cpp/src/dbclient.cpp - master - ihtiandr9/httpserver

cpp/src/dbclient.cpp
137 строк3 KB
Sergey Ryabchenkov(fvds)
missprint usage
04 янв 2026, 16:09
04 янв 2026, 16:09dd2d26e
/**
 * src/dbclient.cpp
 *
 *      Test the C module for save connection to
 *      PostgreSQL database frontend library.
 */

#include <stdio.h>
#include <string>
#include <stdlib.h>
#include <libpq-fe.h>
#include "dbclient.h"

static PGconn     *conn;
static char conninfo[128];

void dbclose()
{
    // Проверяем, существует ли соединение перед его закрытием
    if (conn != NULL) {
        PQfinish(conn);
        conn = NULL;  // Обнуляем указатель после закрытия
    }
}

int
dbopen(const char* host, const char* passwd)
{

    sprintf(conninfo,"host=%s dbname=mycomps user=postgres password=%s connect_timeout=10",
        host,
        passwd
    );

    /* Make a connection to the database */
    conn = PQconnectdb(conninfo);

    /* Check to see that the backend connection was successfully made */
    if (PQstatus(conn) != CONNECTION_OK)
    {
        fprintf(stderr, "Connection to database failed: %s",
                PQerrorMessage(conn));
        return 1;
    }
    return 0;
}

std::string dbreport()
{
    PGresult   *res;
    int         nFields;
    int         i,
                j;
    std::string result = "<table class=\"computers\">\n";                

    if (conn == NULL) 
    {
        fprintf(stderr, "Database not opened");
        return "";
    }

    if (PQstatus(conn) == CONNECTION_BAD)
    {
        fprintf(stderr, "Connection to database lost: %s",
                PQerrorMessage(conn));
        return "";
    }
    /* Set always-secure search path, so malicious users can't take control. */
    res = PQexec(conn,
                 "SELECT pg_catalog.set_config('search_path', 'public', false)");

    /* Return empty string if cant configure */
    if (PQresultStatus(res) != PGRES_TUPLES_OK)
    {
        fprintf(stderr, "SET failed: %s", PQerrorMessage(conn));
        PQclear(res);
        return "";
    }

    /*
     * Should PQclear PGresult whenever it is no longer needed to avoid memory
     * leaks
     */
    PQclear(res);

    /* Start a transaction block */
    res = PQexec(conn, "BEGIN");
    if (PQresultStatus(res) != PGRES_COMMAND_OK)
    {
        fprintf(stderr, "BEGIN command failed: %s", PQerrorMessage(conn));
        PQclear(res);
        return "";
    }
    PQclear(res);

    res = PQexec(conn,	"SELECT comp.code,"
    "   comp.name,"
    "   config.cpu,"
    "   config.mb_ram,"
    "   config.compose_date"
    "   FROM computers comp"
    "   LEFT JOIN comp_configs config ON comp.config = config.code"
    "   ORDER BY comp.code");
    
    if (PQresultStatus(res) != PGRES_TUPLES_OK)
    {
        fprintf(stderr, "SELECT failed: %s", PQerrorMessage(conn));
        PQclear(res);
        return "";
    }

    /* first, print out the attribute names */
    nFields = PQnfields(res);
    result += INDENT "<tr>\n";
    for (i = 0; i < nFields; i++)
        result += INDENT INDENT "<th>" + std::string(PQfname(res, i)) + "</th>\n";
    result += INDENT "</tr>\n";

    /* next, print out the rows */
    for (i = 0; i < PQntuples(res); i++)
    {
        for (j = 0; j < nFields; j++)
            if (PQgetisnull(res, i, j))
                result += INDENT INDENT "<td></td>\n";
            else
                result += INDENT INDENT "<td>" + std::string(PQgetvalue(res, i, j)) + "</td>\n";
        result += INDENT "</tr>\n";
    }

    PQclear(res);

    /* end the transaction */
    res = PQexec(conn, "END");
    PQclear(res);

    return result;
}