Attempting to Learn Flask, Part 3

Attempting to Learn Flask, Part 3

I should close the loop on this series. Part 1 and Part 2, if you’re interested.

The conclusion is, I haven’t mastered it, but I’ve definitely figured out the basics. I thought I’d need to learn more from CS350 for some time before getting here. Instead I found myself going back to just two of the videos in Charles Severance’s “Using Databases with Python” several times and jogging memory with code I’d worked with during that course. I’m forgetful so it was great to have his videos on hand. I also spent a lot of time googling, reading, and YouTubing tutorials.

Basically, I had to draw from everywhere at this point, and the range was really, really wide.

The happy news is, I can now:

  • Use Python to do magic on the back end
  • Use Flask to deliver magic to the front end
  • Use SQLite3 and/or PostgreSQL to handle data (Create, Read, Update, Delete)
  • Doll up my web app a little bit with Bootstrap

I’ve made a couple of apps already:

One uses Python to concatenate randomly selected strings from various lists to form grammatically correct English sentences and then displays a new one in the middle of a webpage at regular intervals.

The other draws from the IMDB database, banishes all USA and Western European films, randomly picks 10 from the rest of the world, and displays them along with their trailers from YouTube. This one was not so trivial for me. There was a lot of junk data in the IMDB database to clean up, and I had to work out how to scrape YouTube to embed the trailers on my site.

So, as of early 2017, I can verify that my proposed path of least resistance for learning how to build a web app from scratch is a pretty decent strategy.

I can’t say if it’ll continue this way. Already there are certain things that are falling into doubt. For instance, CS350 leverages AngularJS a little bit to do Flask stuff, and in the course of reading all the other sources I found out that there is a lot of uncertainty surrounding the future of AngularJS right now. That particular case is not terribly important. Just a small example. We can use other JS frameworks anyway.

What’s next for me? I’m going to build up that film site of mine. Add users to it, work on some formulae running in the back end. Get more familiar with PostgreSQL. Get a better handle on how to mash Flask up with Bootstrap. And then maybe learn Cordova next year to build mobile apps.

Coding is great fun, especially since I use it to engage real world problems. For example, the winner-takes-all effect. Films from USA and Western Europe, and especially from Hollywood, saturate almost every single one of our media environments. My film site bans all USA and Western European films in order to allow the diversity of the rest of the world’s film heritage to come to the fore. Turns out, it’s wonderful. Using it, I discovered amazing, beautiful films from Azerbaijan, Indonesia, Malaysia, Turkey, and elsewhere. I think there was even one from Antigua and Barbados. It’s not ready for the public yet, but I hope to put it up somewhere just for show-and-tell soon.

Another big reason that drove my learning was the oppressive pecuniary pressures in the art world. I wonder if I’m ready for an entry level/junior position yet. I have no idea. Time to try looking around for a job now as well, I guess. At the very least, I’ll get a better idea of what the world wants.

How and Where to Take a (PostgreSQL) Dump, or, When Documentation Lacks Detail

How and Where to Take a (PostgreSQL) Dump, or, When Documentation Lacks Detail

I’ve made crazy progress in the last couple of weeks. As a result of that, I’ve managed to get my grubby hands onto SQL and I’ve even wrestled with which database management system to use. I used Digital Oceans’ succinct article to settle on PostgreSQL.

Unfortunately, unlike the SQLite I’m a bit more familiar with, PostgreSQL databases (DB) don’t come in one handy portable file. I spent maybe a couple of hours poking around the PostgreSQL directory wondering where the DB was. Then I googled it and read some articles a bit more closely and figured out it’s more complicated than a single manifestation in a single locus.

So, using the vocabulary I had, I googled “how to export PostgreSQL database” and a couple of other variants related to it. Didn’t work. But at some point, I found out that you have to do a dump. That gets you a file you can move around. But not many were good at explaining it, or even the concept of it. Finally, I read the documentation here and thought, this should be easy. But once I’d done a pg_dump, I couldn’t find the file. I spent another couple of hours trying out various things.

Then, finally, finally, I YouTubed “postgresql dump” or something like that and found this silent video. I watched it carefully and realised that the dump is created in the directory from which I work in the command line. And that has not been mentioned in all the previous places I’d looked in, including the documentation. Maybe it’s obvious to experts. But beginners need something a bit more explicit.