From: lakshminarayanagurram <lakshminarayana@elear.solutions>
Date: Mon, 25 Feb 2019 10:02:24 +0000 (+0100)
Subject: Add a groupchat example program that uses the submesh feature.
X-Git-Url: https://git.meshlink.io/?a=commitdiff_plain;h=9e2e05f3495c883356be93232b26d6cbb796a269;p=meshlink

Add a groupchat example program that uses the submesh feature.
---

diff --git a/examples/Makefile.am b/examples/Makefile.am
index 9243cafb..fbd71382 100644
--- a/examples/Makefile.am
+++ b/examples/Makefile.am
@@ -1,4 +1,4 @@
-noinst_PROGRAMS = meshlinkapp chat chatpp manynodes channels monitor
+noinst_PROGRAMS = meshlinkapp chat chatpp manynodes channels monitor groupchat
 
 AM_CPPFLAGS = $(PTHREAD_CFLAGS) -I${top_srcdir}/src -iquote. -Wall
 AM_LDFLAGS = $(PTHREAD_LIBS)
@@ -22,3 +22,6 @@ if CURSES
 monitor_SOURCES = monitor.c
 monitor_LDADD = ${top_builddir}/src/libmeshlink.la $(NCURSES_LIBS) -lm
 endif
+
+groupchat_SOURCES = groupchat.c
+groupchat_LDADD = ${top_builddir}/src/libmeshlink.la
diff --git a/examples/groupchat.c b/examples/groupchat.c
new file mode 100644
index 00000000..a866943a
--- /dev/null
+++ b/examples/groupchat.c
@@ -0,0 +1,469 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+
+#include "../src/meshlink.h"
+#include "../src/devtools.h"
+
+#define CHAT_PORT 531
+
+static void log_message(meshlink_handle_t *mesh, meshlink_log_level_t level, const char *text) {
+	(void) mesh;
+
+	static const char *levelstr[] = {
+		[MESHLINK_DEBUG] = "\x1b[34mDEBUG",
+		[MESHLINK_INFO] = "\x1b[32mINFO",
+		[MESHLINK_WARNING] = "\x1b[33mWARNING",
+		[MESHLINK_ERROR] = "\x1b[31mERROR",
+		[MESHLINK_CRITICAL] = "\x1b[31mCRITICAL",
+	};
+	fprintf(stderr, "%s:\x1b[0m %s\n", levelstr[level], text);
+}
+
+static void channel_receive(meshlink_handle_t *mesh, meshlink_channel_t *channel, const void *data, size_t len) {
+	if(!len) {
+		if(meshlink_errno) {
+			fprintf(stderr, "Error while reading data from %s: %s\n", channel->node->name, meshlink_strerror(meshlink_errno));
+		} else {
+			fprintf(stderr, "Chat connection closed by %s\n", channel->node->name);
+		}
+
+		channel->node->priv = NULL;
+		meshlink_channel_close(mesh, channel);
+		return;
+	}
+
+	// TODO: we now have TCP semantics, don't expect exactly one message per receive call.
+
+	fprintf(stderr, "%s says: ", channel->node->name);
+	fwrite(data, len, 1, stderr);
+	fputc('\n', stderr);
+}
+
+static bool channel_accept(meshlink_handle_t *mesh, meshlink_channel_t *channel, uint16_t port, const void *data, size_t len) {
+	(void)data;
+	(void)len;
+
+	// Only accept connections to the chat port
+	if(port != CHAT_PORT) {
+		fprintf(stderr, "Rejected incoming channel from '%s' to port %u\n", channel->node->name, port);
+		return false;
+	}
+
+	fprintf(stderr, "Accepted incoming channel from '%s'\n", channel->node->name);
+
+	// Remember the channel
+	channel->node->priv = channel;
+
+	// Set the receive callback
+	meshlink_set_channel_receive_cb(mesh, channel, channel_receive);
+
+	// Accept this channel
+	return true;
+}
+
+static void channel_poll(meshlink_handle_t *mesh, meshlink_channel_t *channel, size_t len) {
+	(void)len;
+
+	fprintf(stderr, "Channel to '%s' connected\n", channel->node->name);
+	meshlink_set_channel_poll_cb(mesh, channel, NULL);
+}
+
+static void node_status(meshlink_handle_t *mesh, meshlink_node_t *node, bool reachable) {
+	(void)mesh;
+
+	if(reachable) {
+		fprintf(stderr, "%s joined.\n", node->name);
+	} else {
+		fprintf(stderr, "%s left.\n", node->name);
+	}
+}
+
+static meshlink_node_t **nodes;
+static size_t nnodes;
