The project im working on, they would like active server connection detection before each call.
Im trying to find out if its better to use:
WL.Device.getNetworkInfo:isNetworkConnected
or
WL.Client.connect
I know that getNetworkInfo only checks if the phone has contectivity to the net, while wl.client.connect will actually connect to the server. Im just afraid that wl.client.connect will be an expensive call to make before every invokeProcedure call. Is there a better way to check for connectivity before the invokeProcedure call?
getNetworkInfo API can be used to verify whether device currently has an internet connectivity.
As for WL server connectivity there is only one way to verify that server is accessible and this is by issuing a request to WL server and verifying whether it succeeded. However this is not right way to go. Every WL server invocation API, e.g. WL.Client.connect(), WL.Client.login(), WL.Client.invokeProcedure(), has onSuccess and onFailure callbacks. Use them to verify whether server connectivity was successful or not.
Technically, even if you do additional request like WL.Client.connect() before making a real request it will not give you 100% assurance that the real request will succeed.
In addition you may want to utilize WORKLIGHT_IS_CONNECTED and WORKLIGHT_IS_DISCONNECTED events which are fired each time last WL server invocation status toggles success<->failure. Check out the offline training module at Worklight Getting Started page.
Related
I have an X-code app integrated with Mobile first platform 7.0. I want to implement idle session timeout for the app. I have tried two scenarios to resolve this issue.
First I have added below line in server.xml
<httpSession invalidationTimeout="10m" />
Second I have added below line in worklight.properties
serverSessionTimeout=10
I am still not getting time out after being idle for more than 10 mins.
What am I missing?
The serverSessionTimeout property is a server property. Meaning that the session expires in the server and if the client attempts to connect to the server after the set expiration time, then the client will act accordingly.
If you have a security challenge in place, then once the expiration took place, the challenge would've been invoked (once the client attempts to connect the server). Otherwise, you cannot detect this through this property.
What you can do, is set a "timer" on the client side that runs and counts until the session time has met, and do some logic based on it. This of course solely depends on what your required scenario is.
I have a Web Server implemented using dot net MVC4. There are clients connected to this web server which perform some operations and upload live logs to the server using WebClient.UploadString method. Sending these logs from client to server is being done in group of 2500 characters at a time.
Things work fine until 2-3 client upload logs. However when more than 3 clients try to upload logs simultaneously they start receiving "http 500 internal server error".
I might have to scale up and add more slaves but that will make the situation worse.
I want to implement Jenkins like live logging, where logs from slave are updated live.
Please suggest some better and scalable solution to this problem.
Have you considered looking into SignalR?
It can be used for anything from instant messaging to stocks! I have implemented both a chatbox, and a custom system that sends off messages, does calculations and then passes them back down to client. It is very reliable, there are some nice tutorials, and I think it's awesome.
In our project we are trying to figure our what the best process to connect to the server will be - especially when taking care of offline/online scenarios etc.
Right now, for us, it seems that all three options to connect to the WL server are similar. Whatever option we use, we can call our Adapter Procedures perfectly and we receive Notification Messages that are set in the console.
We are not sure about Direct Update - this is not working properly yet.
Are there any important differences between these three ways of connecting to the WL server, or is basically the same connection procedure being executed in all three cases?
How about WL.Client.init() before connecting - could we call that again (in addition to the standard window load EventListener) in our code before we connect using a WL.Client.connect manually - or is init() supposed to be called only once?
Tied to that is also offline and re-connecting.
As far as I have read in the tutorials, the WL Client framework is managing the connection state. Does that mean that when the WL client is connected to the server through any of these three ways and loses it's WLAN/3G/4G connection (or it's access to the WL server due to internet connection blocker or so) it re-connects automatically (regularly tries to re-connect until successful) when a connection to the WL server is available again?
EDIT
I was thinking about Events or Threads that provide more low-level information (not WORKLIGHT_IS_CONNECTED) - basically events that would be triggered when the device loses/gets WIFI/3G/4G connection and/or internet connection. Or is there only polling using WL.Device.getNetworkInfo() available?
Would the use of Cordova Event like:
document.addEventListener("offline", yourCallbackFunction, false);
provide a functionality close to that?
Though those three ways do have some similarities the differences between them are very important.
