Mike Allen Systems

Doing Smarter Things With IT

Application Authenticate using public/private key pairs

Recently I’ve been using no-code and low-code solution to build small business applications. I’ve had to learn more about authentication using public/private key pairs, which I’ve normally had other people look after for me, but now it’s time for me to do it myself. After a read of the Wikipedia article https://en.wikipedia.org/wiki/X.509

First up the business scenarios. My web site uses https://letsencrypt.org/ certificates, a fantastic free service, it’s built into my web portal so I just nee to know it’s there, simple. Then there was the e-commerce site where I had to take a commercial certificate and install it on an Azure web site, a little bit of manual prep, bit largely automated by the portal.

Then something more complex, I wanted to use an Azure function to talk to SharePoint online. I checked out this post https://blogs.msdn.microsoft.com/richard_dizeregas_blog/2015/05/03/performing-app-only-operations-on-sharepoint-online-through-azure-ad/ , which told me almost everything that I needed to know. One important lesson was that the AAD app acts as a portal to SharePoint online, so once I had one app working, all my azure functions then used the same AAD app for access to SharePoint online. This is still a work in progress for me, I was motivated by a need to insert images from a Power App, then I realized that this opened the door to other business needs, such a creating a PDF from a SharePoint item.

Then I got back to my core business driver, Business Intelligence, and my current area of interest, Xero. I was looking for drag and drop access to Xero data, with a simple connector. At this point I looked at the new https://linx.software/ Xero connector, and was a little put off that I needed a Consumer Key, and a secret to use the Xero API. All too hard I thought! Then I looked close and realized if all used a certificate, I read this https://developer.xero.com/documentation/api-guides/create-publicprivate-key and then created a new cert. The I created a private Xero App with my certificate and it all fell into place.

I’m not an expert on certificates  by any measure, but now I know enough to integrate my Xero with Power BI using Linx, that will be my next adventure.

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