Tutorial by Examples: en

The += operator is a common extension that adds the specified content to the end of the variable, separated by a space. x = hello x += world Variable references in the right-hand side will be expanded if and only if the original variable was defined as a simply-expanded variable.

This is such a common requirement in iOS development, and it was always something that had to be done purely in code (or using images - yuck!). Now it's incredibly easy to preview his kind of thing in Interface Builder, there's absolutely no excuse for not using it. Here's the code:- import UIKit ...

Yield true on the stack if currentpoint executes successfully, or false if it signals a /nocurrentpoint error. {currentpoint pop pop} stopped not % bool

The sequence for an error is usually: error is triggered by looking up the error name in errordict and executing this procedure. the errordict procedure calls signalerror, passing it the error name. signalerror takes snapshots of the stacks, saving the snapshots in $error, and then calls stop. ...

The documentation for docker events provides details, but when debugging it may be useful to launch a container and be notified immediately of any related event: docker run... & docker events --filter 'container=$(docker ps -lq)' In docker ps -lq, the l stands for last, and the q for quiet. Th...

The replica set is a group of mongod instances that maintain the same data set. This example shows how to configure a replica set with three instances on the same server. Creating data folders mkdir /srv/mongodb/data/rs0-0 mkdir /srv/mongodb/data/rs0-1 mkdir /srv/mongodb/data/rs0-2 Starting ...

Defining the list of Ints trait IntList { ... } class Cons(val head: Int, val tail: IntList) extends IntList { ... } class Nil extends IntList { ... } but what if we need to define the list of Boolean, Double etc? Defining generic list trait List[T] { def isEmpty: Boolean def head:...

Loading custom fonts can be lead to a bad performance. I highly recommend to use this little helper which saves/loads your already used fonts into a Hashtable. public class TypefaceUtils { private static final Hashtable<String, Typeface> sTypeFaces = new Hashtable<>(); /** * Get...

As an alternative to using Html.ActionLink to generate links in a view, you can use Html.RouteLink To make use of this feature, you need to configure a route, for example: public static void RegisterRoutes(RouteCollection routes) { routes.MapRoute( "SearchResults", "{...

Usually the case when one wants to change a field type to another, for instance the original collection may have "numerical" or "date" fields saved as strings: { "name": "Alice", "salary": "57871", "dob": "198...

Puppet provide official documention for both open-source and enterprise versions. you can find it here

// Mixin to generate hidden classes @mixin generate-hidden-classes { @each $bp in map-keys($grid-breakpoints) { .hidden-#{$bp} { @include media-breakpoint-only($bp) { display: none !important; } } } } // Call to the mixin @include generate-hidden-classes(...

@Component @Lazy public class Demo { .... .... } @Component public class B { @Autowired @Lazy // If this is not here, Demo will still get eagerly instantiated to satisfy this request. private Demo demo; ....... }

Remove the token from the client storage to avoid usage Tokens are issued by the server and you can not force browsers to delete a cookie/localStorage or control how external clients are managing your tokens. Obviously if attackers have stolen the token before logout they still could use the token,...

Mark invalid tokens, store until their expiration time and check it in every request. Blacklist breaks JWT statelessness because it requires maintaining the state. One of the benefits of JWT is no need server storage, so if you need to revoke tokens without waiting for the expiration, think also ab...

Set expiration time short and rotate tokens. Issue a new access token every few request. Use refresh tokens to allow your application to obtain new access tokens without needing to re-authenticate Refresh and access tokens access token: Authorize access to a protected resource. Limited lifetim...

Basic architecture examples on how development for embedded systems works (i.e. IDEs, cross-compiling, downloading, in-line debugging, JTAG,...) and what would be the minimum requirements for starting. It would be worth mentioning different approaches and platforms from begginers-higher level to ad...

Project structure project/ group_vars/ development inventory.development playbook.yaml These variables will be applied to hosts under the development group due to the filename. --- ## Application app_name: app app_url: app.io web_url: cdn.io app_friendly: New App env_type: ...

Sometimes it is necessary to do an action on repeat or in a sequence. This example will make the node fade in and out a total of 3 times. In Swift: let node = SKSpriteNode(imageNamed: "image") let actionFadeOut = SKAction.fadeOutWithDuration(1.0) let actionFadeIn = SKAction.fadeInWithD...

To select an element by an exact HTML attribute use the css locator pattern [attribute=value] //selects the first element with href value '/contact' element(by.css('[href="/contact"]')); //selects the first element with tag option and value 'foo' element(by.css('option[value="f...