I'm acting as an acceptor. Is there a way to set sequence numbers manually?
The first idea I had, was to modify .seqnums files, but it does not work.
Google mentions existence of setNextSenderMsgSeqNum and setNextTargetMsgSeqNum methods, however I can't tell on which object I should call them (using quickfixj 1.4).
I'm aware that setting sequence numbers by hand is discouraged and there are bunch of flags like ResetOnLogon and ResetOnDisconnect, but I have no control over initiator and there are bunch of other acceptors (test-tools) which are using the same session.
Application myApp = new FIXSender();
settings = new SessionSettings(sessionConfig);
MessageFactory messageFactory = new MessageFactory();
MessageStoreFactory storeFactory = new FileStoreFactory(settings);
LogFactory logFactory = new FileLogFactory(settings);
Acceptor acceptor = new SocketAcceptor(myApp, storeFactory, settings, logFactory, messageFactory);
acceptor.start();
First of all you need to explore the quickfixJ code to see how it is done.
Secondly what is the reason to use such an old version of quickfixJ ? Why not upgrade to the most recent version.
Thirdly you should be very wary of changing sequence numbers if you don't understand properly how they are used in the communication. If you don't understand you are guaranteed to get into murky problems.
You can do something like
Session.lookupSession(sessionID).setNextSenderMsgSeqNum())
But before you do it, it is very important to understand how sequence numbers are used
You can set the FIX fields, override the toAdmin callback
#Override
public void toAdmin(Message message, SessionID sessionId) {
message.setBoolean(ResetSeqNumFlag.FIELD, true);
}
Related
Env: Mac OS 12.1, JDK 17, Vert.x 4.2.4
Question: how to capture command line input from a verticle? Tried so far following in the public void start(Promise<Void> startPromise) throws Exception method:
getVertx().createSharedWorkerExecutor("sys-in").executeBlocking(promise -> {
try (final BufferedReader br = new BufferedReader(new InputStreamReader(System.in))) {
String line;
int count = 0;
do {
System.out.print("message to MC: ");
line = br.readLine();
count++;
//doSth(line); // e.g. send line over multicast
} while (count < 3);
} catch (Throwable t) {
// log.info("<start> ", t);
} finally {
// bye(); // send a final message and close vertx
promise.complete();
}
});
This will start, get 3 nulls from br, and exit. Also tried a separated ExecutorService, in vain. Couldn't find any help in Vert.x doc either. Any hints are appreciated:
aware of the warnings of Vert.x when doing blocking stuff
Vert.x might not meant to be used this way, but would be cool if it (reading from command line) can be done with the same toolkit
I understand what you are trying to accomplish, but the problem is that that goes against fundamentals of verticles concept. Waiting for user input is potentially infinitely blocking operation i.e. there is no guarantee user will ever input the values. In that case, you are left with the verticle that is hung forever, spending resources and stuck in one spot. Multiply this if you are using worker verticles and you might have serious problems with the app. This issue is also emphasized here: https://vertx.io/docs/vertx-core/java/#blocking_code (under Warning).
In the link provided you can also find a suggested solution with a separate thread solution. Non-vertx thread won't mind being blocked and when the user input is provided can inform the vertx part of the application via the event bus that the user input dependent code can now be executed.
This might not be the solution you had in mind since it's not pure vertx, but have in mind that vert.x is just another tool, and that tool is not a good fit for what you are trying to accomplish here. However, it can be paired well with plain Java and it won't mind.
I'm trying to use Casablanca to consume a REST api.
I've been following the microsoft tutorial, how ever i'm getting a crash and I cannot figure it out.
I'm using visual studio 2017 with C++11
I've codded a function GetRequest() that do work when used in a new empty project, but when I try to use it on my Project (Very big project with millions of code lines).
I'm crashing in the constructor of http_client, in the file xmemory0 line 118.
const uintptr_t _Ptr_container = _Ptr_user[-1];
This is a link to the callstack : https://i.imgur.com/lBm0Hv7.png
void RestManager::GetRequest()
{
auto fileStream = std::make_shared<ostream>();
// Open stream to output file.
pplx::task<void> requestTask = fstream::open_ostream(U("results.html")).then([=](ostream outFile)
{
*fileStream = outFile;
// Create http_client to send the request.
http_client client(U("XXX/XXX.svc/"));
// Build request URI and start the request.
uri_builder builder(U("/IsLive"));
builder.append_query(U("q"), U("cpprestsdk github"));
return client.request(methods::GET, builder.to_string());
})
// Handle response headers arriving.
.then([=](http_response response)
{
printf("Received response status code:%u\n", response.status_code());
// Write response body into the file.
return response.body().read_to_end(fileStream->streambuf());
})
// Close the file stream.
