Error “Unable to load assembly group” upon redeploying a sandbox solution with a feature receiver

IT operations set up a fresh new SharePoint webapplication for my current project on the development farm, and provisioned it with a root site collection based on the publishing template. Next I took over the deployment control by following the sandbox route; in this preliminary phase merely to provision the first version of the branding: master page, CSS files, images and page layouts. A known artifact of sandbox solutions is that the provisioned files are by default still checked-out in the content database by the person who activated the solution, and thus not visible for anyone else. [It is a mysterie to me why Microsoft implemented it such; and moreover why they didn’t delivered us a setting to configure this provisioning behavior to automatic checkin and publish/activate the provisioned SharePoint artifacts.] Instead of manually via the browser or SharePoint Designer having to lookup in the site collection all the provisioned SharePoint artifacts to check them in and publish them, I more favor the approach to have this done automatically in the context of the feature activation. This can be easily accomplished via a feature receiver (Waldek Mastykarz has a good start/example for this in his blogpost Automatically publishing files provisioned with Sandboxed Solutions). So I added a feature receiver to the provisioning feature in the sandboxed solution, and in the FeatureActivated event let all the provisioned SharePoint artifacts be located in the content database and automatically checked in + published if applicable. Tested it locally, works like a charm. Deactivated and deleted the previous uploaded version of the sandboxed solution, and uploaded the new version with the feature receiver inside. However, upon activating this sandbox solution version, I consistently got the following error:

Error occurred in deployment step 'Add Solution': Unable to load assembly group. The user assembly group provider threw an exception while trying to provide user assemblies for the specified assembly group.

And in the ULS logging the following detail info:

Unable to load assembly group. The user assembly group provider threw an exception
Assembly Group Id: GroupId = "7C00665459714EEC9BDA8727AD711EC7-FES7hxwCdYldvtgExF/L+b259Rh3T1thWDeijNWTrSU="" - Inner Exception: System.ArgumentOutOfRangeException: Specified argument was out of the range of valid values.
at Microsoft.SharePoint.SPListItemCollection.get_Item(Int32 iIndex)
at Microsoft.SharePoint.Administration.SPSolutionLanguagePack.
GetSolutionInfoFromGallery(Guid siteId, Guid solutionId, String solutionHash, String& fileName, String& hash, Byte[]& fileBytes)
at Microsoft.SharePoint.UserCode.SPUserCodeLightweightSolutionAssemblyGroupProvider.
GetAssembliesInGroup(Guid siteId, String assemblyGroupId)
at Microsoft.SharePoint.UserCode.SPUserCodeAssemblyCacheManager.
EnsureUserCodeAssemblyGroupIsCached(Guid siteId, SPUserCodeAssemblyGroupId userCodeAssemblyGroupId)

An internet search did not give many nor useful hits; and neither could the SharePoint development gurus in my neighborhood help me. So it left me rather puzzled at first how to analyze and solve this. A good clue however was that a sandboxed solution from another SharePoint (web)application with also a feature receiver inside, had the same problem trying to activate it in our site collection, while it successfully activated in the own site collection. So it must be something at SharePoint infra level, not caused by code development. With this insight I went back to my operations companion, and provided him with a sandboxed solution to monitor what events occurred at system level upon trying to activate the solution. This quickly let to a conclusive result: somehow the permission state of the User Code service account on the C:\ProgramData\Microsoft\SharePoint\UCCache subfolder got compromized, which disallowed it to re-copy the new version of the sandboxed solution with code inside to the UCCache subfolder. The problem was not even resolved by restarting the User Code service; instead it was needed to manually reset the User Code service account, so that upon the next invocation the ACL on the UCCache subfolder was again built up.

Our operations guy was very thoughful to make a note of this behavior in the internal SharePoint operations Knowledge Base, and document it in a work instruction.

Duet Enterprise lessons learned for custom application scenario

The Duet Enterprise proposition is multi-faceted. It is a product with ready-to-use functionalities. It is a composition environment for constructing your own solution by composing delivered functional and technical building blocks, e.g. SharePoint Site templates for SAP business objects, SAP reports scheduling and publication into SharePoint, expose SAP workflow decision points as SharePoint tasks. And it is an Integration Foundation for building your own custom application scenario.

