I would like to write a Web Application that can interact with 3D Cad program for our company. So I was thinking that I would create a program that would be locally installed on the client machines which would send and receive data back and forth from Client App to Web App. I would like to use xml for moving the data back and forth too. Does anyone suggestions or can this even be done?
In this case you need 2 way communication between app and service. and for solving that there are two way:
use two service and they must be client of each other (Hard way)
use Duplex Services. (you can use WCF-Duplex services - it's not simple)
in this case you must handle too many issue's.(take look at this)
As example:
app need to notify self on your service and service save address of active client's. so every time service want's to call one of client, service must find client's address in active-client's and then call that.
Let me know if this help you.
Related
I'm writing a windows desktop service that is supposed to download content from a file server on a weekly basis, but it requires users login information to function.
I need the service to be able to "talk back" to the simple tray application I've developed to inform it when things have happened. Things like
Is the users login info good?
Did the content start downloading?
Did the content finish downloading?
I've seen posts on WCF, but, at a glance, WCF feels to me like it's just designed to go around web services. This is going to be a desktop service, not a web service, so unless I'm mistaken in my interpretation, I do not think that WCF is going to work for me? What's my alternative? (or, if I'm mistaken about WCF, can someone point me to a simple tutorial?)
You need to use either a Socket or a NamedPipe. Typically NamedPipe is preferred because it won't trigger some restrictive firewalls that monitor loopback interface as well.
Example of Named Pipes
Write a WCF service and configure a key in the web config(which specifies the user name and password" of the WCF service. Pass the same key from the windows service and authenticate it, once authentication is success, Download the files
eg:
http://www.codeproject.com/Articles/166763/WCF-Streaming-Upload-Download-Files-Over-HTTP
I'm trying to create a WCF service for our existing product.
The service should provide normal "webservice" features (one-way), but also act independently.
Sample scenario:
The client connects to the server
The server saves the client in a collection
Now I use an admin client / database entry to tell the client to do sth. (For example change config for log4net/NHibernate)
I've read some things about callbacks (mostly a chat system), but I'm still not sure if this will work.
Now my question is, will WCF be suitable for such a scenario or should I use TCPClient/TCPListener?
I am creating a client application that downloads and displays market data from Yahoo! for a university project, but that also sends out notifications to mobiles (so far using Google cloud messaging). So far it's a WPF client and the "server" is a class library - so far working. What I was wondering, is can you mix this server with a WCF service - the WCF service I was planning on using for registering devices, as well as accepting and parsing commands.
So I would call .Start() on my server object, and it will be constantly running in the background, while a WCF REST service runs alongside it - or would I be better simply having a thread running on the server that can accept input... sorry if this is confusing, but just wondering if it can, or has been done before or any advice. :)
Just to explain a bit better
The client front end and the "server" are running on the same machine - I was calling it a server because it is not only updating the front end, but sending out GCM notifications at the same time. I was wondering if maybe a WCF service could be added to make it simpler to handle adding devices to a database ("server" reads a list of device reg ids from a database, sends notifications to these) by allowing an android app to details via REST or something similiar
I would explore wrapping the class library in a Windows Service (which is essentially a process that runs continuously, and can be stopped/started/paused) and keep your WCF service as a web service for client communication.
How the WCF client service communicates with the Windows service is up to you - whether you store the data in a shared database, keep it in memory and have another WCF layer communicating between the two, etc. A shared database would be the most straightforward, especially if you want to persist the data for use by other apps/services as well.
WCF Service would be useful if you had one notification service on your server with multiple WPF client application connecting to it. If you have just one application running on the same server then not sure if it will be worth the overhead.
The usual pattern is to host WCF service in IIS, that way it always starts whenever first request is received. WCF is very flexible though, therefore you can host in in Windows Service, Console Application, etc.
I want to control application (in my case it is corelDraw) ,I know I should use it's application object and I do this, but the issue now is I want to do this in webservice,
so as far as I understand if I put this code which control the application in the web-service ,my code will try to control the corel application which is on the server not on the client :(
so any hint/advice how could I do this, and control the application on the client not server ?!!!
