Calling a SAP PI Web Service (using WCF bindings) from a SharePoint 2007 Workflow

There are 2 rules when calling a SAP PI web service from a SharePoint workflow:

1. You have to use custom bindings to get authentication to work.
2. After you've added your web service via the "Add Service" dialog, you have to copy the all of the contents under into the SharePoint web.config - as per http://blogs.msdn.com/sharepointdesigner/archive/2008/11/02/calling-a-wcf-service-from-a-sharepoint-workflow-using-visual-studio.aspx. This is because the contents of app.config are (obviously) not accessible by the SharePoint Workflow runtime - you have to use the web.config instead.

Point 1 - Custom Bindings

If you try to call a web service in SAP PI which requires credentials, none of the normal authentication methods seem to work. You will always get the following error in WCF.

The HTTP request is unauthorized with client authentication scheme 'Anonymous'.
The authentication header received from the server was 'Basic realm="XISOAPApps"

To fix this, you need to use the following custom bindings rather than the normal basicHttpBinding, like so:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <system.serviceModel>
    <bindings>
      <customBinding>
        <binding name="CustomHttpTransportBinding">
          <textMessageEncoding maxReadPoolSize="64" maxWritePoolSize="16"
              messageVersion="Soap11" writeEncoding="utf-8">
            <readerQuotas maxDepth="10000000" maxStringContentLength="10000000"
                maxArrayLength="67108864" maxBytesPerRead="65536" maxNameTableCharCount="100000" />
          </textMessageEncoding>
          <httpTransport authenticationScheme="Basic" bypassProxyOnLocal="false"
              hostNameComparisonMode="StrongWildcard" keepAliveEnabled="false"
              proxyAuthenticationScheme="Basic" realm="XISOAPApps" useDefaultWebProxy="true" />
        </binding>
      </customBinding>
    </bindings>
    <client>
      <endpoint address="http://servername:50000/XISOAPAdapter/MessageServlet?channel=:INTEGRATION_SERVER_DPI:SOAPSenderPOCreate&version=3.0&Sender.Service=INTEGRATION_SERVER_DPI&Interface=http://zz"
        binding="customBinding" bindingConfiguration="CustomHttpTransportBinding"
        contract="PurchaseOrderProcessingService.PurchaseOrderProcessing_Out"
        name="PurchaseOrderProcessing_OutPort" />
      <endpoint address="http://servername:50000/XISOAPAdapter/MessageServlet?channel=:INTEGRATION_SERVER_DPI:SOAPSenderPORelease&version=3.0&Sender.Service=INTEGRATION_SERVER_DPI&Interface=http://zz"
        binding="customBinding" bindingConfiguration="CustomHttpTransportBinding"
        contract="PurchaseOrderReleaseService.PurchaseOrderRelease_Out"
        name="PurchaseOrderRelease_OutPort" />
      <endpoint address="http://servername:50000/XISOAPAdapter/MessageServlet?channel=:INTEGRATION_SERVER_DPI:SOAPSenderGOS_URL_CREATE&version=3.0&Sender.Service=INTEGRATION_SERVER_DPI&http://zz"
        binding="customBinding" bindingConfiguration="CustomHttpTransportBinding"
        contract="PurchaseOrderAttachUrlService.MI_GOS_URL_CREATE_Syn_Out"
        name="MI_GOS_URL_CREATE_Syn_OutPort" />
    </client>
  </system.serviceModel>
</configuration>

Point 2 - Web Service Configuration Settings
(from http://blogs.msdn.com/sharepointdesigner/archive/2008/11/02/calling-a-wcf-service-from-a-sharepoint-workflow-using-visual-studio.aspx)

1. Open web.config in VS for editing. You can find the file in the "\inetpub\wwwroot\wss\VirtualDirectories\80" directory, where 80 corresponds to the port of your SharePoint application.
2. Copy the "System.ServiceModel" element from app.config into web.config. If you already have a "System.ServiceModel” element, you’ll need to merge the and elements in manually.
3. To complete your changes, open a windows command window (Start/Run/cmd.exe) and type "iisreset", which will cycle the sharepoint web application, so it can pick up the web.config changes.