wcf linq to sql error - wcf

Question

I am getting an error returning a linq query over http to an ASP.Net application
I have the following wcf service running in IIS
public class ProductService : IProductService
{
NorthwindEntities context = new NorthwindEntities();
public List<Customer> GetCustomers()
{
return context.Customers.Select(c => c).ToList();
}
}
Web Config
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<system.web>
<compilation debug="true" targetFramework="4.0">
<assemblies>
<add assembly="System.Data.Entity, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
</assemblies>
</compilation>
</system.web>
<system.serviceModel>
<services>
<service name="WCF_Entity.ProductService">
<endpoint address="" binding="wsHttpBinding" contract="WCF_Entity.IProductService" />
</service>
</services>
<behaviors>
<serviceBehaviors>
<behavior>
<!-- To avoid disclosing metadata information, set the value below to false and remove the metadata endpoint above before deployment -->
<serviceMetadata httpGetEnabled="true" />
<!-- To receive exception details in faults for debugging purposes, set the value below to true. Set to false before deployment to avoid disclosing exception information -->
<serviceDebug includeExceptionDetailInFaults="true" />
</behavior>
</serviceBehaviors>
</behaviors>
<serviceHostingEnvironment multipleSiteBindingsEnabled="true" />
</system.serviceModel>
<system.webServer>
<modules runAllManagedModulesForAllRequests="true" />
</system.webServer>
<connectionStrings>
<add name="NorthwindEntities" connectionString="metadata=res://*/Northwind.csdl|res://*/Northwind.ssdl|res://*/Northwind.msl;provider=System.Data.SqlClient;provider connection string="Data Source=SHLOMOKATZ-PC;Initial Catalog=Northwind;Integrated Security=True;MultipleActiveResultSets=True"" providerName="System.Data.EntityClient" />
</connectionStrings>
</configuration>
I created a ASP.Net application to use the service
myService.ProductServiceClient objService = new ProductServiceClient();
var customers = objService.GetCustomers();
on debuging, I get the following error
An existing connection was forcibly closed by the remote host
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host
Source Error:
Line 2454:
Line 2455: public ASPWFC.myService.Customer[] GetCustomers() {
Line 2456: return base.Channel.GetCustomers();
Line 2457: }
Line 2458: }
Source File: D:\My Documents\Visual Studio 2010\Projects\wcf\WCF_Entity\ASPWFC\Service References\myService\Reference.cs Line: 2456
Stack Trace:
[SocketException (0x2746): An existing connection was forcibly closed by the remote host]
System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags) +6132200
System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size) +134
[IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host.]
System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size) +300
System.Net.PooledStream.Read(Byte[] buffer, Int32 offset, Int32 size) +26
System.Net.Connection.SyncRead(HttpWebRequest request, Boolean userRetrievedStream, Boolean probeRead) +265
[WebException: The underlying connection was closed: An unexpected error occurred on a receive.]
System.Net.HttpWebRequest.GetResponse() +6038435
System.ServiceModel.Channels.HttpChannelRequest.WaitForReply(TimeSpan timeout) +103
[CommunicationException: An error occurred while receiving the HTTP response to http://localhost/WCF_Entity_SVC/ProductService.svc. This could be due to the service endpoint binding not using the HTTP protocol. This could also be due to an HTTP request context being aborted by the server (possibly due to the service shutting down). See server logs for more details.]
System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg) +9464367
System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type) +345
ASPWFC.myService.IProductService.GetCustomers() +0
ASPWFC.myService.ProductServiceClient.GetCustomers() in D:\My Documents\Visual Studio 2010\Projects\wcf\WCF_Entity\ASPWFC\Service References\myService\Reference.cs:2456
ASPWFC._Default.Page_Load(Object sender, EventArgs e) in D:\My Documents\Visual Studio 2010\Projects\wcf\WCF_Entity\ASPWFC\Default.aspx.cs:36
System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +37
System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +95
System.Web.UI.Control.OnLoad(EventArgs e) +145
System.Web.UI.Control.LoadRecursive() +134
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3412
changing the buffer length, etc... Didn't solve the issue. The database is the sample NorthWind database
I am able to browse to the service
It seems that Aliostad is correct as I recreated the service without using IIs and used ASP to consume the service, and get the below error. So it is a problem invoking the svc from the app, I can still run the service directly via http
The underlying connection was closed: The connection was closed unexpectedly.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.Net.WebException: The underlying connection was closed: The connection was closed unexpectedly.
Source Error:
Line 2337:
Line 2338: public NorthwindApp.myService.Customer[] getCustomers() {
Line 2339: return base.Channel.getCustomers();
Line 2340: }
Line 2341: }
Source File: d:\my documents\visual studio 2010\Projects\wcf\NorthwindServices\NorthwindApp\Service References\myService\Reference.cs Line: 2339
Stack Trace:
[WebException: The underlying connection was closed: The connection was closed unexpectedly.]
System.Net.HttpWebRequest.GetResponse() +6038435
System.ServiceModel.Channels.HttpChannelRequest.WaitForReply(TimeSpan timeout) +51
[CommunicationException: The underlying connection was closed: The connection was closed unexpectedly.]
System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg) +9464367
System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type) +345
NorthwindApp.myService.INorthwindService.getCustomers() +0
NorthwindApp.myService.NorthwindServiceClient.getCustomers() in d:\my documents\visual studio 2010\Projects\wcf\NorthwindServices\NorthwindApp\Service References\myService\Reference.cs:2339
NorthwindApp._Default.Page_Load(Object sender, EventArgs e) in d:\my documents\visual studio 2010\Projects\wcf\NorthwindServices\NorthwindApp\Default.aspx.cs:18
System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +14
System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +46
System.Web.UI.Control.OnLoad(EventArgs e) +83
System.Web.UI.Control.LoadRecursive() +120
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3954

Answer 1

I found an article that says that with entity framework 4 there is a problem to serialize entities in wcf with lazy loading enabled
I added the following code to the service and everything works
context.ContextOptions.LazyLoadingEnabled = false;
link to article http://geekswithblogs.net/danemorgridge/archive/2010/05/04/entity-framework-4-wcf-amp-lazy-loading-tip.aspx

Answer 2

How many records are being returned? There are a couple of things in play here:
From a WCF Perspective:
MaxBufferSize: Gets or sets the maximum size of the buffer to use. For buffered messages this value is the same as MaxReceivedMessageSize. For streamed messages, this value is the maximum size of the SOAP headers, which must be read in buffered mode. For a non-streamed message, if the message size is greater than this property, then the message is dropped.
If not specified, this defaults to 65536.
This is only 0.0625 megabytes!
MaxReceivedMessageSize: Gets and sets the maximum allowable message size that can be received.
Default here is also 65536 bytes.
MaxStringContentLength: Gets and sets the maximum string length returned by the reader.
Your service is probably returning a value greater in size than the defaults.
So, you could try modifying your service behavior to include these attributes with higher limits, say 6 MB or so to see if it resolves your issue.
Also - remember there is maxRequestLength limit which is enforced by IIS which trumps any WCF setting, the default is 4096 KB, so you may have to tweak that if you alter the above properties.