I need to implement a TCP Server connection with TIdTCPServer component.
I already did it with GUI (drag & drop) and its working. But I need to Split form and TCP implementations. Example codes I've seen so far always uses TIdTCPServer as the member of TForm class.(result of drag and drop).
How I Call TCPConnection class that I've implemented from the TForm
TCPConnection CConnection = new TCPConnection(Owner, this);
Here is how I try to create a TCP Server Connection.
TCPConnection::TCPConnection(TComponent* Owner, TForm4* TSuperForm){
IdTCPServer1 = new TIdTCPServer(Owner);
IdTCPServer1->Bindings->Clear();
//IdTCPServer1->Bindings->Add()->SetBinding("10.10.2.103", 774);
IdTCPServer1->OnConnect = (TIdServerThreadEvent)(&OnConnect);
IdTCPServer1->OnExecute = (TIdServerThreadEvent)&OnExecute;
IdTCPServer1->OnDisconnect = (TIdServerThreadEvent)&OnConnect;
IdTCPServer1->OnException = (TIdServerThreadExceptionEvent)&OnException;
IdTCPServer1->DefaultPort = 774;
IdTCPServer1->Bindings->Add();
IdTCPServer1->Bindings->Items[0]->IP="10.10.2.103";
IdTCPServer1->Bindings->Items[0]->Port=774;
IdTCPServer1->ListenQueue = 15;
IdTCPServer1->MaxConnections = 15;
IdTCPServer1->TerminateWaitTime = 5000;
IdTCPServer1->Active = true;
this->TSuperForm = TSuperForm;
}
So far that codes work. But when I try to reach the context, connection is lost and throws an exception
void TCPConnection::OnConnect(TIdContext *AContext){
String IP = AContext->Binding()->PeerIP;
}
void TCPConnection::OnException(TIdContext *AContext, Exception *AException)
{
ShowMessage("Error:" + AException->ToString());
}
Error says TIdTaskThreadWork (I'll edit error, might be wrong)
If I don't try to reach AContext, connection stays without problem.
Might be something about thread, locking list, ...
Any Suggestions?
Those function casts look very smelly. Are you sure you've defined the functions as __fastcall, as the function casts should not be required at all.
This should be all you need, if you've defined them correctly.
IdTCPServer1->OnConnect = &OnConnect;
// ... etc...
This is what I do:
TIdTCPServer *TCPServer = new TIdTCPServer( this );
TCPServer->Active = false;
TCPServer->OnExecute = MyExecute;
TCPServer->DefaultPort = XXX;
TCPServer->Active = true;
Then my MyExecute call is defined like this:
void __fastcall MyExecute( TIdContext* AContext );
Other callbacks are handled the same way, don't forget __fastcall and it should work.
Related
I've been using DI for a game engine project for a while and I just hit a wall; given the below order of creation: The job system does not depend on anything and everything depends on the file logger. It makes sense to create the job system, then the file logger, then pass the created references for each dependency down to its dependents' constructors.
App::App(const std::string& cmdString)
: EngineSubsystem()
, _theJobSystem{std::make_unique<JobSystem>(-1, static_cast<std::size_t>(JobType::Max), new std::condition_variable)}
, _theFileLogger{std::make_unique<FileLogger>(*_theJobSystem.get(), "game")}
, _theConfig{std::make_unique<Config>(KeyValueParser{cmdString})}
, _theRenderer{std::make_unique<Renderer>(*_theJobSystem.get(), *_theFileLogger.get(), *_theConfig.get())}
, _theInputSystem{std::make_unique<InputSystem>(*_theFileLogger.get(), *_theRenderer.get())}
, _theUI{std::make_unique<UISystem>(*_theFileLogger.get(), *_theRenderer.get(), *_theInputSystem.get())}
, _theConsole{std::make_unique<Console>(*_theFileLogger.get(), *_theRenderer.get())}
, _theAudioSystem{std::make_unique<AudioSystem>(*_theFileLogger.get()) }
, _theGame{std::make_unique<Game>()}
{
SetupEngineSystemPointers();
SetupEngineSystemChainOfResponsibility();
LogSystemDescription();
}
void App::SetupEngineSystemPointers() {
g_theJobSystem = _theJobSystem.get();
g_theFileLogger = _theFileLogger.get();
g_theConfig = _theConfig.get();
g_theRenderer = _theRenderer.get();
g_theUISystem = _theUI.get();
g_theConsole = _theConsole.get();
g_theInputSystem = _theInputSystem.get();
g_theAudioSystem = _theAudioSystem.get();
g_theGame = _theGame.get();
g_theApp = this;
}
void App::SetupEngineSystemChainOfResponsibility() {
g_theConsole->SetNextHandler(g_theUISystem);
g_theUISystem->SetNextHandler(g_theInputSystem);
g_theInputSystem->SetNextHandler(g_theApp);
g_theApp->SetNextHandler(nullptr);
g_theSubsystemHead = g_theConsole;
}
As you can see, passing the different subsystems around to the other subsystem constructors is starting to get messy. In particular when dealing with jobs, logging, console commands, UI, configuration, and audio (and physics, not pictured).
