swiftUI笔记之WCDB实践

目标

为chatGpt聊天窗口添加支持本地持久化，操作方式分为：

1、新增聊天项，即在chat数据库增加数据 （聊天项列表）

CREATE TABLE "main"."chat" (
  "sessionId" INTEGER,
  "chatId" TEXT,
  "content" TEXT,
  "isChatgpt" INTEGER,
  "createTime" REAL
);

2、新增会话，即在session数据库中增加数据 （会话列表）

CREATE TABLE "main"."session" (
  "sessionId" INTEGER,
  "title" TEXT,
  "createTime" REAL
);

可以类比使用微信的过程，数据进行的本地化存储持久化。

实践

• 封装文件目录操作
  我们先封装一下对文件目录的操作
  QFileManage.swift

  import Foundation
  struct QFileManage {
      /// 创建文件夹
      static func createDirectory(at path: String) {
          let isExisted = FileManager.default.fileExists(atPath: path)
          guard !isExisted else { return }
          let url = URL(fileURLWithPath: path)
          do {
              try FileManager.default.createDirectory(at: url, withIntermediateDirectories: true, attributes: nil)
          } catch let error {
              debugPrint("创建文件夹失败！Path: \(path), Error: \(error.localizedDescription)")
          }
      }
  }
  
  extension QFileManage {
      /// 库目录
      static func libraryDirectory() -> String {
          return NSSearchPathForDirectoriesInDomains(.libraryDirectory, .userDomainMask, true).last!
      }
      
      /// 数据库目录
      static func databaseDirectory() -> String {
          let path = libraryDirectory() + "/database"
          createDirectory(at: path)
          return path
      }
      
      /// 文档目录
      static func documentsDirectory() -> String {
          return NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true).last!
      }
      
      /// 图片目录
      static func imagesDirectory() -> String {
          let path = documentsDirectory() + "/images"
          createDirectory(at: path)
          return path
      }
  }

• 模型绑定
  聊天模型：ChatDbModel.swift

  import Foundation
  import WCDBSwift
  
  final class ChatDbModel: TableCodable {
      static var tableName: String { "chat" }
      
      var sessionId: Int64 = 0
      var chatId: String = ""
      var content: String = ""
      var isChatgpt: Bool = false
      var createTime: Date? = nil
      
      enum CodingKeys: String, CodingTableKey {
          typealias Root = ChatDbModel
          static let objectRelationalMapping = TableBinding(CodingKeys.self)
          
          case sessionId
          case chatId
          case content
          case isChatgpt
          case createTime
      }
      
      init(sessionId: Int64, chatId: String, content: String, isChatgpt: Bool, createTime: Date) {
          self.sessionId = sessionId
          self.chatId = chatId
          self.content = content
          self.isChatgpt = isChatgpt
          self.createTime = createTime
      }
  }

  会话模型：SessionDbModel.swift

  import Foundation
  import WCDBSwift
  
  final class SessionDbModel: TableCodable {
      static var tableName: String { "session" }
      
      var sessionId: Int64 = 0
      var title: String? = nil
      var createTime: Date? = nil
      
      enum CodingKeys: String, CodingTableKey {
          typealias Root = SessionDbModel
          static let objectRelationalMapping = TableBinding(CodingKeys.self)
          case sessionId
          case title
          case createTime
      }
      
      init(sessionId: Int64, title: String? = nil, createTime: Date? = nil) {
          self.sessionId = sessionId
          self.title = title
          self.createTime = createTime
      }
  }
  extension SessionDbModel {
      static func insert(objects: [SessionDbModel]) {
          do {
              try db?.insert(objects, intoTable: SessionDbModel.tableName)
          } catch let error {
              debugPrint("插入session失败 ->\n\(error.localizedDescription)")
          }
      }
  }

• 启动时，创建数据库

  import SwiftUI
  import WCDBSwift
  
  var db: Database?
  
  @main
  struct tableViewApp: App {
      @AppStorage("appearance") var appearance: String = "system"
      var body: some Scene {
          WindowGroup {
              ContentView().preferredColorScheme(appearance == "system" ? nil : (appearance == "dark" ? .dark : .light))
          }
      }
      init() {
          // 创建数据库
          let path = QFileManage.databaseDirectory() + "/chatgpt.db"
          debugPrint("数据库路径：\(path)")
          db = Database(at:path)
          do {
              // 建表
              try db?.run(transaction: {_ in
                  try db?.create(table: SessionDbModel.tableName, of: SessionDbModel.self)
                  try db?.create(table: ChatDbModel.tableName, of: ChatDbModel.self)
              })
          } catch let error {
              debugPrint("创建数据库失败！Error: \(error.localizedDescription)")
          }
      }
  }

操作数据库 TODO: viewModel方式操作

• 新增对话

  SessionDbModel.insert(objects: [SessionDbModel(sessionId: 2, title: "111", createTime: Date())])