To change RAM size, VDISK size or VCPU count of an openstack instance you have to use nova resize. You can't change for e.g. just the RAM size with a parameter, you have to assign a new/other flavor. If there is no suitable flavor for the new properties of the VM, create a new one.

nova resize [--poll] <server> <flavor>

The resize could take a while, after it is finished, the VM boots up with the new specifications. SSH into the VM and check if everything is alright...

Small web application where you can upload an image (PNG, JPEG, GIF) and generate a base64-encoded version of it.

You can copy the result as

• HTML <img> tag with data URI,
• CSS rule with background-image and data URI,
• plain Base64-encoded data URI string.

Surprisingly exhaustive new icon set by Google.

Available as PNG, SVG and as a icon font.

Comment from Henning

I tried using the icon set in a project. I found the quality, selection and handling far worse than what we are used to in FontAwesome.

Note: Making a reverse proxy with nginx is much more straightforward.

A reverse proxy is a "man in the middle" server that tunnels requests to another server. You can use for things like:

• Expose a local service that you cannot directly reach over the internet
• "Change" the domain or path of a web application by rewriting them on the fly
• Instantly change servers that respond to a name or ...

Bad

# Given the following models

class Image < ActiveRecord::Base
  has_many :album_images
  has_many :albums, through: :album_images
end

class Album < ActiveRecord::Base
  has_many :album_images
  has_many :images, through: :album_images
end

# Join model
class AlbumImage < ActiveRecord::Base
  belongs_to :album
  belongs_to :image
end

Destroying a record in this setup will only remove the record itself, and leave orphaned join records behind.

image = Image.last
image.destroy # removes only the `image` record,
   ...

There are some frontends available, but they all suck, are no longer maintained or are hard to install.

As a surprisingly comfortable alternative I have found a command line tool s3cmd:

sudo apt-get install s3cmd

When you run s3cmd the first time it will ask you for your access key ID and secret access key. This information is cached somewhere so you only need to write them once. To reconfigure later, call s3cmd --configure.

Once you're done setting up, s3cmd gives you shell-like commands like s3cmd ls or `s3cmd del som...

Awesome hack by Tim VanFosson:

<img src="some.jpg" onerror="this.src='alternative.jpg'" />

Instead of this:

Image.order('images.created_at DESC')

You can write this:

Image.order(created_at: :desc)

Not only do you not have to write SQL, you also get qualified column names (created_at becomes images.created_at) for free.

Multiple order criteria

To add secondary order criteria, use a hash with multiple keys and :asc / :desc values:

Image.order(title: :asc, created_at: :desc)

Here's a pretty useful steps that hasn't made it into Spreewald yet.

It is best used with the auto-mapper for BEM classes in features/support/selectors.rb

When I hover above [selector] element

When /^I hover above (.*) element$/ do |selector|
  page.find(selector_for(selector)).hover
end

Example:

When I hover above the album's image element

→ triggers a hover event on .album--image

Write a // and indent every subsequent line by two spaces.

This is great for documenting BEM blocks!

//
  An action button
  ================
  
  Basic usage
  -----------
  
      <a href="/path" class="action">New booking</a>
      <button class="action">Save</a>
      <input type="submit" class="action">Save</a>
  
  Colors
  -------
  
      <a href="/path" class="action is-red">Primary</a>
      <a href="/path" class="action is-grey">Secondary</a>
  
  Small inline buttons
  --------------------
  
      <p>
        Recor...

When a CSS3 animation makes the animated element flicker, it may well be due to pixel fragments being handled differently during animation. You can force the browser into rendering the element on the GPU by adding certain properties. In Chrome, the combination of the following properties has the best effect.

box-shadow: 0 0 0 #000
transform: translate3d(0,0,0) # remember to add vendor prefixes

Depending on your markup, you might need to set these properties on several elements (presumably all those that have height or width in %)...

When uploading images, adding more than one process to a version can cause MiniMagick to run multiple commands. In order to have all processing done in one mogrify system call, you'll need to define only one process that combines all options you'd like to pass in.

When you are using the #selector_for helper in Cucumber steps, as e.g. Spreewald does, the following snippet will save you typing. It recognizes a prose BEM-style selector and maps it to the corresponding BEM class.