(Side note: These are going to eventually be replaced with interfaces created via factories for cross-compatibility, i.e. the Renderer is strictly a DirectX/Windows-only renderer but I want to eventually support OpenGL/Linux; that's why everything is passed around as references and created as pointers instead of a concrete types)
I've run in to situations where pretty much all the subsystems are in some way dependent on every other subsystem.
But, due to construction-order problems, Dependency Injection does not work because one or more of the required-to-exist subsystems hasn't been constructed yet. Same problem with two-phase construction: the subsystem may not have been initialized by the time it's needed further downstream.
I looked in to the service locator pattern and this question deems it a bad idea, but the game industry likes using bad ideas (like global variables to every subsystem for game-specific code to use) if they work.
Would converting to a service locator fix this problem?
What other implementations do you know of that could also fix the issue?
I ultimately went with the ServiceLocator pattern, deriving every subsystem that was a dependency as a Service:
App::App(const std::string& cmdString)
: EngineSubsystem()
, _theConfig{std::make_unique<Config>(KeyValueParser{cmdString})}
{
SetupEngineSystemPointers();
SetupEngineSystemChainOfResponsibility();
LogSystemDescription();
}
void App::SetupEngineSystemPointers() {
ServiceLocator::provide(*static_cast<IConfigService*>(_theConfig.get()));
_theJobSystem = std::make_unique<JobSystem>(-1, static_cast<std::size_t>(JobType::Max), new std::condition_variable);
ServiceLocator::provide(*static_cast<IJobSystemService*>(_theJobSystem.get()));
_theFileLogger = std::make_unique<FileLogger>("game");
ServiceLocator::provide(*static_cast<IFileLoggerService*>(_theFileLogger.get()));
_theRenderer = std::make_unique<Renderer>();
ServiceLocator::provide(*static_cast<IRendererService*>(_theRenderer.get()));
_theInputSystem = std::make_unique<InputSystem>();
ServiceLocator::provide(*static_cast<IInputService*>(_theInputSystem.get()));
_theAudioSystem = std::make_unique<AudioSystem>();
ServiceLocator::provide(*static_cast<IAudioService*>(_theAudioSystem.get()));
_theUI = std::make_unique<UISystem>();
_theConsole = std::make_unique<Console>();
_theGame = std::make_unique<Game>();
g_theJobSystem = _theJobSystem.get();
g_theFileLogger = _theFileLogger.get();
g_theConfig = _theConfig.get();
g_theRenderer = _theRenderer.get();
g_theUISystem = _theUI.get();
g_theConsole = _theConsole.get();
g_theInputSystem = _theInputSystem.get();
g_theAudioSystem = _theAudioSystem.get();
g_theGame = _theGame.get();
g_theApp = this;
}
void App::SetupEngineSystemChainOfResponsibility() {
g_theConsole->SetNextHandler(g_theUISystem);
g_theUISystem->SetNextHandler(g_theInputSystem);
g_theInputSystem->SetNextHandler(g_theRenderer);
g_theRenderer->SetNextHandler(g_theApp);
g_theApp->SetNextHandler(nullptr);
g_theSubsystemHead = g_theConsole;
}
In regard to Indy 10 of IdHTTP, many things have been running perfectly, but there are a few things that don't work so well here. That is why, once again, I need your help.
