1 /*
2 * src/test/examples/testlibpq2.c
3 *
4 *
5 * testlibpq2.c
6 * Test of the asynchronous notification interface
7 *
8 * Start this program, then from psql in another window do
9 * NOTIFY TBL2;
10 * Repeat four times to get this program to exit.
11 *
12 * Or, if you want to get fancy, try this:
13 * populate a database with the following commands
14 * (provided in src/test/examples/testlibpq2.sql):
15 *
16 * CREATE SCHEMA TESTLIBPQ2;
17 * SET search_path = TESTLIBPQ2;
18 * CREATE TABLE TBL1 (i int4);
19 * CREATE TABLE TBL2 (i int4);
20 * CREATE RULE r1 AS ON INSERT TO TBL1 DO
21 * (INSERT INTO TBL2 VALUES (new.i); NOTIFY TBL2);
22 *
23 * Start this program, then from psql do this four times:
24 *
25 * INSERT INTO TESTLIBPQ2.TBL1 VALUES (10);
26 */
27
28 #ifdef WIN32
29 #include <windows.h>
30 #endif
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <string.h>
34 #include <errno.h>
35 #include <sys/time.h>
36 #include <sys/types.h>
37 #ifdef HAVE_SYS_SELECT_H
38 #include <sys/select.h>
39 #endif
40
41 #include "libpq-fe.h"
42
43 static void
exit_nicely(PGconn * conn)44 exit_nicely(PGconn *conn)
45 {
46 PQfinish(conn);
47 exit(1);
48 }
49
50 int
main(int argc,char ** argv)51 main(int argc, char **argv)
52 {
53 const char *conninfo;
54 PGconn *conn;
55 PGresult *res;
56 PGnotify *notify;
57 int nnotifies;
58
59 /*
60 * If the user supplies a parameter on the command line, use it as the
61 * conninfo string; otherwise default to setting dbname=postgres and using
62 * environment variables or defaults for all other connection parameters.
63 */
64 if (argc > 1)
65 conninfo = argv[1];
66 else
67 conninfo = "dbname = postgres";
68
69 /* Make a connection to the database */
70 conn = PQconnectdb(conninfo);
71
72 /* Check to see that the backend connection was successfully made */
73 if (PQstatus(conn) != CONNECTION_OK)
74 {
75 fprintf(stderr, "%s", PQerrorMessage(conn));
76 exit_nicely(conn);
77 }
78
79 /* Set always-secure search path, so malicious users can't take control. */
80 res = PQexec(conn,
81 "SELECT pg_catalog.set_config('search_path', '', false)");
82 if (PQresultStatus(res) != PGRES_TUPLES_OK)
83 {
84 fprintf(stderr, "SET failed: %s", PQerrorMessage(conn));
85 PQclear(res);
86 exit_nicely(conn);
87 }
88
89 /*
90 * Should PQclear PGresult whenever it is no longer needed to avoid memory
91 * leaks
92 */
93 PQclear(res);
94
95 /*
96 * Issue LISTEN command to enable notifications from the rule's NOTIFY.
97 */
98 res = PQexec(conn, "LISTEN TBL2");
99 if (PQresultStatus(res) != PGRES_COMMAND_OK)
100 {
101 fprintf(stderr, "LISTEN command failed: %s", PQerrorMessage(conn));
102 PQclear(res);
103 exit_nicely(conn);
104 }
105 PQclear(res);
106
107 /* Quit after four notifies are received. */
108 nnotifies = 0;
109 while (nnotifies < 4)
110 {
111 /*
112 * Sleep until something happens on the connection. We use select(2)
113 * to wait for input, but you could also use poll() or similar
114 * facilities.
115 */
116 int sock;
117 fd_set input_mask;
118
119 sock = PQsocket(conn);
120
121 if (sock < 0)
122 break; /* shouldn't happen */
123
124 FD_ZERO(&input_mask);
125 FD_SET(sock, &input_mask);
126
127 if (select(sock + 1, &input_mask, NULL, NULL, NULL) < 0)
128 {
129 fprintf(stderr, "select() failed: %s\n", strerror(errno));
130 exit_nicely(conn);
131 }
132
133 /* Now check for input */
134 PQconsumeInput(conn);
135 while ((notify = PQnotifies(conn)) != NULL)
136 {
137 fprintf(stderr,
138 "ASYNC NOTIFY of '%s' received from backend PID %d\n",
139 notify->relname, notify->be_pid);
140 PQfreemem(notify);
141 nnotifies++;
142 PQconsumeInput(conn);
143 }
144 }
145
146 fprintf(stderr, "Done.\n");
147
148 /* close the connection to the database and cleanup */
149 PQfinish(conn);
150
151 return 0;
152 }
153