sdb.3

.TH SDB 3 LOCAL

.SH NAME

sdb_init, sdb_open, sdb_query, sdb_close \- the Simple Database Library.

.SH SYNOPSIS

.B #include <sdb.h>
.sp
.BI "void sdb_init();"
.br
.BI "char *sdb_open(char *" url ");"
.br
.BI "void sdb_close(char *" id ");"
.br
.BI "int sdb_query(char *" url ", char *" query ", int (*" callback ")(int, char **, void *), void *" closure ");"

.SH DESCRIPTION

The SDB library allows applications to support multiple database management
systems with negligeable overhead, in terms of code as well as system
resources.

.PP
.B sdb_init()
initializes the library and registers the database drivers. It is
not necessary to call sdb_init explicitly, since it will be done
automatically when needed.
.PP
.B sdb_open()
opens a database connection that can be used for multiple queries. This
is optional; calling sdb_query directly will simply open and close the
connection for each query. sdb_open returns a connection id which is used
in place of the url in calls to sdb_query.
.PP
.B sdb_query()
calls the callback once for each row returned. No rows does not indicate
an error condition. sdb_query returns the number of rows or -1 for error.
The callback takes three arguments, an integer indicating the number of
columns in the result, an array of pointers to the fields and a pointer
to some arbitrary data that the callback might need. Values are always
returned as strings.
.PP
.B sdb_close()
closes the database connection opened by sdb_open.

.SH EXAMPLES

This minimal program runs queries from the command line.

.nf

#include <stdio.h>
#include <stdlib.h>
#include <sdb.h>

static int callback(int n, char **p, void *closure)
{
    int i;
    for (i = 0; i < n; i++) {
        printf("%s\\t", p[i]);
    }
    printf("\n");
    return 0;
}

int main(int argc, char **argv)
{
    if (argc != 3) {
        fprintf(stderr, "Usage: sdb_demo url query\\n");
        return EXIT_FAILURE;
    }
    sdb_query(argv[1], argv[2], callback, NULL);
    return EXIT_SUCCESS;
}

.fi

This program can be used to authenticate Squid proxy users.

.nf

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sdb.h>

static int cb_db(int n, char **p, void *closure)
{
    return 0;
}

int main(int argc, char **argv)
{
    char *url, query[1024];
    int n;
    char buf[256];
    char *user, *passwd, *p;
    setbuf(stdout, NULL);
    if (argc != 2) {
        fprintf(stderr, "Usage: sdb_auth url\\n");
        exit(1);
    }
    url = argv[1];
    while (fgets(buf, 256, stdin) != NULL) {
        if ((p = strchr(buf, '\\n')) != NULL)
            *p = '\\0';          /* strip \\n */
        if ((user = strtok(buf, " ")) == NULL) {
            printf("ERR\\n");
            continue;
        }
        if ((passwd = strtok(NULL, "")) == NULL) {
            printf("ERR\\n");
            continue;
        }
        sprintf(query,
                "select * from htpasswd "
                "where user = '%s' "
                "and passwd = '%s'",
                user, passwd);
        n = sdb_query(url, query, cb_db, NULL);
        if (n < 1) {
            printf("ERR\\n");
        } else {
            printf("OK\\n");
        }
    }
    exit(0);
}

.fi

.SH SEE ALSO

sdbd.8

Example clients in sdb_client.c and sdbd_client.c.

.SH AUTHOR

Copyright (c) 2000-2005  Ulric Eriksson <ulric@siag.nu>

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the Licence, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA.