Private packages with Azure DevOps

Recently Microsoft announced a rebranding of Visual Studio Team Services (VSTS) to Azure DevOps and as a big fan of Azure, I wanted to check out if the changes were just a new name or if it’d progressed to be a little more welcoming.
I say this because as someone with limited experience using VSTS, I always found it to be a little intimidating so tended to use simpler services like App Center for building my apps and Trello for my Kanban boards. I hoped that the change would include some UI enhancements that could help me ease into DevOps rather than being thrown into the deep end.
Thankfully the team has done some fantastic work in making Azure DevOps easier to get started with and I’ve now adopted it for managing my personal long term project.
In this post, I’m going to discuss how and most importantly why I’ve configured Azure DevOps to allow me to have confidence in the code I’m writing.
In this post, I’m going to discuss how and most importantly why I’ve configured Azure DevOps to allow me to have confidence in the code I’m writing.

One huge solution to rule them!

The project I’m working on is big, or at least it’s going to be massive. Right now its just a minimum viable product and it contains 17 projects, which I originally put into a single Git repository. This worked well for the beginning of the project but as I started to add more and more projects it became difficult to keep things separate.

It’s for this reason that I decided to create two separate solutions to make a clear separation of concerns. Ultimately I’ll probably end up splitting up Lighting Core Solution further as the project develops but for now I think two solutions provides me with enough separation.
Simple Archteicture.png

Smaller Solutions

Having two separate solutions rather than one beast makes my life significantly easier for ensuring that the Lighting Core code doesn’t become too sticky with my UI and vice-versa. It does, however, cause me some difficulties in how I should reference the dependancies as I don’t have an easy way to ensure that the UI project has all the code required to build. To solve this, I went ahead and moved all my code in Azure DevOps as a stepping stone towards fully embracing the tool.


Private Nuget Feed

With all the code hosted in Azure DevOps I have a one-stop shop for my projects development.

I went ahead and defined build processes and hooked them up so they’d be triggered everytime I pushed code to the master branch.


The build steps is very simple. I restore packages, build and then pack up the DLLs ready for release.


I’ve defined separate pack tasks for each project that I wanted to turn into a Nuget package. This task handles packaging up the results from the build ready for releasing either publicly or privately.


I’ve then defined the most basic release pipeline possible to take the results of the build pipeline and push to Nuget.


Because I’m releasing the packages privately, I host them in Azure DevOps and can access them in Visual Studio with minimal configuration required!


Wrapping up

This blog post covers at a very high-level how I’ve gone about setting up the basics of a continuous integration and deployment system for my pet project. If you want to learn how you can also configure your own CI/CD system then checkout the great tutorial over at Microsoft Docs.


Continuous delivery of macOS apps built with Swift

Anyone familiar with my ramblings will be aware that I mostly develop in C# using a mixture of Xamarin and .NET Core depending on what I’m building. Earlier this year I took the decision that I’d be serious about learning Swift and got started with building a simple utility app for macOS to help me find training images for some machine learning.

Screen Shot 2018-05-10 at 11.11.55

The app has mostly just sat on Github with little love since I originally published it, so this week I dusted it off (I actually just cloned it again from Github but I like the metaphor) and started implementing a few of the features that didn’t make it to the first release. The most obvious is file tagging, which makes it possible to add file system tags to exported images, for easier discovery of exported images.

Screenshot 2018-09-28 at 10.25.14

I shared a gif of the new build with a colleague, and he loved it so much that he wanted a copy. Now I could have easily have behaved like an animal and built a version on my development machine and sent over the results, but instead, I opted to listen to the sane part of my brain that was calling for me to set up a CI/CD pipeline.

Enter Microsoft’s App Center

If you’re not familiar with App Center then you’re in for a treat! App Center provides a one-stop-shop for services that app developers will likely need. This includes building, testing, distribution, analytics and crash reporting to name a few. Today I’m going to focus on the build aspect, but I’ll cover other features in upcoming posts.

Microsoft has been working hard on adding new features to App Center, and one of those new features in the preview is the ability to build Swift macOS apps. The setup process only requires a few clicks, and we’re up and running. Below a gif of the process recorded in real-time which shows how quickly I managed to get a build setup and running.


