【Swift】GRDB数据库本地存储聊天记录

　　

//
//  DataManager.swift
//  GRDBDemo
//
//  Created by Apple on 2021/4/21.
//


import GRDB

struct DataBaseName {
    /// 数据库名字
    static let test = "conversation.db"
}

/// 数据库表名
struct TableName {
    
    static let message = "ChatMessage"
}

/// 数据库连接
class DBManager: NSObject {
    /// 数据库路径
    private static var dbPath: String = {
        // 获取工程内容数据库名字
        let filePath: String = NSSearchPathForDirectoriesInDomains(FileManager.SearchPathDirectory.documentDirectory, FileManager.SearchPathDomainMask.userDomainMask, true).first!.appending("/(DataBaseName.test)")
        
        //print("数据库地址：", filePath as Any)
        return filePath
    }()
    
    /// 数据库配置
    private static var configuration: Configuration = {
        // 配置
        var configuration = Configuration()
        // 设置超时
        configuration.busyMode = Database.BusyMode.timeout(5.0)
        // 试图访问锁着的数据
        //configuration.busyMode = Database.BusyMode.immediateError
        
        return configuration
    }()
    
    // MARK: 创建数据 多线程
    /// 数据库 用于多线程事务处理
    static var dbQueue: DatabaseQueue = {
        // 创建数据库
        let db = try! DatabaseQueue(path: DBManager.dbPath, configuration: DBManager.configuration)
        db.releaseMemory()
        // 设备版本
        return db
    }()
}

//
//  ChatMessage.swift
//  GRDBDemo
//
//  Created by Apple on 2021/4/21.
//

import Foundation
import GRDB

/// 聊天消息类
struct ChatMessage: Codable {
    
    var messageId : String?
    var messageType : String?
    var messageContent : String?
    var senderId : String?
    var targetId : String?
    
    private enum Columns: String, CodingKey, ColumnExpression {
        
        case messageId
        case messageType
        case messageContent
        case senderId
        case targetId
    }
}

extension ChatMessage: MutablePersistableRecord, FetchableRecord {
    /// 获取数据库对象
    private static let dbQueue: DatabaseQueue = DBManager.dbQueue
    
    //MARK: 创建
    /// 创建数据库
    private static func createTable() -> Void {
        try! self.dbQueue.inDatabase { (db) -> Void in
            // 判断是否存在数据库
            if try db.tableExists(TableName.message) {
                debugPrint("表已经存在")
                return
            }
            // 创建数据库表
            try db.create(table: TableName.message, temporary: false, ifNotExists: true, body: { (t) in
                t.column(Columns.messageId.rawValue, Database.ColumnType.text)
                t.column(Columns.messageType.rawValue, Database.ColumnType.text)
                t.column(Columns.messageContent.rawValue, Database.ColumnType.text)
                t.column(Columns.senderId.rawValue, Database.ColumnType.text)
                t.column(Columns.targetId.rawValue, Database.ColumnType.text)
            })
        }
    }
    
    //MARK: 插入
    /// 插入单个数据
    static func insert(message: ChatMessage) -> Void {
        // 判断是否存在
        guard ChatMessage.query(messageId: message.messageId!) == nil else {
            debugPrint("插入消息 内容重复")
            // 更新
            self.update(message: message)
            return
        }
        
        // 创建表
        self.createTable()
        // 事务
        try! self.dbQueue.inTransaction { (db) -> Database.TransactionCompletion in
            do {
                var messageTemp = message
                // 插入到数据库
                try messageTemp.insert(db)
                return Database.TransactionCompletion.commit
            } catch {
                return Database.TransactionCompletion.rollback
            }
        }
    }
    
    //MARK: 查询一条记录
    static func query(messageId: String) -> ChatMessage? {
        // 创建数据库
        self.createTable()
        // 返回查询结果
        return try! self.dbQueue.unsafeRead({ (db) -> ChatMessage? in
            return try ChatMessage.filter(Column(Columns.messageId.rawValue) == messageId).fetchOne(db)
        })
    }
    
    //MARK:查询与某人聊天的多条记录 - 从第几页开始
    static func query(userId:String,page:Int) -> [ChatMessage] {
        // 创建数据库
        self.createTable()
        
        return try! self.dbQueue.unsafeRead({ (db) -> [ChatMessage] in
            return try ChatMessage.fetchAll(db, sql: "Select * from ChatMessage where senderId = '(userId)' or targetId = '(userId)' limit (20 * page),20")
        })
    }
    
    /// 查询所有
    static func queryAll() -> [ChatMessage] {
        // 创建数据库
        self.createTable()
        // 返回查询结果
        return try! self.dbQueue.unsafeRead({ (db) -> [ChatMessage] in
            return try ChatMessage.fetchAll(db)
        })
    }
    
    //MARK: 更新
    /// 更新
    static func update(message: ChatMessage) -> Void {
        /// 创建数据库表
        self.createTable()
        // 事务 更新场景
        try! self.dbQueue.inTransaction { (db) -> Database.TransactionCompletion in
            do {
                // 赋值
                try message.update(db)
                return Database.TransactionCompletion.commit
            } catch {
                return Database.TransactionCompletion.rollback
            }
        }
    }
    
    //MARK: 删除
    /// 根据messageId删除聊天记录
    static func delete(messageId: String) -> Void {
        // 查询
        guard let message = self.query(messageId: messageId) else {
            return
        }
        // 删除
        self.delete(message: message)
    }
    
    /// 删除单个聊天信息
    static func delete(message: ChatMessage) -> Void {
        // 是否有数据库表
        self.createTable()
        // 事务
        try! self.dbQueue.inTransaction { (db) -> Database.TransactionCompletion in
            do {
                // 删除数据
                try message.delete(db)
                return Database.TransactionCompletion.commit
            } catch {
                return Database.TransactionCompletion.rollback
            }
        }
    }
}

 　　使用示例：

override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
   
        let user1 = ChatMessage(messageId: "1010", messageType: "text", messageContent: "12345", senderId: "1", targetId: "2")
        ChatMessage.insert(message: user1)
        
        let user2 = ChatMessage(messageId: "1012", messageType: "text", messageContent: "12345", senderId: "123", targetId: "2")
        ChatMessage.insert(message: user2)
        
        let user3 = ChatMessage(messageId: "1013", messageType: "text", messageContent: "12345", senderId: "1", targetId: "123")
        ChatMessage.insert(message: user3)
        
        let user4 = ChatMessage(messageId: "1014", messageType: "text", messageContent: "12345", senderId: "1", targetId: "2")
        ChatMessage.insert(message: user4)
        
        let user5 = ChatMessage(messageId: "1015", messageType: "text", messageContent: "12345", senderId: "1", targetId: "123")
        ChatMessage.insert(message: user5)
        
        let user6 = ChatMessage(messageId: "1016", messageType: "text", messageContent: "12345", senderId: "123", targetId: "2")
        ChatMessage.insert(message: user6)
        
        let user7 = ChatMessage(messageId: "1017", messageType: "text", messageContent: "12345", senderId: "1", targetId: "2")
        ChatMessage.insert(message: user7)
        
        let user8 = ChatMessage(messageId: "1018", messageType: "text", messageContent: "12345", senderId: "1", targetId: "123")
        ChatMessage.insert(message: user8)
        
        let message1 = ChatMessage.query(userId: "123", page: 0)
        print(message1)

    }