When you repeat a subpattern with a *, + or {...} operator, you may choose between greedy, lazy and possessive modes. Switching modes may affect the result and performance of your regular expressions...
...In the worst case, an ill-suited mode may make your regular expression so slow that it can DoS your application (Examples are the ActiveRecord's PostgreSQL CVE...
These steps are now part of Spreewald. The step definitions below allow you to test the filename suggested by the server: When I follow "Export as ZIP"
...absence of error end end end Standard validations can be tested with less code The shoulda-matchers gem gives you some RSpec matchers to test the application of standard Rails...
...validations. Under the hood should-matchers uses the same recipe as outlined above (set invalid state, run validations, check for message, etc.), but your tests will have a lot less...
...full-app localization before and assign an hour estimate to each of these points. Static text Static strings and template text in app must be translated: Screens, mailer templates, PDF...
...templates, helpers, sometimes models. Use the native Rails I18n API. Avoid Gettext if possible. Native I18n has good integration with Rails (you already have it!), but you need to come...
...be a quick fix for an existing app. It also ensures that future uploaders get safe-ish defaults when the developer forgets to define an allowlist for concrete uploaders (see...
...you can also go with this more relaxed CSP: Content-Security-Policy: default-src 'self'; script-src 'none'; object-src 'none' While this does not fix users uploading executables etc...
Database connections are not thread-safe. That's why ActiveRecord uses a separate database connection for each thread. For instance, the following code uses 3 database connections: 3.times do
...a new connection end end These three connections will remain connected to the database server after the threads terminate. This only affects threads that use ActiveRecord. You can rely on...
Sometimes you want to find the inverse of an ActiveRecord scope. Depending on what you want to achieve, this is quite easy with Rails 7, and a bit more complicated...
...with Rails 6 and below, or when the inverse scope may contain NULL values. [1] There are two different ways of "inverting a scope": As an example, consider the following...
The Node Version Manager allows installing multiple NodeJS versions and switching between them. By default, it does not automatically switch versions when entering a directory that holds a .nvmrc file...
...COMMAND feature. So here is my take on it. Note that it is much shorter, it probably does a few less smart things, but has been working great for me...
...example, the configuration for SASS files looks like this: { test: /\.(scss|sass)$/i, use: [ { loader: 'style-loader', options: {...
{ loader: 'css-loader', options: {...
{ loader: 'postcss-loader', options: {...
{ loader: 'sass-loader', options...
...loaders (which are usually npm modules) are run on it in reverse order. First, the sass-loader converts SASS to regular CSS. Then, the postcss-loader uses PostCSS to postprocess...
...Saving files to a directory that is not shared between deploys or servers If you save your uploads to a made up directory like "RAILS_ROOT/uploads", this directory goes away...
...after every deploy (since every release gets a new). Also this directory is not shared between multiple application servers, so your uploads are randomly saved to one local filesystem or...
Sentry offers a UI to define custom fingerprint and stack trace rules at https://sentry.io/settings/projects/$project-id/issue-grouping. Fingerprint rules have this syntax: 1 or more key:value conditions, followed by...
...exception(self, fingerprint: [self.class.name]) end end Overriding the fingerprint from within the application (with the sentry-ruby gem) You can also set a custom fingerprint from within the application:
...features, this concept might be confusing for developers who have been programming in more static languages, such as Java or C#. This card should help understanding the basic concepts of...
...you might think of a "container" that holds metadata, variables and methods. Metadata describes stuff like the object's class or its object_id which uniquely identifies it. From an...
Rails has configurable time zones, while Ruby is always in the server's time zone Thus, using Ruby's time API will give you wrong results for...
...zones, because their existence is a fact. You can, however, tell Rails the only single time zone you'll need is the server's. config.time_zone = "Berlin" # Local time zone...
Speaker today is Henning Koch, Head of Development at makandra. This talk will be in German with English slides. Introduction As web developers we work with JavaScript every day, even...
...that inherits all properties form User's // child prototype and may then be extended with Student-specific methods. Student.prototype = Object.create(User.prototype) Student.prototype.isEnrolled = function() { return typeof this.studentNumber === 'number' }
The shell variable PS1 holds your bash prompt. You might want to change it to serve your needs best. Here is how to: General non-printing escape sequences in your...
=> ✔ mycomputer ~/projects/platforms master > _ # Arne's epic timestamped prompt with return status indicator and status-colored (green if fresh, or red if unstaged, or yellow if staged) git branch:
...this matter, as the image rendering depends on multiple factors. At least the operation system, browser or image viewer software and monitor influence the resulting image colors on your screen...
...possibility to upload images, they will most likely contain tons of EXIF metadata and sometimes exotic color profiles like eciRGB. We want to get rid of the metadata, as it...
This guide shows how to create an AngularJS application that consumes more and more memory until, eventually, the browser process crashes on your users. Although this guide has been written...
...for Angular 1 originally, most of the advice is relevant for all client-side JavaScript code. How to observe memory consumption To inspect the amount of memory consumed by your...
...to load fast it's recommended to optimize images. Ideally an image's file size should be as small as possible while still being of decent quality. This card demonstrates...
...tools for image optimization Use identify to fetch information about pictures. convert can change size/quality and strip meta information. Both commands are supplied by ImageMagick. $ identify in.jpg in.jpg JPEG 294x440...
...response includes caching headers like Expires or Cache-Control, their validity depends on the server's Date header if present. Otherwise, the browser uses its local time. This can lead...
...for authentication. The cookie for this feature might include an Expires attribute, specifying its validity: Set-Cookie: remember_me=abc123; Expires=Fri, 15 Dec 2023 12:00:00 GMT
MySQL will use the index when your query is well-formed: mysql> EXPLAIN SELECT * FROM users WHERE email = 'foo@example.com'; +----+-------------+-------+-------+----------------------+----------------------+---------+-------+------+-------+ | id | select_type | table | type | possible_keys | key | key_len...
...ref | rows | Extra | +----+-------------+-------+-------+----------------------+----------------------+---------+-------+------+-------+ | 1 | SIMPLE | users | const | index_users_on_email | index_users_on_email | 768 | const | 1 | | +----+-------------+-------+-------+----------------------+----------------------+---------+-------+------+-------+ However, indexes are not used if you are passing incorrect data types...
...have a README that gives the reader a quick overview of the project. Its size will vary as projects differ in complexity, but there should always be some introductory prose...
...for a developer to read when starting on it. Purpose That's already the main purpose of a project README: Give a new developer a quick overview of the project...
...good to know them all, but we recommend Option 0 or Option 1. Option 0: Sub-query with conditions from a scope You may also pass the existing User.active scope...
...the joined table: Post.where(user: User.active) This will make a single query. It uses a sub-query, which is slow in MySQL, but fast in PostgreSQL: SELECT * FROM posts WHERE...
...partial template. # _weather.html.erb The weather is <%= condition %> # index.html.erb render partial: 'weather', locals: { condition: 'good' } Since this is a common use-case, there's a shorthand way of rendering the partial...
...Notice that it's not possible to mix the explicit partial: 'template' and the shorthand arguments for defining local variables. So either use longform variant or the shorthand variant, but...
This raises "Could not find first Keyword": describe Keyword do it { should validate_uniqueness_of(:text) } end Do this instead...