App Center Build Setup

To get started we have to create a new app within App Center and specify a name OS and platform as a minimum. In my case, I only really need to worry about selecting macOS as App Center currently only supports Objective-C and Swift as languages for macOS app development. Screenshot 2018-09-28 at 10.33.06.png

Setting up the build pipeline

Once we’ve clicked “Add New App”, we’ll be presented with a screen encouraging us to integrate App Center SDKs into your app. I’ll cover the advantages of this in another post as it’s not needed to use App Center. Did I mention that every feature in App Center is optional? In the post, we’re only going to use the build and distribute functionality and ignore everything else.

Screenshot 2018-09-28 at 10.40.21

Build Configuration

As mentioned earlier in the post, the code is hosted on Github which is integrated with App Center. This allows me to connect App Center to the repository and anytime I push to a branch I can have App Center automatically trigger a build.

Screenshot 2018-09-28 at 10.43.40.png

Once I’ve selected Github I’m presented with a list of all my repositories for me to select which one I wish to link to my App Center App.

Screenshot 2018-09-28 at 10.45.12.png

In this example, the repository only has one branch so I’ll select that puppy and move onto configuration.

Screenshot 2018-09-28 at 10.46.56.png

Screenshot 2018-09-28 at 10.50.24.png

Build Configuration

We want to do a few things with the build configuration. Number one, it has to sign the build for distribution using my Apple Certificates and secondly I want to increment the version number of the app automatically.

Screenshot 2018-09-28 at 10.51.15.png

Signing builds

In order to sign builds for distribution, we’ll need to upload a copy of our .p12 file and a valid provisioning profile.

Screenshot 2018-09-28 at 10.52.31.png

Incrementing build numbers

App Center has native understanding of our projects info.plist file (thanks to the work they did on supporting iOS) so incrementing the build number only requires a few button clicks to configure.

Screen Recording 2018-09-28 at 10.56 am.gif


We’re almost finished configuring the build process but we’ve one last step to configure and that’s distribution!

By default, the distribution list is a little lonely as it’ll just be you, but as you find people excited to try your apps you can add them to lists and control what versions of the app they get. For example, you might want your VIPs to get GM access and staff to have access to betas.

Screenshot 2018-09-28 at 10.58.42.png

Adding distribution groups

To setup my VIPs distribution list I head over to the “distribution” beacon on the left hand menu and click “Add Group”.

Screenshot 2018-09-28 at 11.08.00.png

Right now I’ve only one VIP and that’s my colleague Dean but this is enough to demonstrate the functionality. It’s worth noting that I need to pop back to the build configuration to update the distribution to VIPs if I want Dean to get a copy of the builds triggered from Master.

Screenshot 2018-09-28 at 11.13.45.png

Distribution email

And with only a few clicks, my users will now get a nice email with a link to install the latest and greatest builds of my app!

Screenshot 2018-09-28 at 11.17.45.png


App Center is a powerful tool for app developers to streamline their development processes from building, distribution to monitoring after release. I hope this post has helped you understand how easy it can be to set up a CI/CD pipeline for macOS apps developed with Swift 4.0. If you’ve any questions or feedback then please don’t hesitate to reach out.

Xamarin with macOS 10.14 (mojave)

It’s that time of year again where we all ask ourselves “should I install this beta software on my devices and risk my development setup?”. If you’ve only one iPhone and Mac then it can be difficult to decide when it’s the right time to install the latest and greatest offerings from Apple, for fear of breaking your development environment.

This year I’ve not needed to be so worried about breaking my environment as my current projects see me developing more with ASP.NET and Swift than Xamarin, so I went ahead and downloaded both iOS 12 and macOS 10.14 as soon as I could.

Screenshot 2018-06-05 at 00.03.18

How does it run?
First impressions of running macOS Mojave and Xamarin are better than expected! I fired up Visual Studio for Mac and opened the workshop myself and Robin-Manuel Thiel created to see if I could get the iOS app to build using Xcode 9. The good news is that it works without any modification assuming you had a working setup before upgrading.

With that said, I have experienced some crashes with resizing VS4Mac but issues are expected at this stage.

Screenshot 2018-06-05 at 00.26.15

If you can avoid it, don’t update just yet if your day-to-day development requires the Xamarin tooling to work. The Xamarin engineers will need some time to test and ensure things work properly as they too have only just downloaded a copy of the OS.

On the other hand, if you simply cannot wait to play with macOS Mojave,  then know that at a minimum, you can continue to build and deploy with the latest beta software from our friends in Cupertino.

