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首页 云数据库 Memcache 版 快速入门 客户端连接实例 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。

    1.  tar -xvf libmemcached-1.0.18.tar.gz 
    2.  cd libmemcached-1.0.18 
    3.  ./configure --enable-sasl
    4.  make 
    5.  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。

    1. tar -xvf ocs_test.tar.gz 
    2. cd ocs_test 
    3. 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：

    1.  #include <iostream>
    2.  #include <string>
    3.  #include <libmemcached/memcached.h>
    4.  using namespace std;
    6.  #define TARGET_HOST  ""
    7.  #define USERNAME ""
    8.  #define PASSWORD ""
    10.  int main(int argc, char *argv[])
    11.  {
    12.      memcached_st *memc = NULL;
    13.      memcached_return rc;
    14.      memcached_server_st *server;
    15.      memc = memcached_create(NULL);
    16.      server = memcached_server_list_append(NULL, TARGET_HOST, 11211,&rc);
    18.      /* SASL */
    19.      sasl_client_init(NULL);
    20.      rc = memcached_set_sasl_auth_data(memc, USERNAME, PASSWORD);
    21.      if(rc != MEMCACHED_SUCCESS) {
    22.          cout<<"Set SASL err:"<< endl;
    23.      }
    24.      rc = memcached_behavior_set(memc,MEMCACHED_BEHAVIOR_BINARY_PROTOCOL,1);
    25.      if(rc != MEMCACHED_SUCCESS) {
    26.          cout<<"Binary Set err:"<<endl;
    27.      }
    28.      /* SASL */
    30.      rc = memcached_server_push(memc,server);
    31.      if(rc != MEMCACHED_SUCCESS) {
    32.        cout <<"Connect Mem err:"<< rc << endl;
    33.      }
    34.      memcached_server_list_free(server);
    36.      string key = "TestKey";
    37.      string value = "TestValue";
    38.      size_t value_length = value.length();
    39.      size_t key_length = key.length();
    40.      int expiration = 0;
    41.      uint32_t flags = 0;
    43.      //Save data
    44.      rc = memcached_set(memc,key.c_str(),key.length(),value.c_str(),value.length(),expiration,flags);
    45.      if (rc != MEMCACHED_SUCCESS){
    46.        cout <<"Save data failed: " << rc << endl;
    47.        return -1;
    48.      }
    49.      cout <<"Save data succeed, key: " << key << " value: " << value << endl;
    51.      cout << "Start get key:" << key << endl;
    53.      char* result = memcached_get(memc,key.c_str(),key_length,&value_length,&flags,&rc);
    54.      cout << "Get value:" << result << endl;
    56.      //Delete data
    57.      cout << "Start delete key:" << key << endl;
    58.      rc = memcached_delete(memc,key.c_str(),key_length,expiration);
    59.      if (rc != MEMCACHED_SUCCESS) {
    60.        cout << "Delete key failed: " << rc << endl;
    61.      }
    62.      cout << "Delete key succeed: " << rc << endl;
    63.      //free
    64.      memcached_free(memc);
    65.      return 0;
    66.  }

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。

    1. mysql -h host -uUSER -pPASSSWORD
    2. create database testdb;
    3.  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。

    1. tar -xvf ocs_test_2.tar.gz 
    2. cd ocs_test 
    3. 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：