In case of that last context, a Duet Enterprise project is a software development project. However, it is not just like any other development project. The application of the Duet Enterprise Integration Foundation in custom SAP / SharePoint application scenarios imposes specific prerequisites to be successful. From experiences with applying Duet Enterprise in custom application scenario, we have learned several lessons.

Starting with Duet Enterprise

Before you are ready to apply Duet Enterprise in a custom application scenario, the project team needs to invest time to get familiar with the product. Get acquainted with the Duet Enterprise concepts, architecture, capabilities, configuration, development approach, constraints and its restrictions. It proofs a steep learning curve to become familiarized with Duet Enterprise and the diverse aspects. This learning experience is made more difficult by the lack yet of concise study material and available reference cases in the open to learn from.

Also you need to install Duet Enterprise in your combined SAP and Microsoft IT landscape. It’s common that this task is performed by the IT operations in your company. Be aware that installation and configuration of Duet Enterprise is more than a simple ‘next-next-OK’ click exercise. Especially on the SAP side, the installation of the Duet Enterprise SAP Add-on consists of configuration steps in diverse parts of the SAP landscape (e.g. SE80, IMG, SOA Manager, …). The total elapse time for installing and configuring Duet Enterprise can easily extend to 5 or more workdays. For the major part the SAP and SharePoint installation and configuration can be done isolated and in parallel. However, there are also multiple moments where it is essential to work together, and exchange system information. From SAP imported into the SharePoint farm, and later on SharePoint security settings required at the SAP NetWeaver / Service Consumption Layer (SCL) side.

Starting within a custom SAP / Microsoft application scenario

This is no different from any SAP / MS integration scenario. Don’t start with the tool, start with the business question! Make sure you understand which problem(s) you are trying to solve. Invest proper time for performing the business and information analysis. Agree with the customer what kind of user experience is asked for. With these demand aspects sufficiently clear, continue with deriving the integration and the software architecture design. In this process both SAP and Microsoft solution architects should be involved. They bring in the insights, knowledge of best and bad practices from the experiences on their own turf. When sketching the integration architecture, continually evaluate whether and where Duet Enterprise can add value, given the Foundation capabilities and the imposed constraints. Don’t make the application of Duet Enterprise your goal; but determine for the application context if and where Duet Enterprise adds value.

Functional system architecture

Input here are the business process, the requested functionalities, the end-user audience, and the workplace characteristics. Decompose the system functionality in use cases. Often not all of the system use cases have the same set of actors. The functional and process architect(s) must carefully decide for which of the use cases there is a business case to expose outside of the SAP boundaries, and for which not. Example of the last is an approval task by a manager or the HR department. They are SAP power users, spending a large part of the day within the SAP GUI. The GUI has no secrets for them, it’s their familiar workplace. The larger workforce in the company is instead a non-casual user of the SAP environment. They are not used to the SAP GUI, and loose valuable time finding out how to operate within the GUI. The financial business case here is reducing the amount of required SAP licenses, and reducing the time spend by this larger set of employees due the unfamiliarity with the SAP UI. A soft business case is that the employee satisfaction is improved by integrating the SAP related work within their common and familiar workplace.

Starting with Development approach

Again, this is no different from other enterprise application integration scenarios. A proven best practice is to start with establishing and defining the contracts via which the application counterparts will communicate. Initially these contracts are defined in abstract format, focusing on the identification and separation of system responsibilities. Microsoft architects recognize this as applying the ‘Contract-First’ approach; SAP architects are more familiar with the term ‘Outside-In’. Do a design time validation on paper or whiteboard that all of the identified functional use cases can be realized by the set of identified interfaces. Augment and tune the interfaces until this design check leaves no more gaps.