– Opinions are my own and not the views of my employer

Consuming Microsoft Cognitive Services with Swift 4

This post is a direct result of a conversation with a colleague in a taxi in Madrid. We were driving to Santiago Bernabéu (the Real Madrid Stadium) to demonstrate to business leaders the power of artificial intelligence.

The conversation was around the ease of use of Cognitive Services for what we call “native native” developers. We refer to those that use Objective-C, Swift or Java as ‘native native’ as frameworks like ReactNative and Xamarin are also native, but we consider these “XPlat Native”. He argued that the lack of Swift SDKs prevented the adoption of our AI services such as our Vision APIs.

I maintained that all Cognitive Service APIs are well documented, and we provide an easy to consume suit of REST APIs, which any Swift developer worth their salt should be able to use with minimal effort.

Putting money where my mouth is

Having made such a statement, it made sense for me to test if my assertion was correct by building a sample app that integrates with Cognitive Services using Swift.

Introducing Bing Image Downloader. A fully native macOS app for downloading images from Bing, developed using Swift 4.

Screen Shot 2018-05-10 at 11.11.55.png

I’ve put the code on Github for you to download and play with if you’re interested in using Cognitive Services within your Swift apps, but I’ll also explain below how I went about building the app.

Where the magic happens

In the interest of good development practices, I started by creating a Protocol (C# developers should think of these as Interfaces) to define what functions the ImageSearch class will implement.


protocol ImageServiceProtocol {
// We will take the results and add them to hard-coded singleton class called AppData. 
func searchForImageTerm(searchTerm : String)

// We pass in a completion handler for processing the results of this func
func searchForImageTerm(searchTerm : String, completion : @escaping ([ImageSearchResult]) -> ())

Two Implementations for one problem

I’ve made sure to include two implementations to give you options on how you’d want to interact with Cognitive Services. The approach used in the App makes use of the Singleton class for storing AppData as well as using Alamofire for handling network requests. We’ll look at this approach first.

search For Image Term

This is the public func, which is easiest to consume.

func searchForImageTerm(searchTerm : String) {

    //Search for images and add each result to AppData .background).async {
        let totalPics = 100
        let picsPerPage = 50 
        let numPages = totalPics / picsPerPage 
        (0 ..< numPages)             
            .compactMap { self.createUrlRequest(searchTerm: searchTerm, pageOffset: $0 }             
            .foreach{ self.fetchRequest(request: $0 as NSURLRequest) }             } 

create Url Request

private func createUrlRequest(searchTerm : String, pageOffset : Int) -> URLRequest {

    let encodedQuery = searchTerm.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)!
    let endPointUrl = ""

    let mkt = "en-us"
    let imageType = "photo"
    let size = "medium" 

    // We should move these variables to app settings
    let imageCount = 100
    let pageCount = 2
    let picsPerPage = totalPics / picsPerPage 

    let url = URL(string: "\(endPointUrl)?q=\(encodedQuery)&count=\(picsPerPage)&offset=\(pageOffset * picsPerPage)&mkt=\(mkt)&imageType=\(imageType)&size=\(size)")!
    var request = URLRequest(url: url)
    request.setValue(apiKey, forHTTPHeaderField: "Ocp-Apim-Subscription-Key")
    return request

fetch Request

This is where we attempt to fetch and parse the response from Bing. If we detect an error, we log it (I’m using SwiftBeaver for logging).

If the response contains data we can decode, we’ll loop through and add each result to our AppData singleton instance.

private func fetchRequest(request : NSURLRequest){
    //This task is responsbile for downloading a page of results
    let task = URLSession.shared.dataTask(with: request as URLRequest){ (data, response, error) -> Void in
    //We didn't recieve a response
    guard let data = data, error == nil, response != nil else {
        self.log.error("Fetch Request returned no data : \(request.url?.absoluteString)")
    //Check the response code
    guard let httpResponse = response as? HTTPURLResponse,
        (200...299).contains(httpResponse.statusCode) else {
        self.handleServerError(response : response!)
    //Convert data to concrete type
        let decoder = JSONDecoder()
        let bingImageSearchResults = try decoder.decode(ImageResultWrapper.self, from: data)
        let imagesToAdd = bingImageSearchResults.images.filter { $0.encodingFormat != EncodingFormat.unknown }
        } catch {
            self.log.error("Error decoding ImageResultWrapper : \(error)")
            self.log.debug("Corrupted Base64 Data: \(data.base64EncodedString())")
     //Tasks are created in a paused state. We want to resume to start the fetch.

