Sage 300 Web UI Internals
At Sage Summit 2015 we introduced our new Web UIs for Sage 300. I’ve blogged a bit on the various user facing parts and a bit on the technologies used, but I haven’t had a chance yet to get into the internals of how they work. We’ve released the Web UIs for the Financial Modules and will be releasing the Operations Modules early in 2016. With these we will be releasing our SDK as well. Over time I’ll blog quite a bit about the details of all the components, but first we need to layout the major building blocks. Below is the architecture diagram I’ve shared before which is the architecture for the main Web UIs and a block for RESTful Web APIs, but there are some other components that need mentioning as well.
I’m going to start at the bottom of this diagram and work up. However there are some other components that aren’t mentioned here that we will bring in.
Within our framework we provide a lot base classes that you can inherit from, so generally the only code you need to provide is where something is different than the standard protocols or behaviors. When looking for framework components to help you, besides looking for services to call, look for classes that do 90% of what you need that you can extend (inherit from). ASP.Net MVC also makes extensive use of “convention over configuration”, so for a lot of things if you follow the standards then it saves you a lot of work and makes a number of things just work magically. Similarly we do the same things, so we can find and use your components as long as you follow the standards as outlined.
The Sage 300 Views are still the same. We didn’t even update the C View template for supporting this new framework. All the regular Sage 300 Business Logic (Views) is accessed through our .Net API.
The Business Repositories convert our View API into something more like an ASP.Net MVC API. The Business Repositories are similar to the definitions that we generate from ViewDoc for different systems to make accessing all the various View fields more natural in the given framework. They provide support for all the usual View UI related items like presentation lists and field masks. Generally this is where all the View programming is placed that is needed by the UI. This makes all this programming available to everyone including UIs, standard components and Web APIs.
The models are true ASP.Net MVC Models. They are typically built on a given business repository. The reason for the separation between the Business Repositories and the Models is that the Business Repositories are more general use and can easily be consumed by UI elements whose Models are more generic like for Finders or Import/Export.
State-full Versus Stateless
There are two basic ways that our UIs operate, stateless and state-full. Ideally everything should be stateless, but this becomes somewhat impractical when dealing with large accounting documents. Basically in stateless operation, each RPC operation is completely independent and can be processed with no knowledge of what’s gone before. For state-full transaction a document is built up in the Sage 300 Business Logic as the user enters the document, this is more similar to how the VB UIs work. Generally only the bigger document entry UIs are state-full now. Use of the two is similar and most of the details are hidden by which base class you inherit from (whether a state-full or stateless one), but you must beware of the context as you do your programming.
Often in VB programming, you handle events from the user and as a result of a UI event you do a certain amount of View calls (perhaps say 20 of these). This sort of thing also happens in the Web UI, but we certainly can’t do 20 or so RPC calls to the server as a result of a single UI interaction. This is where services come in. Then when such a UI event is triggered, a single RPC call is made to the server, the controller dispatches this to the service who calls the correct method in the Business Repository which then makes the 20 or so View calls to do the real work. The service then marshals any returned data in the response. Of course this all happens asynchronously. Generally if you are wondering where to move your processing code from a VB UI it would be into one of the Business Repositories and then wire up a service to allow it to be called from the Browser. Services are also used to initiate long running processes which we’ll talk about later.
We don’t want to run long running processes like I/C Day End or Posting Batches directly from IIS, since even with full multi-threading support this can adversely affect the responsiveness of the UIs for other users. So we run a Windows Service and when a long running process is initiated we ask the Windows Service to run it, and just return from IIS. Then the UI can inquire periodically for meter status updates and to notify the user when it’s done. There is a lot of standard framework support for doing this and you just need to setup a service to initiate and monitor the process. Generally we do this for any Sage 300 process that pops up a progress meter.
KPIs are really just like any other UI. They just have a different size and are run in a different place on the Home Page. There are a few standards to follow to match the other KPIs and a few UI controls that aren’t used anywhere else, but are otherwise just standard UIs.
Although this component isn’t included in the original Sage 300 2016 release, there is full support for exposing RESTful Web Service APIs. These leverage your Model code to expose the model as an API. Then there is some support for hiding inappropriate methods and adding a bit more attribute information to help users.
Like previous versions of Sage 300, we use Crystal Reports to print out our reports. We basically use the same report API as we used in VB. We then have support to call this API from our UI framework and to render the report in the Crystal HTML Viewer. Then the rest of the report UI is just the same as any other UI, gathering up data from input fields. Printing might also have to initiate a process on the Windows service before printing, like generating the data for an aging report, before initiating the report.
Other System Components
There are system components for things like Finders and Import Export. These just need to be setup and wired in correctly. Then there are components like the editable grid which requires a certain amount more support in your UI. And then higher level components like the Optional Fields Control that is built on the Grid. There are a few other controls and wrappers for things like dates, fiscal year/periods, masked edit control, drop down list based on presentation strings, etc.