Next, model the identified abstract service interfaces in the Duet Enterprise SAP Add-on. The tool for this is the ES Builder, a Java-based modeling environment delivered either as part of SAP PI, or of SAP NetWeaver Composite Environment (CE). In this development step the technology-agnostic service interfaces must be translated into specific SAP service-technology format: data structures, message types, interface operations. Here you also augment the abstract service interfaces with the specific Duet Enterprise requisites: Correlation ID and Business Object Instance Key . These 2 specific parameters are required to enable the Duet Enterprise system monitoring and routing capabilities. Also add here SOAP standards-based fault handling to each service operation. The ES Builder directly supports this via the SAP ESA SOAPFaultException datatype. The SharePoint consumer of the Duet Enterprise service interface can handle the received SOAP Faults in a standard manner through WCF, transparent to any SAP specifics in the fault notification. When all the identified service interfaces are modeled in ES Builder, generate in the ESB the WSDL service description. This W3* standards-based and platform independent service description is utilized and needed on both the SAP service provider and the SharePoint service consumer sides for building the integrated application.

Building the SAP / SharePoint integrated application

With the WSDL service description available, the SAP and SharePoint development teams can each go ahead with the realization of their respective application responsibilities.

At the SAP side the identified service interfaces must be implemented by concrete service realizations. In a Duet Enterprise landscape the term Service Provider refers to the SCL system, and SAP Backend refers to the system that hosts the Business Functionality. SAP Duet Enterprise service implementations are thus positioned in the SCL. The SCL services connect to the SAP Backend to consume the business functionalities and data. Since this SCL-SAP Backend connection is strictly within the SAP environment, it is possible to rely on SAP proprietary connection technology. In fact, between the SCL and the SAP backend it does not add anything additional to connect via web services (BAPI or Enterprise Services). Using web services to connect to the Backend brings some additional performance overhead so RFC-based connection is faster. The development work inside the SCL further consists of mapping the external faced service signatures to the internal SAP processing and data structures. This involves the technical mapping from the W3* standards-based integration handling to the SAP internal invocation model and data structures. And potentially at business process level the composition of multiple SAP actions in the scope of a single Duet Enterprise service operation.

The required work at the SharePoint Duet Enterprise consumption side is largely dependent on the operation and data signature of the provided SCL services. At SharePoint side, Duet Enterprise builds on Business Connectivity Services. Implication of this is that the SCL services must exhibit a CRUD+Q operation signature. If not, consumption via BCS is not even possible. If BCS-based consumption of the external SCL services is possible, another aspect is the data structure. SharePoint 2010 out-of-the-box delivers the concept of the External List UI to interoperate with external data. A practical limitation of the External List UI metaphor is that it requires a flat data structure. If not flat, it is not possible to display the external data in a row-based manner. Non-flattened / hierarchical data can still be consumed via BCS in SharePoint, however not via the External List concept. The project will have to build a custom UI to interoperate with hierarchical SAP data structures. The custom UI must connect to the BCS Object Model to interoperate with the external SCL services. Current drawback is that the BCS API only supports a weakly-typed programming model. You have to program per exchanged hierarchical SAP data structure an ORM-based mapping from strong-typed data representation at the SharePoint front-end to the BCS weakly-typed representation.

Debugging Duet Enterprise connection problems

Here is where the application of Duet Enterprise clearly adds additional value. If you obey to the Duet Enterprise constraints; that is if you have per service operation included the Correlation ID parameter; the Duet Enterprise landscape supports the problem analysis via an integral audit trail through the combined SharePoint + SAP systems chain. You look up the Correlation ID value in the SharePoint ULS logs for where the BCS-based connection starts, and follow it through the SCL layer via the SAP system monitoring. Problems can be of infrastructure nature, e.g. SSL certificate at SAP and SharePoint not in sync; SharePoint BCS-SCL service connection level as result of a wrongly chosen SAP proxy endpoint; SAP authentication and/or authorization due incomplete Duet Enterprise user mapping. The Correlation ID based audit trails proofs a big help in tracing where in the integrated SharePoint / SCL / SAP Backend landscape the actual problem cause manifests itself.

Duet Enterprise development work plus applicability

At the global level, following development activity is involved in building a custom Duet Enterprise scenario.

SAP side

Plain and simple: Provide SCL-ready services, that are SharePoint BCS consumable.
There is no other option here, this work is required to deliver SAP data + processing services that are enabled for SCL-publishing. At minimum this involves ABAP custom development for mapping the W3*-standards based SCL data representation onto the native SAP data representation, and vice versa; and invoking from within the SCL runtime context the inner SAP processing at either RFC, BAPI web services or SAP Enterprise Services level.

