Instead of using this hack you might want to use MariaDB 10.x which can work with both old and new apps.

An alternative could be to use the MySQL Docker image which is still updated for 5.6.

Ubuntu 16.04 only provides packages for MySQL 5.7 which has a range of backwards compatibility issues with code written against older MySQL versions.

Oracle maintains a list of official APT repositories for MySQL 5.6, but those repositories do...

Tool to show you which gems are slow to load:

➜  git:(master) ✗ bundle exec bumbler
[#################################################                             ]
(49/65) travis-lint...
Slow requires:
    110.21  render_anywhere
    147.33  nokogiri
    173.83  haml
    179.62  sass-rails
    205.04  delayed_job_active_record
    286.76  rails
    289.36  mail
    291.98  capistrano
    326.05  delayed_job
    414.27  pry
    852.13  salesforce_bulk_api

Git commands tend to come in groups. Avoid typing git over and over and over by running them in a dedicated git shell.

You might want to run git config --global help.autocorrect true before using gitsh. This will silently swallow a muscle-memory "git" prefix to your commands inside the git shell.

jQuery's deferred objects behave somewhat like standard promises, but not really.

One of many subtle differences is that there are two ways to chain callbacks to an async functions.

The first one is done, which only exists in jQuery:

$.ajax('/foo').done(function(html) {
  console.debug("The server responded with %s", html);
});

There is also then, which all promise libraries have:

$.ajax('/foo').then(function(html) {
  console.debug("The server resp...

This card existed before, but was outdated due to browser implementation changes. The information below is validated for the current list of browsers we support.

By default your html and body elements are only as high as the actual page content inside their container. If you only have two lines of text in your page, your html and body elements will only be around 40 pixels high, regardless of the size of your browser window.

You might be surprised by this, since setting a background on either html and `body...

Enter any command into explainshell and it will explain it to you: split into separate commands (if present), with each option explained.

About

Hello,
This site contains 29761 parsed manpages from sections 1 and 8 found in Ubuntu's manpage repository. A lot of heuristics were used to extract the arguments of each program, and there are errors here and there, especially in manpages that have a non-standard layout.
It is written in Python and uses bashlex, a bit of NLTK (to find the interesting parts of the manpage), a little d3....

To upload a file via AJAX (e.g. from an <input type='file'>) you need to wrap your params in a FormData object.

You can initialize a FormData using the contents of a form:

var form = document.querySelector('form.my-form') // Find the <form> element
var formData = new FormData(form); // Wrap form contents

Or you can construct it manually, param by param:

var fileInput = document.querySelector('form input[type=file]');
var attachment = fileInput.files[0];

var f...

If you want to inspect the compiled code of your erb (or haml) templates, you can run the following code in your view or your controller:

template = lookup_context.find_template(action_name, lookup_context.prefixes)
template.handler.call(template.refresh(self))

The output will be something like

@output_buffer = output_buffer || ActionView::OutputBuffer.new;@output_buffer.safe_append='My template
'.freeze;@output_buffer.to_s

If you are on a Linux shell and want to open a file with whatever default application is configured for that type, this often works:

xdg-open Quote.odt
xdg-open invoice.pdf
xdg-open index.html

Pro Tip

Make an alias so you have a simpler API (like Mac OS): alias open=xdg-open or alias x=xdg-open.

Background

You can choose your "Default applications" via UI in the Ubuntu "Settings" application (gnome-control-center). This is just a very rough setting (e.g. open Photos with Shotwell Viewer).

If a certain file...

Let's say you want to find the element with the text hello in the following DOM tree:

<html>
  <body>
    <article>
      <strong>hello</strong>
      <strong>world</strong>
    </article>
  </body>
</html>

You might think of XPath's contain() function:

page.find(:xpath, ".//*[contains(text(), 'hello')")

Unfortunately that returns a lot more elements than you expect:

[ <html>...<html>,
  <body>...</body>,
  <article>...</article>,
  <strong>hello</strong> ]

What you need to do instead is to *find all...

Imagine you have a list you want to render inline on large screens, but stacked on small screens.

