• PS5 Release Date
• PS5 Price
• Will PS5 Be Backwards Compatible With PS4 games?
• PS5 Specs And Disc Drive
• PS5 Controller
• Will PS5 Support PSVR?
• The Logo
• Energy Efficiency
• PS5 Games
• PS5 UI

Sony's official video comparing performance of PS4 Pro vs next-gen PlayStation pic.twitter.com/2eUROxKFLq

— Takashi Mochizuki (@mochi_wsj) May 21, 2019

Do you want to replace all occurrences of a pattern in a string? You’re in the right place! This article is all about the re.sub(pattern, string) method of Python’s re library.

Let’s answer the following question:

How Does re.sub() Work in Python?

The re.sub(pattern, repl, string, count=0, flags=0) method returns a new string where all occurrences of the pattern in the old string are replaced by repl.

Here’s a minimal example:

>>> import re

>>> text = 'C++ is the best language. C++ rocks!'

>>> re.sub('C\+\+', 'Python', text) 'Python is the best language. Python rocks!'

>>> 

The text contains two occurrences of the string ‘C++’. You use the re.sub() method to search all of those occurrences. Your goal is to replace all those with the new string ‘Python’ (Python is the best language after all).

Note that you must escape the ‘+’ symbol in ‘C++’ as otherwise it would mean the at-least-one regex.

You can also see that the sub() method replaces all matched patterns in the string—not only the first one.

But there’s more! Let’s have a look at the formal definition of the sub() method.

Specification

re.sub(pattern, repl, string, count=0, flags=0)

The method has four arguments—two of which are optional.

• pattern: the regular expression pattern to search for strings you want to replace.
• repl: the replacement string or function. If it’s a function, it needs to take one argument (the match object) which is passed for each occurrence of the pattern. The return value of the replacement function is a string that replaces the matching substring.
• string: the text you want to replace.
• count (optional argument): the maximum number of replacements you want to perform. Per default, you use count=0 which reads as replace all occurrences of the pattern.
• flags (optional argument): a more advanced modifier that allows you to customize the behavior of the method. Per default, you don’t use any flags. Want to know how to use those flags? Check out this detailed article on the Finxter blog.

The initial three arguments are required. The remaining two arguments are optional.

You’ll learn about those arguments in more detail later.

Return Value:

A new string where count occurrences of the first substrings that match the pattern are replaced with the string value defined in the repl argument.

Regex Sub Minimal Example

Let’s study some more examples—from simple to more complex.

The easiest use is with only three arguments: the pattern ‘sing’, the replacement string ‘program’, and the string you want to modify (text in our example).

>>> import re

>>> text = 'Learn to sing because singing is fun.'

>>> re.sub('sing', 'program', text) 'Learn to program because programing is fun.'

Just ignore the grammar mistake for now. You get the point: we don’t sing, we program.

But what if you want to actually fix this grammar mistake? After all, it’s programming, not programing. In this case, we need to substitute ‘sing’ with ‘program’ in some cases and ‘sing’ with ‘programm’ in other cases.

You see where this leads us: the sub argument must be a function! So let’s try this:

import re def sub(matched): if matched.group(0)=='singing': return 'programming' else: return 'program' text = 'Learn to sing because singing is fun.'

print(re.sub('sing(ing)?', sub, text))

# Learn to program because programming is fun.

In this example, you first define a substitution function sub. The function takes the matched object as an input and returns a string. If it matches the longer form ‘singing’, it returns ‘programming’. Else it matches the shorter form ‘sing’, so it returns the shorter replacement string ‘program’ instead.

How to Use the count Argument of the Regex Sub Method?

What if you don’t want to substitute all occurrences of a pattern but only a limited number of them? Just use the count argument! Here’s an example:

>>> import re

>>> s = 'xxxxxxhelloxxxxxworld!xxxx'

>>> re.sub('x+', '', s, count=2) 'helloworld!xxxx'

>>> re.sub('x+', '', s, count=3) 'helloworld!'

In the first substitution operation, you replace only two occurrences of the pattern ‘x+’. In the second, you replace all three.

You can also use positional arguments to save some characters:

>>> re.sub('x+', '', s, 3) 'helloworld!'

But as many coders don’t know about the count argument, you probably should use the keyword argument for readability.

How to Use the Optional Flag Argument?

As you’ve seen in the specification, the re.sub() method comes with an optional fourth flag argument:

re.sub(pattern, repl, string, count=0, flags=0)

What’s the purpose of the flags argument?

