[453850] Add -C option to mosquitto_sub.

Allows the client to quit after receiving count messages.

Replaces the (unreleased) -1 option.

Bug: https://bugs.eclipse.org/bugs/show_bug.cgi?id=453850

ChangeLog.txt

@@ -70,7 +70,8 @@ Broker:
 
 Clients:
 - Both clients can now load default configuration options from a file.
-- Add -1 (oneshot) option to mosquitto_sub.
+- Add -C option to mosquitto_sub to allow the client to quit after receiving a
+  certain count of messages. Closes bug #453850.
 - Add --proxy SOCKS5 support for both clients.
 - Pub client supports setting its keepalive. Closes bug #454852.
 - Add support for config files with default options.

client/client_shared.c

@@ -252,12 +252,6 @@ int client_config_line_proc(struct mosq_config *cfg, int pub_or_sub, int argc, c
 				}
 			}
 			i++;
-		}else if(!strcmp(argv[i], "-1") || !strcmp(argv[i], "--oneshot")){
-			if(pub_or_sub == CLIENT_PUB){
-				goto unknown_option;
-			}else{
-				cfg->oneshot = true;
-			}
 		}else if(!strcmp(argv[i], "-A")){
 			if(i==argc-1){
 				fprintf(stderr, "Error: -A argument given but no address specified.\n\n");
@@ -300,6 +294,22 @@ int client_config_line_proc(struct mosq_config *cfg, int pub_or_sub, int argc, c
 			}
 			i++;
 #endif
+		}else if(!strcmp(argv[i], "-C")){
+			if(pub_or_sub == CLIENT_PUB){
+				goto unknown_option;
+			}else{
+				if(i==argc-1){
+					fprintf(stderr, "Error: -C argument given but no count specified.\n\n");
+					return 1;
+				}else{
+					cfg->msg_count = atoi(argv[i+1]);
+					if(cfg->msg_count < 1){
+						fprintf(stderr, "Error: Invalid message count \"%d\".\n\n", cfg->msg_count);
+						return 1;
+					}
+				}
+				i++;
+			}
 		}else if(!strcmp(argv[i], "-d") || !strcmp(argv[i], "--debug")){
 			cfg->debug = true;
 		}else if(!strcmp(argv[i], "-f") || !strcmp(argv[i], "--file")){

client/client_shared.h

@@ -79,7 +79,7 @@ struct mosq_config {
 	int filter_out_count; /* sub */
 	bool verbose; /* sub */
 	bool eol; /* sub */
-	bool oneshot; /* sub */
+	int msg_count; /* sub */
 #ifdef WITH_SOCKS
 	char *socks5_host;
 	int socks5_port;

client/sub_client.c

@@ -31,6 +31,7 @@ Contributors:
 #include "client_shared.h"
 
 bool process_messages = true;
+int msg_count = 0;
 
 void my_message_callback(struct mosquitto *mosq, void *obj, const struct mosquitto_message *message)
 {
@@ -73,9 +74,12 @@ void my_message_callback(struct mosquitto *mosq, void *obj, const struct mosquit
 			fflush(stdout);
 		}
 	}
-	if(cfg->oneshot){
-		process_messages = false;
-		mosquitto_disconnect(mosq);
+	if(cfg->msg_count>0){
+		msg_count++;
+		if(cfg->msg_count == msg_count){
+			process_messages = false;
+			mosquitto_disconnect(mosq);
+		}
 	}
 }
 
@@ -126,7 +130,7 @@ void print_usage(void)
 	printf("mosquitto_sub is a simple mqtt client that will subscribe to a single topic and print all messages it receives.\n");
 	printf("mosquitto_sub version %s running on libmosquitto %d.%d.%d.\n\n", VERSION, major, minor, revision);
 	printf("Usage: mosquitto_sub [-c] [-h host] [-k keepalive] [-p port] [-q qos] [-R] -t topic ...\n");
-	printf("                     [-1] [-T filter_out]\n");
+	printf("                     [-C msg_count] [-T filter_out]\n");
 #ifdef WITH_SRV
 	printf("                     [-A bind_address] [-S]\n");
 #else
@@ -262,7 +266,7 @@ int main(int argc, char *argv[])
 	mosquitto_destroy(mosq);
 	mosquitto_lib_cleanup();
 
-	if(cfg.oneshot && rc == MOSQ_ERR_NO_CONN){
+	if(cfg.msg_count>0 && rc == MOSQ_ERR_NO_CONN){
 		rc = 0;
 	}
 	if(rc){

man/mosquitto_sub.1.xml

@@ -17,9 +17,9 @@
 	<refsynopsisdiv>
 		<cmdsynopsis>
 			<command>mosquitto_sub</command>
-			<arg><option>-1</option></arg>
 			<arg><option>-A</option> <replaceable>bind_address</replaceable></arg>
 			<arg><option>-c</option></arg>
+			<arg><option>-C</option> <replaceable>msg count</replaceable></arg>
 			<arg><option>-d</option></arg>
 			<arg><option>-h</option> <replaceable>hostname</replaceable></arg>
 			<arg><option>-i</option> <replaceable>client_id</replaceable></arg>
@@ -95,19 +95,6 @@
 			<option>#</option> as the first character are treated as comments
 			and not processed any further.</para>
 		<variablelist>
-			<varlistentry>
-				<term><option>-1</option></term>
-				<listitem>
-					<para>Disconnect and exit the program immediately after the
-						first message is received. This may be useful in shell
-						scripts where on a single status value is required, for
-						example.</para>
-					<para>Combine with <option>-R</option> to print only the
-						first fresh message (i.e. that does not have the
-						retained flag set), or with <option>-T</option> to
-						filter which topics are processed.</para>
-				</listitem>
-			</varlistentry>
 			<varlistentry>
 				<term><option>-A</option></term>
 				<listitem>
@@ -170,6 +157,19 @@
 						for more information.</para>
 				</listitem>
 			</varlistentry>
+			<varlistentry>
+				<term><option>-C</option></term>
+				<listitem>
+					<para>Disconnect and exit the program immediately after
+						the given count of messages have been received. This
+						may be useful in shell scripts where on a single status
+						value is required, for example.</para>
+					<para>Combine with <option>-R</option> to print only the
+						first set of fresh messages (i.e. that does not have
+						the retained flag set), or with <option>-T</option> to
+						filter which topics are processed.</para>
+				</listitem>
+			</varlistentry>
 			<varlistentry>
 				<term><option>-d</option></term>
 				<term><option>--debug</option></term>