.then([=](size_t)
{
return fileStream->close();
});
// Wait for all the outstanding I/O to complete and handle any exceptions
try
{
requestTask.wait();
}
catch (const std::exception &e)
{
printf("Error exception:%s\n", e.what());
}
}
EDIT : I just want to add that the http_client constructor is the issue. It always crash inside it no matter what I send as parameter.
The wierd thing is that it's not crashing when i just make a main() that call this function.
I guess it must be due to some memory issues, however I have no idea how could I debug that.
Does anyone would have an idea about it?
Thanks and have a great day!
I've experienced a similar issue on ubuntu. It works in an empty project, but crashes randomly when put into an existing large project, complaining memory corruptions.
Turns out that the existing project loaded a proprietary library, which is using cpprestsdk (casablanca) internally. Even cpprestsdk is static linked, its symbols are still exported as Weak Symbols. So either my code crashes, or the proprietary library crashes.
Ideally, my project can be divided into several libraries, and load them with RTLD_LOCAL to avoid symbol clashes. But the proprietary library in my project only accept RTLD_GLOBAL, otherwise it crashes... So the import order and flags become important:
dlopen("my-lib-uses-cpprest", RTLD_LOCAL); //To avoid polluting the global
dlopen("proprietary-lib-with-built-in-cpprest", RTLD_GLOBAL); //In my case, this lib must be global
dlopen("another-lib-uses-cpprest", RTLD_DEEPBIND); //To avoid being affected by global
"it will probably never concern anyone."
I agree with that.
I guess this issues was very specific, and it will probably never concern anyone, but still I'm going to update on everything I found out about it.
On this project, we are using custom allocator, if i'm not wrong, it's not possible to give our custom allocator to this lib, which result to many random crash.
A good option to fix it would be to use the static version to this lib, however, since we are using a lot of dynamic lib, this option wasn't possible for us.
If you are on my case, I would advice to use the libcurl and rapidjson, it's a bit harder to use, but you can achieve the same goal.
I have a C# application, which I'm writing to try automate data extraction from a serial device. As the title of my question says, I have tried the exact same commands in Putty and I get data back. Could somebody please tell me what I have missed out, so that I can get the same data out with my C# application please?
Basically, I need to COM6, a speed/baud of 57600, and send the command without quotes "UH". I should be presented with a few lines of text data, which appears to only work on Putty.
As a quick test, I threw this together:
private void SerialPort serialPort = new SerialPort();
private void getHistory_Click(object sender, EventArgs e)
{
serialPort.DataReceived += new SerialDataReceivedEventHandler(serialPort_DataReceived);
serialPort.PortName = "COM6";
serialPort.BaudRate = 57600;
serialPort.Open();
if (serialPort.IsOpen())
{
serialPort.Write("UH");
}
}
private void serialPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
string result = serialPort.ReadExisting();
Invoke(new MethodInvoker(delegate{ textbox1.AppendText(result); }));
}
The DataReceived event does get fired, but it only returns back the "UH" I sent up, no further data. Any help with this problem would be highly appreciated!
Justin
Well, without further detail of the device in question, it is hard to say for sure, but two things spring to mind:
Firstly, what comms protocol does the device require? You have set up the baud rate, but have no mention of data bits, parity, or stop bits. I think the .NET serial port class defaults to 8,N,1. If your device is the same then you should be fine. If it is not, then it won't work.
Secondly, does the device require any kind of termination to the data to define a complete packet? Commonly this can be the data sent is appended with a carriage return and a line feed (0x0D and 0x0A), or perhaps is has a prefix of STX (0x02) and a suffix of ETX (0x03).
Any message that the device responds with is likely to be in the same format too.
I don't know how Putty works, but check the setup and see if it is appending anything to the message you type, and the protocol. Hyperterminal does this too, so you could test it with this also.
Strange one. We have a multi-threaded app which pulls messages off a MSMQ Queue and then subsequently performs actions based on the messages. All of this is done using DTC.
Sometimes, for some reason I can't describe, we get message read errors when pulling Messages off the queue.
The code that is being used in the app:
Message[] allMessagesOnQueue = this.messageQueue.GetAllMessages();
foreach (Message currentMessage in allMessagesOnQueue)
{
if ((currentMessage.Body is IAMessageIDealWith))
{
// do something;
}
}
When the currentMessage.Body is accessed, at times it throws an exception:
System.InvalidOperationException: Property Body was not retrieved when receiving the message. Ensure that the PropertyFilter is set correctly.
Now - this only happens some of the time - and it appears as though the MessageReadPropertyFilter on the queue has the Body property set to false.