SharePoint 2010 side

Here the amount of development work depends, namely on the signature of the SCL-published services. Ideally the services provide a CRUD+Q signature (required) + a flattened data structure (optional). If both aspects are present in the SCL-services, these can be directly consumed and displayed in SharePoint External List. Then there is no development work required at SharePoint side, it is all configuration done in SharePoint Designer. You get the maximum added Duet Enterprise value in case of flattened data: SAP/SharePoint connection, authorization, system monitoring; and out-of-the-box presentation of the SAP data.

In case of non-flattened, complex/hierarchical data structures, the External List UI metaphor is not viable. Duet Enterprise can still have its value, on the connection, authorization + system monitor aspects (plumping). What you loose here is the out-of-the-box UI presentation. You will have to build a custom UI instead, and program directly against the BCS Object Model. Thus more work, but Duet Enterprise still has standards-based value and role for SAP/SharePoint interoperability.

Connection requirements / BCS implication for Duet Enterprise

The Duet Enterprise SharePoint Add-on builds and relies upon BCS. Consequence is that BCS prerequisites are imposed on the SAP / SharePoint service connection, provided by the SCL-publishing and BCS-consumption. The SCL provided SAP-services must expose a CRUD+Q interface, with at minimal a ‘ReadList’ (= Query) and ‘ReadItem’ (= Read) type of operation. If the SAP processing behavior cannot be mapped on the CRUD+Q signature, you cannot reasonable apply Duet Enterprise. Point. The SAP .NET Connector 3.0 may be a alternative for such connections.

Schematic overview of the Duet Enterprise applicability

Positioning of .NET Connector 3.0 versus Duet Enterprise

In a timeframe of a couple of weeks, SAP independently released 2 products for .NET interoperability: first [December 2010] the next version of the .NET Connector – NCo 3.0; followed a few weeks [Februari 2011] later by the public launch of Duet Enterprise – a combined effort of SAP and Microsoft. These near overlapping release moments may raise questions and uncertainty on the positioning of the 2 .NET interoperability products. Are they competing? Are the successive release moments a symptom of independent products groups within SAP, and will market acceptance determine which one will ‘win’? And what about the SAP ES Explorer? Earlier, SAP spokesman declared the .NET connector outdated in favor of the ES Explorer.

In my thoughts and analysis, the story is differently. NCo3.0 and ES Explorer on one side, and Duet Enterprise all have a distinct positioning. The 3 products are neither competing nor exclusive for .NET interoperability. Each serves a specific and dedicated purpose.

NCo3.0 and ES Explorer

Both NCo3.0 and ES Explorer are in essence .NET Interoperability technologies. Neither of them is positioned as a product. You can not purchase or license it, but instead can download them from SAP Marketplace if you have a valid S-User ID that acknowledges you as a SAP developer. The release of .NET Connector 3.0 passed rather silently, with only an announcement on SDN. It has not received attention from any of the influencing IT business magazines, nor IT Research Analysts. There was a Ramp-Up with selected beta-testers, but with minimal noise ahead and attention during.

• NCO 3.0 is intended as a general purpose technology tool for low level integration plumping. Basically it enables bi-directional interoperability between .NET custom code and SAP RFCs and BAPI Function Modules. Nothing more, nothing less.
• The role of SAP ES Explorer is in essence the same. In the earlier SAP statement, Rima Rudnik-Sirich characterized it as 'It succeeds SAP .NET Connector 2.0 for .NET'. The difference is within the interoperability manner. SAP ES Explorer works at the level of SAP Enterprise Services, W3*-compliant. You apply it as Visual Studio Add-In, to search through all the SAP Enterprise Services available in your landscape; standards ones from SAP, from third parties deployed in your landscape, and your customer-build Enterprise Services. Runtime invocation of the selected Enterprise Services occurs via a generated WCF service proxy.

