7
産業用コントローラからプロセスデータの配列を読み取るアプリケーションがあります。そのデータが変更されると、そのデータをWebページにプッシュしたいと思います。そのために、私はプロセスデータをスキャンし、データ値が変更されたときにイベントを発生させようとするC++のnode.jsアドオンを書きました。それはイベントを発生しようとするまで、すべてはアドオンで正常に動作、その時点で、Node.jsのはエラーで終了：Node.jsでイベントを出力するC++ Addon
undefined:0
TypeError: undefined is not a function
CPP、以下の通りですjavascriptのjavascriptのシムとテスト。どんな洞察力も大変ありがとうございます。
ありがとうございます。
node_corelink.cpp
typedef struct CoreLinkValue
{
// pointer to a CTS variant value
CtsVariant* value;
// copy of the last value that was broadcast
CtsVariant lastValue;
} CoreLinkValue;
//
// An event structure for pushing events to node.js
// Requires the javascript shim code in node_corelink.js
//
struct Emitter: ObjectWrap
{
static Handle<Value> New(const Arguments& args);
static Handle<Value> DataChange(const char* topic, CtsVariant* value);
};
//
// Create a message payload based on the variant type and
// initiate sending out on the topic
//
static Handle<Value>
createVariantHandle(CtsVariant* value)
{
Handle<Value> ret;
switch (value->type)
{
case CTSTYPE_BIT:
case CTSTYPE_BYTE:
ret = Integer::New(value->value.byte[0]);
break;
case CTSTYPE_WORD:
ret = Integer::New(value->value.word[0]);
break;
case CTSTYPE_DWORD:
ret = Integer::New(value->value.dword[0]);
break;
case CTSTYPE_WORD64:
ret = Number::New(value->value.word64);
break;
case CTSTYPE_REAL64:
ret = Number::New(value->value.real64);
break;
default:
ret = Undefined();
break;
}
return ret;
}
Handle<Value> Emitter::New(const Arguments& args)
{
HandleScope scope;
assert(args.IsConstructCall());
Emitter* self = new Emitter();
self->Wrap(args.This());
return scope.Close(args.This());
}
// emits DataChange Event
Handle<Value> Emitter::DataChange(const char* topic, CtsVariant* value)
{
HandleScope scope;
Handle<Value> argv[3] = {
String::New("DataChange"), // event name
String::New(topic), // topic argument
createVariantHandle(value) // value argument
};
printf ("C++ Emitting event!\n");
MakeCallback(context_obj_, "emit", 2, argv);
return True();
}
//
// Triggered by the event loop on a regular interval.
// Scans the registered data to see if the latest value has been
// broadcast and does so if needed.
//
void
scan_task(uv_timer_t* timer, int status)
{
std::map<std::string, CoreLinkValue>::iterator it;
bool doUpdate;
for( it = pdos_.begin();
it != pdos_.end();
++it)
{
if (forceRefreshPdos_ == true)
{
//
// An update of this value was requested.
//
doUpdate = true;
}
else if (it->second.value->type != it->second.lastValue.type)
{
//
// If the types don't match, then this variant was obviously
// updated.
//
doUpdate = true;
}
else if (it->second.value->value.word64 != it->second.lastValue.value.word64)
{
//
// Word64 contains all bits of the value. If this value has
// changed, then they've all changed.
//
doUpdate = true;
}
else
{
doUpdate = false;
}
if (doUpdate)
{
it->second.lastValue.value = it->second.value->value;
Emitter::DataChange(it->first.c_str(), it->second.value);
}
}
if (forceRefreshPdos_)
{
forceRefreshPdos_ = false;
printf("Completed refresh all.\n");
}
}
//
// Start the execution of the scan loop
//
int
startScanLoop(void)
{
uv_timer_init(uv_default_loop(), &scanTimer_);
uv_timer_start(
&scanTimer_, // timer instance
&scan_task, // callback function
0, // startup delay (ms)
100); // repeat interval (ms)
return 1;
}
//
// Stop the execution of the scan loop
//
void
stopScanLoop(void)
{
uv_timer_stop(&scanTimer_);
}
//
// Connects to the kernel IPC
//
Handle<Value>
connect(const Arguments& args)
{
HandleScope scope;
...
startScanLoop();
return scope.Close(True());
}
//
// Shuts down the kernel IPC
//
Handle<Value>
close(const Arguments& args)
{
HandleScope scope;
stopScanLoop();
...
return scope.Close(True());
}
//
// Called by node.js to initialize the library.
//
void
init(Handle<Object> target)
{
target->Set(String::NewSymbol("connect"),
FunctionTemplate::New(connect)->GetFunction());
target->Set(String::NewSymbol("close"),
FunctionTemplate::New(close)->GetFunction());
//
// Events interface
//
Local<FunctionTemplate> t = FunctionTemplate::New(Emitter::New);
t->InstanceTemplate()->SetInternalFieldCount(1);
t->SetClassName(String::New("Emitter"));
target->Set(String::NewSymbol("Emitter"), t->GetFunction());
}
NODE_MODULE(node_corelink, init)
node_corelink.js
module.exports = require(__dirname + '/build/Release/node_corelink.node');
var Emitter = require(__dirname + '/build/Release/node_corelink.node').Emitter;
var events = require('events');
inherits(Emitter, events.EventEmitter);
exports.Emitter = Emitter;
// extend prototype
function inherits(target, source) {
for (var k in source.prototype)
target.prototype[k] = source.prototype[k];
}
test.js
process.stdin.resume(); //so the program will not close instantly
process.on('exit', function() {
corelink.close();
console.log('Goodbye!');
});
process.on('SIGINT', function() {
console.log('Got SIGINT.');
process.exit();
});
var corelink = require('./node_corelink');
var Emitter = require('./node_corelink').Emitter;
var e = new Emitter();
e.on('DataChange', function(s) {
console.log('DataChange');
});
corelink.connect();