For a variation on this idea, see An auto-mapper for ARIA labels and BEM classes in Cucumber selectors.

Examples

"the main menu" -> '.main-menu'
"the item box's header" -> '.item-box--header'

Here are some examples of steps (using Spreewald, too):

T...

The CSS property z-index is not as global as you might think. Actually, it is scoped to a so-called "stacking context". z-indexes only have meaning within their stacking context, while stacking contexts are treated as a single unit in their parent stacking context. This means indices like 99999 should never actually be needed.

Creating a new stacking context

In order to create a stacking context with the least possible side effects, use the isolation property on an...

If you get this error (probably because you want to load some modules):

# modprobe xt_comment
FATAL: Could not load /lib/modules/3.2.0-40-generic/modules.dep: No such file or directory

The reason could be that apt-get autoremove already removed /lib/modules/.../modules.dep even if you still using this kernel version:

# uname -r
3.2.0-40-generic
# ls -l /lib/modules/
total 24
drwxr-xr-x 4 root root 4096 Oct 22 17:05 3.2.0-68-generic
drwxr-xr-x 4 root root 4096 Jan  7 16:38 3.2.0-69-generic
drwxr-...

Jonas Nicklas, the author of Carrierwave and Capybara, has released Refile, a gem for handling file uploads in Rails. It handles direct uploads (also direct uploads to Amazon S3) better than Carrierwave.

The story and reasoning behind some of the decisions in Refile, and how it's different from Carrierwave, by the author himself, is a good read before deciding which way you'll go.

Big Caveat: Refile only stores the original image and r...

ImageMagick takes a string with several options when cropping an image. See the command line options for how to provide the expected image geometry for details.

Note that ImageMagick tends to preserve the original aspect ratio of the source image automatically.

Examples:

• crop 200x200 means Maximum values of height and width given, aspect ratio preserved.
• crop 200x200! means Width and height emphatically given, original aspect ratio ignored.

Capybara-screenshot can automatically save screenshots and the HTML for failed Capybara tests in Cucumber, RSpec or Minitest.

Requires Capybara-Webkit, Selenium or poltergeist for making screenshots. Screenshots are saved into $APPLICATION_ROOT/tmp/capybara.

Manually saving a page

Additionally you can trigger the same behavior manually from the test using Capybara::Session#save_and_open_page and [...

Responsive Lightbox JavaScript that just works.

You can use it for single images or a gallery. Animations are optional.

When accepting GIF images, you will also accept animated GIFs. Resizing them can be a time-consuming task and will block a Rails worker until the image is processed.

Save yourself that trouble, and simply tell ImageMagick to drop any frames but the first one.

Add the following to your uploader class:

process :remove_animation

private

def remove_animation
  if content_type == 'image/gif'
    manipulate! { |image| image.collapse! }
  end
end

You may also define that process for specific versions only (e.g. only for thum...

A set of javascript tools for working with files.

It offers different kinds of things:

• A cross-browser JS API to work with File objects.
• Image helper methods, like rotating images, or generating thumbnails in the browser (because you don't want your browser to scale tons of 20MB-JPEGs just for an upload preview)
• Webcam access
• Uploads

When HTML5 support is unavailable, it uses Flash polyfills.

Check out the documentation and demos at their GitHub page.

To install via bower, simply add the `...

The benefit of the Rails asset pipeline is that it compiles your stylesheets and javascripts to a single file, respectively. However, the consequences are startling if you don't understand them. Among others, the raw asset pipeline requires you to have all your asset libraries in the same folder, which quickly becomes confusing as your set of assets grows. To overcome this, we have two different solutions.

Custom solution

We are using a custom workaround to keep library files apart in their own directories. To avoid b...

The Rails asset pipeline improves delivery of application assets (javascripts, stylesheets, images, fonts). Here are some basic facts about its inner workings.

No magic

Manifests are the handle on your assets:

app/assets/stylesheets/application.css # use via: stylesheet_link_tag 'application'

The asset pipeline only considers files you explicitly require within your manifest files. The most common directives used in manifests are require some/file and require_tree some/directory. Paths may be **relative to the current director...

To fix this:

• Right-click on the frame
• Select Frame...
• Open Background
• Set As to "Color"
• Set the background color to "No fill"