Duet Enterprise

Duet Enterprise is a whole other story. Both SAP and Microsoft position it as a product that will directly provide business value. The Duet Enterprise release was done at large: a Virtual Launch Event, press releases and articles within the important IT business magazines, analysis reports by Forrester and CITO Research. Application of Duet Enterprise requires a license, the product can be purchased via SAP and Microsoft. (Note: at moment of writing there is no information disclosed on pricing and licensing model). Before reaching General Availability, Duet Enterprise has been evaluated in a combined Ramp-Up / Rapid Deployment Program hosted by SAP and Microsoft together. Participating in the RDP was given substantial noise ahead, and intensive attention during the program course self. (Note: TopForce participated together with a large Dutch insurance company in this RDP).

The role of Duet Enterprise is twofold. It comes out of the box with direct usable functionalities, and capabilities to compose customer-specific solutions. Its second face is what distinguished Duet Enterprise from the previous Duet versions: integration Foundation to build integration + interoperability that is specific for your situation. Also, SAP and Microsoft believe and want ISVs (the ecosystem) to deliver add-ons on the Duet Enterprise products, e.g. for specific vertical markets. To stimulate this, SAP and Microsoft also launched a partner program: Unite Partner Connection Program.

The Duet Enterprise Foundation is also interoperability plumping, but of higher level as NCo 3.0 and ES Explorer. SAP / .NET interoperability occurs via standard W3* services; there is out-of-the-box support for SSO, Authorization, landscape monitoring. All aspects that earlier you typically had to handcraft yourself, and thus also maintain.

Duet Enterprise is bounded to usage from within a SharePoint 2010 context, and via SharePoint 2010 as intermediary layer in Office 2010 clients. Duet Enterprise has no role in other .NET contexts, e.g. SharePoint 2007 or 2003, Silverlight, WinForms or WPF apps, WCF handling, BizTalk.

Implications

The added value of Duet Enterprise [product, foundation] wrt NCo 3.0 and SAP Explorer [basic interoperability technologies] is that it raises the level of SAP - .NET interoperability. In addition to the bi-directional SAP - .NET runtime communication, it also provides interoperability concepts as SSO, Authorization, System Monitoring. And on top, it comes with direct usable functionalities, and capabilities to compose solutions [building blocks].

The limitation is that it only works from a SharePoint 2010 context (and via SharePoint in Office 2010 clients). If you need .NET interoperability from different .NET context, you have to resort to another approach. SAP provides for this both the NCo 3.0 and SAP ES Explorer; which one is usable is dependent on the level of SAP back-end consumption. If SAP Enterprise Services are available; apply SAP ES Explorer; for RFCs and FMs you can use NCo 3.0.

Note: there are also several technologies and products delivered outside SAP to enable .NET interoperability. For instance Microsoft provides the BizTalk WCF LOB Adapter SDK, BizTalk itself; third parties provide product like Sitrion, Ometa, ERP Connect. For the scope of this article they are however not considered.

Development Approach with Duet Enterprise

This blog is, with some minor changes, earlier published on SAP Community Network Blogs

TopForce participated in the 2nd half of 2010 within the Duet Enterprise Rapid Deployment Program. Together with our RDP partner, we followed a well-chosen approach to evaluate this SAP – SharePoint integration product on it’s capabilities and potential.

In the Ramp-Up / RDP I was involved in plotting the Duet Enterprise prerequisites in the company IT infrastructure, selecting the PoC scenario, architecting the integration approach, and configuration + realization of the Duet Enterprise services for the PoC scenario. In this article I highlight the main points of our journey.

Product evaluation via a custom Proof-of-Concept

Both partners in the RDP regarded it as essential to evaluate Duet Enterprise as interoperability product via a custom Proof-of-Concept. Only such we are confronted wih actual experiences and issues in the application and potential of the Duet Enterprise capabilities. We do not suffice with merely a rather simple out-of-the-box scenario provided by Duet Enterprise.

Selection criteria for the PoC scenario

For us the main reason to consider Duet Enterprise is as integration foundation for company-specific SAP / Microsoft interoperability. To best evaluate the product capabilities on this aspect, we defined the selection criteria for the PoC scenario. We weighted the possible scenarios on the following aspects:

1. A real application context, with current and/or future purpose
2. Give input to SAP / Microsoft integration design guidelines

Validation approach

The PoC is intentionally approached as a regular development project. Thus functional specification, architectural and technical design, realization and testing, with ultimate ending in product implementation. In these Agile times, the phases are not necessarily in linear order; especially the integration architecture and realization have had some iterations as results of lessons learned.

