Joël shares his experiences with handling JSON in a Postgres database. He talks about his challenges with ActiveRecord and JSONB columns, particularly the unexpected behavior of storing and retrieving JSON data. Stephanie shares her recent discovery of bookmarklets and highlights a bookmarklet named "Check This Out," which streamlines searching for books on Libby, an ebook and audiobook lending app.
The conversation shifts to using constants in code as a form of documentation. Stephanie and Joël discuss how constants might not always accurately reflect current system behavior or logic, leading to potential misunderstandings and the importance of maintaining accurate documentation.
Bookmarklets (https://www.freecodecamp.org/news/what-are-bookmarklets/)
"Check This Out" Bookmarklet (https://checkthisout.today/)
Libby (https://libbyapp.com/interview/welcome#doYouHaveACard)
Productivity Tricks (https://www.bikeshed.fm/403)
12 Factor App Config (https://12factor.net/config)
A Hierarchy of Documentation (https://challahscript.com/hiearchy_of_documentation)
Sustainable Rails (https://sustainable-rails.com/)
rails-erd gem (https://github.com/voormedia/rails-erd)
Transcript
STEPHANIE: Hello and welcome to another episode of the Bike Shed, a weekly podcast from your friends at thoughtbot about developing great software. I'm Stephanie Minn.
JOËL: And I'm Joël Quenneville. And together, we're here to share a bit of what we've learned along the way.
STEPHANIE: So, Joël, what's new in your world?
JOËL: What's new in my world is JSON and how to deal with it in a Postgres database. So, I'm dealing with a situation where I have an ActiveRecord model, and one of the columns is a JSONB column. And, you know, ActiveRecord is really nice. You can just throw a bunch of different data at it, and it knows the column type, and it will do some conversions for you automatically.
So, if I'm submitting a form and, you know, form values might come in as strings because, you know, I typed in a number in a text field, but ActiveRecord will automatically parse that into an integer because it knows we're saving that to an integer column. So, I don't need to do all these, like, manual conversions.
Well, I have a form that has a string of JSON in it that I'm trying to save in a JSONB column. And I expected ActiveRecord to just parse that into a hash and store it in Postgres. That is not what happens. It just stores a raw string, so when I pull it out again, I don't have a hash. I have a raw string that I need to deal with. And I can't query it because, again, it is a raw string. So, that was a bit of an unexpected behavior that I saw there.
STEPHANIE: Yeah, that is unexpected. So, is this a field that has been used for a while now? I'm kind of surprised that there hasn't been already some implementations for, like, deserializing it.
JOËL: So, here's the thing: I don't think you can have an automatic deserialization there because there's no way of knowing whether or not you should be deserializing. The reason is that JSON is not just objects or, in Ruby parlance, hashes. You can also have arrays. But just raw numbers not wrapped in hashes are also valid JSON as are raw strings.
And if I just give you a string and say, put this in a JSON field, you have no way of knowing, is this some serialized JSON that you need to deserialize and then save? Or is it just a string that you should save because strings are already JSON? So, that's kind of on you as the programmer to make that distinction because you can't tell at runtime which one of these it is.
STEPHANIE: Yeah, you're right. I just realized it's [laughs] kind of, like, an anything goes [laughs] situation, not anything but strings are JSON, are valid JSON, yep [laughs]. That sounds like one of those things that's, like, not what you think about immediately when dealing with that kind of data structure, but...
JOËL: Right. So, the idea that strings are valid JSON values, but also all JSON values can get serialized