WL.Client.init() initializes client side WL framework.
WL.Client.connect() triggers connection request to WL server.
initOptions.connectOnStartup defines whether WL.Client.connect() will be invoked automatically during WL.Client.init().
In general - most of the functionality (e.g. adapters, remote disable) will function even if you call WL.Client.invokeProcedure() without calling WL.Client.connect(). But there are several things that will not function:
You will not be able to fully utilize push notifications without calling WL.Client.connect()
Direct update is triggered during WL.Client.connect()
WL.Client.connect() will get security related info from server, e.g. names of realms, whether user authenticated in those realms etc. Therefore all APIs like WL.Client.getUserInfo, .isAuthenticated(), .getUserName() etc will not function.
It is strongly recommended to start your session with WL.Client.connect() (or initOptions.connectOnStartup=true).
On openstack cloud plantform ，If I want to close a instance on compute node, what does the openstack do? can you tell me the process?
I assume by close you mean "terminate".
When terminating an instance the running virtual machine with an instance id of X is shut down and removed from the physical host it exists on.
The nova client query for this would be:
nova delete <instance-id> or something to that effect.
When you make that query the python-novaclient is interfacing with its own internal API to reach out to the nova-api RESTful API. It authenticates itself with an auth token in the http header of its query. Then nova-api interprets the instance termination request. It will verify any ACLs it needs to against keystone. And then it will perform necessary methods to shut down and remove the instance freeing up resources for future instances. It will then return a result.
Going deeper the scheduler will send out requests over the messaging system as a result of the nova-api queries. Those messages will be received by the targeted physical hosts. There nova-compute will interpret the request to delete the instance and it will perform its own local necessary tasks. Usually this involves interfacing with libvirt to shut down and free the instance resource. After this is completed or failed it will respond to the messaging bus the status. And the API will eventually get that message back and send it on to the user who initially requested the action.
This may be a shot in the dark (I don't know much about the internals of WCF), but here goes...
I'm currently working with a legacy application at a client site and we're experiencing a persistent issue with a WCF service. The application is using the Microsoft Sync Framework 2.0 and syncing through the aforementioned service. The server-side implementation of the service has a lot of custom code in various states of "a mess."
Anyway, we're seeing an error on the client application most of the time and the pattern we're narrowing down centers around different users using the application on the same machine hitting the same service. It seems that the service and the client are getting out of sync in some way on an authentication level.
The error is discussed in an article here, and we're currently investigating the approach of switching from message layer security to transport layer security, which will hopefully solve the problem. However, we may be able to solve it in a less invasive manner if this question makes sense.
In the linked article, one of the suggestions was to forcibly terminate the connection if the specific exception is caught, try again, and if it fails again it wasn't because of this particular theory. Sounds good, and easy to implement. However, I find myself unable to say with confidence if the connection is being properly terminated.
The service operates through a custom interface, which is implemented on the server-side. The only thing that interface can do to end the connection is call EndSession() on the proxy itself, which calls EndSession() on the server which is a custom method.
So...
From a WCF service method, is there a way to properly and gracefully terminate the connection with the client in a way the client will like?
That is, in this custom EndSession() is there some last step I can take to cause the server to completely forget that this connection was open? Because it seems like when another user on the same machine tries to hit the service within the application, that's when it fails with the error in the linked article.
The idea is that, at the client side of things, code which calls EndSession() is followed by nulling out the proxy object, then a factory method is called to supply another one the next time it's needed. So I wonder if something additional needs to happen on the server side (and does by default in WCF were it not for all this custom implementation code) to terminate the connection on that end?
Like I said, a shot in the dark. But maybe in answers/discussions here I can at least further diagnose the problem, so any help is much appreciated. Thanks.
Unfortunately there are only really three ways in which a session can terminated
The client closes the proxy
The service's receiveTimeout is exceeded
before the client sends another
request
the service throws a
non-fault exception which will fault
the channel and so terminate the
session
if you don't want the client involved then you only have 2 and 3 neither of which end well for the client - they will get an exception in both situation on the next attempt to talk to the service.
You could use Duplex messaging and get the service to notify the client that its requires session termination - the client then gets an opportunity to close down the proxy gracefully but this is a cooperative strategy