PHP Best Practices a short, practical guide for common and confusing PHP tasks anoxia neonatal definicion

Despite that, it’s the most popular language on the web today. Because of its long history, you’ll find lots of tutorials on how to do basic things like password hashing and database access. The problem is that out of five tutorials, you have do anxiety attacks cause chest pain a good chance of finding five totally different ways of doing something. Which way is the “right” way? Do any of the other ways have subtle bugs or gotchas? It’s really hard to find out, and you’ll be bouncing around the internet trying to pin down the right answer.

It’s a guide suggesting the best direction to take when facing one of the common low-level tasks a PHP programmer might encounter that are unclear because nanoxia deep silence 4 claw of the many options PHP might offer.

For example: connecting to a database is a common task with a large amount of possible solutions in PHP, not all of them good ones—thus, it’s included in this document.

You should use PDO’s prepared statement functions to help prevent SQL injection attacks. Using the bindvalue() function ensures that your SQL is safe from first-order SQL injection attacks. (this isn’t 100% foolproof though, see further reading for more details.) in the past, this had to be achieved with some arcane combination of “magic quote” functions. PDO makes all that gunk unnecessary. Example

There are a few different ways to delimit blocks of PHP: , , , and . While the shorter ones might be more convenient to type, they’re disabled by default and must be enabled by configuring the PHP server with anoxia adalah the short_open_tag option. Therefore the only method that’s guaranteed to work on all PHP servers is . If you ever plan on deploying your PHP to a server whose configuration you can’t control, then you should always use .

• when including a closing ?> tag in a pure PHP file (for example, in a file that only contains a class definition), make sure not to leave any trailing newlines after it. While the PHP parser safely “eats” a single newline character after the closing tag, any other newlines hypoxic ischemic encephalopathy emedicine might be outputted to the browser and possibly confuse things if you’re outputting any HTTP headers later.

• when writing a web app targeting older versions of IE, make sure not to leave a newline between any closing ?> tag and the html tag. Old versions of IE will enter quirks mode if they encounter any white space, including newlines, before the doctype declaration. This isn’t an issue for newer versions of IE and other, more advanced browsers. (read: every other browser besides IE.)

A lot of ink has been anxiety disorder nhs spilled about whether to define strings with single quotes (‘) or double quotes (“). Single-quoted strings aren’t parsed, so whatever you’ve put in the string, that’s what will show up. Double-quoted strings are parsed and any PHP variables in the string are evaluated. Additionally, escaped characters like \n for newline and \t for tab are not evaluated in single-quoted strings, but are evaluated in double-quoted strings.

Because double-quoted strings are evaluated at run time, the theory is that using single-quoted strings will improve performance because PHP won’t have to evaluate every single string. While nanoxia deep silence 120mm pwm this might be true on a certain scale, for the average real-life application the difference is so small that it doesn’t really matter. So for an average app, it doesn’t matter what you choose. For extremely high-load apps, it might matter a little. Make a choice depending cerebral anoxia on what your app needs, but whatever you choose, be consistent. Further reading

Before ubuntu 14.04, the APC project was both an opcode cache and a memcached-like key-value store. Since the version of PHP that ships since ubuntu 14.04 now includes a built-in opcode cache, APC was split into the apcu project, which is essentially APC’s key-value storage functionality—AKA the “user cache”, or the “u” in apcu anoxie cérébrale—without the opcode-cache parts. Installing apcu

You might also find advice suggesting you use the strip_tags() function. While strip_tags() is technically safe to use, it’s a “dumb” function in the sense that if the input is invalid HTML (say, is missing an ending tag), then strip_tags() might remove much more content than you expected. As such it’s not a great choice either, because non-technical users often use the characters in communications.

If you read the section on validating email addresses, you might also be considering using the filter_var() function anoxia. However the filter_var() function has problems with line breaks, and requires non-intuitive configuration to closely mirror the htmlentities() function. As such it’s not a good choice either. Sanitization for simple requirements

HTML purifier has the advantage over strip_tags() because it validates the HTML before sanitizing it. That means if the user has inputted invalid HTML, HTML purifier has a better chance of preserving the intended meaning of the HTML than strip_tags() does. It’s also highly customizable, allowing you to whitelist a subset of HTML to keep in the output.

The basic string operations, like concatenating two strings and assigning strings to variables, don’t need anything special for UTF-8. However most string functions, like strpos() and strlen(), do need special consideration. These functions often have an mb_* counterpart: for example, mb_strpos() and mb_strlen(). Together, these counterpart functions are called the multibyte string functions. The multibyte string functions are specifically what is anoxic encephalopathy mean designed to operate on unicode strings.

Additionally, you should use the mb_internal_encoding() function at the top of every PHP script you write (or at the top of your global include script), and the mb_http_output() function right after it if your script is outputting to a browser. Explicitly defining the encoding of your strings in every script will save you a lot of headaches down the road.

Finally, many PHP functions that operate on strings have an optional parameter letting you specify the character encoding. You should always explicitly indicate UTF-8 when given the option. For example, htmlentities() has an option for character encoding, and you anoxic zone should always specify UTF-8 if dealing with such strings. UTF-8 at the OS level

Fortunately for us, the version of PHP we’re talking about features the hypoxic anoxic brain injury anthony much friendlier datetime class. This class encapsulates all the functionality and more of the old date functions in one easy-to-use class, with the bonus of making time zone conversions much simpler. Always use the datetime class for creating, comparing, changing, and displaying dates in PHP. Example

PHP’s loose typing system offers many different ways of checking a variable’s value. However it also presents a lot of problems. Using == to check if a value is null or false can return false positives if the value is actually an empty string or 0. Isset() checks whether a variable has a value that is not null, but doesn’t check against boolean false.

The is_null() function accurately checks if a value is null, and the is_bool() function checks if it’s a boolean value (like false), but there anxiety attack cure tips’s an even better option: the === operator. === checks if the values are identical, which is not the same as equivalent in PHP’s loosely-typed world. It’s also slightly faster than is_null() and is_bool(), and looks nicer than using a function for comparison. Example