Hello.

I am Paul Kinlan.

A Developer Advocate for Chrome and the Open Web at Google.

Puppeteer Go🔗

Paul Kinlan

I love Puppeteer - it lets me play around with the ideas of The Headless Web - that is running the web in a browser without a visible browser and even build tools like DOM-curl (Curl that runs JavaScript). Specifically I love scripting the browser to scrape, manipulate and interact with pages.

One demo I wanted to make was inspired by Ire’s Capturing 422 live images post where she ran a puppeteer script that would navigate to many pages and take a screenshot. Instead of going to many pages, I wanted to take many screenshots of elements on the page.

The problem that I have with Puppeteer is the opening stanza that you need to do anything. Launch, Open tab, navigate - it’s not complex, it’s just more boilerplate than I want to create for simple scripts. That’s why I created Puppeteer Go. It’s just a small script that helps me build CLI utilities easily that opens the browser, navigates to a page, performs your action and then cleans up after itself.

Check it out.

const { go } = require('puppeteer-go');

go('https://paul.kinlan.me', async (page) => {
    const elements = await page.$$("h1");
    let count = 0;
    for(let element of elements) {
      try {
        await element.screenshot({ path: `${count++}.png`});
      } catch (err) {
        console.log(count, err);
      }
    }
});

The above code will find the h1 element in my blog and take a screenshot. This is nowhere near as good as Ire’s work, but I thought it was neat to see if we can quickly pull screenshots from canisuse.com directly from the page.

const { go } = require('puppeteer-go');

go('https://caniuse.com/#search=css', async (page) => {
    const elements = await page.$$("article.feature-block.feature-block--feature");
    let count = 0;
    for(let element of elements) {
      try {
        await element.screenshot({ path: `${count++}.png`});
      } catch (err) {
        console.log(count, err);
      }
    }
});
4.png
3.png
2.png
1.png
0.png

Enjoy!

Picture of me smiling.

Paul Kinlan

Trying to make the web and developers better.

RSS Github Medium

A simple video insertion tool for EditorJS🔗

Paul Kinlan

I really like EditorJS. It’s let me create a very simple web-hosted interface for my static Hugo blog.

EditorJS has most of what I need in a simple block-based editor. It has a plugin for headers, code, and even a simple way to add images to the editor without requiring hosting infrastructure. It doesn’t have a simple way to add video’s to the editor, until now.

I took the simple-image plugin repository and changed it up (just a tad) to create a simple-video plugin (npm module). Now I can include videos easily in this blog.

If you are familar with EditorJS, it’s rather simple to include in your projects. Just install it as follows

npm i simple-video-editorjs

And then just include it in your project as you see fit.

const SimpleVideo = require('simple-video-editorjs');

var editor = EditorJS({
  ...
  
  tools: {
    ...
    video: SimpleVideo,
  }
  
  ...
});

The editor has some simple options that let you configure how the video should be hosted in the page:

  1. Autoplay - will the video play automatically when the page loads
  2. muted - will the video not have sound on by default (needed for autoplay)
  3. controls - will the video have the default HTML controls.

Below is a quick example of a video that is embedded (and showing some of the options).

Anyway, I had fun creating this little plugin - it was not too hard to create and about the only thing that I did was defer the conversion to base64 which simple-images uses and instead just use the Blob URLs.

Test post Video upload

Friendly Project Name Generator with Zeit🔗

Paul Kinlan

I’ve got some ideas for projects that make it easier to create sites on the web - one of the ideas is to make a netlify-like drag and drop interface for zeit based projects (I like zeit but it requires a tiny bit of cli magic to deploy).

This post covers just one small piece of the puzzle: creating project names.

Glitch is a good example of this, when you create a project it gives it a whimsical randomly generated name. The team also created a good dictionary of fairly safe words that combine well (and if you want they have a simple server to host).

So, the side project this Sunday was to create a simple micro-service to generate random project names using Zeit’s serverless-functions and the dictionary from Glitch.

And here it is (code), it’s pretty short and not too complex.

const words = require("friendly-words");

function generate(count = 1, separator = "-") {
  const { predicates, objects } = words;
  const pCount = predicates.length;
  const oCount = objects.length;
  const output = [];

  for (let i = 0; i < count; i++) {
    const pair = [predicates[Math.floor(Math.random() * pCount)], objects[Math.floor(Math.random() * oCount)]];
    output.push(pair.join(separator));
  }

  return output;
}

module.exports = { generate }

If you don’t want to include it in your project directly, you can use the HTTP endpoint to generate random project names (in the form of “X-Y”) by making a web request to https://friendly-project-name.kinlan.now.sh/api/names, which will return something like the following.