Download button has been running perfectly. I'm using the following code :
void __fastcall TForm1::DownloadClick(TObject *Sender)
{
MyFile = SaveDialog->FileName;
TFileStream* Fist = new TFileStream(MyFile, fmCreate | fmShareDenyNone);
Download->Enabled = false;
Urlz = Edit1->Text;
Url->Caption = Urlz;
try
{
IdHTTP->Get(Edit1->Text, Fist);
IdHTTP->Connected();
IdHTTP->Response->ResponseCode = 200;
IdHTTP->ReadTimeout = 70000;
IdHTTP->ConnectTimeout = 70000;
IdHTTP->ReuseSocket;
Fist->Position = 0;
}
__finally
{
delete Fist;
Form1->Updated();
}
}
However, a "Cancel Resume" button is still can't resume interrupted downloads. Meant, it is always sending back the entire file every time I call Get() though I've used IdHTTP->Request->Ranges property.
I use the following code:
void __fastcall TForm1::CancelResumeClick(TObject *Sender)
{
MyFile = SaveDialog->FileName;;
TFileStream* TFist = new TFileStream(MyFile, fmCreate | fmShareDenyNone);
if (IdHTTP->Connected() == true)
{
IdHTTP->Disconnect();
CancelResume->Caption = "RESUME";
IdHTTP->Response->AcceptRanges = "Bytes";
}
else
{
try {
CancelResume->Caption = "CANCEL";
// IdHTTP->Request->Ranges == "0-100";
// IdHTTP->Request->Range = Format("bytes=%d-",ARRAYOFCONST((TFist->Position)));
IdHTTP->Request->Ranges->Add()->StartPos = TFist->Position;
IdHTTP->Get(Edit1->Text, TFist);
IdHTTP->Request->Referer = Edit1->Text;
IdHTTP->ConnectTimeout = 70000;
IdHTTP->ReadTimeout = 70000;
}
__finally {
delete TFist;
}
}
Meanwhile, by using the FormatBytes function, found here, has been able to shows only the size of download files. But still unable to determine the speed of download or transfer speed.
I'm using the following code:
void __fastcall TForm1::IdHTTPWork(TObject *ASender, TWorkMode AWorkMode, __int64 AWorkCount)
{
__int64 Romeo = 0;
Romeo = IdHTTP->Response->ContentStream->Position;
// Romeo = AWorkCount;
Download->Caption = FormatBytes(Romeo) + " (" + IntToStr(Romeo) + " Bytes)";
ForSpeed->Caption = FormatBytes(Romeo);
ProgressBar->Position = AWorkCount;
ProgressBar->Update();
Form1->Updated();
}
Please advise and give an example. Any help would sure be appreciated!
In your DownloadClick() method:
Calling Connected() is useless, since you don't do anything with the result. Nor is there any guarantee that the connection will remain connected, as the server could send a Connection: close response header. I don't see anything in your code that is asking for HTTP keep-alives. Let TIdHTTP manage the connection for you.
You are forcing the Response->ResponseCode to 200. Don't do that. Respect the response code that the server actually sent. The fact that no exception was raised means the response was successful whether it is 200 or 206.
You are reading the ReuseSocket property value and ignoring it.
There is no need to reset the Fist->Position property to 0 before closing the file.
Now, with that said, your CancelResumeClick() method has many issues.
You are using the fmCreate flag when opening the file. If the file already exists, you will overwrite it from scratch, thus TFist->Position will ALWAYS be 0. Use fmOpenReadWrite instead so an existing file will open as-is. And then you have to seek to the end of the file to provide the correct Position to the Ranges header.
You are relying on the socket's Connected() state to make decisions. DO NOT do that. The connection may be gone after the previous response, or may have timed out and been closed before the new request is made. The file can still be resumed either way. HTTP is stateless. It does not matter if the socket remains open between requests, or is closed in between. Every request is self-contained. Use information provided in the previous response to govern the next request. Not the socket state.
You are modifying the value of the Response->AcceptRanges property, instead of using the value provided by the previous response. The server tells you if the file supports resuming, so you have to remember that value, or query it before then attempting to resumed download.
When you actually call Get(), the server may or may not respect the requested Range, depending on whether the requested file supports byte ranges or not. If the server responds with a response code of 206, the requested range is accepted, and the server sends ONLY the requested bytes, so you need to APPEND them to your existing file. However, if the server response with a response code of 200, the server is sending the entire file from scratch, so you need to REPLACE your existing file with the new bytes. You are not taking that into account.