<ul>
  <li>high</li>
  <li>medium</li>
  <li>low</li>
</ul>

ul { white-space: nowrap } /* optional: keep items in one line no matter the available width */
li { display: inline-block }

@media (max-width: 600px) {
  li { display: block }
}

Now imagine you want the rightmost item to be the topmost item on small screens. You'll need to invert the order of list items, but only for large screens. Here are some approaches to do so:...

TL;DR There are three dimensions you can control when scoping routes: path helpers, URL segments, and controller/view module.

scope module: 'module', path: 'url_prefix', as: 'path_helper_name' do
  resources :examples, only: :index
end

as → prefixes path helpers: path_helper_name_examples_path and path_helper_name_examples_url
path → prefixes URL segments: /url_prefix/examples
module → nests the controller: controller Module::ExamplesController, found at app/controllers/module/examples_controller.rb with views ...

Talking with APIs makes more fun using Postman. As an alternative you can also use command line tools like cURL.

snap install postman

How does it help me?

• Editing multiline JSON bodies is much more comfortable than in the terminal
• Saving named requests in a collection (can be shared with others)
• Syntax highlighting when writing JSON bodies
• History with all my requests
• Multiple environments
• Cookie manager

Our preferred way of testing ActiveRecord is to simply create/update/destroy the record and then check if the expected behavior has happened.

We used to bend over backwards to avoid touching the database for this. For this we used a lot of stubbing and tricks like it_should_run_callbacks.

Today we would rather make a few database queries than have a fragile test full of stubs.

Example

Let's say your User model creates a first Project on cr...

Angular's directives have a transclude option, that allows for rendering an element's original content within the directive's template:

# HTML
<wrapping-directive>
  Content ...
</wrapping-directive>

# Directive template
<div class="wrapper">
  <ng-transclude></ng-transclude>
</div>

# Result
<div class="wrapper">
  Content ...
</div>

However, if you need more control over the transcludable content you need heavier armor. For this case, Angular provides you with a transclusion function as the 5th argument of...

A HTTP 302 Found redirect to PATCH and DELETE requests will be followed with PATCH or DELETE. Redirect responses to GET and POST will be followed with a GET. The Rails form_for helper will use a workaround to send POST requests with a _method param to avoid this issue for PATCH/DELETE.

If you make requests yourself, watch out for the following behavior.

When you make an AJAX request PATCH /foo and the /foo action redirects to /bar, browsers will request PATCH /bar. You probably expected the second requ...

Using Scenic, you can bring the power of SQL views to your Rails application without having to switch your schema format to SQL. Scenic provides a convention for versioning views that keeps your migration history consistent and reversible and avoids having to duplicate SQL strings across migrations. As an added bonus, you define the structure of your view in a SQL file, meaning you get full SQL syntax highlighting in the editor of your choice and can easily test your SQL in the database console during development.

[https://robots.thoughtb...

Note

The maintenance mode is enabled on all application server as soon as the file /public/system/maintenance.html is present.

Installation

Add this line to your application's Gemfile:

 gem 'capistrano', '~> 3.0'
 gem 'capistrano-maintenance', '~> 1.0'

Add this line to you application's Capfile:

require 'capistrano/maintenance'

Enable task

Present a maintenance page to visitors. Disables your application's web interface by writing a #{maintenance_basename}.html file to each web server. The servers m...

Once Rails knows a given string is html_safe, it will never escape it. However, there may be times when you still need to escape it. Examples are some safe HTML that you pipe through JSON, or the display of an otherwise safe embed snippet.

There is no semantically nice way to do this, as even raw and h do not escape html_safe strings (the former just marks its argument as html_safe). You need to turn your string into an unsafe string to get the escaping love from Rails:

embed = javascript_tag('var foo = 1337;') # This is an h...

You know that layouting HTML e-mails is terrible.

For more fun, check Litmus' list of top 10 e-mail developments of 2015 that did not make things better.

There are cases when you need to select DOM elements without jQuery, such as:

• when jQuery is not available
• when your code is is extremely performance-sensitive
• when you want to operate on an entire HTML document (which is hard to represent as a jQuery collection).

To select descendants of a vanilla DOM element (i.e. not a jQuery collection), one option is to use your browser's native querySelector and [querySelectorAll](https://developer.mozilla.org/de/docs/We...