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/* This work is licensed under a Creative Commons CCZero 1.0 Universal License.
* See http://creativecommons.org/publicdomain/zero/1.0/ for more information. */
/**
* Adding Methods to Objects
* -------------------------
*
* An object in an OPC UA information model may contain methods similar to
* objects in a programming language. Methods are represented by a MethodNode.
* Note that several objects may reference the same MethodNode. When an object
* type is instantiated, a reference to the method is added instead of copying
* the MethodNode. Therefore, the identifier of the context object is always
* explicitly stated when a method is called.
*
* The method callback takes as input a custom data pointer attached to the
* method node, the identifier of the object from which the method is called,
* and two arrays for the input and output arguments. The input and output
* arguments are all of type :ref:`variant`. Each variant may in turn contain a
* (multi-dimensional) array or scalar of any data type.
*
* Constraints for the method arguments are defined in terms of data type, value
* rank and array dimension (similar to variable definitions). The argument
* definitions are stored in child VariableNodes of the MethodNode with the
* respective BrowseNames ``(0, "InputArguments")`` and ``(0,
* "OutputArguments")``.
*
* Example: Hello World Method
* ^^^^^^^^^^^^^^^^^^^^^^^^^^^
* The method takes a string scalar and returns a string scalar with "Hello "
* prepended. The type and length of the input arguments is checked internally
* by the SDK, so that we don't have to verify the arguments in the callback. */
#include <open62541/client_config_default.h>
#include <open62541/plugin/log_stdout.h>
#include <open62541/server.h>
static UA_StatusCode
helloWorldMethodCallback(UA_Server *server,
const UA_NodeId *sessionId, void *sessionHandle,
const UA_NodeId *methodId, void *methodContext,
const UA_NodeId *objectId, void *objectContext,
size_t inputSize, const UA_Variant *input,
size_t outputSize, UA_Variant *output) {
UA_String *inputStr = (UA_String*)input->data;
UA_String tmp = UA_STRING_ALLOC("Hello ");
if(inputStr->length > 0) {
tmp.data = (UA_Byte *)UA_realloc(tmp.data, tmp.length + inputStr->length);
memcpy(&tmp.data[tmp.length], inputStr->data, inputStr->length);
tmp.length += inputStr->length;
}
UA_Variant_setScalarCopy(output, &tmp, &UA_TYPES[UA_TYPES_STRING]);
UA_String_clear(&tmp);
UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_SERVER, "Hello World was called");
return UA_STATUSCODE_GOOD;
}
static void
addHelloWorldMethod(UA_Server *server) {
UA_Argument inputArgument;
UA_Argument_init(&inputArgument);
inputArgument.description = UA_LOCALIZEDTEXT("en-US", "A String");
inputArgument.name = UA_STRING("MyInput");
inputArgument.dataType = UA_TYPES[UA_TYPES_STRING].typeId;
inputArgument.valueRank = UA_VALUERANK_SCALAR;
UA_Argument outputArgument;
UA_Argument_init(&outputArgument);
outputArgument.description = UA_LOCALIZEDTEXT("en-US", "A String");
outputArgument.name = UA_STRING("MyOutput");
outputArgument.dataType = UA_TYPES[UA_TYPES_STRING].typeId;
outputArgument.valueRank = UA_VALUERANK_SCALAR;
UA_MethodAttributes helloAttr = UA_MethodAttributes_default;
helloAttr.description = UA_LOCALIZEDTEXT("en-US","Say `Hello World`");
helloAttr.displayName = UA_LOCALIZEDTEXT("en-US","Hello World");
helloAttr.executable = true;
helloAttr.userExecutable = true;