["momentous-professor"]

You can also control how many names to generate with the a query-string parameter of count=x, e.g. https://friendly-project-name.kinlan.now.sh/api/names?count=100

["melon-tangerine","broad-jury","rebel-hardcover","far-friend","notch-hornet","principled-wildcat","level-pilot","steadfast-bovid","holistic-plant","expensive-ulna","sixth-gear","political-wrench","marred-spatula","aware-weaver","awake-pair","nosy-hub","absorbing-petunia","rhetorical-birth","paint-sprint","stripe-reward","fine-guardian","coconut-jumbo","spangle-eye","sudden-euphonium","familiar-fossa","third-seaplane","workable-cough","hot-light","diligent-ceratonykus","literate-cobalt","tranquil-sandalwood","alabaster-pest","sage-detail","mousy-diascia","burly-food","fern-pie","confusion-capybara","harsh-asterisk","simple-triangle","brindle-collard","destiny-poppy","power-globeflower","ruby-crush","absorbed-trollius","meadow-blackberry","fierce-zipper","coal-mailbox","sponge-language","snow-lawyer","adjoining-bramble","deserted-flower","able-tortoise","equatorial-bugle","neat-evergreen","pointy-quart","occipital-tax","balsam-fork","dear-fairy","polished-produce","darkened-gondola","sugar-pantry","broad-slouch","safe-cormorant","foregoing-ostrich","quasar-mailman","glittery-marble","abalone-titanosaurus","descriptive-arch","nickel-ostrich","historical-candy","mire-mistake","painted-eater","pineapple-sassafras","pastoral-thief","holy-waterlily","mewing-humor","bubbly-cave","pepper-situation","nosy-colony","sprout-aries","cyan-bestseller","humorous-plywood","heavy-beauty","spiral-riverbed","gifted-income","lead-kiwi","pointed-catshark","ninth-ocean","purple-toucan","tundra-cut","coal-geography","icy-lunaria","agate-wildcat","respected-garlic","polar-almandine","periodic-narcissus","carbonated-waiter","lavish-breadfruit","confirmed-brand","repeated-period"]

You can control separator with the a query-string parameter of separator. i.e, separator=@ , e.g. https://friendly-project-name.kinlan.now.sh/api/names?separator=@

["handsomely@asterisk"]

A very useful aspect of this project is that if a combination of words tends towards being offensive, it is easy to update the Glitch repo to ensure that it doesn’t happen again.

Assuming that the project hosting doesn’t get too expensive I will keep the service up, but feel free to clone it yourselves if you ever want to create a similar micro-service.

Live example

What follows is a super quick example of the API in action.

const render = (promise, elementId) => {
  promise.then(async(response) => {
    const el = document.getElementById(elementId);
    el.innerText = await response.text();
  })
};


onload = () => {
  render(fetch("https://friendly-project-name.kinlan.now.sh/api/names"), "basic");
  render(fetch("https://friendly-project-name.kinlan.now.sh/api/names?count=100"), "many");
  render(fetch("https://friendly-project-name.kinlan.now.sh/api/names?separator=@"), "separator");
}

Single response


Many resposnses


Custom separators









  
        
      

Frankie and Bennys: Pay for your meal via the web

Paul Kinlan

Whenever I see a restaurant say that you can pay on mobile, I always check it out, mostly so I can bemoan the fact that you need to use an app. Imagine my surprise when the QR code lead to a web-based payments flow….. and it worked. Awesome work Frankie and Benny’s! At this point, I did select Google Pay, but it didn’t work (email internally sent!

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Podroll

Adding "dark mode" to my blog

Paul Kinlan

I saw Jeremy Keith’s post about adding dark mode to his blog and it seemed simple, so I decided to give it a whirl. Here is the diff of the work for all to see. It was surprisingly easy (outside of silly errors on my part). There was a small refactor to support CSS variables and ensuring I have fallback if there’s a browser that doesn’t support CSS custom properties, but that is about it.

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Using Web Mentions in a static site (Hugo)

Paul Kinlan

My blog is an entirely static site, built with Hugo and hosted with Zeit. This is a great solution for me, a simple blog has a pretty simple deployment process and it loads blazingly fast. Statically generated sites do have some drawbacks, the largest is when you need anything dynamic to be integrated into your page (comments for example). Not being able to easily host dynamic content will mean that you end up relying on 3rd party JavaScript that will then get full access to your page and you won’t know what it is doing - it could be tracking your users or slowing down your page load.

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Creating a pop-out iframe with adoptNode and "magic iframes"

Paul Kinlan

Update: 8th October - Significant issues with this doc. I caught up with Jake Archibald about this post because I thought I had something novel, during the conversation we uncovered a lot of things that make some of this post invalid, and I also learnt a lot in the process that I don’t think most developers know. Calling .append() and .appendChild() adopt the node. This makes the usage of adoptNode in this instance useless because the append Algorithm ensures that the node is adopted.