+
+static void parse_command(meshlink_handle_t *mesh, char *buf) {
+	char *arg = strchr(buf, ' ');
+	char *arg1 = NULL;
+	meshlink_submesh_t *s = NULL;
+	static meshlink_submesh_t **submesh = NULL;
+	static size_t nmemb = 0;
+	size_t i;
+
+	if(arg) {
+		*arg++ = 0;
+
+		arg1 = strchr(arg, ' ');
+
+		if(arg1) {
+			*arg1++ = 0;
+		}
+
+	}
+
+	if(!strcasecmp(buf, "invite")) {
+		char *invitation;
+
+		if(!arg) {
+			fprintf(stderr, "/invite requires an argument!\n");
+			return;
+		}
+
+		if(arg1) {
+
+			submesh = devtool_get_all_submeshes(mesh, submesh, &nmemb);
+
+			if(!submesh || !nmemb) {
+				fprintf(stderr, "Group does not exist!\n");
+				return;
+			}
+
+			for(i = 0; i < nmemb; i++) {
+				if(!strcmp(arg1, submesh[i]->name)) {
+					s = submesh[i];
+					break;
+				} else {
+					s = NULL;
+				}
+			}
+
+			if(!s) {
+				fprintf(stderr, "Group is not yet creted!\n");
+				return;
+			}
+		}
+
+		invitation = meshlink_invite(mesh, s, arg);
+
+		if(!invitation) {
+			fprintf(stderr, "Could not invite '%s': %s\n", arg, meshlink_strerror(meshlink_errno));
+			return;
+		}
+
+		fprintf(stderr, "Invitation for %s: %s\n", arg, invitation);
+		free(invitation);
+	} else if(!strcasecmp(buf, "canonical")) {
+		bool set;
+		char *host = NULL, *port = NULL;
+
+		if(!arg) {
+			fprintf(stderr, "/canonical requires an argument!\n");
+			return;
+		}
+
+		if((0 == strncasecmp(arg, "-h", 2)) && (strlen(arg) > 2)) {
+			host = arg + 2;
+		} else if((0 == strncasecmp(arg, "-p", 2)) && (strlen(arg) > 2)) {
+			port = arg + 2;
+		} else {
+			fprintf(stderr, "Unknown argument: %s!\n", arg);
+			return;
+		}
+
+		if(arg1) {
+			if((0 == strncasecmp(arg1, "-h", 2)) && (strlen(arg1) > 2)) {
+				host = arg1 + 2;
+			} else if((0 == strncasecmp(arg1, "-p", 2)) && (strlen(arg1) > 2)) {
+				port = arg1 + 2;
+			} else {
+				fprintf(stderr, "Unknown argument: %s!\n", arg1);
+				return;
+			}
+		}
+
+		if(!host && !port) {
+			fprintf(stderr, "Unable to set Canonical address because no valid arguments are found!\n");
+			return;
+		}
+
+		set = meshlink_set_canonical_address(mesh, meshlink_get_self(mesh), host, port);
+
+		if(!set) {
+			fprintf(stderr, "Could not set canonical address '%s:%s': %s\n", host, port, meshlink_strerror(meshlink_errno));
+			return;
+		}
+
+		fprintf(stderr, "Canonical address set as '%s:%s'\n", host, port);
+	} else if(!strcasecmp(buf, "group")) {
+		if(!arg) {
+			fprintf(stderr, "/group requires an argument!\n");
+			return;
+		}
+
+		if(!(s = meshlink_submesh_open(mesh, arg))) {
+			fprintf(stderr, "Could not create group: %s\n", meshlink_strerror(meshlink_errno));
+		} else {
+			fprintf(stderr, "Group '%s' created!\n", s->name);
+		}
+	} else if(!strcasecmp(buf, "join")) {
+		if(!arg) {
+			fprintf(stderr, "/join requires an argument!\n");
+			return;
+		}
+
+		meshlink_stop(mesh);
+
+		if(!meshlink_join(mesh, arg)) {
+			fprintf(stderr, "Could not join using invitation: %s\n", meshlink_strerror(meshlink_errno));
+		} else {
+			fprintf(stderr, "Invitation accepted!\n");
+		}
+
+		if(!meshlink_start(mesh)) {
+			fprintf(stderr, "Could not restart MeshLink: %s\n", meshlink_strerror(meshlink_errno));
+			exit(1);
+		}
+	} else if(!strcasecmp(buf, "kick")) {
+		if(!arg) {
+			fprintf(stderr, "/kick requires an argument!\n");
+			return;
+		}
+
+		meshlink_node_t *node = meshlink_get_node(mesh, arg);
+
+		if(!node) {
+			fprintf(stderr, "Error looking up '%s': %s\n", arg, meshlink_strerror(meshlink_errno));
+			return;
+		}
+
+		meshlink_blacklist(mesh, node);
+