Flags allow you to control the regular expression engine. Because regular expressions are so powerful, they are a useful way of switching on and off certain features (for example, whether to ignore capitalization when matching your regex).

Here’s how you’d use it in a minimal example:

>>> import re

>>> s = 'xxxiiixxXxxxiiixXXX'

>>> re.sub('x+', '', s) 'iiiXiiiXXX'

>>> re.sub('x+', '', s, flags=re.I) 'iiiiii'

In the second substitution operation, you ignore the capitalization by using the flag re.I which is short for re.IGNORECASE. That’s why it substitutes even the uppercase ‘X’ characters that now match the regex ‘x+’, too.

What’s the Difference Between Regex Sub and String Replace?

In a way, the re.sub() method is the more powerful variant of the string.replace() method which is described in detail on this Finxter blog article.

Why? Because you can replace all occurrences of a regex pattern rather than only all occurrences of a string in another string.

So with re.sub() you can do everything you can do with string.replace() but some things more!

Here’s an example:

>>> 'Python is python is PYTHON'.replace('python', 'fun') 'Python is fun is PYTHON'

>>> re.sub('(Python)|(python)|(PYTHON)', 'fun', 'Python is python is PYTHON') 'fun is fun is fun'

The string.replace() method only replaces the lowercase word ‘python’ while the re.sub() method replaces all occurrences of uppercase or lowercase variants.

Note, you can accomplish the same thing even easier with the flags argument.

>>> re.sub('python', 'fun', 'Python is python is PYTHON', flags=re.I) 'fun is fun is fun'

How to Remove Regex Pattern in Python?

Nothing simpler than that. Just use the empty string as a replacement string:

>>> re.sub('p', '', 'Python is python is PYTHON', flags=re.I) 'ython is ython is YTHON'

You replace all occurrences of the pattern 'p' with the empty string ''. In other words, you remove all occurrences of 'p'. As you use the flags=re.I argument, you ignore capitalization.

Related Re Methods

There are five important regular expression methods which you should master:

• The re.findall(pattern, string) method returns a list of string matches. Read more in our blog tutorial.
• The re.search(pattern, string) method returns a match object of the first match. Read more in our blog tutorial.
• The re.match(pattern, string) method returns a match object if the regex matches at the beginning of the string. Read more in our blog tutorial.
• The re.fullmatch(pattern, string) method returns a match object if the regex matches the whole string. Read more in our blog tutorial.
• The re.compile(pattern) method prepares the regular expression pattern—and returns a regex object which you can use multiple times in your code. Read more in our blog tutorial.
• The re.split(pattern, string) method returns a list of strings by matching all occurrences of the pattern in the string and dividing the string along those. Read more in our blog tutorial.

These five methods are 80% of what you need to know to get started with Python’s regular expression functionality.

Where to Go From Here?

You’ve learned the re.sub(pattern, repl, string, count=0, flags=0) method returns a new string where all occurrences of the pattern in the old string are replaced by repl.

Learning Python is hard. But if you cheat, it isn’t as hard as it has to be:

Download 8 Free Python Cheat Sheets now!

Last modified on December 3rd, 2019 by Vincy.

Do you know online consumers in the US spent $517 billion last year? Which is a 15% increase from the previous year? eCommerce is an old domain, but still, it disrupts the tech world.

These days, the live shopping cart software have a remarkable business scope. They are increasing in the number day by day. There is a significant market today to sell products in an online store.

PHP is the main technology that runs the majority of the shopping cart software on the Internet. Developing a full-fledged PHP shopping cart software is not as easy as it looks.

In this article, we are going to see how to create a featured sticky shopping cart script in PHP.  In Shopify like the eCommerce platform, it gives sticky shopping cart checkout as a feature.

I used jQuery and CSS to make the shopping cart unit sticky on a fixed position on page scroll. So, it will make the cart unit be always near to access and encourage the users to checkout.

This article will guide you with simple steps to create a shopping cart in PHP. If you are planning to create a shopping cart with a modern outlook and features,  it will help you to achieve this.

What is inside?

1. Advantages of sticky shopping cart
2. PHP sticky shopping cart example overview
3. File structure
4. Landing page with product gallery and shopping cart components
5. Render product tiles in a gallery
6. Display cart items from PHP Session
7. Manage Cart actions edit, delete, empty
8. Product database table SQL script
9. PHP Shopify like sticky shopping cart example output

eCommerce software with sticky shopping cart checkout has many advantages,

• It gives an enriched modern feel to the application.
• It helps users to see the cart status at any moment.
• It encourages users to checkout and thus increasing the conversion.

