = db.Column(db.Integer, primary_key=True, autoincrement=True)
+    user_id = db.Column(db.Integer, db.ForeignKey("users.id"), 
                         nullable=False, index=True)
     date = db.Column(db.Date, nullable=False, index=True)
     model = db.Column(db.String(64), nullable=False)

backend/utils/helpers.py

@@ -1,11 +1,13 @@
 """Common helper functions"""
 import json
-from datetime import datetime, date
+from datetime import date, datetime
+from typing import Any
+from flask import jsonify
 from backend import db
-from backend.models import Conversation, Message, User, TokenUsage
+from backend.models import Conversation, Message, TokenUsage, User
 
 
-def get_or_create_default_user():
+def get_or_create_default_user() -> User:
     """Get or create default user"""
     user = User.query.filter_by(username="default").first()
     if not user:
@@ -22,13 +24,11 @@ def ok(data=None, message=None):
         body["data"] = data
     if message is not None:
         body["message"] = message
-    from flask import jsonify
     return jsonify(body)
 
 
 def err(code, message):
     """Error response helper"""
-    from flask import jsonify
     return jsonify({"code": code, "message": message}), code