+		fprintf(stderr, "Node '%s' blacklisted.\n", arg);
+	} else if(!strcasecmp(buf, "who")) {
+		meshlink_submesh_t *node_group = NULL;
+
+		if(!arg) {
+			nodes = meshlink_get_all_nodes(mesh, nodes, &nnodes);
+
+			if(!nnodes) {
+				fprintf(stderr, "Could not get list of nodes: %s\n", meshlink_strerror(meshlink_errno));
+			} else {
+				fprintf(stderr, "%zu known nodes:\n", nnodes);
+
+				for(size_t i = 0; i < nnodes; i++) {
+					fprintf(stderr, " %lu. %s", i, nodes[i]->name);
+
+					if((node_group = meshlink_get_node_submesh(mesh, nodes[i]))) {
+						fprintf(stderr, "\t%s", node_group->name);
+					}
+
+					fprintf(stderr, "\n");
+				}
+
+				fprintf(stderr, "\n");
+			}
+		} else {
+			meshlink_node_t *node = meshlink_get_node(mesh, arg);
+
+			if(!node) {
+				fprintf(stderr, "Error looking up '%s': %s\n", arg, meshlink_strerror(meshlink_errno));
+			} else {
+				fprintf(stderr, "Node %s found", arg);
+
+				if((node_group = meshlink_get_node_submesh(mesh, node))) {
+					fprintf(stderr, " in group %s", node_group->name);
+				}
+
+				fprintf(stderr, "\n");
+			}
+		}
+	} else if(!strcasecmp(buf, "listgroup")) {
+		if(!arg) {
+			fprintf(stderr, "/listgroup requires an argument!\n");
+			return;
+		}
+
+		submesh = devtool_get_all_submeshes(mesh, submesh, &nmemb);
+
+		if(!submesh || !nmemb) {
+			fprintf(stderr, "Group does not exist!\n");
+			return;
+		}
+
+		for(i = 0; i < nmemb; i++) {
+			if(!strcmp(arg, submesh[i]->name)) {
+				s = submesh[i];
+				break;
+			} else {
+				s = NULL;
+			}
+		}
+
+		if(!s) {
+			fprintf(stderr, "Group %s does not exist!\n", arg);
+			return;
+		}
+
+		nodes = meshlink_get_all_nodes_by_submesh(mesh, s, nodes, &nnodes);
+
+		if(!nodes) {
+			fprintf(stderr, "Group %s does not contain any nodes!\n", arg);
+			return;
+		}
+
+		if(nnodes <= 0) {
+			fprintf(stderr, "Could not get list of nodes for group %s: %s\n", arg, meshlink_strerror(meshlink_errno));
+		} else {
+			fprintf(stderr, "%zu known nodes in group %s:", nnodes, arg);
+
+			for(size_t i = 0; i < nnodes; i++) {
+				fprintf(stderr, " %s", nodes[i]->name);
+			}
+
+			fprintf(stderr, "\n");
+		}
+	} else if(!strcasecmp(buf, "quit")) {
+		fprintf(stderr, "Bye!\n");
+		fclose(stdin);
+	} else if(!strcasecmp(buf, "help")) {
+		fprintf(stderr,
+		        "<name>: <message>     			  Send a message to the given node.\n"
+		        "                      			  Subsequent messages don't need the <name>: prefix.\n"
+		        "/group <name>				  Create a new group"
+		        "/invite <name> [submesh]		  Create an invitation for a new node.\n"
+		        "                      			  Node joins either coremesh or submesh depending on submesh parameter.\n"
+		        "/join <invitation>				  Join an existing mesh using an invitation.\n"
+		        "/kick <name>          			  Blacklist the given node.\n"
+		        "/who [<name>]         			  List all nodes or show information about the given node.\n"
+		        "/listgroup <name>         		  List all nodes in a given group.\n"
+		        "/canonical -h<hostname> -p<port> Set Canonical address to be present in invitation.\n"
+		        "                      			  Any one of two options an be specified. Atleast one option must be present\n"
+		        "/quit                 			  Exit this program.\n"
+		       );
+	} else {
+		fprintf(stderr, "Unknown command '/%s'\n", buf);
+	}
+}
+
+static void parse_input(meshlink_handle_t *mesh, char *buf) {
+	static meshlink_node_t *destination;
+	size_t len;
+
+	if(!buf) {
+		return;
+	}
+
+	// Remove newline.