This Shopify-like sticky shopping cart software in PHP uses database and PHP sessions. It manages products in the database and shopping cart items in the PHP session.

It has a product gallery, cart HTML table and supports cart actions like add, edit and delete. These action handlers use AJAX to invoke code added with server endpoints.

The functionalities supported by this example are here with the corresponding description.

Fetching product data from the database:
A PHP MySQL code section accesses product database to read the data like product name, code, price, and preview images. If data found then this will result in an array of products.

Create product gallery with add-to-cart option:
Create a product gallery with an add-to-cart option. A PHP loop iterates product array to form the gallery view. Each product in the gallery has an add-to-cart button.

Manage the cart with PHP session:
I have used the PHP session array to store and manage the cart items.

Handling the add, edit, delete and empty cart:
This example code supports users to add a new product into the cart. A HTML table will display the cart item with edit quantity, remove an entry and more options.

File structure

The below screenshot shows the file structure of this example.

• view/product-gallery.php – It includes a PHP loop to iterate the products to form the gallery.
• view/shopping-cart.php – It contains a HTML table to display the cart item from the PHP session.
• css/style.css – It has the styles to showcase product gallery. It helps in shopping cart software design containing appropriate cart action controls.
• cart.js – This JavaScript file contains action handlers to process requests via AJAX. It also contains code to fix the shopping cart panel in a fixed position while scrolling.
• handle-cart-ep.php – This is the PHP endpoint invoked from AJAX code to add, edit, remove cart items.
• tblproduct.sql – This SQL contains product database CREATE and INSERT statements.
• DataSource.php – This is a generic file we used for our examples requires a database.
• data – This directory is the product image source used while creating the gallery.

A landing page with product gallery and shopping cart components

This HTML code includes the PHP source to render product gallery, shopping cart software pagee. It also shows a sticky cart icon with the current cart items count.

By clicking this icon, a script will toggle the shopping cart window.

This HTML includes cart.js JavaScript file. It contains all the jQuery AJAX code needed for performing cart actions and UI update.

<?php namespace Phppot; use \Phppot\Cart; session_start(); require_once 'Model/Cart.php'; $cartModel = new Cart(); ?> <HTML> <HEAD> <TITLE>Shopify like sticky shopping cart in PHP</TITLE> <link href="./assets/css/phppot-style.css" type="text/css" rel="stylesheet" /> <script src="./vendor/jquery/jquery.min.js" type="text/javascript"></script> <script src="./vendor/jquery/jquery-ui.js"></script> </HEAD> <BODY> <?php require_once './view/product-gallery.php'; ?> <div id="floating-cart-container"> <div id="cart-icon-container"> <img id="cart-icon" src="./view/images/cart-icon.png" alt="cartimg"> <div id="count"> <?php echo $cartModel->cartSessionItemCount; ?> </div> </div> <div id="shopping-cart"> <div id="tbl-cart"> <div id="txt-heading"> <div id="cart-heading">Shopping Cart</div> <div id="close"></div> </div> <div id="cart-item"> <?php require_once './view/shopping-cart.php'; ?> </div> </div> </div> </div> <script src="./assets/js/cart.js"></script> </BODY> </HTML> 

Render product tiles in a gallery

The product gallery is a HTML container embedded with PHP-MySQL script. The PHP code prepares MySQL select statement to get the product result in an array.

By iterating this array result with a PHP foreach statement, it reads the database row data. With this product data, it forms the gallery tile on each loop iteration.

The gallery tile shows products name, price and a preview image in a card-like view. Also, it contains an add-to-cart button.

This’s button’s click event invokes AJAX to add the particular product to the cart session. Each product has a unique code which is the reference to create and manage each cart session index.

Below code shows the HTML used to show a gallery view for this shopping cart software example.

