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首页 云数据库 Memcache 版 快速入门 客户端连接实例 C++

C++

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客户端下载

客户端下载地址

客户端介绍

客户端版本介绍

环境配置

  1. 下载编译安装C++客户端。

    https://launchpad.net/libmemcached/1.0/1.0.18/+download/libmemcached-1.0.18.tar.gz

  2. 执行以下命令。

     tar -xvf libmemcached-1.0.18.tar.gz 
 cd libmemcached-1.0.18 
 ./configure --enable-sasl
 make 
 make install (可能需要sudo权限)

C++代码示例

  1. 下载ocs_test.tar.gz。

  2. 执行以下命令。

    tar -xvf ocs_test.tar.gz 
cd ocs_test 
vim ocs_test_sample1.cpp

  3. 修改TARGET_HOST为购买到的Memcache地址，USERNAME为购买到的用户名，PASSWORD为设置好的密码。

  4. 执行build.sh生成ocs_test。运行./ocs_test即可看到写入一个key到Memcache中，再从Memcache获取到，最后将这个key从Memcache中删除。

    ocs_test_sample1.cpp的代码如下：

     #include <iostream>
 #include <string>
 #include <libmemcached/memcached.h>
 using namespace std;

 #define TARGET_HOST  ""
 #define USERNAME ""
 #define PASSWORD ""

 int main(int argc, char *argv[])
 {
     memcached_st *memc = NULL;
     memcached_return rc;
     memcached_server_st *server;
     memc = memcached_create(NULL);
     server = memcached_server_list_append(NULL, TARGET_HOST, 11211,&rc);

     /* SASL */
     sasl_client_init(NULL);
     rc = memcached_set_sasl_auth_data(memc, USERNAME, PASSWORD);
     if(rc != MEMCACHED_SUCCESS) {
         cout<<"Set SASL err:"<< endl;
     }
     rc = memcached_behavior_set(memc,MEMCACHED_BEHAVIOR_BINARY_PROTOCOL,1);
     if(rc != MEMCACHED_SUCCESS) {
         cout<<"Binary Set err:"<<endl;
     }
     /* SASL */

     rc = memcached_server_push(memc,server);
     if(rc != MEMCACHED_SUCCESS) {
       cout <<"Connect Mem err:"<< rc << endl;
     }
     memcached_server_list_free(server);

     string key = "TestKey";
     string value = "TestValue";
     size_t value_length = value.length();
     size_t key_length = key.length();
     int expiration = 0;
     uint32_t flags = 0;

     //Save data
     rc = memcached_set(memc,key.c_str(),key.length(),value.c_str(),value.length(),expiration,flags);
     if (rc != MEMCACHED_SUCCESS){
       cout <<"Save data failed: " << rc << endl;
       return -1;
     }
     cout <<"Save data succeed, key: " << key << " value: " << value << endl;

     cout << "Start get key:" << key << endl;

     char* result = memcached_get(memc,key.c_str(),key_length,&value_length,&flags,&rc);
     cout << "Get value:" << result << endl;

     //Delete data
     cout << "Start delete key:" << key << endl;
     rc = memcached_delete(memc,key.c_str(),key_length,expiration);
     if (rc != MEMCACHED_SUCCESS) {
       cout << "Delete key failed: " << rc << endl;
     }
     cout << "Delete key succeed: " << rc << endl;
     //free
     memcached_free(memc);
     return 0;
 }

下面是另一个C++程序使用Memcache实例，在这里我们可以看见Memcache缓存与MySQL数据库相结合的场景。编译安装C++客户端的步骤还是与上一个例子相同。

  1. 在MySQL数据库中创建示例database和table。

    mysql -h host -uUSER -pPASSSWORD
create database testdb;
 create table user_info (user_id int, user_name char(32) not null, password char(32) not null, is_online int, primary key(user_id) );

  2. 下载ocs_test_2.tar.gz，并执行以下命令。

    tar -xvf ocs_test_2.tar.gz 
cd ocs_test 
vim ocs_test_sample2.cpp

    注意：修改OCS_TARGET_HOST为购买到的Memcache地址，OCS_USERNAME为Memcache的实例名，OCS_PASSWORD为设置好的密码；MYSQL_HOST为MySQL地址， MYSQL_USERNAME为数据库的用户名，MYSQL_PASSWORD为数据库的密码。

  3. 执行build.sh生成ocs_test，执行/ocs_test即可。

    ocs_test_sample2.cpp代码如下：

     #include <iostream>
 #include <string>
 #include <sstream>
 #include <libmemcached/memcached.h>
 #include <mysql/mysql.h>

 using namespace std;

 #define OCS_TARGET_HOST  "xxxxxxxxxx.m.yyyyyyyyy.ocs.aliyuncs.com"
 #define OCS_USERNAME "your_user_name"
 #define OCS_PASSWORD "your_password"

 #define MYSQL_HOST        "zzzzzzzzzz.mysql.rds.aliyuncs.com"
 #define MYSQL_USERNAME    "db_user"
 #define MYSQL_PASSWORD    "db_paswd"
 #define MYSQL_DBNAME      "testdb"

 #define TEST_USER_ID      "100"

 MYSQL *mysql = NULL;
 memcached_st *memc = NULL;
 memcached_return rc;

 int InitMysql()
 {
   mysql = mysql_init(0);
   if (mysql_real_connect(mysql, MYSQL_HOST, MYSQL_USERNAME, MYSQL_PASSWORD, MYSQL_DBNAME, MYSQL_PORT, NULL, CLIENT_FOUND_ROWS) == NULL )
   {
     cout << "connect mysql failure!" << endl;
     return EXIT_FAILURE;
   }
   cout << "connect mysql success!" << endl;
   return 0;
 }

 bool InitMemcached()
 {
   memcached_server_st *server;
   memc = memcached_create(NULL);
   server = memcached_server_list_append(NULL, OCS_TARGET_HOST, 11211,&rc);

