You can use scheme-less URLs (or protocol-relative URLs) to have browsers use the current protocol (HTTP or HTTPS) when loading content referenced with such an URL.
...relative URL doesn’t contain a protocol. For example, http://stevesouders.com/images/book-84x110.jpg becomes //stevesouders.com/images/book-84x110.jpg Browsers substitute the protocol of the page itself for the resource’s missing protocol. Problem solved...
Sometimes you want to see what data you get through a TCP or UDP connection. For example, you want to know how a HTTP Request look like.
...easy with netcat. Example to listen on port 80 and the output gets to stdout. sudo nc -kl 80 It's also possible write it into a file:
...will never return the current element itself, even if the element matches the given selector. Require the attached file and you can now say: $('.container').findWithSelf('.selector')
RSpec's let allows you to super into "outside" definitions, in parent contexts. Example: describe '#save' do subject { described_class.new(attributes) } let(:attributes) { title: 'Example', user: create(:user) } it 'saves' do...
...expect(subject.save).to eq(true) end context 'when trying to set a disallowed title' do let(:attributes) { super().merge(title: 'Hello') } # <== it 'will not save' do expect(subject.save).to eq...
When you're getting this error, one possibility is that you've created a select field for an association instead of the associated object's id. Example: form.select :unit, Unit.for...
will be expected to deliver a real Unit object, whereas form.select :unit_id, Unit.for_select will make Rails typecast the String value from the select field to the unit...
To read the Rails session from a Rack middleware, use env['rack.session']. It's an ActionDispatch::Request::Session object. class MyMiddlware def initialize(app) @app = app end def call(env...
...status, headers, body = @app.call(env) session = env['rack.session'] Rails.logger.info("Value of session['foo'] is: " + session['foo'].inspect) [status, headers, body] end end You may not be able to write to...
You have to specify the environment with -e env_name or RAILS_ENV=env_name if you want to run a script on the server. at Rails 2 it's...
bundle exec script/runner -e env_name path/to/script.rb argument1 argument2 ... at Rails 3 it's rails runner RAILS_ENV=env_name bundle exec rails runner path/to/script.rb argument1 argument2...
JavaScript engines such as Google’s V8 (Chrome, Node) are specifically designed for the fast execution of large JavaScript applications. As you develop, if you care about memory usage and...
...what’s going on in your user’s browser’s JavaScript engine behind the scenes...
The colors in Rails log files are helpful when watching them but, since they are ANSI color codes like ^[[4;36;1m, can be annoying when you are reading the...
...that does just prints those control characters (like less or vim). Remove them with sed: cat staging.log | sed -r "s/\x1B\[([0-9]{1,3}((;[0-9]{1,3})*)?)?[m...
Sometimes you want Angular to watch an object only until a certain state is reached (e.g. an object appears in the scope). Angular's $watch returns a method that you...
...can call to remove that watch. For example: unwatch = $scope.$watch 'user', (user) -> if user?
unwatch()
DevDocs combines multiple API documentations in a fast, organized, and searchable interface. Here's what you should know before you start: You don't have to use your mouse — see...
...the list of keyboard shortcuts The search supports fuzzy matching (e.g. "bgcp" brings up "background-clip") To search a specific documentation, type its name (or an abbreviation), then Tab
In the DevTools settings, there's a "Shortcuts" section. Found these keyboard shortcuts there: General ESC Toggle drawer CTRL + ~ or CTRL + ` Show console in drawer Styles SHIFT + up/down
...debugging page repaint times) CTRL + hover above element in the DOM list Don't show the yellow dimensions tooltip (useful when the tooltip covers just the area you need to...
It's every developer's nightmare: SQL queries that get large and unwieldy. This can happen fairly quickly with the addition of multiple joins, a subquery and some complicated filtering...
...logic. I have personally seen queries grow to nearly one hundred lines long in both the financial services and health industries. Luckily Postgres provides two ways to encapsulate large queries...
Most coding agents (Codex, Cursor, Copilot, etc. have standardized on AGENTS.md as the shared instruction file. Only Claude uses CLAUDE.md, never AGENTS.md. If your repo only has an AGENTS.md, Claude...
...Code silently ignores it. Fix A: Import AGENTS.md into CLAUDE.md Create a CLAUDE.md at the repo root that imports your AGENTS.md: @AGENTS.md Claude loads the imported file at session start...
Current webkit browsers like Chrome and Safari have a special variable in their consoles that refers to the selected DOM node in the elements panel. This lets us easily inspect...
...Angular scopes. Right click in the page and click "Inspect" to open the Dev Tools Select the element you're interested in from the elements panel Focus the console (in...
Deadlocks only occur if two transactions in separate threads compete for the same rows in the database. They usually (but not necessarily) only happen when trying to update or otherwise...
...lock several rows in different order. Solving deadlocks is potentially complicated, so here are a few pointers: MySQL should always detect the deadlock right when it happens, and will throw...
...clean out the database before each example. Use :transaction where possible. Use :deletion for Selenium features or when you have a lot of MyISAM tables. Understanding database cleaning
...to clean out your test database after each test, so the next test can start from a blank database. To do so you have three options: Wrap each test in...
We use CarrierWave in many of our projects to store and serve files of various formats - mostly images. A common use case of CarrierWave's DSL is to "process" the...
...versions", for example different resolutions of the same image. Now we could go one step further: What if we want to create versions that have a different file extension than...
When dealing with external data sources, you may have to deal with improperly encoded strings. While you should prefer deciding on a single encoding with the data-providing party, you...
...can not always force that on external sources. It gets worse when you receive data with encoding declaration that does not reliably fit the accompanying string bytes.
...end up with web page bloat. But loading a webpage is much more than shipping bytes down the wire. Once the browser has downloaded our page’s scripts it then...
...dive into this phase for JavaScript, why it might be slowing down your app’s start-up & how you can fix it. The article author also tested 6000+ production sites...
There are several ways to merge two (or more) PDF files to a single file using the Linux command line. If you're looking for graphical tools to edit or...
...annotate a PDF, we have a separate card for that. PDFtk (recommended) PDFtk is a great toolkit for manipulating PDF documents. You may need to install it first (sudo apt...
...context) is run outside of transactions, so data created here will bleed into other specs before(:example) is run before each spec inside it, Generally, you'll want a clean...
...setup for each spec so that they are independent of other specs in the same context. Example Consider this spec: describe User, 'something' do before :context do @user = User.make
Ubuntu has a package mysql-sandbox that lets you install multiple MySQL versions into your user home: Install mysql-sandbox sudo apt install mysql-sandbox Download the version of MySQL...
...you want to use from mysql.com: https://dev.mysql.com/downloads/file/?id=480427 Make sure to choose "Generic Linux" instead of "Ubuntu" so you get a .tar.gz instead of .deb cd into the directory...
...duplication from the code is a seemingly easy task. In many cases it is pretty straight-forward – you look at similar bits of code and you move them to a...
...in other places. Right? No, not really. It is true that code that looks similar might be an indicator that there’s a duplication but it’s not the definitive...