<?php require_once __DIR__ . './../Model/Product.php'; $productModel = new Product(); ?> <div id="product-grid"> <div class="txt-heading">Products</div> <?php $productResult = $productModel->getAllProduct(); if (! empty($productResult)) { foreach ($productResult as $key => $value) { ?> <div class="product-item" data-name="<?php echo $productResult[$key]["name"]; ?>" data-price="<?php echo "$" . $productResult[$key]["price"]; ?>"> <div class="product-image"> <img src="<?php echo $productResult[$key]["image"]; ?>" id="<?php echo $productResult[$key]["code"]; ?>"> </div> <div> <strong><?php echo $productResult[$key]["name"]; ?></strong> </div> <div class="product-price"><?php echo "$" . $productResult[$key]["price"]; ?></div> <input type="button" id="add_<?php echo $productResult[$key]["code"]; ?>" value="Add to cart" class="btnAddAction" on‌Click="cartAction('add', '<?php echo $productResult[$key]["code"]; ?>')" /> </div> <?php } } ?> </div> 

Add-to-Cart from Product Gallery

The add-to-cart button in each product tile is the trigger to add a cart item into the PHP session. When the user clicks on the ‘Add to Cart’ button, it calls the cartAction() function to execute the add action via AJAX.

In this function call, it has the product id as an argument. In PHP the code fetches the product code, price to add to the cart session.

In this example, the switch case handles cart actions. It request and process add, edit (item quantity), remove (single cart item) and empty cart.

In the “add” case I checked if the current cart item already exists in the cart session. If so, I will update its quantity, otherwise, I will push the entire item array into the session index. The product code is the session index of each cart item to keep the uniqueness. The addToCart function has the code to add the cart item into the PHP session.

case "add": $cartModel->addToCart(); break; 

Model/Product.php

<?php use \Phppot\DataSource; class Product { private $ds; function __construct() { require_once __DIR__ . './../lib/DataSource.php'; $this->ds = new DataSource(); } function getAllProduct() { $query = "SELECT * FROM tblproduct ORDER BY id ASC"; $result = $this->ds->select($query); return $result; } } 

Display shopping cart items from PHP Session

This code shows the HTML table containing the list of cart items added by the user. The cart data is dynamic from the PHP session.

In shopping-cart.php file, it iterates the $_SESSION[“cart”] array and displays the cart row. Each row has data like product title, price, quantity. It also has the option to edit the item quantity and to delete a single item from the cart.

This cart window is sticky that lets the users access the cart and see the status at any time. Also, it shows the total item price by summing up the individual cart items.

<?php namespace Phppot; use \Phppot\Cart; require_once __DIR__ . './../Model/Cart.php'; $cartModel = new Cart(); ?> <input type="hidden" id="cart-item-count" value="<?php echo $cartModel->cartSessionItemCount; ?>"> <?php if ($cartModel->cartSessionItemCount > 0) { ?> <table width="100%" id="cart-table" cellpadding="10" cellspacing="1" border="0"> <tbody> <tr> <th>Name</th> <th>Quantity</th> <th class="text-right">Price</th> <th class="text-right">Action</th> </tr> <?php $item_total = 0; $i = 1; foreach ($_SESSION["cart_item"] as $item) { ?> <tr> <td><?php echo $item["name"]; ?></td> <td><input type="number" name="quantity" class="quantity" value="<?php echo $item['quantity']; ?>" data-code='<?php echo $item["code"]; ?>' size=2 on‌Change="updatePrice(this)" /> <input type="hidden" class='total' name="total" value="<?php echo $item["price"]; ?>" /></td> <td align=right class="prc" id="price" <?php echo $i;?>><?php echo $item["price"]; ?></td> <?php $i++; ?> <td class="text-right"><a on‌Click="cartAction('remove','<?php echo $item["code"]; ?>')" class="btnRemoveAction"><img src="./view/images/icon-delete.png" alt="Remove Item" /></a></td> </tr> <?php $item_total += ($item["price"] * $item['quantity']); } ?> <tr id="tot"> <td colspan="3" align=right><strong>Total (USD): </strong> <span id="total"><?php echo $item_total;?></span></td> <td align="right"><a id="btnEmpty" on‌Click="cartAction('empty', '');">Empty Cart</a></td> </tr> </tbody> </table> <div id="checkout">Checkout</div> <?php } else { ?> <div id="empty-cart">Your cart is empty</div> <?php } ?> 

Handle shopping cart actions edit, remove, empty on checkout page

In each row of the showing cart tabular window, it displays editable quantity with an input box. Users can increment or decrement the cart item quantity of a particular item.

On changing the quantity, and AJAX code will send the data to get the calculated price based on the new quantity. Then, it will update the price in the row.

There is a remove option for each cart item. By clicking the remove action, an ajax call will request PHP code to perform the remove action. It will pass the product code as an argument to clear the particular cart session index.

Also, the shopping cart window has the option to empty the cart with one single click.