In your IdHTTPWork() method, in order to calculate the download/transfer speed, you have to keep track of how many bytes are actually being transferred in between each event firing. When the event is fired, save the current AWorkCount and tick count, and then the next time the event is fired, you can compare the new AWorkCount and current ticks to know how much time has elapsed and how many bytes were transferred. From those value, you can calculate the speed, and even the estimated time remaining.
As for your progress bar, you can't use AWorkCount alone to calculate a new position. That only works if you set the progress bar's Max to AWorkCountMax in the OnWorkBegin event, and that value is not always know before a download begins. You need to take into account the size of the file being downloaded, whether it is being downloaded fresh or being resumed, how many bytes are being requested during a resume, etc. So there is lot more work involved in displaying a progress bar for a HTTP download.
Now, to answer your two questions:
How to retrieve and save the download file to a disk by using its original name?
It is provided by the server in the filename parameter of the Content-Disposition header, and/or in the name parameter of the Content-Type header. If neither value is provided by the server, you can use the filename that is in the URL you are requesting. TIdHTTP has a URL property that provides the parsed version of the last requested URL.
However, since you are creating the file locally before sending your download request, you will have to create a local file using a temp filename, and then rename the local file after the download is complete. Otherwise, use TIdHTTP.Head() to determine the real filename (you can also use it to determine if resuming is supported) before creating the local file with that filename, then use TIdHTTP.Get() to download to that local file. Otherwise, download the file to memory using TMemoryStream instead of TFileStream, and then save with the desired filename when complete.
when I click http://get.videolan.org/vlc/2.2.1/win32/vlc-2.2.1-win32.exe then the server will process requests to its actual url. http://mirror.vodien.com/videolan/vlc/2.2.1/win32/vlc-2.2.1-win32.exe. The problem is that IdHTTP will not automatically grab through it.
That is because VideoLan is not using an HTTP redirect to send clients to the real URL (TIdHTTP supports HTTP redirects). VideoLan is using an HTML redirect instead (TIdHTTP does not support HTML redirects). When a webbrowser downloads the first URL, a 5 second countdown timer is displayed before the real download then begins. As such, you will have to manually detect that the server is sending you an HTML page instead of the real file (look at the TIdHTTP.Response.ContentType property for that), parse the HTML to determine the real URL, and then download it. This also means that you cannot download the first URL directly into your target local file, otherwise you will corrupt it, especially during a resume. You have to cache the server's response first, either to a temp file or to memory, so you can analyze it before deciding how to act on it. It also means you have to remember the real URL for resuming, you cannot resume the download using the original countdown URL.
Try something more like the following instead. It does not take into account for everything mentioned above (particularly speed/progress tracking, HTML redirects, etc), but should get you a little closer:
void __fastcall TForm1::DownloadClick(TObject *Sender)
{
Urlz = Edit1->Text;
Url->Caption = Urlz;
IdHTTP->Head(Urlz);
String FileName = IdHTTP->Response->RawHeaders->Params["Content-Disposition"]["filename"];
if (FileName.IsEmpty())
{
FileName = IdHTTP->Response->RawHeaders->Params["Content-Type"]["name"];
if (FileName.IsEmpty())
FileName = IdHTTP->URL->Document;
}
SaveDialog->FileName = FileName;
if (!SaveDialog->Execute()) return;
MyFile = SaveDialog->FileName;
TFileStream* Fist = new TFileStream(MyFile, fmCreate | fmShareDenyWrite);
try
{
try
{
Download->Enabled = false;
Resume->Enabled = false;
IdHTTP->Request->Clear();
//...
IdHTTP->ReadTimeout = 70000;
IdHTTP->ConnectTimeout = 70000;
IdHTTP->Get(Urlz, Fist);
}
__finally
{
delete Fist;
Download->Enabled = true;
Updated();
}
}
catch (const EIdHTTPProtocolException &)
{
DeleteFile(MyFile);
throw;
}
}
void __fastcall TForm1::ResumeClick(TObject *Sender)
{
TFileStream* Fist = new TFileStream(MyFile, fmOpenReadWrite | fmShareDenyWrite);
try
{
Download->Enabled = false;
Resume->Enabled = false;
IdHTTP->Request->Clear();
//...