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Meatspace Augmented Reality: From Chester to Nagoya

Paul Kinlan

Some thoughts on AR after finding some during my travels. TL;DR - cheaper content creation and better discovery tools are needed.

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Photos from Carlisle Castle

Paul Kinlan

I recently went on holiday with the boys and we swung past Carlisle Castle (birthplace of the world rebound Jake Archibald). It is one of the better castles that we’ve been to in the UK and I would heartily recommend spending some time visiting it if you are in the area. I didn’t how significant the role was that Carlisle Castle played in the history of the England and Scotland, and it was great to find out more whilst we were there.

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Idle observation: Indexing text in images

Paul Kinlan

I was out with the boys in Llangollen the other day (it’s a beautiful town) and I was taking pictures of the informational signs containing some of the history of the area so that I could read it later, and I thought that I would look on the web to see if the information was available for more than just the people walking past the sign - and it’s not. I then got thinking about the leaflets, the content in them is nearly impossible to find on the web.

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Liverpool World Museum

Paul Kinlan

I took the kids to the Liverpool World History Museum the other week, it was pretty neat. The Space and Time section has not changed in about 30 years, a large section of the Bug enclosure was closed off, and the Aquarium seemed a tad smaller than I remember. The Egyptian section was open (it wasn’t when I last went) and it was rather awesome.

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Bookstore - Llangollen

Paul Kinlan

I love this place, it’s on top of a cafe in Llangollen. I came here with my grandparents nearly 30 years ago and it’s pretty much the same now. My only wish is that there was even more Commix books - I swear there was a heap more when I was a kid. Check it out

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Webmention.app🔗

Paul Kinlan

I love the idea of Webmentions, yet I’ve not had the time to implement it on my site. At a high-level web mentions let you comment, like and reply to other content on the web and have it be visible to that content without being centralised with tools like Disqus (which I am keen to remove from my site).

Web Mentions are split in to two components, the sender and the receiver. The receiver is the site that I am writing a post about and they might have something on their site that shows inbound links or reactions to their blog; and the sender is, well, me. I need to let the remote site that I have written or reacted to some content that they have created.

The rather awesome Remy Sharp created webmention.app to solve one part of the problem: sending pings. Remy’s tool  makes it easy to send ‘pings’ to potential receivers that I have linked to, by simply calling a CLI script.

I host my blog using Zeit using Hugo and the static-builder tool, so it was relatively trivial for me to add in support for webmention app. I just npm i webmention and then call the CLI version of the tool from my build.sh file - it really is that simple.

Now when I create a post, it should send a quick ping to all new URL’s that I have created some content about their site.

Creating a commit with multiple files to Github with JS on the web

Paul Kinlan

My site is entirely static. It’s built with Hugo and hosted with Zeit. I’m pretty happy with the setup, I get near instant builds and super fast CDN’d content delivery and I can do all the things that I need to because I don’t have to manage any state. I’ve created a simple UI for this site and also my podcast creator that enables me to quickly post new content to my statically hosted site.

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Screen Recorder: recording microphone and the desktop audio at the same time🔗

Paul Kinlan

I have a goal of building the worlds simplest screen recording software and I’ve been slowly noodling around on the project for the last couple of months (I mean really slowly).

In previous posts I had got the screen recording and a voice overlay by futzing about with the streams from all the input sources. One area of frustration though was that I could not work out how to get the audio from the desktop and overlay the audio from the speaker. I finally worked out how to do it.

Firstly, getDisplayMedia in Chrome now allows audio capture, there seems like an odd oversight in the Spec in that it did not allow you to specify audio: true in the function call, now you can.

const audio = audioToggle.checked || false;
desktopStream = await navigator.mediaDevices.getDisplayMedia({ video:true, audio: audio });

Secondly, I had originally thought that by creating two tracks in the audio stream I would be able to get what I wanted, however I learnt that Chrome’s MediaRecorder API can only output one track, and 2nd, it wouldn’t have worked anyway because tracks are like the DVD mutliple audio tracks in that only one can play at a time.

The solution is probably simple to a lot of people, but it was new to me: Use Web Audio.

It turns out that WebAudio API has createMediaStreamSource and createMediaStreamDestination, both of which are API’s needed to solve the problem. The createMediaStreamSource can take streams from my desktop audio and microphone, and by connecting the two together into the object created by createMediaStreamDestination it gives me the ability to pipe this one stream into the MediaRecorder API.

const mergeAudioStreams = (desktopStream, voiceStream) => {
  const context = new AudioContext();
    
  // Create a couple of sources
  const source1 = context.createMediaStreamSource(desktopStream);
  const source2 = context.createMediaStreamSource(voiceStream);
  const destination = context.createMediaStreamDestination();
  
  const desktopGain = context.createGain();
  const voiceGain = context.createGain();
    
  desktopGain.gain.value = 0.7;
  voiceGain.gain.value = 0.7;
   
  source1.connect(desktopGain).connect(destination);
  // Connect source2
  source2.connect(voiceGain).connect(destination);
    
  return destination.stream.getAudioTracks();
};

Simples.