    1.  #include <iostream>
    2.  #include <string>
    3.  #include <sstream>
    4.  #include <libmemcached/memcached.h>
    5.  #include <mysql/mysql.h>
    7.  using namespace std;
    9.  #define OCS_TARGET_HOST  "xxxxxxxxxx.m.yyyyyyyyy.ocs.aliyuncs.com"
    10.  #define OCS_USERNAME "your_user_name"
    11.  #define OCS_PASSWORD "your_password"
    13.  #define MYSQL_HOST        "zzzzzzzzzz.mysql.rds.aliyuncs.com"
    14.  #define MYSQL_USERNAME    "db_user"
    15.  #define MYSQL_PASSWORD    "db_paswd"
    16.  #define MYSQL_DBNAME      "testdb"
    18.  #define TEST_USER_ID      "100"
    20.  MYSQL *mysql = NULL;
    21.  memcached_st *memc = NULL;
    22.  memcached_return rc;
    24.  int InitMysql()
    25.  {
    26.    mysql = mysql_init(0);
    27.    if (mysql_real_connect(mysql, MYSQL_HOST, MYSQL_USERNAME, MYSQL_PASSWORD, MYSQL_DBNAME, MYSQL_PORT, NULL, CLIENT_FOUND_ROWS) == NULL )
    28.    {
    29.      cout << "connect mysql failure!" << endl;
    30.      return EXIT_FAILURE;
    31.    }
    32.    cout << "connect mysql success!" << endl;
    33.    return 0;
    34.  }
    36.  bool InitMemcached()
    37.  {
    38.    memcached_server_st *server;
    39.    memc = memcached_create(NULL);
    40.    server = memcached_server_list_append(NULL, OCS_TARGET_HOST, 11211,&rc);
    42.    /* SASL */
    43.    sasl_client_init(NULL);
    44.    rc = memcached_set_sasl_auth_data(memc, OCS_USERNAME, OCS_PASSWORD);
    45.    if (rc != MEMCACHED_SUCCESS)
    46.    {
    47.      cout<<"Set SASL err:"<< endl;
    48.      return false;
    49.    }
    50.    rc = memcached_behavior_set(memc,MEMCACHED_BEHAVIOR_BINARY_PROTOCOL,1);
    51.    if (rc != MEMCACHED_SUCCESS)
    52.    {
    53.      cout<<"Binary Set err:"<<endl;
    54.      return false;
    55.    }
    56.    /* SASL */
    57.    rc = memcached_server_push(memc,server);
    58.    if (rc != MEMCACHED_SUCCESS)
    59.    {
    60.      cout <<"Connect Mem err:"<< rc << endl;
    61.      return false;
    62.    }
    63.    memcached_server_list_free(server);
    64.    return true;
    65.  }
    67.  struct UserInfo
    68.  {
    69.    int user_id;
    70.    char user_name[32];
    71.    char password[32];
    72.    int is_online;
    73.  };
    75.  bool SaveToCache(string &key, string &value, int expiration)
    76.  {
    77.    size_t value_length = value.length();
    78.    size_t key_length = key.length();
    79.    uint32_t flags = 0;
    80.    //Save data
    81.    rc = memcached_set( memc,key.c_str(), key.length(), value.c_str(), value.length(), expiration, flags);
    82.    if (rc != MEMCACHED_SUCCESS){
    83.        cout <<"Save data to cache failed: " << rc << endl;
    84.        return false;
    85.    }
    86.    cout <<"Save data to cache succeed, key: " << key << " value: " << value << endl;
    87.    return true;
    88.  }
    90.  UserInfo *GetUserInfo(int user_id)
    91.  {
    92.    UserInfo *user_info = NULL;
    93.    //get from cache
    94.    string key;
    95.    stringstream out;
    96.    out << user_id;
    97.    key = out.str();
    98.    cout << "Start get key:" << key << endl;
    99.    size_t value_length;
    100.    uint32_t flags;
    101.    char* result = memcached_get(memc, key.c_str(), key.size(), &value_length, &flags, &rc);
    102.    if (rc != MEMCACHED_SUCCESS)
    103.    {
    104.      cout << "Get Cache Failed, start get from mysql."<< endl;
    105.      int status;
    106.      char select_sql[1024];
    107.      memset(select_sql, 0x0, sizeof(select_sql));
    108.      sprintf(select_sql, "select * from user_info where user_id = %d", user_id);
    109.      status = mysql_query(mysql, select_sql);
    110.      if (status !=0 )
    111.      {
    112.        cout << "query from mysql failure!" << endl;
    113.        return NULL;
    114.      }
    115.      cout << "the status is :" << status << endl;
    116.      MYSQL_RES *mysql_result = mysql_store_result(mysql);
    117.      user_info = new UserInfo;
    118.      MYSQL_ROW row;
    119.      while (row = mysql_fetch_row(mysql_result))
    120.      {
    121.        user_info->user_id = atoi(row[0]);
    122.        strncpy(user_info->user_name, row[1], strlen(row[1]));
    123.        strncpy(user_info->password, row[2], strlen(row[2]));
    124.        user_info->is_online = atoi(row[3]);
    125.      }
    126.      mysql_free_result(mysql_result);
    127.      return user_info;
    128.    }
    129.    cout << "Get from cache succeed" << endl;
    130.    user_info = new UserInfo;
    131.    memcpy(user_info, result, value_length);
    132.    return user_info;
    133.  }
    135.  bool DeleteCache(string &key, int expiration)
    136.  {
    137.    rc = memcached_delete(memc, key.c_str(), key.length(), expiration);
    138.    if (rc != MEMCACHED_SUCCESS) {
    139.      cout << "Delete key failed: " << rc << endl;
    140.      return false;
    141.    }
    142.    cout << "Delete key succeed: " << rc << endl;
    143.    return true;
    144.  }
    146.  void PrintUserInfo(UserInfo *user_info)
    147.  {
    148.    cout << "user_id: " << user_info->user_id << " " << " name: " << user_info->user_name << endl;
    149.  }
    151.  bool SaveMysql(UserInfo *user_info)
    152.  {
    153.    char insert_sql[1024];
    154.    memset(insert_sql, 0x0, sizeof(insert_sql));
    155.    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);
    156.    int status = mysql_query(mysql, insert_sql);
    157.    if (status != 0)
    158.    {
    159.      cout << "insert failed" << endl;
    160.      return false;
    161.    }
    162.    cout << "insert user_info" << endl;
    163.    //insert mysql
    164.    return true;
    165.  }
    167.  int main(int argc, char *argv[])
    168.  {
    169.    if (InitMysql() != 0)
    170.    {
    171.      return -1;
    172.    }
    173.    if (!InitMemcached())
    174.    {
    175.      return -1;
    176.    }
    178.    //generate user_info
    179.    UserInfo user_info;
    180.    user_info.user_id = atoi(TEST_USER_ID);
    181.    strcpy(user_info.user_name, "James");
    182.    strcpy(user_info.password, "12345678");
    183.    user_info.is_online = 1;
    185.    //save to mysql
    186.    if (!SaveMysql(&user_info))
    187.    {
    188.      //return -1;
    189.    }
    190.    string user_str;
    191.    user_str.assign((char*)&user_info, sizeof(UserInfo));
    192.    //save to memcached
    193.    string key_str = TEST_USER_ID;
    194.    SaveToCache(key_str, user_str, 10);
    196.    //start get, exist in memcahced
    197.    UserInfo *get_user_info = GetUserInfo(user_info.user_id);
    198.    PrintUserInfo(get_user_info);
    200.    //wait 10 secons
    201.    sleep(2);
    202.    //delete memcached or expired
    203.    DeleteCache(key_str, 0);
    205.    //start get, exist in mysql
    206.    delete get_user_info;
    207.    get_user_info = GetUserInfo(user_info.user_id);
    209.    PrintUserInfo(get_user_info);
    210.    delete get_user_info;
    211.    //free
    212.    memcached_free(memc);
    213.    mysql_close(mysql);
    214.    return 0;
    215.  }
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