Cluster chat server: Framework Design of model data layer and encapsulation of database code

framework design

User, Group, GroupUser It is a user related operation , That is, set or return to the user 、 Group or group member information . and Model It represents the addition, deletion, modification and query of the database .

Functions of each class

User

User That is, you can manage users' information

#ifndef USER_H
#define USER_H

#include <string>
using namespace std;

class User
{
    
public:
    User(int id = -1, string name = "", string password = "", string state = "offline")
        : m_id(id), m_name(name), m_password(password), m_state(state)
    {
    }

    void setId(int id) {
     this->m_id = id; }
    void setName(string name) {
     this->m_name = name; }
    void setPwd(string password) {
     this->m_password = password; }
    void setState(string state) {
     this->m_state = state; }

    int getId() const {
     return this->m_id; }
    string getName() const {
     return this->m_name; }
    string getPwd() const {
     return this->m_password; }
    string getState() const {
     return this->m_state; }

protected:
    int     m_id;
    string  m_name;
    string  m_password;
    string  m_state;
};

#endif

GroupUser

This class is for group members , Then just inherit User class , Add one more identity , You can know whether a user is an administrator or an ordinary member .

#ifndef GROUPUSER_H
#define GROUPUSER_H

#include "user.hpp"

//  Group users , One more. role The role of information （ Administrator or ordinary member ）
//  from User Direct class inheritance , Reuse User Other information about 
class GroupUser : public User
{
    
public:
    void setRole(string role) {
     this->role = role; }
    string getRole() {
     return this->role; }

private:
    string role;
};

#endif

Group

The design of group class is also relatively simple , Groups only id, Group name and group description .

#ifndef GROUP_H
#define GROUP_H

#include "groupUser.hpp"
#include <vector>
#include <string>
using namespace std;

// User Tabular ORM class 
class Group
{
    
public:
    Group(int id = -1, string name = "", string desc = "")
    {
    
        this->id = id;
        this->name = name;
        this->desc = desc;
    }

    void setId(int id) {
     this->id = id; }
    void setName(string name) {
     this->name = name; }
    void setDesc(string desc) {
     this->desc = desc; }

    int getId() const {
     return this->id; }
    string getName() const {
     return this->name; }
    string getDesc() const {
     return this->desc; }
    vector<GroupUser>& getUsers() {
     return this->users;}

private:
    int id;
    string name;
    string desc;
    vector<GroupUser> users;
};

#endif

UserModel

Model Classes are operations on databases , I.e. add, delete, change and check , Here is a header file that is the database connection pool , Later on .

#ifndef USERMODEL_H
#define USERMODEL_H

#include "user.hpp"
#include "dbConnectionPool.h"

extern ConnectionPool* sp;

// User Data operation class of table 
class UserModel {
    
public:
    // User Add table 
    bool insert(User& user);

    //  Return user information according to user number 
    User query(int id);

    //  Update the user's status information 
    bool updateState(User user);

    //  Reset the user's status information 
    void resetState();
};

#endif

GroupModel

#ifndef GROUPMODEL_H
#define GROUPMODEL_H

#include "group.hpp"

using namespace std;

//  Operation interface method for maintaining group information 
class GroupModel
{
    
public:
    //  Create groups 
    bool createGroup(Group& group);
    //  Join the group 
    void addGroup(int userid, int groupid, string role);
    //  Query the user's group information 
    vector<Group> queryGroups(int userid);

    //  According to the designation groupid Query group users id list 
    //  except userid own , The main user group chat business sends messages to other members of the Group 
    vector<int> queryGroupUsers(int userid, int groupid);

};

#endif

FriendModel

#ifndef FRIENDMODEL_H
#define FIRENDMODEL_H

#include "user.hpp"
#include <string>
#include <vector>
using namespace std;

//  Operation interface method for maintaining friend information 
class FriendModel
{
    
public:
    //  Add friends 
    void insert(int userid, int friendid);

    //  Return to the user's friend list   Joint query of two tables 
    vector<User> query(int userid);
};

#endif

OfflineMsgModel

#ifndef OFFLINEMESSAGEMODEL_H
#define OFFLINEMESSAGEMODEL_H

#include "dbConnectionPool.h"
#include <string>
#include <vector>
using namespace std;

extern ConnectionPool* sp;

//  Provide the operation interface method of offline message table 
class OfflineMsgModel
{
    
public:
    //  Store offline messages of users 
    void insert(int userId, string msg);
    //  Delete the user's offline message 
    void remove(int userId);

    //  Query the user's offline message 
    vector<string> query(int userId);
};

#endif

Use database connection pool

In order to improve the MySQL database （ be based on C/S Design ） Access bottleneck of , In addition to adding cache on the server side, the server caches commonly used data （ for example redis）, You can also add connection pools , To improve the MySQL Server Access efficiency , In high concurrency , a large number of TCP Three handshakes 、MySQL Server Connection authentication 、MySQL Server Close the connection to recycle resources and TCP The performance time spent on four waves is also obvious , The purpose of adding connection pool is to reduce the performance loss of this part .

Implementation of connection pool ：【 Database connection pool 】

The connection pool is in singleton mode

	//  Get connection pool object instance   Static 
	static ConnectionPool* getConnectionPool();

	//  Provide an interface to the outside , Provide an idle connection 
	shared_ptr<Connection> getConnection();

//  Initialize connection pool 
ConnectionPool* sp = ConnectionPool::getConnectionPool();

Initialize the connection pool in the source file of the connection pool , Because in Model The layer operates on the database , So we need to visit MySQL File usage extern Introduce the connection pool , Example ：

extern ConnectionPool* sp