As you already noticed web service runs on server and only result is passed to client.
Well you have a few options to control client machine over web service... Here is one of possible scenarios.
1. create web service that will provide commands for client
2. create windows service (client) that will consume your web service commands
3. inside windows service then just execute those commands in appropriate manner
Well I have to say this is not the prefered way I would take to automate corelDraw, but if you insist on using webservice as command provider it will do the job.
You need to ask yourself what is the difference between client and a server. Can a client be a server? Can a server be a client?
You make your client with CorelDraw installed to accept web-service request, i.e. effectively make it a web-service server, and then carry on as normal.
Although I would say web-service is not the best way to control such complex application as CorelDraw. I'd look in some other ways of communication between peers, like lower level network communication that would not have overhead of HTTP.
Hi I have an application that operations like this..
Client <----> Server <----> Monitor Web Site
WCF is used for the communication and each client has its own session on the server. This is so callbacks can be used from the server to callback to the client.
The objective is that a user on the "Monitor Website" can do the following:
a) Look at all of the users currently online - that is using the client application.
b) Select a client and then perform an action on the client.
This is a training system so the idea being the instructor using a web terminal can select his or her target client and then make the client application do something. Or maybe they want to send a message to the client that will be displayed on the clients screen.
What I cant seem to do is to store a list of all the clients in the server application, that can then be retrieved by the server. If I could do this I could then access the callback object for the client and call the appropriate method.
A method on the monitoring website would look something like this...
Service.SendMessage(userhashcode, message)
The service would then somehow look up the callback that matches the hashcode and then do something like this
callback.SendMessage(message)
So far I have tried without look to serialise the callbacks into a centralised DB. However, it doesnt seem possible on the service to serialise a remote object as the callback exists from the client.
Additionally I thought I could create a global hash table in my service but im not sure on how to do this and to make it accesible application wide.
Any help would be appreciated.
Typically, WCF services are "per-call" only, e.g. each caller gets a fresh instance of the service class, it handles the request, formats the response, send it back and then gets disposed. So typically, you don't have anything "session-like" hanging around in memory.
What you do have is not the service classes themselves, but the service host - the class that acts as the host for your service classes. This is either IIS (in that case you just need to monitor IIS), or then it's a custom app (Windows NT Service, console app) that has a ServiceHost instance up and running.
I am not aware what kind of hooks there might be to connect to and "look inside" the service host - but that's what you're really looking for, I guess.
WCF services can also be configured to be session-ful, and keep a session up and running with a service class - but again: you need to have that turned on explicitly. Even then, I'm not really sure if you have many API hooks to get "inside" the service host and have a look around the current sesssions.
Question is: do you really need to? WCF exposes a gazillion of performance counters, so you can monitor and record just about anything that goes on in WCF - wouldn't that be good enough for you?
Right now, WCF services aren't really hosted in a particularly well-designed system - this should become better with the so-called "Dublin" server-addon, which is designed to host WCF services and WF workflows and give admins a great experience monitoring and managing them. "Dublin" is scheduled to be launched shortly after .NET 4.0 becomes available (which Microsoft has promised will be before the end of calendar year 2009).
Marc
What I have done is as follows...
Created a static instance in my service that keeps a dictionary of callbacks keyed by the hashcode of each WCF connection.
When a session is created it publishes itself to a DB table which contains the hash code and additional connection information.
When a user is using the monitor web application, it can get a list of connected clients from the DB and get the hashcode for that client.
If the monitor application user wants to send a command to the client the following happens..
The hashcode for the sessionn is obtained from the db.
A method is called on the service e.g. SendTextMessage(int hashcode, string message).
This method now looks up the callback to the client from the dictionary of callbacks and obtains a reference to it.
The appropriate method in this case SendTextMessage(message) is called on the callback.
Ive tested this and it works ok, Ive also added a functionality to keep the DB table synchronised to the actual WCF sessions and to clean up as required.