C is for cookies

Adventures in creating a cross-domain cookie storage solution

About me

  • Name: Mike Frazier
  • Occupation: Software Engineer at Evernow
  • Past life: High school science teacher
  • Hobbies: (Skate/Snow)boarding, reading, music stuff
  • Zodiac: Aries

How it started

Hey Mike,

 

We are going to be splitting our marketing site from our members site. One will be hosted on a subdomain of ours. We will want a cookie to be available between the domains. 

 

You good with that, dude?

 

Thanks!

The Boss

What happened Next

What really happened

Lots and lots of Stackoverflow search

 

  • How to create cross-domain cookie
  • How to share cookie between domain and sub-domain
  • Domain set cookie for sub-domain

What is a cookie

According to Wikipedia, cookies "are small blocks of data created by a web server while a user is browsing a website and placed on the user's computer or other device by the user’s web browser. Cookies are placed on the device used to access a website, and more than one cookie may be placed on a user’s device during a session."

 

Cookies are useful for storing stateful types of information such as carts, authentication status, and user preferences.

What are the Specs for this?

Cookies have the following structure:

 

Name

Value

Optional Attributes

  • Secure (https?)
  • Expiry date
  • Domain
  • Others

Let's Jump to an example

Set up and Limitations

Dumb little Vite React application

 

Using a cookie library to help set the cookies

 

How do we get this to work in dev? Localhost NEVER acts the same as a production server

What I learned

Setting the domain key on the cookie will either create a host-only (accessible only on the domain that set it) or one available on subdomains

 

It's possible to make localhost act like a real server by updating the /etc/hosts file

 

Hopefully by having done this once, I won't forget or end up in Stackoverflow hell again

Thanks

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