S3cmd is a free command line tool and client for uploading, retrieving and managing data in Amazon S3. S3cmd reads its configuration by default from ~/.s3cfg, which is created once you run s3cmd --configure.

If you have many configurations, we recommend to always specify the configuration you want to use. This prevents applying actions to the wrong bucket.

Examples:

s3cmd -c ~/.s3cfg-github-staging ls
s3cmd -c ~/.s3cfg-github-development ...

Normally you can list all gems of the current ruby version with gem list, which also includes the gems of you Gemfile. These can be uninstalled with gem uninstall gemname.

List and uninstall a gem installed via Bundler from Github

This does not work for gems installed directly from Github. They do not appear in gem list.

Show all gems installed via Github by bundler:

ls ~/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/bundler/

Remove a gem installed via Github by Bundler:

rm -rf ~/.rbenv/versions/2.4.1/lib/ruby/gems/2....

In this example we assume that not only the storage gem changes but also the file structure on disc.

A general approach

Part A: Create a commit which includes a script that allows you to copy the existing file to the new file structure.

Part B: Create a commit which removes all paperclip logic and replace it with the same code you used in the first commit

Part A

Here are some implementation details you might want to reuse:

• Use the existing models to read the files from
• Use your own carrierwave models to write t...

Masonry is a famous library to dynamically arrange a grid of items that have different aspect ratio, like horizontal and vertical images.
Colcade is an alternative masonry-layouting library, developed by the same developer, but with a more modern approach.

It is said to have better performance while being smaller and having no dependencies. It automagically detects jQuery and defines a jQuery initializer, if present.
However, it offers [a few less features](https:...

Geordi provides a pretty neat way to generate beautiful commit messages according to your stories in Linear:

geordi commit

Geordi reads from a .geordi.yml file inside your repo and connects to Linear to list started and finished stories with their title. Choosing one of them generates a commit message including id and title from Linear app and a link to the original issue. For example:

[VW-1337] CRUD Users

Issue: https://linear.app/makandra/issue/VW-1337/crud-user...

Migrating data from a legacy into a new system can be a surprisingly large undertaking. We have done this a few times. While there are significant differences from project to project, we do have a list of general suggestions.

Before you start, talk to someone who has done it before, and read the following hints:

Understand the old system

Before any technical considerations, you need to understand the old system as best as possible. If feasible, do not only look at its API, or database, or frontend, but let a user of the old system sho...

At makandra, we've built a few gems over the years. Some of these are quite popular: spreewald (> 1M downloads), active_type (> 1M downloads), and geordi (> 200k downloads)

Developing a Ruby gem is different from developing Rails applications, with the biggest difference: there is no Rails. This means:

• no defined structure (neither for code nor directories)
• no autoloading of classes, i.e. you need to require all files yourself
• no active_support niceties

Also, their scope...

Just like Ruby Gems tag their version releases to the corresponding Git commit, it can be helpful to track production deploys within the commit history. This task does the tagging for you.

Capistrano 3

# lib/capistrano/tasks/deploy.rb
namespace :deploy do
  ...

  desc 'Tag the deployed revision'
  task :tag_revision do
    date = Date.today.to_s

    puts `git tag deploy-#{date} #{fetch :current_revision}`
    puts `git push --tags origin`
  end

end

# config/deploy/production.rb
after 'deploy:finished', 'deploy:tag_...

Definition

A matcher is a function that returns an object with a compare key. Usually it is registered with beforeEach:

beforeEach(() => {
  jasmine.addMatchers({
  
    // Example matcher
    toBeAnything() {
      return {
        compare(actualValue, ...matcherArguments) {
           // Do some computations here ...
         
           // Return whether the actualValue matches the expectation
           return {pass: true}
         }
      }
    }
  })
})

Usage

expect(actualValue).toBeAnything(...matcherArg...

Using the JS fullscreen API is painful because all browers use different methods and events and you need to use lots of boilerplate code to make your application work in all browsers.

The "screenfull" library wraps that for you, including events.

Examples

The linked GitHub repo contains some information. You basically use the library like this:

// Make an element go fullscreen
screenfull.request(element)

// Leave fullscreen
screenfull.exit()

...

MySQL and MariaDB have an SQL mode setting which changes how MySQL behaves.

The SQL mode value is comprised of multiple flags like "STRICT_TRANS_TABLES, NO_ZERO_IN_DATE". Each flag activates or disables a particular behavior.