Functional specification

In this phase, the application functionality is clearly defined, and agreed plus functional validated with the customer + end-users. Noticeable is that in this phase special attention is / should be given to the UX-factor: the User Experience of the application. This is because the most heard compliant against SAP is typically the lesser user friendliness. And also because nowadays information workers expect no less than a pleasant and familiar workspace, in which one is facilitated and helped to do your daily and also occasional work activities.

Integration and Software Architecture Design

Essential in this phase is close cooperation between the SAP and Microsoft solution architects. Both typically come from different backgrounds (‘different worlds’, almost like Mars versus Venus), yet it is required that they have a sufficient common understanding to architect a proper and future-proof design.

In the architecture itself, a best practice is to apply a layered service integration architecture. Each layer has its own responsibilities. In a nutshell, SharePoint sits at the front-end / presentation layer, SAP at the back-end layer; and Duet Enterprise is the glue as integration layer.

The integration layer is derived from the [use cases of the] functional specification. One of the design principles applied is that the SAP backend is and remains ultimate responsible for correctness of the data. This also implies that business rules are enforced and remain the responsibility of the SAP backend.

Duet Enterprise also imposes some constraints on the service interfaces. At conceptual level this means that Duet Enterprise [currently] only supports data oriented interfaces, operating via CRUD behavior. The explanation is that Duet Enterprise utilizes Business Connectivity Services to exchange data from SAP to and from SharePoint. BCS is a strict data oriented capability, it is not usable for [SAP] process oriented control.

Development Process

Once the service interfaces are derived and defined, the development team can go ahead with implementing the SAP-SharePoint integration via Duet Enterprise. The outline of this development process is as follows:

1. Configure / define the derived interfaces as SAP Enterprise Services in the ESR, using the SAP ES Builder. Hereby you must augment the interfaces as defined with 2 additional parameters required for proper Duet Enterprise handling, namely:
   • Correlation ID; this is used for the end-2-end monitoring of entire runtime flow through the SAP and Microsoft landscapes
   • Business Object Instance Key; this is used as generic identifier in all SCL framework components at runtime and at designtime. It consists of 3 components, Data Value Identier, SCL Business Object Name and the System Alias of the Backend. The key is to be generated in the SCL processing of each SCL service response, in the following structure: <data_value_identifier>_<Business Object Name>_<System Alias Of Backend>. The usage of this key is enable the SCL in subsequent handling to transparently identify the correct backend in a SAP landscape with possible multiple system instances. Notice the implication that if your SAP landscape consists of only a single backend, there is no concrete runtime usage of this field; all your SCL requests will be routed to the single backend. In that case you can simplify the key structure.
2. Export the defined SAP Enterprise Services in WSDL format
3. Hand over the WSDL file to both your SAP developer(s) as SharePoint developer(s). From here, both can in parallel configure and/or build their own side.

SAP NetWeaver 7.02 / Service Consumption Layer

1. In the SCL system, using ABAP Workbench / transaction SPROXY, create service proxy. This generates the skeleton of the provider class that includes the methods specified in the service interface. Later on you will implement the operations which involves some ABAP programming. The explanation of this break-up is that in the construction of the operations you need the GenIL model; and that you do not have yet generated in this stadium.
2. In the SCL system, in transaction se38 create the GenIL model based on the request and response structure of the service proxy. This generates a generic SCL Business Object Model. The reason that it is named ‘generic’ is because it is an intermediate mapping layer between the consumer (SharePoint BCS) specific data structures and the backend (e.g. SAP ECC 6.0) specific part. This enables that the consumer can transparently communicate with different backend systems/versions. That can be simultaneous in case of a distributed SAP landscape, consisting of a multitude of variant backends (e.g. ECC 6.0 for North America, while ECC 4.26 for the Dutch company division). But it is also beneficial when you upgrade your single system SAP environment – the GenIL model shields the client side from such backend environment change. And this also holds in the other direction – via the same GenIL model other clients as SharePoint can in theory also consume the exposed SAP data and functionality. An example is Alloy for IBM WebSphere.
   The GenIL model is actually to be more regarded as a generic Gateway derivative than strict Duet Enterprise specific
3. In the SCL via transaction SIMGH, create per service operation a Backend Operation Proxy that invokes the SAP Backend capability: either a SAP Enterprise Service, BAPI WebService or RFC / Function Module.
4. In the SCL, via transaction se80 create per service operation a Mapper object that implements 2 methods with predefined signatures for inbound and outbond mapping. This involves ABAP code to do the mapping from the GenIL model to the backend specific data format, and vice versa.
5. In the SCL / ABAP Workbench, return to the generated Service Proxy and fill in each of its generated operations. This also involves ABAP code to do the mapping from the received input to the GenIL model, and from the GenIL model to Duet Enterprise service output.
6. In the SCL via transaction SOAMANAGER, create the endpoint for the service proxy.