Fist->Seek(0, soEnd);
IdHTTP->Request->Ranges->Add()->StartPos = Fist->Position;
IdHTTP->Request->Referer = Edit1->Text;
IdHTTP->ConnectTimeout = 70000;
IdHTTP->ReadTimeout = 70000;
IdHTTP->Get(Urlz, Fist);
}
__finally
{
delete Fist;
Download->Enabled = true;
Updated();
}
}
void __fastcall TForm1::IdHTTPHeadersAvailable(TObject*Sender, TIdHeaderList *AHeaders, bool &VContinue)
{
Resume->Enabled = ( ((IdHTTP->Response->ResponseCode == 200) || (IdHTTP->Response->ResponseCode == 206)) && TextIsSame(AHeaders->Values["Accept-Ranges"], "bytes") );
if ((IdHTTP->Response->ContentStream) && (IdHTTP->Request->Ranges->Count > 0) && (IdHTTP->Response->ResponseCode == 200))
IdHTTP->Response->ContentStream->Size = 0;
}
#Romeo:
Also, you can try a following function to determine the real download filename.
I've translated this to C++ based on the RRUZ'function. So far so good, I'm using it on my simple IdHTTP download program, too.
But, this translation result is of course still need value improvement input from Remy Lebeau, RRUZ, or any other master here.
String __fastcall GetRemoteFileName(const String URI)
{
String result;
try
{
TIdHTTP* HTTP = new TIdHTTP(NULL);
try
{
HTTP->Head(URI);
result = HTTP->Response->RawHeaders->Params["Content-Disposition"]["filename"];
if (result.IsEmpty())
{
result = HTTP->Response->RawHeaders->Params["Content-Type"]["name"];
if (result.IsEmpty())
result = HTTP->URL->Document;
}
}
__finally
{
delete HTTP;
}
}
catch(const Exception &ex)
{
ShowMessage(const_cast<Exception&>(ex).ToString());
}
return result;
}
I've racked my brain over this for some hours: pClient is always NULL (0x000000). pClient doesn't seem to initialize the same way as ISkypePtr, IUserCollectionPtr, and IUserPtr?
ISkypePtr pSkype(__uuidof(Skype));
while (TRUE){
IUserCollectionPtr pResults = pSkype->SearchForUsers("john doe");
for (int i = 1; i <= pResults->Count; ++i){
IUserPtr pUser = pResults->GetItem(i); _bstr_t handle = pUser->GetHandle();
IClientPtr pClient;
pClient->OpenAddContactDialog(handle);
Sleep(30000);
}
}
You're not making any effort to initialise pClient: in the other two cases you're giving it a CLSID to instantiate and you're assigning it from a COM object pointer you received back. I'd guess you want the following:
// Start client
IClientPtr pClient = pSkype->GetClient();
if (pClient->IsRunning == VARIANT_FALSE)
pClient->Start(VARIANT_FALSE, VARIANT_FALSE);
(taken from this project on GoogleCode). This won't need to be in the while loop assuming you're not planning to close the client after each contact request.
But please use this responsibly and not for generating spam contact requests. Thanks.
I have created a class and published it as web service. I have created a web method like this:
public void addNewRow(MyObject cob) {
MyAppModule myAppModule = new MyAppModule();
try {
ViewObjectImpl vo = myAppModule.getMyVewObject1();
================> vo object is now null
Row r = vo.createRow();
r.setAttribute("Param1", cob.getParam1());
r.setAttribute("Param2", cob.getParam2());
vo.executeQuery();
getTransaction().commit();
} catch (Exception e) {
e.printStackTrace();
}
}
As I have written in code, myAppModule.getMyVewObject1() returns a null object. I do not understand why! As far as I know AppModule has to initialize the object by itself when I call "getMyVewObject1()" but maybe I am wrong, or maybe this is not the way it should be for web methods. Has anyone ever faced this issue? Any help would be very appreciated.
You can check nice tutorial: Building and Using Web Services with JDeveloper
It gives you general idea about how you should build your webservices with ADF.
Another approach is when you need to call existing Application Module from some bean that doesn't have needed environment (servlet, etc), then you can initialize it like this:
String appModuleName = "org.my.package.name.model.AppModule";
String appModuleConfig = "AppModuleLocal";
ApplicationModule am = Configuration.createRootApplicationModule(appModuleName, appModuleConfig);
Don't forget to release it:
Configuration.releaseRootApplicationModule(am, true);
And why you shouldn't really do it like this.
