I got this question the other day: how to send a POST request from PHP with correctly-formatted JSON data? I referred to the slides from my web services tutorial for the answer, and I thought I’d also put it here, with a bit of explanation. After all, publishing your slides is all very well, but if you didn’t see the actual tutorial, I often think they aren’t too useful.
We can’t send post fields, because we want to send JSON, not pretend to be a form (the merits of an API which accepts POST requests with data in form-format is an interesting debate). Instead, we create the correct JSON data, set that as the body of the POST request, and also set the headers correctly so that the server that receives this request will understand what we sent:
All these settings are pretty well explained on the curl_setopt() page, but basically the idea is to set the request to be a POST request, set the json-encoded data to be the body, and then set the correct headers to describe that post body. The CURLOPT_RETURNTRANSFER is purely so that the response from the remote server gets placed in $result rather than echoed. If you’re sending JSON data with PHP, I hope this might help!
cURL allows transfer of data across a wide variety of protocols, and is a very powerful system. It’s widely used as a way to send data across websites, including things like API interaction and oAuth. cURL is unrestricted in what it can do, from the basic HTTP request, to the more complex FTP upload or interaction with an authentication enclosed HTTPS site. We’ll be looking at the simple difference between sending a GET and POST request and dealing with the returned response, as well as highlighting some useful parameters.
Before we can do anything with a cURL request, we need to first instantiate an instance of cURL – we can do this by calling the function curl_init();, which returns a cURL resource. This function takes one parameter which is the URL that you want to send the request to, however, in our case, we’ll hold off doing that for now and set it an alternatively way later.
Once we’ve got a cURL resource, we can begin to assign some settings, below is a list of some of the core ones that I set
CURLOPT_RETURNTRANSFER – Return the response as a string instead of outputting it to the screen
CURLOPT_CONNECTTIMEOUT – Number of seconds to spend attempting to connect
CURLOPT_TIMEOUT – Number of seconds to allow cURL to execute
CURLOPT_USERAGENT – Useragent string to use for request
CURLOPT_URL – URL to send request to
CURLOPT_POST – Send request as POST
CURLOPT_POSTFIELDS – Array of data to POST in request
We can set a setting by using the curl_setopt() method, which takes three parameters, the cURL resource, the setting and the value. So, to set the URL that we’re sending the request to as http://testcURL.com:
When all of the options are sent, and the request is ready to send, we can call the curl_exec() method which will execute the cURL request. This function can return three different things:
false – if there is an error executing the request
true – if the request executed without error and CURLOPT_RETURNTRANSFER is set to false
The result – if the request executed without error and CURLOPT_RETURNTRANSFER is set to true
Using the previous example, where we are wanting to get the result back, we would use the following:
$result = curl_exec($curl);
With $result now containing the response from the page – which might be JSON, a string or a full blown site’s HTML.
When you’ve sent a request and got the result back, you should look to close the cURL request so that you can free up some system resources, this is as simple as calling the curl_close() method which as with all other functions takes the resource as its parameter.
A GET request is the default request method that is used, and is very straight forward to use, infact all of the examples so far have been GET requests. If you want to send parameters along in the request you simply append them to the URL as a query string such as http://testcURL.com/?item1=value&item2=value2.
So for example to send a GET request to the above URL and return the result we would use:
// Get cURL resource$curl = curl_init();
// Set some options - we are passing in a useragent too here
CURLOPT_RETURNTRANSFER => 1,
CURLOPT_URL => 'http://testcURL.com/?item1=value&item2=value2',
CURLOPT_USERAGENT => 'Codular Sample cURL Request'
// Send the request & save response to $resp$resp = curl_exec($curl);
// Close request to clear up some resources
The sole difference between the POST and GET request syntax is the addition of one setting, two if you want to send some data. We’ll be setting CURLOPT_POST to true and sending an array of data through with the setting CURLOPT_POSTFIELDS
So for example switching the above GET request to be a POST request, we would use the following code:
// Get cURL resource$curl = curl_init();
// Set some options - we are passing in a useragent too here
CURLOPT_RETURNTRANSFER => 1,
CURLOPT_URL => 'http://testcURL.com',
CURLOPT_USERAGENT => 'Codular Sample cURL Request',
CURLOPT_POST => 1,
CURLOPT_POSTFIELDS => array(
item1 => 'value',
item2 => 'value2'
// Send the request & save response to $resp$resp = curl_exec($curl);
// Close request to clear up some resources
There you have a POST request that will work the same as our GET request above and return the response back to the script so that you can use it as you want.
As much as we all hate errors, you really need to take care to account for any eventuality with cURL as ultimately you will not have control over the site(s) that you are sending your request to, you cannot guarantee that the response will be in the format that you want, or that the site will even be available.
There are a few functions that you can use to handle errors and these are:
curl_error() – returns a string error message, will be blank '' if the request doesn’t fail.
You might want to look at using the setting CURLOPT_FAILONERROR as true if you want any HTTP response code greater than 400 to cause an error, instead of returning the page HTML.
cURL is a behemoth, and has many many possibilities. Some sites might only serve pages to some user agents, and when working with APIs, some might request you send a specfici user agent, this is something to be aware of.
If you’ve been wondering about this question, the answer is YES!
There are many tools and libraries in the PHP ecosystem that we can use when developing an application. Some of them are grouped in frameworks which provide us some preconfigured structure. But with such variety of tools, we can easily make our own structure according to our needs.