SharePoint 2010

1. Start SharePoint Designer to generate External ContentType(s) on basis of the imported WSDL from the SAP Enterprise Services.
2. If applicable, generate SharePoint External List as User Interface metaphore. Whether applicable is determined by a) the data structure; External List requires a flat structure (thus no hierarchical / parent-child relationships); b) the User Experience desired by the end-user.
3. if the External List is not applicable, realize in Visual Studio a custom build SharePoint webpart. Hereby you can use the whole richness of available ASP.Net and SharePoint webcontrols – datagrids, calendar, richtextbox, dropdownlist, … Also, SharePoint 2010 allows InfoPath forms for custom UI.
4. Configure the BCS model to connect for this External ContentType to the endpoint in the SCL of the Duet Enterprise specific service.

Conclusion

Introduction and application of Duet Enterprise is not a free ride. It takes time to get familiar with its concepts, and the development approach + tooling add-ons in the ABAP Workbench and SharePoint in the form of BCS Model Generator. It also requires preparation time at front in defining and architecting an application design. But that’s no different from any other software development project. Given that, Duet Enterprise is a noteworthy addition to the SAP / Microsoft interoperability toolbox; and I recommend to consider it for applicability in your specific SAP/MS integration scenario.

CQWP, CSS and jQuery applied to rearrange groups of overview links

A customer requirement for their SharePoint intranet is a reusable 'Overview-of-Handy-Links' capability, with the following specification:

1. Contributors must have a means to manage the overview links. The functional mananagment must be easy, without the need to maintain HTML.
2. The links must be grouped
3. The display-order of the overview groups must be controllable
4. The display-order of the links in a group must be controllable
5. The display space must be optimable used, white-spacing must be minimized
6. The overview backgroundcolor, links color and links hover color must be settable
7. The number of columns must be settable
8. Minimize the amount of custom code, favour the usage of standard SharePoint capabilities

As consequence of the first requirement, application of the ContentEditorWebPart is not an option. That would mean that the contributors are directly confronted with the html-specification of the overview. Utilization of the ContentQueryWebPart appears more promising. The rough solution design is then to 1) maintain the groupheaders in 1 SharePoint SPList; 2) maintain the overview links in another SharePoint SPList, with a Lookup to the GroupHeaders SPList; 3) Connect a ContentQueryWebPart to the OverviewLinks SPList; 4) Group on the GroupHeader Lookup field/column; 5) Codify in the CQWP Main, Group and Item xslt-files the templates to deliver the appropriate html.

The requirement to optimal use the display space can for a large extend be achieved via CSS float-functionality: automatically 'glue' the individual Group DIV's next to each other. In the horizontal direction there is then no lost white-spacing. However, in the vertical direction that cannot be achieved with CSS-float alone. Float flows in horizontal direction, not vertical.

But there is jQuery to the rescue. The basic idea is to first let the CSS-floating capability align the set of DIV's in as much as possible optimal usage of the display space. And afterwards, perform some minor rearrangement to also reduce the lost of white-spacing in vertical direction.

Via CQWP	After jQuery

Reusability of the OverviewLinks-functionality is achieved by applying the Feature capability. The Feature provisions the required SharePoint artifacts: the SharePoint SPLists - including the Lookup relation between them, a preconfigured CQWP, the XSLt-files.

