I have done some research on connecting to the WCF in different environments. I know that I can use the tag in the web.config to specify the addresses for the endpoint in the different environment.
What I don't understand (and can't find answer to) is that if I have specified the endpoint in all environments in the web.config of my client app, how does the client app know which one to connect?
Thanks!
Per your description, I can’t understand the meaning of “different environments”. In my opinion, the client app used to connect the server is accomplished by using the client proxy class. Alternatively, we create a channel factory to communicate with the server.
These above ways all need a service endpoint address.
For the client proxy class, we specify the name of the endpoint in order to instantiate a proxy class when the auto-generated configuration has multiple service endpoints.
ServiceReference1.ServiceClient client = new ServiceClient("BasicHttpBinding_IService1");
For the way that we connect the service by using Channel factory, we ordinarily specify the service address manually in code.
Feel free to let me know if there is anything I can help with.
Related
as you can see, I am relatively new on SO please don't kill me after posting this question :) I will do my best to describe the dilemma I am currently in.
I am creating something like a "Guardian Service" that is hosted on Windows Azure inside a Worker Role. This service has external ports, that can be accessed via HTTPS to allow clients to call it's service methods.
The WCF service is meant to call other services hosted in other Worker Roles that have only internal ports open, and which can be accessed only through the use of the Guardian Service. That's the main idea. Similar to a proxy or something.
I read already an excellent article from Jim O'Neil, what the caveats are when you try to access internal service points from within other WCF Services hosted in worker Roles:
His blog Troubleshooting Endpoints on a WCF Web Role
This is not the point for this question, and totally clear to me how to do that.
I have no idea at the moment, how I could do this, without implementing every contract from every single service I want to make accessible from within the Guardian Service to the outside world.
There must be a better way to decouple those things.
Any tips are appreciated.
Thank you.
I do not know the exact requirements for your project but I would say that what you are looking for is WCF Routing. I've used it in the past to redirect requests for different versions of Workflow instances.
The way it works is completely transparent to the client connecting to its endpoint. The router implementation must decide where to send the requests to, based on the request data (message headers and body).
In your case, if you are using SOAP and namespaces correctly, you might be able to base your decision on the message soap address and then send the request to the correct endpoint. You could also look at the Action property of the message.
Some links that might be useful:
http://msdn.microsoft.com/en-us/library/ee517423.aspx
http://www.codeproject.com/Articles/227699/RoutingService-on-Azure
I'm a WCF newbie, and I need some help to begin with a project:
I will have a managed application (server) that needs to communicate (messaging system) with several clients over the internet and vice versa.
What is the best approach to achieve this?
using wsDualBinding?
UPDATE
I decided to use the NetTcpBinding mode instead.
It depends on what capabilities your service needs to expose, and what type of clients you need to support. Any of the HTTP-based bindings will work over the internet, its simply a question of the way the data is encoded.
A summary of the built-in bindings and what they support can be found here: http://msdn.microsoft.com/en-us/library/ms731092.aspx
But the most common are:
BasicHttpBinding - This is a basic web service-style binding, usable by any SOAP client.
WebHttpBinding - This allows your service to be used by non-SOAP HTTP clients
WsHttpBinding - This allows your service to use extended service features like transactions and sessions.
WsDualHttpBinding - This is required if your service needs a duplex channel, meaning your service needs to make callbacks up to the client.
Since you specifically asked about the dual binding:
If you are writing an application that needs to be able to make a callback from server into the client, then a dual binding is really your only option. Since you specifically mentioned chat, however, I don't think a dual-channel service is going to work very well.
The way the callbacks work in WCF is that your client makes a call to the service, using a dual channel, and must provide an implementation of the callback interface. The server can use this to make calls to the client for the duration of the service method call; the callback context is per-service-call, so once that call returns, it is no longer valid. In other words, your server cannot just asynchronously "call into" your client, it has to wait for the client to "poll" the server. And if you're going to do that, you don't really need the callback anymore.
Honestly, I don't think I would use WCF for an interactive bi-directional chat application, but I can think of two possible options to do so:
Do the polling client option, using a simple BasicHttpBinding on the server and continuously ask for new messages.
Set your client applications up to self-host a local WCF service, and provide the endpoint information to the server when you log in. This requires your clients to accept incoming connections, which gets messy (but if you can pull it off, I'd go for a NetTcpBinding here.)
WSDualHttpBinding is not a good choice for internet. Callback works great only in local network (intranet) that has no Firewall and NAS restrictions.
See this post for more details:
Connecting over internet to WCF service using wsDualHttpBinding times out
Use WsHttpBinding if you want to set up server to server communications (that should work for WPF).
Use WebHttpBinding if you are planning to use data from Javascript.
Is there a way to fetch information from a WCF service meta-data endpoint to know how to configure the proxy client so that you don't have to configure the proxy client manually? So instead of editing the client proxy configuration, it makes a call to the target service's meta-data, fetch the bindings, etc. and caches it on the client side and so when it makes calls to the service, it should be happy.
Thanks
You can use MetadataResolver class for this purpose but be aware that this will make your service call much slower. Also it is not silver bullet. Not all features are automatically configured so using this is not very usual. Why don't you like configuring the proxy manually or by Add service reference? It is not very common for service to change its configuration frequently.
I am developing a wcf service (basicHttpBinding) that should also be consumed by non .net clients (e.g. Java clients). But now I wonder how the client can define his client config file. Or is this file only needed for .net-clients? (I am thinking of configurations like maxReceivedMessageSize or maxItemsInObjectGraph for example).
Each development platform (call it as you want: SOAP stack, Framework, API) has its own way to configure communication. You don't need to bother with it. You just need to expose correct WSDL and client's developer will be responsible for configuring the client application based on his needs.
If you want to extend documentation of your service in WSDL you can use wsdl:documentation. WCF doesn't offer it by default but you can use this technology sample to extend WCF. You can use such documentation for example to describe that service operation can return large amount of data. Another approach to add wsdl:documentation is using WCF Extras.
From the sound of it, the client shouldn't have access to those configuration options. For instance, why should a client to the WCF service be able to specify the maxReceivedMessageSize?
What you probably want to do is define these configuration options on the server-side. If a client makes a call and there is a conflict with one of your options (i.e. the client exceeds maxReceivedMessageSize), you'll want to throw a SoapException back to the client.
If you want to let the client have access to the configuration settings before he or she sends a request, you can always implement a simple web service method that sends back the values.
I'm trying to build a WCF self hosted service (eventually in a windows service) that will receive binary and text base messages from remote thick clients that have no accounts on my hosted machine. I'm trying to figure out both my binding options and security options, and in reading the patterns and practices guides, my head has completely spun around at least once.
The clients would be authenticated against a custom SQL based method, so I'd like to be able to pass that info in the initial login request and then set an authorization token of some kind. (This part of the problem is probably outside the scope of the question, but I included it in case it might make a difference.)
Any thoughts at all would be very helpfull.
Ryan
The choice of binding and security option depends on the usage of your WCF service. Is it just for your rich client or are you planning to expose it to the world as API? If it's just for your rich app, does it run on LAN or over untrusted, unreliable Internet?
With WCF you can configure the service to expose multiple endpoints with different bindings, for example both SOAP and REST. In general, I'd start with something stateless and lightweight like basicHttpBinding and webHttpBinding, passing user and password on every request. Once you have that up and running you can optimize cache authentication, provide binary endpoint etc.. only if it actually helps.
There's no need to have just one binding. Having said that if it's self hosted you're "on your own" here. I've never looked at what's involved.