+
+	len = strlen(buf);
+
+	if(len && buf[len - 1] == '\n') {
+		buf[--len] = 0;
+	}
+
+	if(len && buf[len - 1] == '\r') {
+		buf[--len] = 0;
+	}
+
+	// Ignore empty lines.
+
+	if(!len) {
+		return;
+	}
+
+	// Commands start with '/'
+
+	if(*buf == '/') {
+		parse_command(mesh, buf + 1);
+		return;
+	}
+
+	// Lines in the form "name: message..." set the destination node.
+
+	char *msg = buf;
+	char *colon = strchr(buf, ':');
+
+	if(colon) {
+		*colon = 0;
+		msg = colon + 1;
+
+		if(*msg == ' ') {
+			msg++;
+		}
+
+		destination = meshlink_get_node(mesh, buf);
+
+		if(!destination) {
+			fprintf(stderr, "Error looking up '%s': %s\n", buf, meshlink_strerror(meshlink_errno));
+			return;
+		}
+	}
+
+	if(!destination) {
+		fprintf(stderr, "Who are you talking to? Write 'name: message...'\n");
+		return;
+	}
+
+	// We want to have one channel per node.
+	// We keep the pointer to the meshlink_channel_t in the priv field of that node.
+	meshlink_channel_t *channel = destination->priv;
+
+	if(!channel) {
+		fprintf(stderr, "Opening chat channel to '%s'\n", destination->name);
+		channel = meshlink_channel_open(mesh, destination, CHAT_PORT, channel_receive, NULL, 0);
+
+		if(!channel) {
+			fprintf(stderr, "Could not create channel to '%s': %s\n", destination->name, meshlink_strerror(meshlink_errno));
+			return;
+		}
+
+		destination->priv = channel;
+		meshlink_set_channel_poll_cb(mesh, channel, channel_poll);
+	}
+
+	if(!meshlink_channel_send(mesh, channel, msg, strlen(msg))) {
+		fprintf(stderr, "Could not send message to '%s': %s\n", destination->name, meshlink_strerror(meshlink_errno));
+		return;
+	}
+
+	fprintf(stderr, "Message sent to '%s'.\n", destination->name);
+}
+
+int main(int argc, char *argv[]) {
+	const char *confbase = ".chat";
+	const char *nick = NULL;
+	char buf[1024];
+
+	if(argc > 1) {
+		confbase = argv[1];
+	}
+
+	if(argc > 2) {
+		nick = argv[2];
+	}
+
+	meshlink_set_log_cb(NULL, MESHLINK_DEBUG, log_message);
+
+	meshlink_handle_t *mesh = meshlink_open(confbase, nick, "chat", DEV_CLASS_STATIONARY);
+
+	if(!mesh) {
+		fprintf(stderr, "Could not open MeshLink: %s\n", meshlink_strerror(meshlink_errno));
+		return 1;
+	}
+
+	meshlink_set_node_status_cb(mesh, node_status);
+	meshlink_set_log_cb(mesh, MESHLINK_INFO, log_message);
+
+	// Set the channel accept callback. This implicitly turns on channels for all nodes.
+	// This replaces the call to meshlink_set_receive_cb().
+	meshlink_set_channel_accept_cb(mesh, channel_accept);
+
+	if(!meshlink_start(mesh)) {
+		fprintf(stderr, "Could not start MeshLink: %s\n", meshlink_strerror(meshlink_errno));
+		return 1;
+	}
+
+	fprintf(stderr, "Chat started.\nType /help for a list of commands.\n");
+
+	while(fgets(buf, sizeof(buf), stdin)) {
+		parse_input(mesh, buf);
+	}
+
+	fprintf(stderr, "Chat stopping.\n");
+
+	meshlink_stop(mesh);
+	meshlink_close(mesh);
+
+	return 0;
+}