The below code shows the switch cases created to trigger and perform cart actions.

cart.js

function cartAction(action, product_code) { var queryString = ""; if (action != "") { switch (action) { case "add": queryString = 'action=' + action + '&code=' + product_code + '&quantity=' + $("#qty_" + product_code).val(); break; case "remove": queryString = 'action=' + action + '&code=' + product_code; break; case "empty": queryString = 'action=' + action; break; } } jQuery.ajax({ url: "ajax/handle-cart-ep.php", data: queryString, type: "POST", success: function (data) { $("#cart-item").html(data); $("#count").text($("#cart-item-count").val()); }, error: function () {} }); } function updatePrice(obj){ var quantity = $(obj).val(); var code = $(obj).data('code'); queryString = 'action=edit&code=' + code + '&quantity=' + quantity; $.ajax({ type: 'post', url: "ajax/handle-cart-ep.php", data: queryString, success: function(data) { $("#total").text(data); } }); } $(document).ready(function () { $("#cart-icon-container").click(function () { $("#shopping-cart").toggle(); }); var top = parseInt($("#shopping-cart").height())/2; $("#shopping-cart").css("margin-top", "-" + top + "px"); }); 

ajax/handle-cart-ep.php

<?php namespace Phppot; use \Phppot\Cart; require_once __DIR__ . './../Model/Cart.php'; $cartModel = new Cart(); session_start(); if (! empty($_POST["action"])) { switch ($_POST["action"]) { case "add": $cartModel->addToCart(); break; case "edit": $totalPrice = $cartModel->editCart(); print $totalPrice; exit; break; case "remove": $cartModel->removeFromCart(); break; case "empty": $cartModel->emptyCart(); break; } } require_once '../view/shopping-cart.php'; ?> 

Model/Cart.php

This is the model class used to create, edit and clear cart sessions.

<?php namespace Phppot; use \Phppot\DataSource; class Cart { private $ds; public $cartSessionItemCount = 0; function __construct() { require_once __DIR__ . './../lib/DataSource.php'; $this->ds = new DataSource(); if (! empty($_SESSION["cart_item"]) && is_array($_SESSION["cart_item"])) { $this->cartSessionItemCount = count($_SESSION["cart_item"]); } } function addToCart() { $query = "SELECT * FROM tblproduct WHERE code = ?"; $paramType = "s"; $paramArray = array($_POST["code"]); $productByCode = $this->ds->select($query, $paramType, $paramArray); $itemArray = array( $productByCode[0]["code"] => array( 'name' => $productByCode[0]["name"], 'code' => $productByCode[0]["code"], 'quantity' => '1', 'price' => $productByCode[0]["price"] ) ); if (! empty($_SESSION["cart_item"])) { if (in_array($productByCode[0]["code"], $_SESSION["cart_item"])) { foreach ($_SESSION["cart_item"] as $k => $v) { if ($productByCode[0]["code"] == $k) $_SESSION["cart_item"][$k]["quantity"] = $_POST["quantity"]; } } else { $_SESSION["cart_item"] = array_merge($_SESSION["cart_item"], $itemArray); } } else { $_SESSION["cart_item"] = $itemArray; } if (! empty($_SESSION["cart_item"]) && is_array($_SESSION["cart_item"])) { $this->cartSessionItemCount = count($_SESSION["cart_item"]); } } function editCart() { if (! empty($_SESSION["cart_item"])) { $total_price = 0; foreach ($_SESSION["cart_item"] as $k => $v) { if ($_POST["code"] == $k) { $_SESSION["cart_item"][$k]["quantity"] = $_POST["quantity"]; } $total_price = $total_price + ($_SESSION["cart_item"][$k]["quantity"] * $_SESSION["cart_item"][$k]["price"] ); } return $total_price; } if (! empty($_SESSION["cart_item"]) && is_array($_SESSION["cart_item"])) { $this->cartSessionItemCount = count($_SESSION["cart_item"]); } } function removeFromCart() { if (! empty($_SESSION["cart_item"])) { foreach ($_SESSION["cart_item"] as $k => $v) { if ($_POST["code"] == $k) unset($_SESSION["cart_item"][$k]); if (empty($_SESSION["cart_item"])) unset($_SESSION["cart_item"]); } } if (! empty($_SESSION["cart_item"]) && is_array($_SESSION["cart_item"])) { $this->cartSessionItemCount = count($_SESSION["cart_item"]); } } function emptyCart() { unset($_SESSION["cart_item"]); $this->cartSessionItemCount = 0; } } 

Product database table SQL script

The following SQL script has the CREATE and the INSERT query. It will help to put the product table in your development environment.

