Server side QR code rendering

[kylerwsm]

Problem

• To enable QR codes to be generated on the backend server side.
• Upgrade the QR code to that of v2 designs.
• Use SVG rather than PNG for Go logo for better resolution.
• Part of Email QR code to self #57.
• Closes Bundle QR code with link in same image #56.
• Closes Problem with PNG downloads on IE11 #124.

Solution

I am using jsdom as an alternative dom for node, and d3 to draw our GoGovSg logo on the generated QR code generated from the qrcode library.

TODO

• Generate SVG QR code
• Generate PNG QR code
• Generate JPEG QR code
• Write test for QR code
• Add validation using Joi
• Add short url into QR code
• QR codes can only be generated if user is signed in
• Only QR codes of existing links can be generated

After

Tests

• Download QR code on modern browsers locally
• Download QR code on IE11 locally
• Download QR code on modern browsers on staging
• Download QR code on IE11 on staging

Deploy Notes

New dependencies:

• d3 : To add our Go QR code to the generated QR code.
• jsdom : To render our QR code in a node environment.
• sharp: A convenient tool to convert our source svg QR code to png and jpeg formats.

New dev dependencies:

• jsqr: To read rendered QR code for testing.
• upng-js: To parse rendered .png QR codes for testing.

[yong-jie]

Dropping a review with some comments and questions. Also just to check: is the QR code generation now purely a backend task? What plans do we have to incorporate #113, which allows for shortlinks under the qr code?

[liangyuanruo]

Minor changes requested as commented.