用单例实现数据库操作,弃用全局变量

app/DataBase/msg.py

@@ -1,96 +1,126 @@
 import os.path
 import sqlite3
 import threading
+import traceback
 from pprint import pprint
 
+from app.log import logger
+
 DB = None
 cursor = None
 db_path = "./app/Database/Msg/MSG.db"
 lock = threading.Lock()
 
-# misc_path = './Msg/Misc.db'
-if os.path.exists(db_path):
-    DB = sqlite3.connect(db_path, check_same_thread=False)
-    # '''创建游标'''
-    cursor = DB.cursor()
-
 
 def is_database_exist():
     return os.path.exists(db_path)
 
 
-def init_database():
-    global DB
-    global cursor
-    if not DB:
-        if os.path.exists(db_path):
-            DB = sqlite3.connect(db_path, check_same_thread=False)
-            # '''创建游标'''
-            cursor = DB.cursor()
+def singleton(cls):
+    _instance = {}
+
+    def inner():
+        if cls not in _instance:
+            _instance[cls] = cls()
+        return _instance[cls]
+
+    return inner
 
 
-def get_messages(username_):
-    sql = '''
-        select localId,TalkerId,Type,SubType,IsSender,CreateTime,Status,StrContent,strftime('%Y-%m-%d %H:%M:%S',CreateTime,'unixepoch','localtime') as StrTime
-        from MSG
-        where StrTalker=?
-        order by CreateTime
-    '''
-    try:
-        lock.acquire(True)
-        cursor.execute(sql, [username_])
-        result = cursor.fetchall()
-    finally:
-        lock.release()
-    result.sort(key=lambda x: x[5])
-    return result
+@singleton
+class Msg:
+    def __init__(self):
+        self.DB = None
+        self.cursor = None
+        self.open_flag = False
+        self.init_database()
 
+    def init_database(self):
+        if not self.open_flag:
+            if os.path.exists(db_path):
+                self.DB = sqlite3.connect(db_path, check_same_thread=False)
+                # '''创建游标'''
+                self.cursor = self.DB.cursor()
+                self.open_flag = True
+                if lock.locked():
+                    lock.release()
 
-def get_messages_all():
-    sql = '''
-        select localId,TalkerId,Type,SubType,IsSender,CreateTime,Status,StrContent,strftime('%Y-%m-%d %H:%M:%S',CreateTime,'unixepoch','localtime') as StrTime
-        from MSG
-        order by CreateTime
-    '''
-    try:
-        lock.acquire(True)
-        cursor.execute(sql)
-        result = cursor.fetchall()
-    finally:
-        lock.release()
-    result.sort(key=lambda x: x[5])
-    return result
-
-
-def get_message_by_num(username_, local_id):
-    sql = '''
+    def get_messages(self, username_):
+        if not self.open_flag:
+            return None
+        sql = '''
             select localId,TalkerId,Type,SubType,IsSender,CreateTime,Status,StrContent,strftime('%Y-%m-%d %H:%M:%S',CreateTime,'unixepoch','localtime') as StrTime
             from MSG
-            where StrTalker = ? and localId < ?
-            order by CreateTime desc 
-            limit 10 
+            where StrTalker=?
+            order by CreateTime
         '''
-    try:
-        lock.acquire(True)
-        cursor.execute(sql, [username_, local_id])
-        result = cursor.fetchall()
-    finally:
-        lock.release()
-    # result.sort(key=lambda x: x[5])
-    return result
+        try:
+            lock.acquire(True)
+            self.cursor.execute(sql, [username_])
+            result = self.cursor.fetchall()
+        finally:
+            lock.release()
+        result.sort(key=lambda x: x[5])
+        return result
 
+    def get_messages_all(self):
+        sql = '''
+            select localId,TalkerId,Type,SubType,IsSender,CreateTime,Status,StrContent,strftime('%Y-%m-%d %H:%M:%S',CreateTime,'unixepoch','localtime') as StrTime
+            from MSG
+            order by CreateTime
+        '''
+        if not self.open_flag:
+            return None
+        try:
+            lock.acquire(True)
+            self.cursor.execute(sql)
+            result = self.cursor.fetchall()
+        finally:
+            lock.release()
+        result.sort(key=lambda x: x[5])
+        return result
 
-def close():
-    global DB
-    if DB:
-        DB.close()
+    def get_message_by_num(self, username_, local_id):
+        sql = '''
+                select localId,TalkerId,Type,SubType,IsSender,CreateTime,Status,StrContent,strftime('%Y-%m-%d %H:%M:%S',CreateTime,'unixepoch','localtime') as StrTime
+                from MSG
+                where StrTalker = ? and localId < ?
+                order by CreateTime desc 
+                limit 10 
+            '''
+        result = None
+        if not self.open_flag:
+            return None
+        try:
+            lock.acquire(True)
+            self.cursor.execute(sql, [username_, local_id])
+            result = self.cursor.fetchall()
+        except sqlite3.DatabaseError:
+            logger.error(f'{traceback.format_exc()}\n数据库损坏请删除msg文件夹重试')
+        finally:
+            lock.release()
+        # result.sort(key=lambda x: x[5])
+        return result
+
+    def close(self):
+        if self.open_flag:
+            try:
+                lock.acquire(True)
+                self.open_flag = False
+                self.DB.close()
+            finally:
+                lock.release()
+
+    def __del__(self):
+        self.close()
 
 
 if __name__ == '__main__':
-    msg_root_path = './Msg/'
-    init_database()
-    result = get_message_by_num('wxid_0o18ef858vnu22', 9999999)
+    db_path = "./Msg/MSG.db"
+    msg = Msg()
+    msg.init_database()
+    result = msg.get_message_by_num('wxid_0o18ef858vnu22', 9999999)
     print(result)
     print(result[-1][0])
     local_id = result[-1][0]
-    pprint(get_message_by_num('wxid_0o18ef858vnu22', local_id))
+    pprint(msg.get_message_by_num('wxid_0o18ef858vnu22', local_id))