examples: add example for rdcli

examples/rdcli/Makefile

+# name of your application
+APPLICATION = rdcli
+
+# If no BOARD is found in the environment, use this default:
+BOARD ?= native
+
+# This has to be the absolute path to the RIOT base directory:
+RIOTBASE ?= $(CURDIR)/../..
+
+USEMODULE += gnrc_netdev_default
+USEMODULE += auto_init_gnrc_netif
+USEMODULE += gnrc_ipv6_default
+USEMODULE += gnrc_icmpv6_echo
+
+USEMODULE += rdcli_standalone
+
+USEMODULE += shell
+USEMODULE += shell_commands
+USEMODULE += ps
+USEMODULE += fmt
+
+# Comment this out to disable code in RIOT that does safety checking
+# which is not needed in a production environment but helps in the
+# development process:
+CFLAGS += -DDEVELHELP
+
+# For debugging and demonstration purposes, we limit the lifetime to 60s
+CFLAGS += -DRDCLI_LT=60
+
+# Change this to 0 show compiler invocation lines by default:
+QUIET ?= 1
+
+include $(RIOTBASE)/Makefile.include

examples/rdcli/README.md

+CoRE Resource Directory Client Example
+======================================
+This example application demonstrates the usage of RIOT's Resource Directory
+(RD) client module, called `rdcli`. This module supports the registration,
+update, and removal processes as defined in the
+[Resource Directory Draft](https://tools.ietf.org/html/draft-ietf-core-resource-directory-14).
+
+Usage
+=====
+The examples includes a shell command that you can use to interact with a given
+RD server, called `rdcli`. Simply use that shell command without parameters for
+more information on its usage.
+
+Some connection parameters are configured statically during compile time,
+namely the lifetime (`RDCLI_LT`) and the node's endpoint name (`RDCLI_EP`). You
+can change these values during command line by overriding these values in the
+application's Makefile, e.g. add
+```
+CFLAGS += "-DRDCLI_EP=\"MyNewEpName\""
+```

examples/rdcli/main.c

+/*
+ * Copyright (C) 2017-2018 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     examples
+ * @{
+ *
+ * @file
+ * @brief       CoRE Resource Directory client (rdcli) example application
+ *
+ * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
+ *
+ * @}
+ */
+
+#include <stdio.h>
+
+#include "fmt.h"
+#include "shell.h"
+#include "net/ipv6/addr.h"
+#include "net/gcoap.h"
+#include "net/rdcli_common.h"
+#include "net/rdcli_standalone.h"
+
+#define MAIN_QUEUE_SIZE     (8)
+static msg_t _main_msg_queue[MAIN_QUEUE_SIZE];
+
+/* we will use a custom event handler for dumping rdcli_standalone events */
+static void _on_rdcli_event(rdcli_standalone_event_t event)
+{
+    switch (event) {
+        case RDCLI_REGISTERED:
+            puts("rdcli event: now registered with a RD");
+            break;
+        case RDCLI_DEREGISTERED:
+            puts("rdcli event: dropped client registration");
+            break;
+        case RDCLI_UPDATED:
+            puts("rdcli event: successfully updated client registration");
+            break;
+    }
+}
+
+/* define some dummy CoAP resources */
+static ssize_t _handler_dummy(coap_pkt_t *pdu,
+                              uint8_t *buf, size_t len, void *ctx)
+{
+    (void)ctx;
+
+    /* get random data */
+    int16_t val = 23;
+
+    gcoap_resp_init(pdu, buf, len, COAP_CODE_CONTENT);
+    size_t plen = fmt_s16_dec((char *)pdu->payload, val);
+    return gcoap_finish(pdu, plen, COAP_FORMAT_TEXT);
+}
+
+static ssize_t _handler_info(coap_pkt_t *pdu,
+                             uint8_t *buf, size_t len, void *ctx)
+{
+    (void)ctx;
+
+    gcoap_resp_init(pdu, buf, len, COAP_CODE_CONTENT);
+    size_t slen = sizeof("SOME NODE INFOMRATION");
+    memcpy(pdu->payload, "SOME NODE INFOMRATION", slen);
+    return gcoap_finish(pdu, slen, COAP_FORMAT_TEXT);
+}
+
+static const coap_resource_t _resources[] = {
+    { "/node/info",  COAP_GET, _handler_info, NULL },
+    { "/sense/hum",  COAP_GET, _handler_dummy, NULL },
+    { "/sense/temp", COAP_GET, _handler_dummy, NULL }
+};
+
+static gcoap_listener_t _listener = {
+    .resources     = (coap_resource_t *)&_resources[0],
+    .resources_len = sizeof(_resources) / sizeof(_resources[0]),
+    .next          = NULL
+};
+
+int main(void)
+{
+    /* we need a message queue for the thread running the shell in order to
+     * receive potentially fast incoming networking packets */
+    msg_init_queue(_main_msg_queue, MAIN_QUEUE_SIZE);
+
+    puts("CoRE RD client example!\n");
+
+    /* setup CoAP resources */
+    gcoap_register_listener(&_listener);
+
+    /* register event callback with rdcli_standalone */
+    rdcli_standalone_reg_cb(_on_rdcli_event);
+
+    puts("Client information:");
+    printf("  ep: %s\n", rdcli_common_get_ep());
+    printf("  lt: %is\n", (int)RDCLI_LT);
+
+    char line_buf[SHELL_DEFAULT_BUFSIZE];
+    shell_run(NULL, line_buf, SHELL_DEFAULT_BUFSIZE);
+
+    return 0;
+}