C++ で Redis のデータを読む (Read)

redis_read.cpp

// --------------------------------------------------------------------
/*
    redis_read.cpp

                    May/31/2018

*/
// --------------------------------------------------------------------
#include <iostream>
#include <boost/algorithm/string.hpp>

#include <arpa/inet.h>

using namespace std;
#define PORT 6379
// --------------------------------------------------------------------
string redis_received_data_parser
    (ssize_t bytes_recieved,char incoming_data_buffer[])
{
    string str_rvalue;

    vector<string> vv;
    boost::algorithm::split (vv,incoming_data_buffer,boost::is_any_of("\n"));


    if (vv[0][1] == '-')
        {
        str_rvalue = "";
        }
    else
        {
        str_rvalue = vv[1];
        }

    return  str_rvalue;
}
// --------------------------------------------------------------------
void json_record_display (string key_in,int valread,char buffer[])
{
    cout << key_in << "\t";
    cout << valread << "\n";
    string json_str =  redis_received_data_parser (valread,buffer);
    cout << json_str << "\n";
}

// --------------------------------------------------------------------
int main (int argc,char *argv[])
{
    cerr << "*** 開始 ***\n";

    sockaddr_in address;
    sockaddr_in serv_addr;

    int sock = 0;

    char buffer[1024] = {0};
    if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0)
        {
        printf("\n Socket creation error \n");
        return -1;
        }

    memset(&serv_addr, '0', sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(PORT);

    if(inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr)<=0) 
        {
        printf("\nInvalid address/ Address not supported \n");
        return -1;
        }

    printf("sock = %d\n",sock);
    printf("sizeof(serv_addr) = %ld\n",sizeof(serv_addr));

    if (connect(sock, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0)
        {
        printf("\nConnection Failed \n");
        return -1;
        }

    string keys[] = {"t1851","t1852","t1853","t1854","t1855", 
            "t1856","t1857","t1858","t1859"};
    const int nmax = 9;


    for (int it=0; it < nmax; it++)
        {
        const string key = keys[it];
        cerr << "it = " << it << "\t";
        cerr << "key = " << key << "\t";
        const string str_aa = "get " + key +  "\r\n";
        const char *hello = str_aa.c_str();
        send(sock , hello , strlen(hello) , 0 );
        int valread = read( sock , buffer, 1024);
//      printf("%s\n",buffer );
        json_record_display (key,valread,buffer);
        }


    cerr << "*** 終了 ***\n";

    return 0;
}

// --------------------------------------------------------------------

Makefile

redis_read: redis_read.cpp
    clang++ -o redis_read redis_read.cpp -ljson11
clean:
    rm -f redis_read

実行結果

$ ./redis_read
*** 開始 ***
sock = 3
sizeof(serv_addr) = 16
it = 0  key = t1851 t1851   71
{"date_mod": "1922-8-27", "name": "福井", "population": 76129}
it = 1  key = t1852 t1852   70
{"date_mod": "1922-2-2", "name": "敦賀", "population": 98637}
it = 2  key = t1853 t1853   71
{"date_mod": "1922-7-21", "name": "小浜", "population": 42915}
it = 3  key = t1854 t1854   71
{"date_mod": "1922-5-25", "name": "大野", "population": 51238}
it = 4  key = t1855 t1855   70
{"date_mod": "1922-1-5", "name": "勝山", "population": 83471}
it = 5  key = t1856 t1856   71
{"date_mod": "1922-9-22", "name": "鯖江", "population": 71249}
it = 6  key = t1857 t1857   74
{"date_mod": "1922-7-17", "name": "あわら", "population": 46185}
it = 7  key = t1858 t1858   70
{"date_mod": "1922-3-4", "name": "越前", "population": 61873}
it = 8  key = t1859 t1859   70
{"date_mod": "1922-7-9", "name": "坂井", "population": 74923}
*** 終了 ***

次のバージョンで確認しました。

$ clang++ --version
clang version 11.1.0
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin