Showing posts with label POS. Show all posts
Showing posts with label POS. Show all posts

Interfaces.

When it comes to the ability to interact with the inputs and outputs of software, everything is an interface. For those who aren't aware, the Windows OS was originally named "Microsoft Interface Manager". There is interesting info in the Wikipedia entry on the origins of Windows.


The OS that started it all for Microsoft.


"In computing, an interface is a shared boundary across which two or more separate components of a computer system exchange information. The exchange can be between software, computer hardware, peripheral devices, humans, and combinations of these."

 

Without getting into the omnipresence of interfaces too much (the keyboard is one, the mouse and cursor are as well, the monitor is an interface, all of the windows on the screen are interfaces, every single OS event is taking place between two endpoints of an interface, programming languages use interfaces as "contracts" that can be adhered to, to allow for different implementations of the same kinds of data structures and methods, our own 👀 are interfaces to the world around us and on and on- and each of these relies on their own software!...), let's take a simple example.

Let's say we have some really neat library of unique functionality we want to share with as many developers as possible called "extRS". We have so many options for how to get this into the hands of other developers. But it requires assembling the working software into different languages/compilations to fulfill the needs of the different interfaces.


This is what Windows 1.01 looked like; 1985 my, my...


  • For an API (the interface for web services), we will want to present our software in the form of an API running on a web server. With a live ASP.NET Web API (esp. one that can respond to XML and JSON) you can allow clients (interfaces) to get live data from an implementation of your library's functionality via something like a simple POST to /ConvertXmlToJson with a body of:
 { <car><passenger></passenger></car> }  
...which then returns the appropriate XML-translated-to-JSON:
 {  
   "car": 
     {  
       "passenger": null  
     }    
 }  

This is an example of an API request and response (FedEx API)


  • There is also ASP.NET CoreWCF for interfacing with legacy XML SOAP-based web services:
If you want to interface with a legacy SOAP service in ASP.NET Core- this is what you can use


  • For getting our logic into the hands of JavaScript and NodeJS developers we can create and host an NPM package:
htmx and hyperform.js for validation are the neatest 2 open source things I've discovered in the past 2 years


  • For Python developers we can publish a python libraries to PyPI which makes it download-able via pip:
This shows the installation for the Python package pandas through the Windows CMD prompt


  • And we could even create a Ruby gem version, and packages for other languages to boot.... and on and on....

The problem is that, the more packages and different types of assembled or executable libraries you create, the more code bases you have to continuously test and maintain. But if your logic is simple enough, it makes sense extend the reach of your software as much as possible. Every interface that could use it, should be able to get it, and use it.

We have not even discussed console interface (CLI) which is required if you want your logic to be utilized in scripting and tooling chains that perform logic by piping the results of processes into subsequent processes all in CLI scripts like bash or PowerShell.

  • Custom CLI .exe - We can expose our extRS functionality through a command line interface. We compile a CLI program, ExtRS.CLI.exe that accepts user input such as ConvertXmlToJson ""<mouse name="Micky"><mouse>"" and performs prompts to present information to the CLI interface. I hate to disappoint, but that hasn't yet been implemented for the extRS project .sln 🤷🏽‍♂️

A simple .NET CLI program using extRS; this can easily be modified to implement virtually all of the extRS functionality


  • PowerShell Module - With a PowerShell module, DevOps and CI/CD devs can easily install the PowerShell modules through the official Microsoft PowerShell Gallery Here is the ReportingServicesTools PowerShell module:

Here is the ReportingServicesTools PS module; as you can see (errors)- I've gotta update some things in extRSAuth to get it to work with this module(!)


  • Nuget Package (compiled, portable ".dll" binaries) - allow clients to easily get your library's code into any .NET project. With this, any .NET project can reference extRS via:

This is my SSRS extension library, "extRS" on Nuget.org

  • WinForms - though a bit antiquated, there are millions of SMB and huge corporate software applications running proprietary .NET Framework code through Windows forms interfaces. It is like COBOL and FORTRAN- some things just work, and so they persist. For things like point-of-sale systems, sometimes the best solution- is something proven and established that won't surprise anyone (a WinForms POS app). An extRS WinForms app looks like this:

A mock of what an extRS interface implementation in WinForms might look like


  • MAUI - my experience is limited here, but from what I have experienced, MAUI is a faster, more capable version of Xamarin (with Xamarin and Mono under the hood). The great thing about MAUI is that, with one project, you can target all manner of mobile form factors (phones, tablets, watches- iOS and Android). An interface for my "tickertapes" Android app on MAUI for an Android phone looks like this: 

An example of one of my apps, "Tickertapes", running in an Android emulator using MAUI



As you can see we have so many ways to expose our unique (extRS, tickertapes) functionality. The only limitation on getting your functional code into operating programs is- the right interface implementation!




PS: A note on physical client interfaces as well... While we have discussed the different software interfaces (API, CLI, .dll, NPM, .psm, etc.), from a UI presentation and experience perspective, we have to consider the different types of physical interfaces that our code will be represented on- particularly the screen dimensions and how that will affect the inclusion vs. exclusion and location of certain content.

Never give short shrift to UI compatibility across devices- it is dang hard to present a "consistent" experience in myriad "different" ways. ('kinda competing, incompatible angles).


Hardware Form Factors

  • Mobile Phones
  • Desktop monitors
  • Laptop monitors
  • Tablets
  • TV monitors
  • LED scoreboards
  • Digital scrolling Marquee signs
  • Digital Billboards
  • "Smart" Watches
  • VR Headsets
  • Earbuds
  • "Smart" Eye Glasses
  • IoT devices with little or no display at all (in BAS equipment for example, typically these are used to start/stop or accelerate/slow down, based on some kind of PLC configuration and to collect and report useful data metrics about the device)



*"On November 20, 1985 (38 years ago), the first retail release, Windows 1.01, was released in the United States at a cost of US$99 (equivalent to about $280.00 in 2023)." -Wikipedia