For a user application (not a driver) using WinUSB, I use WinUsb_ControlTransfer in combination with overlapped I/O to asynchronously send a control message. Is it possible to cancel the asynchronous operation? WinUsb_AbortPipe works for all other endpoints but gives an 'invalid parameter' error when the control endpoint is passed (0x00 or 0x80 as the pipe address). I also tried CancelIo and CancelIoEx but both give an 'invalid handle' error on the WinUSB handle. The only related information I could find is on http://www.winvistatips.com/winusb-bugchecks-t335323.html, but offers no solution. Is this just impossible?
Probably not useful to the original asker any more, but in case anyone else comes across this: you can use CancelIo() or CancelIoEx() with the file handle that you originally passed in to WinUsb_Initialize().
This is similar to how the documentation of WinUsb_GetOverlappedResult says:
This function is like the Win32 API routine, GetOverlappedResult, with one difference—instead of passing a file handle that is returned from CreateFile, the caller passes an interface handle that is returned from WinUsb_Initialize. The caller can use either API routine, if the appropriate handle is passed. The WinUsb_GetOverlappedResult function extracts the file handle from the interface handle and then calls GetOverlappedResult.
Related
We have an NServiceBus 6 environment with a number of services that send files between each other using DataBusProperty over a custom SqlDataBus : IDataBus.
This works fine on NSB6 using the built in JSON serializer, but is now broken after we moved to NSB7 and the NewtonsoftSerializer.
Removing DataBusProperty from our classes and just using byte[] works fine. We also tried changing the DataBus to FileShareDataBus but got the same exception:
NServiceBus.MessageDeserializationException: An error occurred while attempting to extract logical messages from incoming physical message c7b5cd47-c1b7-4610-9f6c-aa7800cc9b64 --->
Newtonsoft.Json.JsonReaderException: Error reading bytes. Unexpected token: StartObject. Path 'Data.Key', line 1, position 68.
This fails even if a service is sending messages to itself. Also we can see the files written to the file store, whether on Sql or File Share, so they're serializing fine.
An example payload from the error queue is
{"ExecutionId":"1db85105-a71c-4b29-87da-9b7ae6518c1c","Data":{"Key":"2019-06-26_13\\6a2b63c7-12b0-46dd-8b92-f1fc743d27c1","HasValue":true}}
How can we get this to deserialize in NSB7+NewtonsoftSerializer when it works fine in NSB6+JsonSerializer?
Thanks
I just spent about 8 hours trying to figure out what was going on, and realized, that for whatever reason, NSB7 wants a paramaterless constructor and settable properties. I am going back to Particular to see if this change is expected, but I expect we will have to adjust all of our message classes to fit that paradigm.
Although data bus properties should work there is also an alternative to data bus properties which is using stream attachments via send options:
https://docs.particular.net/nservicebus/messaging/attachments-sql
Depending on the use case using Streams might be a more efficient approach.
I have a D-Bus method that takes a QDBusUnixFileDescriptor as a parameter. But I do not know how to call this method via the bus.
The documentation for QDBusUnixFileDescriptor states:
This allows applications to send and receive Unix file descriptors over
the D-Bus connection, mapping automatically to the D-Bus type 'h'.
To call other methods I am using QDBusInterface::call which takes the method name and a bunch of QVariants. QVariant is not implemented for QDBusUnixFileDescriptor.
I've been unable to locate any examples either in Qt documentation, at github, or with google.
How can I call a bus method that takes a QDBusUnixFileDescriptor as a parameter?
I am rather new in Qt, but as good as I know you can check
QVariant::fromValue(yourQDBusUnixFileDescriptor)
Good luck
My problematic seem to be simple, but I haven't find yet a way to solve it...
I have a legacy system which is working and a new system which will replace it. This is only rest webservices call, so I'm using simple bridge endpoint on http service.
To ensure the iso-functional run, I want to put them behind a camel route dispatching message to both system but returning only the response of the legacy one and log the response of both system to be sure there are running in same way...
I create this route :
from("servlet:proxy?matchOnUriPrefix=true")
.streamCaching()
.setHeader("CamelHttpMethod", header("CamelHttpMethod"))
.to("log:com.mylog?showAll=true&multiline=true&showStreams=true")
.multicast()
.to(urlServer1 + "?bridgeEndpoint=true")
.to(urlServer2 + "?bridgeEndpoint=true")
.to("log:com.mylog?showAll=true&multiline=true&showStreams=true")
;
It works to call each services and to log messages, but response are in a mess...
If the first server doesn't respond, the second is not call, if the second respond an error, only that error is send back to client...
Any Idea ?
