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frugal technology, simple living and guerrilla large-appliance repair
Sat, 21 Oct 2017

My blog-posting program in Ruby

I'm actually doing it. I'm writing a blog-posting program that will take an http link, extract the remote page's title and create a social-media-style blog post (title, body text and link) that can be easily uploaded to my flat-file blogging system's server.

The idea is to make it as easy to post a "social"-style update to my own blog as it is to post to Twitter (or Facebook or Google+).

(I use IFTTT -- and formerly dlvr.it -- to post these social entries on Twitter, but I could see this program taking over that task as well.)

Back to my application. I could have gone several different ways from a conceptual standpoint.

  • I could have done this idea as a web app, but in order to get the files to upload to the blog, I'd either have to write a server component on that side, or create a backend service -- with some measure of security -- to handle the upload (I'm using FTP, but it doesn't have to be that).

  • I thought about a desktop GUI. I want this to be a true cross-platform app. I seriously considered using the now-ancient Tk framework with Ruby. I less-seriously considered Java FX, though I did successfully hack together code to upload via FTP using Java. (At least it was a worthwhile programming exercise.) I could have gone with QT. Maybe I could have done the whole thing with QML.

I'm not ruling out any of these GUI solutions, but I needed to start coding, and the easiest, quickest thing for me to do (or so I thought) is a menu-driven console app. I could have gone with Java, JavaScript, Ruby, even Perl. I did tests of various components in three of those languages.

I'm writing the app for the console with an eye toward re-using the code in a future GUI app, and for that reason maybe I should have used JavaScript.

But I really wanted to use Ruby. I'm trying to grasp object-orientated programming, and there is a whole lot of web-based help for Ruby programmers that often acknowledges that there are beginners out there who need a helping hand.

And I really would love to eventually port this code to Tk, or even as a Sinatra or Rails app. I should want to do it in JavaScript. But Ruby is so friendly, and it's made for use in the console.

So I'm writing it in Ruby. And I have some 190 lines of code that do the following:

  • Display a menu of tasks and wait for input
  • When a URL is entered, grab the HTML title
  • Create a simple document with a title and text derived from the remote HTML title
  • Add a Markdown-formatted link back to the original HTML page
  • Save all as a text file with an auto-generated file name incorporating the current date and text derived from the title
  • Allow user to enter different text for the title or body
  • Let user choose not to include the source site's URL
  • Save all to a text file
  • Upload to website via FTP and "tell" blog to index the new entry

I have all of these features working, and while the app is very far from perfect, it is functional. The code isn't ready for public consumption -- it needs lots of cleanup before I publish it, and it's really meant more for Ode users and blogs that work in a similar way (files are uploaded to a server, from which the blog software renders them for the reader) than it is for flat-file systems such as Hugo, where a dedicated program builds the blog locally and sends files on their way, but the concepts and code used in this app can certainly be modified for that workflow -- and I'm not at all above doing that in the future.

Aside from adding more features, primarily the ability to edit elements instead of re-typing them (maybe by invoking the vi editor), I want to make the code more modular. Right how it's a huge procedural hack, and modularity (and object orientation) will make it cleaner and more flexible. That's the idea anyway.

Before that I need to clean up the configuration, which is all over the place.

Still, I wanted to make an app, I used the skills I had (and Googled and read plenty), and now I have something that works, however ugly it may look on the back end.

Sat, 08 Jul 2017

'Learn Ruby on Rails' by Daniel Kehoe updated for Rails 5.1

'Learn Ruby on Rails' by Daniel Kehoe has been updated for Rails 5.1.

Wed, 30 Nov 2016

Basic operations for arrays in Ruby

From Solid Foundation Web Development: Basic operations for arrays in Ruby

Mon, 12 Sep 2016

Using Dir.glob to delete files with a pattern in Ruby

I have a bunch of files in a directory, and I want to delete all that begin their filename with the letters X16 (e.g. X16data.xml)

I used Dir.glob to select the files and iterated over what comes up in the pattern, using File.delete to get rid of what I don't want (Thanks, Stack Overflow):

Dir.glob("X16*") do |file|

You can put any kind of regex in here, and it'll probably work. That's the theory anyway.

Sat, 10 Sep 2016

The rubyzip gem for creating and opening archives

On my current project, I am trying to use using rubyzip to unzip an archive.

So far it's not working, and I'll probably shell out to Bash and Linux/Unix's unzip to get it done.

I figured it out. Now I have to manage the unzipped files (deleting the unused, renaming the good, then deleting the good at the beginning of the run) and account for NOT running the program if there is no file on the other end.