The default SQL mode varies widly between versions of MySQL and MariaDB. In general, more recent versions of MySQL and MariaDB have stricter settings than older versions, and MySQL has stricter settings than the more liberal MariaDB.

If your app explodes ...

Say you want to move a git repository from one remote (perhaps Github) to another (perhaps Gitlab).

If you have the repo checked out, you still should make sure to mirror all branches of the old remote, not only those you happen to have checked our. Otherwise the target repo will become a copy of your current repo, and not the source repo, potentially missing commits. You can use this:

git remote rename origin old-origin
git remote add origin <new-remote>
git fetch old-origin --prune
git push --prune origin +refs/remotes/old-origin/*:r...

TL;DR Use user.update!(remove_avatar: true) to delete attachments outside of forms. This will have the same behavior as if you were in a form.

As you know, Carrierwave file attachments work by mounting an Uploader class to an attribute of the model. Though the database field holds the file name as string, calling the attribute will always return the uploader, no matter if a file is attached or not. (Side note: use #present? on the uploader to check if the file exists.)

class User < ApplicationRecord
  mount :avatar, ...

Git has two kind of tags:

• annotated
• lightweight

Annotated tags are stored as full objects in the Git database. They’re checksummed; contain the tagger name, email, and date; have a tagging message; and can be signed and verified with GNU Privacy Guard (GPG)

The following command will create a (lightweight) tag:

git tag v0.1

An annotated tag is created by:

git tag -a v0.1 -m "a special tag message"

A normal git push will not push the tag. So in order to publish your (local) tags, you have to

git push --tags
`...

RSpec allows you to mark a single Example/ExampleGroup so that only this will be run. This is very useful when using a test runner like guard.

Add the following config to spec/spec_helper.rb:

RSpec.configure do |config|
  # These two settings work together to allow you to limit a spec run
  # to individual examples or groups you care about by tagging them with
  # `:focus` metadata. When nothing is tagged with `:focus`, all examples
  # get run.
  config.filter_run_including :focus => true
  config.run_all_when_everything_filtere...

An end-to-end test (E2E test) is a script that remote-controls a web browser with tools like Selenium WebDriver. This card shows basic techniques for fixing a flaky E2E test suite that sometimes passes and sometimes fails.

Although many examples in this card use Ruby, Cucumber and Selenium, the techniques are applicable to all languages and testing tools.

Why tests are flaky

Your tests probably look like this:

When I click on A
And I click on B
And I click on C
Then I should see effects of C

A test like this works fine...

Here is some JavaScript code that allows you to click the screen and get the clicked element's text contents (or value, in case of inputs).

The approach is simple: we place an overlay so you don't really click the target element. When you click the overlay, we look up the element underneath it and show its text in a browser dialog. You can then copy it from there.

While moving the mouse, the detected element is highlighted.

Here is the one-liner URL that you can store as a bookmark. Place it in your bookmarks bar and click it to activate....

You can use local copies of gems in your Gemfile like this:

gem 'spreewald', path: '~/gems/spreewald'

As soon as you have bundled your project with the local copy of the gem, all code changes in the copy will be available on your project. So you can for example set a debugger or add console output in the gem and use it from your project.
If you checked out the gem with your versioning tool, you can easily reset your changes afterwards or make a pull request for the gem if you improved it.

Don't commit a Gemfile with local path...

RawGit serves raw files directly from GitHub with proper Content-Type headers, for CDN-like purposes.

Note that they don't offer any uptime guarantee. You probably don't want to use it in production, but it may serve you well for some testing/prototyping/etc.

To easily opt out of notifications for a large number of Github repositories, go to https://github.com/watching.

This card will show you how to use git rebase --onto without confusion.

Use case:

You've got two feature branches (one and two), where two depends on one. Now commits of branch one have changed after you branched two from it (i.e. after code review the commits of branch one are squashed). Thus the commit history of branch one has changed. Branch two's history however didn't change.

Solution:

To make the branches share the same commit history again you will have to rebase and replay (attach) the a...

Sometimes, through some firewall or proxy misconfiguration, you might have to deploy to a server that cannot access the git repository.

Solution 1: HTTP Proxy (this is the preferred fix)

SSH can be tunneled over an HTTP Proxy. For example, when the repo is on github, use this:

1. Install socat

2. Add a ~/.ssh/config on the target server(s) with permission 0600 and this content:

   Host github.com ssh.github.com
     User git
     Hostname ssh.github.com
     Port 443
     ProxyCommand socat - PROXY:<your proxyhost>:%h:%p,...