service code executed in wrong order - wcf

Question

I have a problem with WCF service. It seems that code is executed in unexpected order. My service takes one argument which is class that have array with file attachments (arrays of bytes) and other text fields. My service is responsible for save those files on disk. Also every request to service and response is logged in database (in xml format). For this reason in my service I want to:
Save files on disk;
Clear field with file binary data (that binary data won’t be saved in log in database);
Update field with attachement name with path where file was saved (that this info would be in log record);
Everything works fine when I’m testing service locally in visual studio (not using service client proxy, but directly service).
Problem is when I’m testing service hosted on IIS (v 7.5). In my service, after saved file on disk I’m changing field with file name and clear field with binary data of file. The problem is that system update those fields before saved file on disk (result is that saved file is empty or error is thorwn /wrong save path/ ) . Of course in my service first task in code is to save file on disk.
This is how it looks in my example:
I’m using VS2013, .NET Framework 4.5, WCF
Attachment Class
public class Attachment
{
public string FilePath { get; set; }
public byte[] FileBinary { get; set; }
}
Service code (with some comments about the problem):
public bool AddAttachments(List<Attachment> attachments)
{
bool result = false;
string PathToSaveFile = String.Empty;
string FileNameGuid = String.Empty;
foreach (var a in attachments)
{
FileNameGuid = Guid.NewGuid().ToString();
// step 1. Set file path and name
PathToSaveFile = "C:\\FilesFromWCFService\\" + FileNameGuid + a.FilePath;
try
{
// step 2. saving file
// problem is here. Variable PathToSaveFile have value from step 1 and 3b (which i thing has not yet been executed)
// so value is i.e.: "C:\FilesFromWCFService\{Guid}{FilePath}File localization: {PathToSaveFile}"
// and a.FileBinary is equal to byte[0] step 3a.
// it seems like steps 3a and 3b is executed before step 2
File.WriteAllBytes(PathToSaveFile, a.FileBinary);
result = true;
}
catch (Exception ex)
{
throw new Exception("Error while saving file on disk");
}
// step 3a. clear file binary data (that data won't be saved in db log)
a.FileBinary = new byte[0];
// step 3b. update file localization on server
a.FilePath = String.Format("File localization: {0}", PathToSaveFile);
// reset variables
PathToSaveFile = String.Empty;
FileNameGuid = String.Empty;
}
Return result;
}
When I’m debugging service on iis (by attach iis process in VS) and set breakpoint on the first line of service code i can see that byte file content (a.FileBinary) and file path (a.FilePath) is set from step 3a and 3b (not original from parameter List attachments.
If I comment changing file path and reseting file content (step 3a and step 3b) then everything works fine (but of course save file in binary format in logs - which i want avoid).
Service configuration:
<services>
<service name="AddAttachments">
<endpoint address="AddAttachmentsService" behaviorConfiguration="ServiceEndpointBehavior"
binding="basicHttpBinding" name="httpEndpoint" contract="PlayService.IAddAttachmentsService" />
<endpoint address="AddAttachmentsService" behaviorConfiguration="ServiceEndpointBehavior"
binding="netTcpBinding" name="tcpEndpoint" contract="PlayService.IAddAttachmentsService" />
<endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" />
<host>
<baseAddresses>
<add baseAddress="http://localhost:65045/" />
<add baseAddress="net.tcp://localhost:65055/" />
</baseAddresses>
</host>
</service>
</services>
<bindings>
<basicHttpBinding>
<binding messageEncoding="Mtom"
closeTimeout="00:10:00"
sendTimeout="00:10:00"
maxBufferPoolSize="524288"
maxReceivedMessageSize="2147483647">
</binding>
</basicHttpBinding>
<netTcpBinding>
<binding transferMode="Streamed"
closeTimeout="00:10:00"
sendTimeout="00:10:00"
maxBufferPoolSize="524288"
maxReceivedMessageSize="2147483647"></binding>
</netTcpBinding>
</bindings>
<behaviors>
<endpointBehaviors>
<behavior name="ServiceEndpointBehavior" >
<logMessage_2 />
</behavior>
</endpointBehaviors>
<serviceBehaviors>
<behavior name="mexBehaviour">
<serviceMetadata httpGetEnabled="true" httpsGetEnabled="true" />
<serviceDebug includeExceptionDetailInFaults="true" />
</behavior>
<behavior name="">
<serviceMetadata httpGetEnabled="true" httpsGetEnabled="true" />
<serviceDebug includeExceptionDetailInFaults="true" />
</behavior>
</serviceBehaviors>
</behaviors>
Client configuration:
<system.serviceModel>
<bindings>
<basicHttpBinding>
<binding name="httpEndpoint" messageEncoding="Mtom"
closeTimeout="00:10:00"
sendTimeout="00:10:00"
maxBufferPoolSize="524288"
maxReceivedMessageSize="2147483647"></binding>
<!--<binding name="httpEndpoint" messageEncoding="Mtom" />-->
</basicHttpBinding>
<netTcpBinding>
<binding name="tcpEndpoint"
closeTimeout="00:10:00"
sendTimeout="00:10:00"
maxBufferPoolSize="524288"
maxReceivedMessageSize="2147483647"></binding>
<!--<binding name="tcpEndpoint" transferMode="Streamed" />-->
</netTcpBinding>
</bindings>
<client>
<endpoint address="http://localhost/MyService/MyService.svc/AddAttachmentsService"
binding="basicHttpBinding" bindingConfiguration="httpEndpoint"
contract="PService.IAddAttachmentsService" name="httpEndpoint" />
<endpoint address="net.tcp://myComp/MyService/PlayService.svc/AddAttachmentsService"
binding="netTcpBinding" bindingConfiguration="tcpEndpoint"
contract="PService.IAddAttachmentsService" name="tcpEndpoint">
<identity>
<servicePrincipalName value="host/MyComp" />
</identity>
</endpoint>
</client>
</system.serviceModel>
Problem is the same when I’m using netTcpBinding or basicHttpBinding.
I’m new in WCF and i’m don’t have idea what else I can search on web. I have read about streaming (there is no difference when I’m set transferMode on Streamed or else), about concurrency and instancing (I have setting different option – but I think that this have nothing to do with this problem).
If I’m gave to little information please let me know.

Answer 1

Ok, i found out what the problem is:
when i'm testing my service i'm passing parameter (object) to the first calling of service and then to the secound call of service (but object was changed in first call) - i forgot that object is passing by reference :)
i found out that i can't change message in service calling (for logging purposes) - i log message through message inspector (method AfterReceiveRequest) which is calling earlier than service execution.