As to how it gets like this is a bit of a mystery. The Body property is one of the defaults and we absolutley never explicitly set it to false.
Has anyone else seen this kind of behaivour or has some idea why this value is getting set to be false?
As alluded to earlier, you could explicitly set the boolean values on the System.Messaging.MessagePropertyFilter object that is accessible on your messageQueue object via the MessageReadPropertyFilter property.
If you want all data to be extracted from a message when received or peaked, use:
this.messageQueue.MessageReadPropertyFilter.SetAll(); // add this line
Message[] allMessagesOnQueue = this.messageQueue.GetAllMessages();
// ...
That may hurt performance of reading many messages, so if you want just a few additional properties, create a new MessagePropertyFilter with custom flags:
// Specify to retrieve selected properties.
MessagePropertyFilter filter= new MessagePropertyFilter();
filter.ClearAll();
filter.Body = true;
filter.Priority = true;
this.messageQueue.MessageReadPropertyFilter = filter;
Message[] allMessagesOnQueue = this.messageQueue.GetAllMessages();
// ...
You can also set it back to default using:
this.messageQueue.MessageReadPropertyFilter.SetDefaults();
More info here: http://msdn.microsoft.com/en-us/library/system.messaging.messagequeue.messagereadpropertyfilter.aspx
I have seen it as well, and have tried initializing it with the properties I'm accessing explicitly set, and not setting them anywhere else. I periodically get the same error you are getting, my app is multi-threaded as well, what I ended up doing is trapping that error and reconnecting to MSMQ when I get it.
Sometimes, for some reason I can't describe, we get message read errors when pulling Messages off the queue.
Are you using the same MessageQueue instance from more than one thread, without locking? In that case, you will encounter spurious changes in MessageReadPropertyFilter - at least I did, when I tried.
Why? Because
Only the GetAllMessages method is thread safe.
What can you do? Either
wrap a lock (_messageQueue) around all access to your messageQueue OR
create multiple MessageQueue instances, one per thread
I am trying to register to a "Device added/ Device removed" event using WMI. When I say device - I mean something in the lines of a Disk-On-Key or any other device that has files on it which I can access...
I am registering to the event, and the event is raised, but the EventType propery is different from the one I am expecting to see.
The documentation (MSDN) states : 1- config change, 2- Device added, 3-Device removed 4- Docking. For some reason I always get a value of 1.
Any ideas ?
Here's sample code :
public class WMIReceiveEvent
{
public WMIReceiveEvent()
{
try
{
WqlEventQuery query = new WqlEventQuery(
"SELECT * FROM Win32_DeviceChangeEvent");
ManagementEventWatcher watcher = new ManagementEventWatcher(query);
Console.WriteLine("Waiting for an event...");
watcher.EventArrived +=
new EventArrivedEventHandler(
HandleEvent);
// Start listening for events
watcher.Start();
// Do something while waiting for events
System.Threading.Thread.Sleep(10000);
// Stop listening for events
watcher.Stop();
return;
}
catch(ManagementException err)
{
MessageBox.Show("An error occurred while trying to receive an event: " + err.Message);
}
}
private void HandleEvent(object sender,
EventArrivedEventArgs e)
{
Console.WriteLine(e.NewEvent.GetPropertyValue["EventType"]);
}
public static void Main()
{
WMIReceiveEvent receiveEvent = new WMIReceiveEvent();
return;
}
}
Well, I couldn't find the code. Tried on my old RAC account, nothing. Nothing in my old backups. Go figure. But I tried to work out how I did it, and I think this is the correct sequence (I based a lot of it on this article):
Get all drive letters and cache
them.
Wait for the WM_DEVICECHANGE
message, and start a timer with a
timeout of 1 second (this is done to
avoid a lot of spurious
WM_DEVICECHANGE messages that start
as start as soon as you insert the
USB key/other device and only end
when the drive is "settled").
Compare the drive letters with the
old cache and detect the new ones.
Get device information for those.
I know there are other methods, but that proved to be the only one that would work consistently in different versions of windows, and we needed that as my client used the ActiveX control on a webpage that uploaded images from any kind of device you inserted (I think they produced some kind of printing kiosk).
Oh! Yup, I've been through that, but using the raw Windows API calls some time ago, while developing an ActiveX control that detected the insertion of any kind of media. I'll try to unearth the code from my backups and see if I can tell you how I solved it. I'll subscribe to the RSS just in case somebody gets there first.
Well,
u can try win32_logical disk class and bind it to the __Instancecreationevent.
You can easily get the required info
I tried this on my system and I eventually get the right code. It just takes a while. I get a dozen or so events, and one of them is the device connect code.