   /* SASL */
   sasl_client_init(NULL);
   rc = memcached_set_sasl_auth_data(memc, OCS_USERNAME, OCS_PASSWORD);
   if (rc != MEMCACHED_SUCCESS)
   {
     cout<<"Set SASL err:"<< endl;
     return false;
   }
   rc = memcached_behavior_set(memc,MEMCACHED_BEHAVIOR_BINARY_PROTOCOL,1);
   if (rc != MEMCACHED_SUCCESS)
   {
     cout<<"Binary Set err:"<<endl;
     return false;
   }
   /* SASL */
   rc = memcached_server_push(memc,server);
   if (rc != MEMCACHED_SUCCESS)
   {
     cout <<"Connect Mem err:"<< rc << endl;
     return false;
   }
   memcached_server_list_free(server);
   return true;
 }

 struct UserInfo
 {
   int user_id;
   char user_name[32];
   char password[32];
   int is_online;
 };

 bool SaveToCache(string &key, string &value, int expiration)
 {
   size_t value_length = value.length();
   size_t key_length = key.length();
   uint32_t flags = 0;
   //Save data
   rc = memcached_set( memc,key.c_str(), key.length(), value.c_str(), value.length(), expiration, flags);
   if (rc != MEMCACHED_SUCCESS){
       cout <<"Save data to cache failed: " << rc << endl;
       return false;
   }
   cout <<"Save data to cache succeed, key: " << key << " value: " << value << endl;
   return true;
 }

 UserInfo *GetUserInfo(int user_id)
 {
   UserInfo *user_info = NULL;
   //get from cache
   string key;
   stringstream out;
   out << user_id;
   key = out.str();
   cout << "Start get key:" << key << endl;
   size_t value_length;
   uint32_t flags;
   char* result = memcached_get(memc, key.c_str(), key.size(), &value_length, &flags, &rc);
   if (rc != MEMCACHED_SUCCESS)
   {
     cout << "Get Cache Failed, start get from mysql."<< endl;
     int status;
     char select_sql[1024];
     memset(select_sql, 0x0, sizeof(select_sql));
     sprintf(select_sql, "select * from user_info where user_id = %d", user_id);
     status = mysql_query(mysql, select_sql);
     if (status !=0 )
     {
       cout << "query from mysql failure!" << endl;
       return NULL;
     }
     cout << "the status is :" << status << endl;
     MYSQL_RES *mysql_result = mysql_store_result(mysql);
     user_info = new UserInfo;
     MYSQL_ROW row;
     while (row = mysql_fetch_row(mysql_result))
     {
       user_info->user_id = atoi(row[0]);
       strncpy(user_info->user_name, row[1], strlen(row[1]));
       strncpy(user_info->password, row[2], strlen(row[2]));
       user_info->is_online = atoi(row[3]);
     }
     mysql_free_result(mysql_result);
     return user_info;
   }
   cout << "Get from cache succeed" << endl;
   user_info = new UserInfo;
   memcpy(user_info, result, value_length);
   return user_info;
 }

 bool DeleteCache(string &key, int expiration)
 {
   rc = memcached_delete(memc, key.c_str(), key.length(), expiration);
   if (rc != MEMCACHED_SUCCESS) {
     cout << "Delete key failed: " << rc << endl;
     return false;
   }
   cout << "Delete key succeed: " << rc << endl;
   return true;
 }

 void PrintUserInfo(UserInfo *user_info)
 {
   cout << "user_id: " << user_info->user_id << " " << " name: " << user_info->user_name << endl;
 }

 bool SaveMysql(UserInfo *user_info)
 {
   char insert_sql[1024];
   memset(insert_sql, 0x0, sizeof(insert_sql));
   sprintf(insert_sql, "insert into user_info(user_id, user_name, password, is_online) values(%d, '%s', '%s', %d)", user_info->user_id, user_info->user_name, user_info->password, user_info->is_online);
   int status = mysql_query(mysql, insert_sql);
   if (status != 0)
   {
     cout << "insert failed" << endl;
     return false;
   }
   cout << "insert user_info" << endl;
   //insert mysql
   return true;
 }

 int main(int argc, char *argv[])
 {
   if (InitMysql() != 0)
   {
     return -1;
   }
   if (!InitMemcached())
   {
     return -1;
   }

   //generate user_info
   UserInfo user_info;
   user_info.user_id = atoi(TEST_USER_ID);
   strcpy(user_info.user_name, "James");
   strcpy(user_info.password, "12345678");
   user_info.is_online = 1;

   //save to mysql
   if (!SaveMysql(&user_info))
   {
     //return -1;
   }
   string user_str;
   user_str.assign((char*)&user_info, sizeof(UserInfo));
   //save to memcached
   string key_str = TEST_USER_ID;
   SaveToCache(key_str, user_str, 10);

   //start get, exist in memcahced
   UserInfo *get_user_info = GetUserInfo(user_info.user_id);
   PrintUserInfo(get_user_info);

   //wait 10 secons
   sleep(2);
   //delete memcached or expired
   DeleteCache(key_str, 0);

   //start get, exist in mysql
   delete get_user_info;
   get_user_info = GetUserInfo(user_info.user_id);

   PrintUserInfo(get_user_info);
   delete get_user_info;
   //free
   memcached_free(memc);
   mysql_close(mysql);
   return 0;
 }
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