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.
Related
I am working on a project that uses Mavlink protocol (in c++) to communicate with the ArduPilotMega (2.6).
I am able to read messages such as ATTITUDE for example. The current message rate (for all messages) is 2Hz and I would like to increase this rate.
I found out that I should probably set MESSAGE_INTERVAL using MAV_CMD_SET_MESSAGE_INTERVAL in order to change it.
So my question is:
How do I send this command message using mavlink in c++?
I tried doing it using the code below but it did not work. I guess I have to use the command I mentioned above, but I don't know how.
mavlink_message_t command;
mavlink_message_interval_t interval;
interval.interval_us = 100000;
interval.message_id = 30;
mavlink_msg_message_interval_encode(255, 200, &command, &interval);
p_sensorsPort->write_message(command);
Update: I also tried this code below, maybe I am not giving it the right system id or component id.
mavlink_message_t command;
mavlink_command_long_t interval;
interval.param1 = MAVLINK_MSG_ID_ATTITUDE;
interval.param2 = 100000;
interval.command = MAV_CMD_SET_MESSAGE_INTERVAL;
interval.target_system = 0;
interval.target_component = 0;
mavlink_msg_command_long_encode(255, 0, &command, &interval);
p_sensorsPort->write_message(command);
Maybe I am missing something about the difference between target_system, target_component and sysid, compid. I tried few values for each but nothing worked.
Is there any ACK that will be able to tell me if it even got the command?
I guess you missed start_stop field. the below sample is working.
final msg_request_data_stream msg = new msg_request_data_stream ();
msg.req_message_rate = rate;
msg.req_stream_id = (short) streamId;
msg.target_component = (short)compID;
msg.target_system = (short)sysID;
/*
GCS_COMMON.cpp contains code that sends when value =1
and stop when value = 0
that is it.
*/
if (rate > 0) {
msg.start_stop = 1;
} else {
msg.start_stop = 0;
}
From Robotis Stack Exchange answer,
In order to change the message rate, the simplest way is to change the SR_* parameters value using Mission Planner. The maximum rate is 10Hz.
For example, in order to change the ATTITUDE message rate to be 10Hz I just had to change the SR_EXTRA1 parameter to be 10.
For more information about which parameter changes each message see GCS_Mavlink.cpp file in ArduCopter firmware.
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;
}
Recently, I encountered a problem: in my tableview, I retrieve data from web request, after received response from the network, I need to decode the data and store the data in a C++ object.
However, the tableview datasource, NSArray cannot store C++ object.
I have tried some solutions, like using CFMutableArrayRef or save the C++ object pointer in a NSValue and then put the NSValue into the NSArray. But when I called [tableview reloadData],the data in the CFMutableArray or the NSValue don't have the right data.
Could anybody help me with this problem? Thanks!
Here are some code:
std::list<ImageTextContent> msgs = body->getMsgs();
std::list<ImageTextContent>::iterator itmsgs0;
for(itmsgs0 = msgs.begin();itmsgs0 != msgs.end();itmsgs0++)
{
ImageTextContent *tmpmsgs = &(*itmsgs0);
CFArrayAppendValue(_dataSourceRef, tmpmsgs);
}
and
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
ImageTextContent *itc = (ImageTextContent *)CFArrayGetValueAtIndex(_dataSourceRef, 0);
NSString *title = [NSString stringWithCString:(itc->getSubmitTime()).c_str() encoding:NSUTF8StringEncoding];
cell.contentLabel.text = title;
....
}
in cellForRowAtIndexPath method I can't get the right data, why?
The pointers in your _dataSourceRef array become invalid as soon as the lifetime of msgs ends.
Dereferencing any of them is undefined at that point and anything can happen.
(Very common is that the data has been overwritten and you just find some random stuff there.)
Either make getMsgs return a list of pointers, or dynamically allocate a copy the data when you populate the array, like this:
for(itmsgs0 = msgs.begin();itmsgs0 != msgs.end();itmsgs0++)
{
CFArrayAppendValue(_dataSourceRef, new ImageTextContent(*itmsgs0));
}
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.
While stress testing prototype of our brand new primary system, I run into concurrent issue with AppFabric Cache. When concurrently calling many DataCache.Get() and Put() with same cacheKey, where I attempt to store relatively large objet, I recieve "ErrorCode:SubStatus:There is a temporary failure. Please retry later." It is reproducible by the following code:
var dcfc = new DataCacheFactoryConfiguration
{
Servers = new[] {new DataCacheServerEndpoint("localhost", 22233)},
SecurityProperties = new DataCacheSecurity(DataCacheSecurityMode.None, DataCacheProtectionLevel.None),
};
var dcf = new DataCacheFactory(dcfc);
var dc = dcf.GetDefaultCache();
const string key = "a";
var value = new int [256 * 1024]; // 1MB
for (int i = 0; i < 300; i++)
{
var putT = new Thread(() => dc.Put(key, value));
putT.Start();
var getT = new Thread(() => dc.Get(key));
getT.Start();
}
When calling Get() with different key or DataCache is synchronized, this issue will not appear. If DataCache is obtained with each call from DataCacheFactory (DataCache is supposed to be thread-safe) or timeouts are prolonged it has no effect and error is still received.
It seems to me very strange that MS would leave such bug. Did anybody faced similar issue?
I also see the same behavior and my understanding is that this is by design. The cache contains two concurrency models:
Optimistic Concurrency Model methods: Get, Put, ...
Pessimistic Concurrency Model: GetAndLock, PutAndLock, Unlock
If you use optimistic concurrency model methods like Get then you have to be ready to get DataCacheErrorCode.RetryLater and handle that appropriately - I also use a retry approach.
You might find more information at MSDN: Concurrency Models
We have seen this problem as well in our code. We solve this by overloading the Get method to catch expections and then retry the call N times before fallback to a direct request to SQL.
Here is a code that we use to get data from the cache
private static bool TryGetFromCache(string cacheKey, string region, out GetMappingValuesToCacheResult cacheResult, int counter = 0)
{
cacheResult = new GetMappingValuesToCacheResult();
try
{
// use as instead of cast, as this will return null instead of exception caused by casting.
if (_cache == null) return false;
cacheResult = _cache.Get(cacheKey, region) as GetMappingValuesToCacheResult;
return cacheResult != null;
}
catch (DataCacheException dataCacheException)
{
switch (dataCacheException.ErrorCode)
{
case DataCacheErrorCode.KeyDoesNotExist:
case DataCacheErrorCode.RegionDoesNotExist:
return false;
case DataCacheErrorCode.Timeout:
case DataCacheErrorCode.RetryLater:
if (counter > 9) return false; // we tried 10 times, so we will give up.
counter++;
Thread.Sleep(100);
return TryGetFromCache(cacheKey, region, out cacheResult, counter);
default:
EventLog.WriteEntry(EventViewerSource, "TryGetFromCache: DataCacheException caught:\n" +
dataCacheException.Message, EventLogEntryType.Error);
return false;
}
}
}
Then when we need to get something from the cache we do:
TryGetFromCache(key, region, out cachedMapping)
This allows us to use Try methods that encasulates the exceptions. If it returns false, we know thing is wrong with the cache and we can access SQL directly.