client_json_config.c

/* This work is licensed under a Creative Commons CCZero 1.0 Universal License.
 * See http://creativecommons.org/publicdomain/zero/1.0/ for more information. */

#include <open62541/client.h>
#include <open62541/client_highlevel.h>
#include <open62541/client_config_default.h>
#include <open62541/plugin/log_stdout.h>

#include <stdlib.h>
#include "common.h"

int main(int argc, char** argv) {
    UA_ByteString json_config = UA_BYTESTRING_NULL;

    if(argc >= 2) {
        /* Load client config */
        json_config = loadFile(argv[1]);
        if (UA_String_isEmpty(&json_config)) {
            UA_LOG_FATAL(UA_Log_Stdout, UA_LOGCATEGORY_APPLICATION,
                         "Failed to load the client configuration from file '%s'.",
                         argv[1]);
            return EXIT_FAILURE;
        }
    } else {
        UA_LOG_FATAL(UA_Log_Stdout, UA_LOGCATEGORY_APPLICATION,
                     "Missing argument. Argument are "
                     "<client-config.json5>");
        return EXIT_FAILURE;
    }

    /*
     * Create the client directly from the JSON file.  Alternatively, the configuration
     * can be loaded into a UA_ClientConfig and then used to create the client.  The
     * following is identical to the line below:
     *
     *    UA_ClientConfig clientConfig;
     *    UA_StatusCode res = UA_ClientConfig_loadFromFile(&clientConfig, json_config);
     *    UA_Client *client = UA_Client_new(&clientConfig);
     *
     */
    UA_Client *client = UA_Client_newFromFile(json_config);

    /* identical to first steps example */
    UA_StatusCode retval = UA_Client_connect(client, "opc.tcp://localhost:4840");
    if(retval != UA_STATUSCODE_GOOD) {
        UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_APPLICATION,
                    "The connection failed with status code %s",
                    UA_StatusCode_name(retval));
        UA_Client_delete(client);
        UA_ByteString_clear(&json_config);
        return 0;
    }

    /* Read the value attribute of the node. UA_Client_readValueAttribute is a
     * wrapper for the raw read service available as UA_Client_Service_read. */
    UA_Variant value;
    UA_Variant_init(&value);

    /* NodeId of the variable holding the current time */
    const UA_NodeId nodeId = UA_NS0ID(SERVER_SERVERSTATUS_CURRENTTIME);
    retval = UA_Client_readValueAttribute(client, nodeId, &value);

    if(retval == UA_STATUSCODE_GOOD &&
       UA_Variant_hasScalarType(&value, &UA_TYPES[UA_TYPES_DATETIME])) {
        UA_DateTime raw_date = *(UA_DateTime *) value.data;
        UA_DateTimeStruct dts = UA_DateTime_toStruct(raw_date);
        UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_APPLICATION,
                    "date is: %u-%u-%u %u:%u:%u.%03u",
                    dts.day, dts.month, dts.year, dts.hour,
                    dts.min, dts.sec, dts.milliSec);
    } else {
        UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_APPLICATION,
                    "Reading the value failed with status code %s",
                    UA_StatusCode_name(retval));
    }

    /* Clean up */
    UA_Variant_clear(&value);
    UA_Client_delete(client); /* Disconnects the client internally */

    /* clean up */
    UA_ByteString_clear(&json_config);

    return retval == UA_STATUSCODE_GOOD ? EXIT_SUCCESS : EXIT_FAILURE;
}