Thu, 16 Jun 2016

The Bastards Book of Ruby

While it calls itself out as old and out of date, I really like The Bastards Book of Ruby.

I recognize that Ruby is no longer the new hotness, but it's still so useful and, dare I say, user-friendly. For those reasons, I'd love to see updated versions of just about every book out there.

I'm using the old (as the hills) "Learning Ruby" by Michael Fitzgerald (2007, O'Reilly), The Pickaxe book ("Programming Ruby") from Ruby version 1.9.2 (2010/11, Pragmatic Programmers, though do I realize there is a 2013 edition).

The beginners books seem to be the oldest. At my level, everything seems to be working, so I will maybe complain a little less.

I do have a Rails book, "Rails Crash Course," by Anthony Lewis, that's much newer, but I'm not there quite yet. And there's always Michael Hartl's "The Ruby on Rails Tutorial", of which the more I see, the more I like.

Using Ruby to delete blocks of text across multiple lines

I tend to learn things in programming when I have a problem to solve. This is just such a case.

I was working with a huge XML file, and I needed to trim elements out of it that begin with <generic tag> and end with </generic tag>, and include a random amount of text and other tags, across multiple lines, in between.

At first I tried using the Nokogiri gem, but it just wasn't happening. I was working on my Election Results script, and ... the election -- they hold it on a certain date, you know.

I would have to brute-force it. Like I always do.

My whole idea this cycle was to dump my giant sed hack from elections past and use mostly (if not all) Ruby to parse the XML I get from the state of California and provide the JSON output my fellow dev needed for the front end. (I also have a ton of fixed-width ASCII from Los Angeles County to deal with, as well as scraped HTML from San Bernardino County, but those are other tales for other times.)

With the state data, I had the XML-to-JSON conversion covered with Ruby's Crack gem. But I just couldn't pare down the XML to make the JSON a manageable size.

Read the rest of this post

Wed, 15 Jun 2016

A great Ruby loops tutorial from Prograils

A company called Prograils offers a great tutorial, Loops in Ruby - all possible approaches.

It looks like a good reference for when you're writing a Ruby program and need to figure out which kind of loop will work best in a particular situation.

Tue, 14 Jun 2016

Quick Ruby: Open and write a file

Need to open an existing file, create a new one and write to that file in Ruby?

This Stack Overflow answer makes it super simple.

I already used this in one of my little Ruby programs.

In the same thread (but earlier), here's another one.

Sun, 12 Jun 2016

Learning Ruby: Loops and arrays

This entry shows what I'm doing when I practice programming. I find it helpful to write little programs that use the concepts I'm trying to learn.

Why Ruby? you might ask. No particular reason. I've spend a semester learning C++, and I was pleasantly surprised to find out that the things I learned are applicable in many other programming languages. Ruby is one of them.

Writing scripting-type programs is one of the things I do. I have "practiced" recently with Bash (and all the little Unixy utilities that go along with it) and Perl (for the add-on that does the statistics for this blog).

Ruby just happens to interest me. I'm also interested in Elixir, but for the kind of things I'm interested in doing right now, Ruby with its many, many Gems and "make programmers happy" philosophy looks like a good fit.

I could say the same thing about Perl (or Python, or Java), but for now I'm playing around with Ruby.

I find that writing little programs like these is a great way to learn. And writing the "same" program in different languages is also very helpful. I could re-write this one in, say, Perl or JavaScript (using either Node in the console or rendering it on an HTML.

Here is the program I wrote to practice using Ruby loops and arrays. I also worked with strings (and converting arrays to strings and back again) and outputting results to the terminal.

What is an array? Here's what it is (in my mind anyway): A collection of pieces of data that can be manipulated as a whole. You can mix numbers and strings. In Ruby, arrays can even contain other arrays. I read that somewhere.

Here is the program:

#!/usr/bin/env ruby


The purpose of this program is to experiment
with Ruby loops, arrays, strings, integers and output.

The program creates an array, uses loops
to *push* numbers into that array, shows what
the array looks like at every stage using *puts*
and *inspect*, then uses *shift* to remove
numbers from the array, also showing
what it looks like at every stage.

There are two more loops in this script.
One prints out numbers ascending, the other


# Create an array

number_array = Array.new

# loop uses *push* to add a number,
# *puts and *inspect* to print it

(1..10).each do |i|
    puts number_array.inspect


# loop uses *shift* to remove
# an array element
# 1...10 with three dots runs
# the loop until 9, not 10

(1...10).each do |i|
    puts number_array.inspect

# *puts* on its own adds a blank line


# *print* prints the output without adding
# a newline character (aka \n) like *puts*

for i in 1..10
    print i
    print " "


10.downto(1).each do |i|
    print i
    print " "