UA_Server_addMethodNode(server, UA_NODEID_NUMERIC(1,62541),
UA_NODEID_NUMERIC(0, UA_NS0ID_OBJECTSFOLDER),
UA_NODEID_NUMERIC(0, UA_NS0ID_HASCOMPONENT),
UA_QUALIFIEDNAME(1, "hello world"),
helloAttr, &helloWorldMethodCallback,
1, &inputArgument, 1, &outputArgument, NULL, NULL);
}
/**
* Increase Array Values Method
* ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
* The method takes an array of 5 integers and a scalar as input. It returns a
* copy of the array with every entry increased by the scalar. */
static UA_StatusCode
IncInt32ArrayMethodCallback(UA_Server *server,
const UA_NodeId *sessionId, void *sessionContext,
const UA_NodeId *methodId, void *methodContext,
const UA_NodeId *objectId, void *objectContext,
size_t inputSize, const UA_Variant *input,
size_t outputSize, UA_Variant *output) {
UA_Int32 *inputArray = (UA_Int32*)input[0].data;
UA_Int32 delta = *(UA_Int32*)input[1].data;
/* Copy the input array */
UA_StatusCode retval = UA_Variant_setArrayCopy(output, inputArray, 5,
&UA_TYPES[UA_TYPES_INT32]);
if(retval != UA_STATUSCODE_GOOD)
return retval;
/* Increate the elements */
UA_Int32 *outputArray = (UA_Int32*)output->data;
for(size_t i = 0; i < input->arrayLength; i++)
outputArray[i] = inputArray[i] + delta;
return UA_STATUSCODE_GOOD;
}
static void
addIncInt32ArrayMethod(UA_Server *server) {
/* Two input arguments */
UA_Argument inputArguments[2];
UA_Argument_init(&inputArguments[0]);
inputArguments[0].description = UA_LOCALIZEDTEXT("en-US", "int32[5] array");
inputArguments[0].name = UA_STRING("int32 array");
inputArguments[0].dataType = UA_TYPES[UA_TYPES_INT32].typeId;
inputArguments[0].valueRank = UA_VALUERANK_ONE_DIMENSION;
UA_UInt32 pInputDimension = 5;
inputArguments[0].arrayDimensionsSize = 1;
inputArguments[0].arrayDimensions = &pInputDimension;
UA_Argument_init(&inputArguments[1]);
inputArguments[1].description = UA_LOCALIZEDTEXT("en-US", "int32 delta");
inputArguments[1].name = UA_STRING("int32 delta");
inputArguments[1].dataType = UA_TYPES[UA_TYPES_INT32].typeId;
inputArguments[1].valueRank = UA_VALUERANK_SCALAR;
/* One output argument */
UA_Argument outputArgument;
UA_Argument_init(&outputArgument);
outputArgument.description = UA_LOCALIZEDTEXT("en-US", "int32[5] array");
outputArgument.name = UA_STRING("each entry is incremented by the delta");
outputArgument.dataType = UA_TYPES[UA_TYPES_INT32].typeId;
outputArgument.valueRank = UA_VALUERANK_ONE_DIMENSION;
UA_UInt32 pOutputDimension = 5;
outputArgument.arrayDimensionsSize = 1;
outputArgument.arrayDimensions = &pOutputDimension;
/* Add the method node */
UA_MethodAttributes incAttr = UA_MethodAttributes_default;
incAttr.description = UA_LOCALIZEDTEXT("en-US", "IncInt32ArrayValues");
incAttr.displayName = UA_LOCALIZEDTEXT("en-US", "IncInt32ArrayValues");
incAttr.executable = true;
incAttr.userExecutable = true;
UA_Server_addMethodNode(server, UA_NODEID_STRING(1, "IncInt32ArrayValues"),
UA_NODEID_NUMERIC(0, UA_NS0ID_OBJECTSFOLDER),
UA_NODEID_NUMERIC(0, UA_NS0ID_HASCOMPONENT),
UA_QUALIFIEDNAME(1, "IncInt32ArrayValues"),
incAttr, &IncInt32ArrayMethodCallback,
2, inputArguments, 1, &outputArgument,
NULL, NULL);
}
/** It follows the main server code, making use of the above definitions. */
int main(void) {
UA_Server *server = UA_Server_new();
addHelloWorldMethod(server);
addIncInt32ArrayMethod(server);
UA_Server_runUntilInterrupt(server);
UA_Server_delete(server);
return 0;
}
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