Option two (with no 3rd party dependancies)

As a .NET developer, the next approach threw me for a while and took a little bit of reading about Closures to fully grasp. With this approach, I wanted to return an Array of ImageSearchResult type, but this proved not to be the best approach. Instead, I would need to pass in a function that can handle the array of results instead.

// Search for images with a completion handler for processing the result array
func searchForImageTerm(searchTerm : String, completion : @escaping ([ImageSearchResult]) -> ()) {
    //Because Cognitive Services requires a subscription key, we need to create a URLRequest to pass into the dataTask method of a URLSession instance..
    let request = createUrlRequest(searchTerm: searchTerm, pageOffset: 0)
    //This task is responsbile for downloading a page of results
    let task = URLSession.shared.dataTask(with: request, completionHandler: { (data, response, error) -> Void in
    //We didn't recieve a response
    guard let data = data, error == nil, response != nil else {
        print("something is wrong with the fetch")
    //Check the response code
    guard let httpResponse = response as? HTTPURLResponse,
    (200...299).contains(httpResponse.statusCode) else {
        self.handleServerError(response : response!)
    //Convert data to concrete type
        let decoder = JSONDecoder()
        let bingImageSearchResults = try decoder.decode(ImageResultWrapper.self, from: data)
        //We use a closure to pass back our results.
    } catch { self.log.error("Decoding ImageResultWrapper \(error)") }

Wrapping Up

You can find the full project on my Github page which contains everything you need to build your own copy of this app (maybe for iOS rather than macOS?).

If you have any questions, then please don’t hesitate to comment or email me!


How to fix the IPv4 loopback interface: port already in use error.

Super quick post here. Sometimes when debugging your .NET Core application on Mac, you’ll find the port won’t free up, and thus you can’t redeploy without getting the following fatal error:

Unable to start Kestrel. System.IO.IOException: Failed to bind to address http://localhost:5000 on the IPv4 loopback interface: port already in use.

To fix this, you’ll need to fire up Terminal and enter the following:

sudo lsof -i :5000

In my case, this outputted the following:

Screen Shot 2017-10-20 at 18.54.54.png

I know the error is referencing the IPv4 Type which allows me to quickly find the PID number, which I’ll use to kill the connection. I do this with the following command

kill -9 18057

With that done, I can now get back to debugging my .NET Core web API on macOS.

App Services Custom Domain, SSL & DNS

We’ve all seen tutorials which demonstrate how to deploy a simple todo list backend to Azure but how many have you read that go onto secure it? In this post, I’m going to cover how I’m securing the Bait News v2 backend infrastructure as well as covering how to configure custom domains.

Why bother?

Apple announced in 2015 that Apps and their corresponding backend servers would need to support App Transport Security (ATS).

ATS was introduced with iOS 9 as a security enhancement to ensure all connections by apps use HTTPs. Initially slated to go into effect for all new app store submissions from January 2017, it has since been postponed with no update on when it’ll be coming into effect. Although the requirement has been delayed, it’s still something that all app developers should be implementing as it provides our users with added security, making man in the middle attacks impossible to go unnoticed.

Historically, you’ll see most developers (including myself), opt to turn ATS off to make our lives easier. Some will take a lighter touch and only disable ATS for a single domain (they’re backend) which is not much more secure than turning ATS off altogether. Either approach opens up your users and data to attack and should be avoided.

So what do we need to do to secure our app? Lets first register a domain for our backend.

Custom Domains


I’ve been using 123-Reg as my domain registrar for 10 years and continue to use them as I migrate my websites to Azure. Most domain registrars will also provide some basic DNS functionality but you would normally want to use a 3rd party DNS Service for more advance situations. In my case, I’m using 123-Regs DNS service and have added a number of CNAMEs pointing to Azure.

Adding records

Below you see the minimum required records needed to enable my custom domain.

Permanent Records

Screen Shot 2017-09-02 at 15.20.53

Temporary Records

Screen Shot 2017-09-02 at 15.32.15

To get started, I have added an A record pointing to the App Service instance using its IP address. You can find your App Service IP address by going into it’s Custom Domain blade within the Azure portal.

Once you’ve added the A record, you can then create the CNAME which will map www requests to your backends url. You can find your destination in the Overview blade of the App Service.