You can check for some more details in multicast docs http://camel.apache.org/multicast.html
Default behaviour of multicast (your case) is:
parallelProcessing is false so routes are called one by one
To correctly implement your case you need probably:
add error handling for each external service call so exception will not stop correct processing
configure or implement some aggregator strategy and put it to the strategyRef so you can combine results from all calls to the single multicast result
I am trying to use Skype's DBus API in order to retrieve the list of messages (message IDs) I've exchanged with a contact. However, both the SEARCH CHATMESSAGES <target> (protocol >= 3) and the SEARCH MESSAGES <target> (protocol < 3) commands return unexpectedly empty results.
Here is the trace of a few exchanges I had with the API. I used d-feet to send my requests, but the result is exactly the same when I send the request from my own program.
Bus name: com.Skype.API
Object: /com/Skype
Interface: com.Skype.API
Method used: Invoke(String request)
Trace:
-> NAME dfeet
<- OK
-> PROTOCOL 8
<- PROTOCOL 8
-> SEARCH CHATMESSAGES mycontact
<-
The same thing happens with two other SEARCH commands:
SEARCH MESSAGES <target> (with PROTOCOL 2).
SEARCH CHATS
Additionally, I also get an empty result when I try to request a message list based on a chat ID: GET CHAT <chat_id> GETMESSAGES.
However, commands such as SEARCH FRIENDS, SEARCH CALLS, or SEARCH ACTIVECHATS work just fine, and return their lists of IDs (contacts IDs, calls IDs, or chat IDs) as expected.
It might also be worth noting that this happens for all contacts, regardless of how many messages I've exchanged with them (I thought at first that there might be too many messages involved, but the result is the same, whether I've sent 3, or thousands of messages to the contact).
Is there anything that would explain why I get these empty responses through DBus, for these requests?
Skype will not use Invoke's return value when its reply is too heavy. As it so happens, when Skype has too much data to prepare and transfer after a request, it automatically returns an empty string to the Invoke call. The true, heavy reply is then prepared asynchrously by Skype, and the client program must be ready to receive it when it eventually arrives.
Whenever you are communicating with Skype over DBus, your application must act as both a client (calling Invoke), and a server (providing a DBus object for Skype to reach). This design was a little unexpected (I guess we could argue on its quality), but here is what it requires you to do:
Make your program a DBus "server" (providing objects to reach). Through your bus name to Skype, register an object path called /com/Skype/Client implementing the com.Skype.API.Client interface.
Prepare a message handler for the only method of this interface: Notify(s). This is the method Skype will try to call to send you the heavy reply to one of your previous requests.
Program your own mechanism to match your Invoke request with the asynchronous Notify message coming in as an answer later on.
The creation of an object can be done through dbus_connection_register_object_path, the parameters for which are:
The DBusConnection structure representing your bus name.
The object path you are registering, here /com/Skype/Client.
A table of message handlers (DBusObjectPathVTable) used to process all incoming requests.
Data to be sent to these handlers when they are called. This is additional data, not the actual message being received since you're just setting up the handler here.
For instance...
DBusHandlerResult notify_handler(DBusConnection *connection,
DBusMessage *message,
void *user_data){
return DBUS_HANDLER_RESULT_HANDLED;
}
void unregister_handler(DBusConnection *connection,
void *user_data){}
DBusObjectPathVTable vtable = {
unregister_handler,
message_handler,
NULL
};
if(!dbus_connection_register_object_path(connection,
"/com/Skype/Client",
&vtable, NULL)){
// Error...
}
Note that this is just an object's definition. In order to actually hook on the Notify calls, you'll have to select() on a DBusWatch file descriptor, and dispatch the incoming DBusMessage in order to have your message handler called.
If you are working with other bindings, you'll probably find much faster ways to setup objects and start working as a client application. See:
GLib's g_dbus_connection_register_object
Exporting objects with dbus-python
QtDBus's QDBusConnection::registerObject
... (other bindings)
If, as part of a single Meteor.call, I make two calls to the database on the server, will these happen synchronously or do I need to use a callback?
Meteor.methods({
reset: function(id) {
Players.remove(_id:id);
// Will the remove definitely have finished before the find?
Players.find();
...
}
From the docs:
In Meteor, your server code runs in a single thread per request, not in the asynchronous callback style typical of Node. We find the linear execution model a better fit for the typical server code in a Meteor application.
If you read the docs on docs.meteor.com/#remove
you can find this :
Blockquote
On the server, if you don't provide a callback, then remove blocks until the database acknowledges the write and then returns the number of removed documents, or throws an exception if something went wrong. If you do provide a callback, remove returns immediately. Once the remove completes, the callback is called with a single error argument in the case of failure, or a second argument indicating the number of removed documents if the remove was successful.
Blockquote
On the client, remove never blocks. If you do not provide a callback and the remove fails on the server, then Meteor will log a warning to the console. If you provide a callback, Meteor will call that function with an error argument if there was an error, or a second argument indicating the number of removed documents if the remove was successful.
So on server side you choose if you want it to run in a sync or async way, it depends if you send a callback or not.