CREATE TABLE IF NOT EXISTS `tblproduct` ( `id` int(8) NOT NULL AUTO_INCREMENT, `name` varchar(255) NOT NULL, `code` varchar(255) NOT NULL, `image` text NOT NULL, `price` double(10,2) NOT NULL, PRIMARY KEY (`id`), UNIQUE KEY `product_code` (`code`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=14 ; -- -- Dumping data for table `tblproduct` -- INSERT INTO `tblproduct` (`id`, `name`, `code`, `image`, `price`) VALUES (1, 'FinePix Pro2 3D Camera', '3DcAM01', 'product-images/camera.jpg', 1500.00), (2, 'Luxury Ultra thin Wrist Watch', 'wristWear03', 'product-images/watch.jpg', 300.00), (3, 'XP 1155 Intel Core Laptop', 'LPN45', 'product-images/laptop.jpg', 800.00), (4, 'Water Bottle', 'wristWear02', 'product-images/external-hard-drive.jpg', 600.00); 

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We’ve made it to the end of yet another week, this time bringing with it a successful legal battle for Nintendo relating to the Wii Remote and the news that the DOOM team has “bantered” with Nintendo to get Doomguy in Smash. We can dream.

Now, though, it’s time to put all of that aside and discuss our weekend gaming plans. Members of Team Nintendo Life have done just that and we’d love you to join in via the comment and poll sections below. Enjoy!

PJ O’Reilly, reviewer

This weekend I’m going to be taking advantage of the slight lull in big releases to jump back into some stuff I really need to finish up. I’ll be polishing off Luigi’s Mansion 3 and Yoshi’s Crafted World with my kids as well as jumping into my latest purchase Dragon Quest XI, which I’ve only just discovered is absolutely amazing, a proper must-own game in my opinion.

I’m also still making my way through my Xmas Labo kits, although I‘ve now entirely abandoned the instructions as they’re too complex for me and am instead creating a giant cardboard Jeff Goldblum to keep me company when I feel a bit lonely or sad.

Anthony Dickens, managing director

It’s long overdue but I’m in desperate need to blow away the physical cobwebs after an over-indulgent Christmas and New Year. Having finally gotten my hands on a copy of Ring Fit Adventure from overseas (it’s still out of stock in the UK) I intend to clear away the coffee table and see what the fuss is all about in this fitness-based RPG adventure. Deep Heat plasters are on standby, as will be the coffee. Wish me luck, my body is ready.

Ollie Reynolds, reviewer

At the moment, I’m still spending more or less every spare moment playing DOOM (OG) – I’m working my way through the game on Nightmare difficulty, and there’s just something so immediately compelling about its gameplay that few modern games can replicate. Or maybe it’s just the nostalgia!

Time permitting, I’m also quite tempted to jump back into Pokémon Sword at some point. Since the Diamond and Pearl days, I always seem to lose steam with Pokémon games about halfway through, and the exact same has happened with Sword. I feel like if I can’t get back into it this time, then I may well be done for good…

Austin Voigt, contributing writer

I’ve been getting very into Ring Fit Adventure, people. I was sceptical at first, but it’s quickly become a very addictive game to play. In fact, every time I sit down to play a different game, I usually end up picking up Ring Fit and gamer-cising instead (yeah, I just made that up). So I’ll be totally honest – that’s probably all I’ll play this weekend… at least, until the holiday weight and guilt are gone.

Ryan Craddock, staff writer

I’m getting ever closer to completing Luigi’s Mansion 3 – I’m pretty sure I’ve only got about four-or-so floors to go – and I’ve been really enjoying seeing the variety of design choices for each one as you make your way up the hotel. Hopefully I’ll find enough time to get through another floor or two over the weekend, leaving me with just the finale to enjoy next week.

I’ve also been playing Animal Crossing: New Leaf for the first time (I know, sorry!) in preparation for the new game, but I’ve actually stopped playing over the last few days so that I don’t get burnt out from it. I think I’m pretty much sold on grabbing the new game in March after this short playthrough, so I’m now having to keep myself away from the thing I’ve just fell in love with to prepare. What a first-world problem, huh?

Gavin Lane, staff writer

With the return of Captain Picard to our TV screens after a 26-year hiatus, I’m rather excited to sit down for an hour and watch the first episode of Star Trek: Picard. Once that’s done and I’ve wiped the space dust from my eyes, I’ll probably be in the mood for some space-based gaming but, as discussed earlier this week, there really aren’t many games set in the Trek universe that measure up to the show itself – certainly not on Nintendo systems. With that in mind, I’ll probably get my space kicks from something like Everspace or perhaps I’ll make a start on that Starlink: Battle For Atlas pack I picked up for a tenner before Christmas.

