Generating and parsing data URI's in Ruby

I'm fond of data-URI's (MDN Link). 12 years ago I reappropriated a tool that stored a webpage with its related resources in a Microsoft specific format and rewrote it into something that would store it in normal HTML where the related resources were encoded in data URI's. Recently the topic came up again at a project I was working in, where microservices are still a thing. And while discussing it with colleagues it seemed as if knowledge about this quite useful URI-scheme wasn't on top of everyone else's mind. Instead, the original idea was, we could upload the resource to S3, pass the link, download the resource from S3 at the receiving end, and then have some policy that takes care of deleting it… nah…

data-URI: The basics

This is the most simple data-URI:

data:,Hello%2C%20World%21

You [can open it in your browser](dat…

Resizing images before upload

The resolution of photo's increases every year. And while some of that information may be worthy of retaining, not all is. High resolution images come at a price. Not only storage, but, especially in a mobile context, also data transfer. In this post I explain how you could create an uploader that fixes this.

The old form

Traditionally your form would look something like this:

`
  Upload image:
  
  
`

If you want to be forgiving to your end users (and not requiring them to manually resize the images themselves) you could configure your server to accept files > 20MB and resize the images server side.

However, to save bandwidth you you might want to resize the images just before uploading.

Enter canvas

To manipulate pixels we need a canvas. So we need a canvas element.

Note: Canvas support is barely an issue, but if things don’t work we’ll write to code as such that the traditional form submit will continue to work

...