Creating a 4G router using a Raspberry Pi and a mobile phone

A few days ago these workmen were using cutting machinery dangerously close to my broadband cables:

Shortly after this picture was taken – bang! No internet! They cut the cables while doing their work!

Two adults working from home on back to back video calls, one high-schooler also on video classes, and one primary-schooler with streaming classes – all suddenly disconnected from the world!

That afternoon we huddled around the kitchen table, mobile phones on with hotspots enabled to get through the rest of the day – but this wouldn’t work for regular use.

The broadband company said it wouldn’t be fixed for weeks due to how badly everything was damaged; the pavement would have to come up! I had to think of a pragmatic solution.

In this article I’ll go through the steps I took to completely swap my home broadband for a Raspberry Pi and a spare mobile phone – and show the results!

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Setting up an Android phone as a WebPageTest agent

Pixel 2 connected to a raspberry pi

Running detailed website performance tests is often necessary to understand how a website is experienced by an end user in order to identify opportunities for improvements.

WebPageTest.org gives us the ability to run these tests from all over the world – the public instance even gives us access to real devices, so we can check how a site works across different browsers on different versions of different operating systems on different real devices!

In my previous articles I explained how to easily set up your very own private, autoscaling, WebPageTest server. This private instance creates test agents in AWS, dotted around AWS regions, which can emulate a mobile browser; this uses the device emulation in Chrome to throttle network, CPU, memory, etc and change the available screen size.

While this mobile emulation is simple to set up and use, sometimes an emulator isn’t enough; device-specific edge cases, operating system limitations, and performance on a real device may need to be validated to get confidence that everything works as expected in the real world.

In this article I’ll show you how to set up an Android phone as your own WebPageTest agent to connect to your private WebPageTest server, controlled by a Raspberry Pi!

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AI Awesomeness: 2020 Update! Microsoft Cognitive Services Speaker Recognition API

A while back I showed how to use the Microsoft Speaker Recognition APIs in the simplest way I could think of; using a web page to record audio and call the various APIs to set up and test Speaker Verification and Speaker Identification.

Honestly, the hardest part of this by far was getting the audio recorded in the correct format for the APIs to accept! I hacked the wonderful recorderjs from Matt Diamond to set the correct bitrate, channels, etc, and eventually got there through trial and error (and squinting at the minified source code of the Microsoft demo page)!

In the run up to //Build this year, there have been a lot of changes in the Microsoft AI space.

One of these changes managed to break my existing Speaker Recognition API applications (it’s still in Preview, so don’t be surprised!) by moving Speaker Recognition under the Speech Service project, slightly changing the APIs and their endpoints, and adding new functionality (exciting!)

In this article I’ll show the same web page implementation, but use the updated 2020 Speaker Recognition APIs, and introduce the new Verification API that doesn’t rely on a predefined list of passphrases.

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Customized WebPageTest Lighthouse Results using a Custom Test Agent

In my recent article Eco Worriers: Saving the Planet, One Unoptimized Website at a Time for the fantastic annual Perf Planet advent calendar, I mentioned how I created a Private WebPageTest setup to use my own custom test agents, which were configured to use an extra Lighthouse plugin (The Green Web Foundation’s "greenhouse").

In this article I’ll show how to create custom WebPageTest agents, and how to configure your Private WebPageTest instance to use these instead of the default test agents.

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Automating WebPageTest using the nodejs webpagetest-api package

WebPageTest-api NodeJS

Hopefully you’ve already had a chance to play around with the amazing WebPageTest during your website performance testing adventure so far.

In case not, I have a few articles you might like to browse, to help you get up to speed using this fantastic, free, open source, website performance testing tool.

It has a website interface and also an API, which I went through in the previous article.

In this article I’ll show you how to use the incredible webpagetest-api nodejs package to make the orchestration and automation of your WebPageTest setup even easier!

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Automating WebPageTest via the WebPageTest API

webpagetest robots

WebPageTest is incredible. It allows us to visit a web page, enter a few values and then produce performance results from any destination around the world. Best of all, you can do this in many different possible browser configurations; even on many different real devices.

If you’re doing this a lot, then using that simple web form can become the bottleneck to rapidly iterating on your web performance improvements.

In this article I’ll show you how to easily execute your web performance tests in a simple, repeatable, automated way using the WebPageTest API.

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A Step by Step Guide to using Terraform to define an AutoScaling Private WebPageTest instance in code

WebPagetest Terraform

In a previous article I went through the steps needed to create your own private, autoscaling, WebPageTest setup in Amazon AWS. It wasn’t particularly complicated, but it was quite manual; I don’t like pointing and clicking in a GUI since I can’t easily put it in version control and run it again and again on demand.

Fortunately, whatever you create within AWS can be described using a language called CloudFormation which allows you to define your infrastructure as code.

Unfortunately it’s not easy to understand (in my opinion!) and I could never quite get my head around it, which annoyed me no end.

In this article I’ll show you how to use Terraform to define your private autoscaling WebPageTest setup in easily understandable infrastructure as code, enabling an effortless and reproducable web performance testing setup, which you can then fearlessly edit and improve!

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A Step by Step Guide to setting up an AutoScaling Private WebPageTest instance

If you have any interest in website performance optimisation, then you have undoubtedly heard of WebPageTest. Being able to test your websites from all over the world, on every major browser, on different operating systems, and even on physical mobile devices, is the greatest ever addition to a web performance engineer’s toolbox.

One small shelf of Pat Meenan's epic WebPageTest device lab

The sheer scale of WebPageTest, with test agents literally global (even in China!), of course means that queues for the popular locations can get quite long – not great when you’re in the middle of a performance debug session and need answers FAST!

Also since these test agents query your website from the public internet they won’t be able to hit internal systems – for example pre-production or QA, or even just a corporate intranet that isn’t accessible outside of a certain network.

In this article I’ll show you how to set up your very own private instance of WebPageTest in Amazon AWS with autoscaling test agents to keep costs down

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AI Awesomeness Part Deux! Microsoft Cognitive Services Speaker Identification

The Speaker Recognition API: AI Awesomeness

In a recent article I introduced Microsoft Cognitive Services’ Speaker Verification service, using a recording of a person repeating one of a set of key phrases to verify that user by their voiceprint.

The second main feature of the Speaker Recognition API is Speaker Identification, which can compare a piece of audio to a selection of voiceprints and tell you who was talking! For example, both Barclays and HSBC banks have investigated using passive speaker identification during customer support calls to give an added layer of user identification while you’re chatting to customer support. Or you could prime your profiles against all the speakers in a conference, and have their name automatically appear on screen when they’re talking in a panel discussion.

In this article I’m going to introduce you to the Speaker Identification API from the Cognitive Services and go through an example of using it for fun and profit! Though mainly fun.

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