chore: 基础设施 — 阿里云源、北京时间、HEX计数器、打印机配置

backend/app/services/counter_service.py

@@ -0,0 +1,26 @@
+"""16进制自增计数器 — 基于 PostgreSQL Sequence，生成 16 位 HEX 唯一 ID"""
+from sqlalchemy import text
+from sqlalchemy.ext.asyncio import AsyncSession
+
+SEQUENCE_NAME = "product_hex_counter"
+
+
+async def ensure_sequence(db: AsyncSession) -> None:
+    """确保 counter sequence 存在（幂等）"""
+    await db.execute(
+        text(f"CREATE SEQUENCE IF NOT EXISTS {SEQUENCE_NAME} START 1;")
+    )
+
+
+async def next_hex_id(db: AsyncSession, length: int = 16) -> str:
+    """
+    生成下一个 hex ID。
+
+    示例: 1 → "0000000000000001"
+          15 → "000000000000000F"
+          16 → "0000000000000010"
+          255 → "00000000000000FF"
+    """
+    result = await db.execute(text(f"SELECT nextval('{SEQUENCE_NAME}');"))
+    counter: int = result.scalar_one()
+    return format(counter, f"0{length}X")

backend/app/services/print_config.py

@@ -0,0 +1,44 @@
+"""打印机配置管理 — JSON 文件持久化"""
+import json
+import os
+from pathlib import Path
+
+CONFIG_DIR = Path(__file__).resolve().parent.parent.parent / "data"
+CONFIG_FILE = CONFIG_DIR / "printer_config.json"
+
+DEFAULT_CONFIG = {
+    "label_printer": {
+        "ip": "192.168.9.221",
+        "port": 9100,
+        "enabled": False,
+    },
+}
+
+
+class PrintConfigManager:
+    """打印机 IP/端口 配置读写"""
+
+    @staticmethod
+    def _ensure_file() -> None:
+        if not CONFIG_DIR.exists():
+            CONFIG_DIR.mkdir(parents=True)
+        if not CONFIG_FILE.exists():
+            PrintConfigManager.save_config(DEFAULT_CONFIG)
+
+    @staticmethod
+    def get_config() -> dict:
+        PrintConfigManager._ensure_file()
+        with open(CONFIG_FILE, "r", encoding="utf-8") as f:
+            return json.load(f)
+
+    @staticmethod
+    def save_config(config: dict) -> None:
+        if not CONFIG_DIR.exists():
+            CONFIG_DIR.mkdir(parents=True)
+        with open(CONFIG_FILE, "w", encoding="utf-8") as f:
+            json.dump(config, f, indent=2, ensure_ascii=False)
+
+    @staticmethod
+    def get_printer(name: str = "label_printer") -> dict:
+        config = PrintConfigManager.get_config()
+        return config.get(name, DEFAULT_CONFIG.get("label_printer", {}))