If they don’t scratch the itch, I may fire up Catastronauts for some calamitous co-op fun. Overcooked 2 might have received an update this week, but you can’t run around a spaceship pretending you’re Geordi La Forge in that game, can you?

Gonçalo Lopes, contributing writer

SD Gundam G Generation Cross Rays is my equivalent to your Pokémon. I can’t stop playing or thinking about it every other minute and will continue to further develop my ever-growing army of SD metal monstrosities this weekend. On the other mech front, DAEMON X MACHINA continues to process smoothly yet I can hardly recognize my avatar any more due to extensive augmentation.

Could not resist so I already cleared the wonderful 198X last night and hope the second half of it manages to surpass these original five ‘retro’ games. Unexpected package from the East brought Super Robot Wars X along with an old favourite Ninja Jajamaru Collection and both will see some action this weekend for sure. Now, if only I could find some free time to use my Mario Kart Racing Wheel Pro Deluxe…

My game of the week is obviously Warhammer 40,000: Space Wolf because picking anything else would clearly be heresy. Remain vigilant, brothers.

As always, thanks for reading! Make sure to leave a vote in the poll above and a comment below with your gaming choices over the next few days…

In this 2017 GDC talk, UX designer Celia Hodent discusses the UX challenges of retention and how to use cognitive science and the scientific method to make your game enjoyable and engaging in the long term.

Hodent’s talk was rich with practical advice and useful examples, as well as insights gleaned during her time at Epic Games working on games like Fortnite.

It was a practical and useful talk, especially if you’re passionate about how good design can make players’ lives better, and now it’s free to watch over on the official GDC YouTube channel!

In addition to this presentation, the GDC Vault and its accompanying YouTube channel offers numerous other free videos, audio recordings, and slides from many of the recent Game Developers Conference events, and the service offers even more members-only content for GDC Vault subscribers.

Those who purchased All Access passes to recent events like GDC or VRDC already have full access to GDC Vault, and interested parties can apply for the individual subscription via a GDC Vault subscription page. Group subscriptions are also available: game-related schools and development studios who sign up for GDC Vault Studio Subscriptions can receive access for their entire office or company by contacting staff via the GDC Vault group subscription page.

Systems management can be a difficult task. Not only does one need to determine what the end state should be but, more importantly, how to ensure systems attain and remain at this state. Doing so in an automated fashion is just as critical, because there may be a large number of target instances. In regard to enterprise Java middleware application servers, these instances are typically configured using a set of XML based files. Although these files may be manually configured, most application servers have a command-line based tool or set of tools that abstracts the end user from having to worry about the underlying configuration. WebSphere Liberty includes a variety of tools to manage these resources, whereas JBoss contains the jboss-cli tool.

Although each tool accomplishes its utilitarian use case as it allows for proper server management, it does fail to adhere to one of the principles of automation and configuration management: idempotence. Ensuring the desired state does not equate to executing the same action with every iteration. Additional intelligence must be introduced. Along with idempotence, another core principle of configuration management is that values be expressed declaratively and stored in a version control system.

Jcliff is a Java-based utility that is built on top of the JBoss command-line interface and allows for the desired intent for the server configuration to be expressed declaratively, which in turn can be stored in a version control system. We’ll provide an overview of the Jcliff utility including inherent benefits, installation options, and several examples showcasing the use.

The problem space

Before beginning to work with Jcliff, one must be cognizant of the underlying JBoss architecture. The configuration of the JBoss server can be expressed using Dynamic Model Representation (DMR) notation. The following is an example of DMR:

{ "system-property" => { "foo" => "bar", "bah" => "gah" } } 

The DMR example above describes several Java system properties that will be stored within the JBoss configuration. These properties can be added using the JBoss CLI by executing the following command:

/system-property=foo:add(value=bar) /system-property=bah:add(value=gah) 

The challenge is that the same commands cannot be executed more than once. Otherwise, an error similar to the following is produced.

{ "outcome" => "failed", "failure-description" => "WFLYCTL0212: Duplicate resource [(\"system-property\" => \"foo\")]", "rolled-back" => true } 

Where Jcliff excels is that it includes the necessary intelligence to determine the current state of the JBoss configuration and then applying the appropriate configurations necessary. This is critical to adopting proper configuration management when working with JBoss.

