opc source code

2026-06-09 17:27:24 +08:00
parent 70f675a48b
commit f0da5cb3c3
2002 changed files with 269812 additions and 7 deletions
--- a/third_party/open62541/examples/client_connect_loop.c
+++ b/third_party/open62541/examples/client_connect_loop.c
@@ -0,0 +1,83 @@
+/* This work is licensed under a Creative Commons CCZero 1.0 Universal License.
+ * See http://creativecommons.org/publicdomain/zero/1.0/ for more information. */
+
+/**
+ * Client disconnect handling
+ * --------------------------
+ * This example shows you how to handle a client disconnect, e.g., if the server
+ * is shut down while the client is connected. You just need to call connect
+ * again and the client will automatically reconnect.
+ *
+ * This example is very similar to the tutorial_client_firststeps.c. */
+
+#include <open62541/client_config_default.h>
+#include <open62541/client_highlevel.h>
+#include <open62541/plugin/log_stdout.h>
+
+#include <signal.h>
+#include <stdlib.h>
+#include "common.h"
+
+UA_Boolean running = true;
+
+static void stopHandler(int sign) {
+    UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_CLIENT, "Received Ctrl-C");
+    running = 0;
+}
+
+int main(void) {
+    signal(SIGINT, stopHandler); /* catches ctrl-c */
+
+    UA_Client *client = UA_Client_new();
+    UA_ClientConfig *cc = UA_Client_getConfig(client);
+    UA_ClientConfig_setDefault(cc);
+
+    /* default timeout is 5 seconds. Set it to 1 second here for demo */
+    cc->timeout = 1000;
+
+    /* 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; /* Variants can hold scalar values and arrays of any type */
+    UA_Variant_init(&value);
+
+    /* Endless loop reading the server time */
+    while(running) {
+        /* if already connected, this will return GOOD and do nothing */
+        /* if the connection is closed/errored, the connection will be reset and then reconnected */
+        /* Alternatively you can also use UA_Client_getState to get the current state */
+        UA_StatusCode retval = UA_Client_connect(client, "opc.tcp://localhost:4840");
+        if(retval != UA_STATUSCODE_GOOD) {
+            UA_LOG_ERROR(UA_Log_Stdout, UA_LOGCATEGORY_CLIENT, "Not connected. Retrying to connect in 1 second");
+            /* The connect may timeout after 1 second (see above) or it may fail immediately on network errors */
+            /* E.g. name resolution errors or unreachable network. Thus there should be a small sleep here */
+            sleep_ms(1000);
+            continue;
+        }
+
+        /* NodeId of the variable holding the current time */
+        const UA_NodeId nodeId =
+                UA_NODEID_NUMERIC(0, UA_NS0ID_SERVER_SERVERSTATUS_CURRENTTIME);
+
+        retval = UA_Client_readValueAttribute(client, nodeId, &value);
+        if(retval == UA_STATUSCODE_BADCONNECTIONCLOSED) {
+            UA_LOG_ERROR(UA_Log_Stdout, UA_LOGCATEGORY_CLIENT,
+                         "Connection was closed. Reconnecting ...");
+            continue;
+        }
+        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_USERLAND,
+                        "date is: %02u-%02u-%04u %02u:%02u:%02u.%03u",
+                        dts.day, dts.month, dts.year, dts.hour, dts.min, dts.sec, dts.milliSec);
+        }
+        UA_Variant_clear(&value);
+        sleep_ms(1000);
+    };
+
+    /* Clean up */
+    UA_Variant_clear(&value);
+    UA_Client_delete(client); /* Disconnects the client internally */
+    return EXIT_SUCCESS;
+}