Solution partitioning and dependencies with mixed scopes causes farm-deployment trouble

We probably all agree that it is wise to partition your SharePoint application deliverables and deployment into multiple packages. Typical examples are a Base assembly, deployed via a base wsp, providing a general foundation layer with diverse technical and functional building blocks. And then 1 or more functional packages, that provision the SharePoint artifacts and code for a specific application functionality; in which the functional building blocks may use and rely on parts provided via the Base assembly.

However, sometimes this architectural sane decision to partition your application deployment, can result in unforeseen effect. Let me demonstrate via a real-life example, that I encountered today:

• Application deployment deliverable
  1. includes a Base assembly, deployed via solution package Base.wsp. In this wsp package included the Base code, some basic Features, JobDefinitions, generic webparts. In the Base code / assembly there are FeatureReceivers, WebParts. As result of this, SharePoint solution generation (WSPBuilder or VS2010) puts SafeControl settings per contained WebPart in the Solution manifest; which again results in it that the scope of the Solution package is WebApplication.
  2. and also contains a pure functional package; with some Features, SiteTemplates. This functional package does not contain an assembly itself, but instead relies on the assembly of the Base.wsp for reused FeatureReceivers. As result this solution package does not contain any artifacts with are scoped at WebApplication level, and SharePoint solution framework requires to deploy it global in the farm. (nb: the further described situation can even occur in situation were the package does contain managed code, as long as the assembly does not contain SharePoint coded artifacts which transition the scope of the Solution package to WebApplication; e.g. no WebParts, Resources).
• The order of Solution package deployment is to first install the Base.wsp, and then the Functional.wsp. Then you would expect that the deployment dependency of Functional.wsp on Base.wsp is ascertained. However, in this scenario I discover in the SharePoint Solution store an error with the deployment of Functional.wsp. Error details:
  <server 1> : The solution was successfully deployed.
  <server 2> : The solution was successfully deployed.
  <server 3> : Feature '<GUID>' could not be installed because the loading of event receiver assembly "Base, Version=1.0.0.0, Culture=neutral, PublicKeyToken=13a12821e9f69237" failed: System.IO.FileNotFoundException: Could not load file or assembly 'Base, Version=1.0.0.0, Culture=neutral, PublicKeyToken=13a12821e9f69237' or one of its dependencies. The system cannot find the file specified.

At first, I thought this to be a timing issue. The Solution Framework uses timer jobs to deploy solutions throughout the farm, and it looked as if the Functional.wsp was tried to be already deployed on <server 3> while the deployment job for Base.wsp was not yet executed for <server 3>. However, also upon re-deployment of Functional.wsp - while making sure at forehand that the deployment of Base.wsp was now fully completed in the farm - , it resulted in the same error on <server 3>. So it must instead be directly related to the installation on <server 3> apparently the Base.dll was not installed in the GAC on that server; while the Features within Functional.wsp were to be installed on <server 3>. Why is this?

Well, the explanation is twofold. It relates to the SharePoint Farm infrastructure, as well as the scopes of the SharePoint packages. <server 1> and <server 2> have the SharePoint webapplication role in our load-balanced farm; and each contain the SharePoint webapplications. <server 3> however is dedicated as Search Index server; and does not host any SharePoint web applications. The SharePoint solution framework deploys WebApplication scoped packages only to the servers on which SharePoint web applications are hosted (Base.wsp: <server 1> + <server 2>). But it deploys Global scoped packages to ALL the servers in the farmer (Functional.wsp: <server 1>, <server 2> AND <server 3>).

Given this insight, a proper SharePoint Solution Deployment approach is to deploy the Global scoped Package with Force-flag, thus suppressing the error signalment. This worked sufficient in our case. However, it leaves you with the somewhat unwanted situation that via the Force-flag you suppress all error notifications; thus may be too brute. A better approach is to circumvent that Solution Framework deploys your Application package also to the servers on which the web application is not hosted. This can thus be achieved by making sure that each of your Application package as WebApplication scope. Either because it inherently contains such entities (e.g. WebParts), or artificially by including a dummy artifact directed at WebApplication level (e.g. an empty virtual bin file).