Installing Jcliff

With a baseline understanding of Jcliff, let’s discuss the methods in which one can obtain the utility. First, Jcliff can be built from source from the project repository, given that it’s a freely open source project. Alternatively, Jcliff can be installed using popular software packaging tools in each of the primary operating system families.

Linux (rpm)

Jcliff can be consumed on a Linux package when capable of consuming an rpm using a package manager.

First, install the yum repository:

$ cat /etc/yum.repos.d/jcliff.repo [jcliff] baseurl = http://people.redhat.com/~rpelisse/jcliff.yum/ gpgcheck = 0 name = JCliff repository 

Once this repository has been added, JCliff can be installed by using Yum or Dnf:

Using yum:

$ sudo yum install jcliff 

Or using dnf:

$ sudo dnf install jcliff 

Manual installation

Jcliff can also be installed manually without the need to leverage a package manager. This is useful for those on Linux distributions that cannot consume rpm packages. Simply download and unpack the archive from the release artifact from the project repository.

$ curl -O \ https://github.com/bserdar/jcliff/releas...ist.tar.gz $ tar xzvf jcliff-2.12.1-dist.tar.gz 

Place the resulting Jcliff folder in the destination of your choosing. This location is known as JCLIFF_HOME. Add this environment variable and add it to the path as described below:

$ export JCLIFF_HOME=/path/to/jcliff-2.12.1/ $ export PATH=${JCLIFF_HOME}/bin:${PATH} 

At this point, you should be able to execute the jcliff command.

OSX

While users on OSX can take advantage of the manual installation option, those making use of the brew package manager can use this tool as well.

Execute the following commands to install Jcliff using Brew:

$ brew tap redhat-cop/redhat-cop $ brew install redhat-cop/redhat-cop/jcliff 

Windows

Fear not, Windows users; you can also make use of Jcliff without having to compile from source. Windows, in the same vein as OSX, does not have an official package manager, but Chocolatey has been given this role.

Execute the following command to install Jcliff using Chocolatey:

$ choco install jcliff 

Using Jcliff

With Jcliff properly installed on your machine, let’s walk through a simple example to demonstrate the use of the tool. As discussed previously, Jcliff makes use of files that describe the target configuration. At this point, you may have questions like: What is the format of these configurations, and where do I begin?

Let’s take a simple example and look into adding a new system property to the JBoss configuration. Launch an instance of JBoss and connect using the JBoss command-line interface:

$ /bin/jboss-cli.sh --connect [standalone@localhost:9990 /] ls /system-property [standalone@localhost:9990 /] 

Now, use Jcliff to update the configuration. First, we’ll need to create a Jcliff rule. The rule resembles DMR format and appears similar to the following:

$ cat jcliff-prop { "system-property" => { "jcliff.enabled" => "true", } } 

Then we can simply ask JCliff to run this script against our JBoss server:

$ jcliff jcliff-prop Jcliff version 2.12.4 2019-10-02 17:03:40:0008: /core-service=platform-mbean/type=runtime:read-attribute(name=system-properties) 2019-10-02 17:03:41:0974: /system-property=jcliff.enabled:add(value="true") 

Use the JBoss CLI to verify the changes have been applied.

$ “${JBOSS_HOME}/bin/jboss-cli.sh” --connect --command=/system-property=jcliff.enabled:read-resource { "outcome" => "success", "result" => {"value" => "true"} } 

To demonstrate how Jcliff handles repetitive executions, run the previous Jcliff command again. Inspect the output.

$ jcliff jcliff-prop Jcliff version 2.12.4 2019-10-02 17:05:34:0107: /core-service=platform-mbean/type=runtime:read-attribute(name=system-properties) 

Notice that only 1 command was executed against the JBoss server instead of two? This action was a result of assessing the current state within JBoss and determining that no action was necessary to reach the desired state. Mission accomplished.

Next steps

Although the preceding scenario was not overly complex, you should now have the knowledge necessary to understand the capabilities and functionality of the Jcliff utility as well as the benefits afforded through declarative configurations and automation. When building out enterprise-grade systems, however, Jcliff would not be executed manually. You would want to integrate the utility into a proper configuration management tool that employs many of the automation and configuration principles described earlier. Fortunately, Jcliff has been integrated into several popular configuration management tools.

In an upcoming article, we’ll provide an overview of the configuration management options available with Jcliff, along with examples that will allow you to quickly build out enterprise-grade confidence with Jcliff.

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