Verify Domain Ownership

Azure needs to know I own the domain I’m trying to map. To prove this, I’ll add two records to my DNS settings which are the temporary records listed above.

Once I’ve added the verify CNAME records, I can save and sit tight. DNS Records need to propagate across the globe, which can take up to 24 hours.

This is end result of what my DNS setting configuration looked like. I also created some CNAMEs to redirect traffic from subdomains to other Azure services.

Screen Shot 2017-08-17 at 11.50.36

Portal Configuration

To finish off, I need to configure the App Service Custom Domain settings.

Screen Shot 2017-09-02 at 15.53.03.png

Hit the ‘Add Hostname’ button and enter the custom domain.

Screen Shot 2017-09-02 at 15.54.03

After hitting Validate, Azure will check the DNS records to confirm the domain exists and that you own it. You should see something like this.

Screen Shot 2017-09-02 at 15.55.53

Hitting ‘Add hostname’ will complete the process of configuring a custom domain for your App Service. If you’re deploying a mobile backend, you may want to create CNAME record which maps to your mobile backend and whilst keeping mapped to a ASP.NET website.

Adding Security

SSL Certificates

As mentioned at the start of this post, enabling HTTPS prevents MITM attacks and ensures your communication between server and client is secure. Its pretty straight forward to enable within App Services but much like DNS, it can take a while (but this time its human factors rather than waiting for computers to sync up).

First things first, You’ll need to purchase a certificate.  I opted to 123-Reg as they provide a few options to meet most users requirements and its integration with my domain management make it a no brainer to use.

I should admit that I did make a mistake when I first purchase a certificate, which caused a few days of delays, so its important to double check the type of certificate you’re purchasing. I had purchased a certificate which was for only This mean that my mobile api of couldn’t use the certificate. 123-Reg refunded the first certificate and I tried again, but this time making sure to purchase a certificate which support unlimited subdomains. You can see below the original certificate has been revoked and the new certificate supports wildcards.

When you apply for a certificate, you’ll be provided a download which includes your certificate request (CSR) in a PEM format. You also get the private key which you’ll use later to create a new certificate.

Screen Shot 2017-09-02 at 16.13.32

Once you’ve been issued the certificate, you’re ready to create a new certificate which you’ll use in Azure for everything. This is a pretty easy process as we can use OpenSSL on almost any platform. I’m on a Mac but this works the same on both Windows and Linux.

openssl pkcs12 -export -out baitnews.pfx -inkey
/Users/michaeljames/Downloads/SSL-CSR5/private-key.key -in



  • [Output file name] -| What do you want to call the certificate?
  • [private-key.key path] The location of the private key. This would have been provided when requesting the certificate.
  • [wildcard.cert path] The location of the freshly issued certificate.

Once you press enter, you’ll need to type in a couple of passwords and then you’ll be set. It’ll look something like this:

Screen Shot 2017-09-02 at 16.38.43

You now have your certificate ready for uploading to Azure. The conversion of certificates isn’t the easiest of procedures to wrap your head around on the first few goes. If you’re worried about this step then keep in mind you can purchase SSL certificates through the Azure Portal, which skips many of the above steps! It does however add a small premium to the cost involved in securing your backend as you’ll find the certificate a little more expensive but your also required to store it in KeyVault.

Binding Domains with Certificates

Lets upload our new certificate to our App Service. To do this, head over to SSL Certificate blade and hit ‘Upload Certificate’. You’ll need to provide the password used to create the certificate.

Screen Shot 2017-09-07 at 12.26.17.png

If successful, you’ll see your certificate as been imported and is ready to use with your custom domains.

Screen Shot 2017-09-07 at 12.29.33.png

Add Binding

The last step is to bind out SSL certificate with our custom domain. Clicking ‘Add Binding’ will allow you to select both the custom domain and SSL from a drop down.

Screen Shot 2017-09-07 at 12.29.40

Hitting Add Binding will finish the process. You now have a custom domain mapped your App Service instance that supports HTTPS. Any users visiting your backend will be greeted  with the familiar green padlock in the address bar.

Screen Shot 2017-09-07 at 12.31.59.png

Wrapping Up

Adding custom domains and enabling secure connectivity between your mobile app and backend is extremely simple and theres no good reason not to enable it (unless you’re hacking on a demo or POC).

In the next post I’m going to cover how to expand our setup to to route traffic to the nearest App Service instance.