The full code can be found on my glitch, and the demo can be found here: https://screen-record-voice.glitch.me/

Extracting text from an image: Experiments with Shape Detection🔗

Paul Kinlan

I had a little down time after Google IO and I wanted to scratch a long-term itch I’ve had. I just want to be able to copy text that is held inside images in the browser. That is all. I think it would be a neat feature for everyone.

It’s not easy to add functionality directly into Chrome, but I know I can take advantage of the intent system on Android and I can now do that with the Web (or at least Chrome on Android).

Two new additions to the web platform - Share Target Level 2 (or as I like to call it File Share) and the TextDetector in the Shape Detection API - have allowed me to build a utility that I can Share images to and get the text held inside them.

The basic implementation is relatively straight forwards, you create a Share Target and a handler in the Service Worker, and then once you have the image that the user has shared you run the TextDetector on it.

The Share Target API allows your web application to be part of the native sharing sub-system, and in this case you can now register to handle all image/* types by declaring it inside your Web App Manifest as follows.

"share_target": {
  "action": "/index.html",
  "method": "POST",
  "enctype": "multipart/form-data",
  "params": {
    "files": [
      {
        "name": "file",
        "accept": ["image/*"]
      }
    ]
  }
}

When your PWA is installed then you will see it in all the places where you share images from as follows:

The Share Target API treats sharing files like a form post. When the file is shared to the Web App the service worker is activated the fetch handler is invoked with the file data. The data is now inside the Service Worker but I need it in the current window so that I can process it, the service knows which window invoked the request, so you can easily target the client and send it the data.

self.addEventListener('fetch', event => {
  if (event.request.method === 'POST') {
    event.respondWith(Response.redirect('/index.html'));
    event.waitUntil(async function () {
      const data = await event.request.formData();
      const client = await self.clients.get(event.resultingClientId || event.clientId);
      const file = data.get('file');
      client.postMessage({ file, action: 'load-image' });
    }());
    
    return;
  }
  ...
  ...
}

Once the image is in the user interface, I then process it with the text detection API.

navigator.serviceWorker.onmessage = (event) => {  
  const file = event.data.file;
  const imgEl = document.getElementById('img');
  const outputEl = document.getElementById('output');
  const objUrl = URL.createObjectURL(file);
  imgEl.src = objUrl;
  imgEl.onload = () => {
    const texts = await textDetector.detect(imgEl);
    texts.forEach(text => {
      const textEl = document.createElement('p');
      textEl.textContent = text.rawValue;
      outputEl.appendChild(textEl);
    });
  };
  ...
};

The biggest issue is that the browser doesn’t naturally rotate the image (as you can see below), and the Shape Detection API needs the text to be in the correct reading orientation.

I used the rather easy to use EXIF-Js library to detect the rotation and then do some basic canvas manipulation to re-orientate the image.

EXIF.getData(imgEl, async function() {
  // http://sylvana.net/jpegcrop/exif_orientation.html
  const orientation = EXIF.getTag(this, 'Orientation');
  const [width, height] = (orientation > 4) 
                  ? [ imgEl.naturalWidth, imgEl.naturalHeight ]
                  : [ imgEl.naturalHeight, imgEl.naturalWidth ];

  canvas.width = width;
  canvas.height = height;
  const context = canvas.getContext('2d');
  // We have to get the correct orientation for the image
  // See also https://stackoverflow.com/questions/20600800/js-client-side-exif-orientation-rotate-and-mirror-jpeg-images
  switch(orientation) {
    case 2: context.transform(-1, 0, 0, 1, width, 0); break;
    case 3: context.transform(-1, 0, 0, -1, width, height); break;
    case 4: context.transform(1, 0, 0, -1, 0, height); break;
    case 5: context.transform(0, 1, 1, 0, 0, 0); break;
    case 6: context.transform(0, 1, -1, 0, height, 0); break;
    case 7: context.transform(0, -1, -1, 0, height, width); break;
    case 8: context.transform(0, -1, 1, 0, 0, width); break;
  }
  context.drawImage(imgEl, 0, 0);
}

And Voila, if you share an image to the app it will rotate the image and then analyse it returning the output of the text that it has found.

It was incredibly fun to create this little experiment, and it has been immediately useful for me. It does however, highlight the inconsistency of the web platform. These API’s are not available in all browsers, they are not even available in all version of Chrome - this means that as I write this article Chrome OS, I can’t use the app, but at the same time, when I can use it… OMG, so cool.

Small shrine in Engakuji Temple near Kamakura

Paul Kinlan

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Wood Carving found in Engakuji Shrine near Kamakura