And even more...
Better aproach is to get access to binding layer and do call from there.
Here is a nice article.
Per Our PM : If you don't use it in the context of an ADF application then the following code should be used (sample code is from a project I am involved in). Note the release of the AM at the end of the request
#WebService(serviceName = "LightViewerSoapService")
public class LightViewerSoapService {
private final String amDef = " oracle.demo.lightbox.model.viewer.soap.services.LightBoxViewerService";
private final String config = "LightBoxViewerServiceLocal";
LightBoxViewerServiceImpl service;
public LightViewerSoapService() {
super();
}
#WebMethod
public List<Presentations> getAllUserPresentations(#WebParam(name = "userId") Long userId){
ArrayList<Presentations> al = new ArrayList<Presentations>();
service = (LightBoxViewerServiceImpl)getApplicationModule(amDef,config);
ViewObject vo = service.findViewObject("UserOwnedPresentations");
VariableValueManager vm = vo.ensureVariableManager();
vm.setVariableValue("userIdVariable", userId.toString());
vo.applyViewCriteria(vo.getViewCriteriaManager().getViewCriteria("byUserIdViewCriteria"));
Row rw = vo.first();
if(rw != null){
Presentations p = createPresentationFromRow(rw);
al.add(p);
while(vo.hasNext()){
rw = vo.next();
p = createPresentationFromRow(rw);
al.add(p);
}
}
releaseAm((ApplicationModule)service);
return al;
}
Have a look here too:
http://www.youtube.com/watch?v=jDBd3JuroMQ
I am designing a database browsing application, which till now had MySQL support, but recently I have started implementing supporting Sqlite too and I face some ugliness while designing the way the connectivity architecture is being implemented. This is only about the "connection" part (ie: where you get the user/db/host, or for sqlite the filename), not the database functionality. That is sorted out already.
I have a base class "Connection" which exposes "normal" methods like name(), or pure virtual methods which are like virtual string fullLocation() = 0 which returns me a string that can be used to identify the database (such as: database#host for MySql, or /etc/mydb.sqlite for Sqlite).
Now, the user of course needs to specify a database he wants to connect to, so in the GUI of the application he simply chooses the type and then fills in the credentials. And here my troubles start. I have created a MySqlConnection and an SqliteConnectionclasses, both derived from Connection but most of the cases I end up with something like:
Connection* c = 0;
if(gui->engine_name() == "MYSQL")
{
string host = gui->getHost();
string user = gui->getUser();
string password = gui->getPassword();
int port = gui->getPort();
string db = gui->getDatabase();
c = new MySqlConnection(host, user, password, db, port);
}
else
{
string dbFile = gui->getSqliteDbFile();
c = new SqliteConnection(dbFile);
}
string meta = application->use_connection(&c);
and I have the fear, that this will continue through the entire application, due to the so different nature of these two database engines.
Do you have some guidance on how to solve this in an elegant way?
You need pattern Factory, that will create Connection for you in abstract way. It is superficial answer.
This Factory would be nice parametrize with Builder pattern. Something like that:
ParamBuilder *b = new ParamBuilder;
if(gui->engine_name() == "MYSQL")
{
b->setHost(gui->getHost())
->setUser(gui->getUser());
->setPassword(gui->getPassword());
...
}
else
{
b->setFile(gui->getSqliteDbFile());
}
Connection *c = globalConnectionFactory->createConnection(b);
A much more elegant way would be designing a factory class and handling GUI inputs in the GenerateConnection() method of that factory:
void ConnectionFactory::GenerateConnection(Connection* c)
{
if(gui->engine_name() == "MYSQL")
{
string host = gui->getHost();
string user = gui->getUser();
string password = gui->getPassword();
int port = gui->getPort();
string db = gui->getDatabase();
c = new MySqlConnection(host, user, password, db, port);
}
else
{
string dbFile = gui->getSqliteDbFile();
c = new SqliteConnection(dbFile);
}
}
If you do not prefer a dependency on the gui, you can just define a struct named Parameters and update its instance according to the gui inputs and give this object into the connection generating method of connection factory.