In this article I will take a look and list some popular libraries for the different technical needs of our applications, such as talking to the database, routing, providing output to the web and etc.
But first, let’s get back to basics and explain what a framework is.
According to the general definition:
Framework is a universal, reusable software platform to develop software applications, products and solutions. To simplify, it is kind of library, piece of software which provides web developers with code base and consistent, standardized ways of creating web applications.
Your project will have to choose from tons of PHP libraries, frameworks and components. In addition, there are many PHP libraries, frameworks and components to adopt from. And these are called project dependencies like Composer and PEAR. Until recently PHP didn’t find acceptable way to manage these project dependencies. Some of the dependencies explained below show how can you use PHP without frameworks.
Composer repositories like Composer, PEAR, VSC
A dependency manager which installs packages locally with package description and name and version. In basics, package is just a directory containing something. In this case, it is a PHP code, but in theory it could be anything.
Repository is a package source. Practically it is a list of packages/versions. The composer will search in all your repositories to find the packages your project requires.
Databases like MySQL, PostgreSQL, NoSQL
There will be times when your PHP code will use database to persist information and there are few options to connect and interact with your database.
Object-relational mapping (ORM) like Doctrine, Readbean, Eloquent
The ORM manages the translation of object into relational databases and vice-versa. This creates so-called “virtual object database” which can be used from within the programming language.
Templating like Twig, Blade, Mustache, Plain PHP Templates
Templates provide convenient way of separating the controller and domain logic from your presentation logic. They typically contain the HTML of the application, but may be also used for other formats such as XML. Templates are often referred to as “views” which make up part of the second component of the model-view-controller (MVC) software architecture pattern.
HTTP like Guzzle, Buzz, HTTPFul, Requests
This is protocol destined for sending documents back and forth over the World Wide Web. A protocol is a set of rules that is used to identify which messages can be transferred and which are suitable answers to other queries.
Mailers like PHPMailer, SwiftMailer, Stampie
Mailers are libraries used in order to give the application an ability to send mails.
File Systems like Gaufrette, Flysystem, CSV
Libraries for file manipulation and MIME (Multipurpose Internet Mail Extensions) type detection.
Testing like PHP Spec, PHP Unit
Writing automated tests for your PHP code is considered to be a best practice and can lead to well-build applications. Automated tests are a great tool for making sure your application does not break when you are making changes or adding new functionality and should not be ignored.
However some of the dependencies will not be used by your application and may not be essential, therefore you can easily create your own PHP project containing custom dependencies that are most suitable for the project.
To sum up, using framework can bring to faster development as it tries to save your work by make you define an overly complex configuration that has to accommodate every possible use case.
Learning something from scratch is almost always an arduous affair — you simply have no idea as to where to start, or not to start, to kick things off. I loathed learning about the idiosyncrasies of C++’s syntax when all I wanted to learn were some darn programming concepts. As I’m sure you can agree, this is a less than ideal situation.
This is where the Nettuts+ “The Best Way to Learn” series comes into the picture. This series is intended to be your blueprint, your road map, your plan of action for learning your topic of choice! You don’t have to worry about finding the best resources, sorting out the bad ones, and figuring out what to learn next. It’s all here. Just follow it, step by step.
Today, we’re going to figure out the best way to learn PHP.
Looking for a Quick Solution?
If you need immediate help, try working with one of the experienced PHP developers on Envato Studio. They can fix PHP errors, add features, or even create new apps for you.
Assignment #1: Disregard the Naysayers
If you’re reading this, chances are that you’ve Googled a lot to decide which language to learn and how. And without a doubt, you must have run into a ton of articles about how language X is so much better than PHP – and PHP is going to die through obscurity soon.
Haters gonna hate!
As the popular saying goes, haters gonna hate! PHP has been at the helm of the web as you know it and that’s for a very good reason. It’s a mature language, has excellent documentation and a massive number of learning resources along with a great variety of utilities built around it.
And let’s not forget the sheer proliferation of hosts and frameworks PHP has spawned. Like Heroku like hosting? Don’t worry, there are a number of excellent options for PHP as well!
Assignment #2: Install PHP through [X]AMP
You could just install PHP but it gets quite boring without a server and some sort of database to play around with. And as a beginner, it’s not really trivial work to get all of these installed and configure each to work with the others without issue.
This is where you grab a package such as XAMPP. These life savers typically install Apache, your web server, along with mySQL, a database system along with PHP significantly cutting down on set up time.
Bonus points if you’re the code monkey type and install everything by hand.
You can also try LAMP, WAMP…….
Assignment #3: Learn the Fundamentals
Before I send you off to alternate sources for PHP enlightenment, let me first refer you to our very own series for absolute beginners from none other than your favorite editor, Jeffrey Way.
In this series, over the course of 40+ screencasts, everything from installing PHP to variables, from functions to working with MySQL is covered.
For learning basics, w3schools can be a great place. try it……..
Assignment #4: Sign up with Khan Academy and Lynda
Khan Academy may sound like an odd choice since there are no PHP lessons in there but trust me, it’s a good choice. What you can’t find in pure PHP, you can find in the basic of programming. For example, if you’re new to the entire programming hoopla, this is a great place to start.
Another great place to start is Lynda. Here at Envato we have immense respect for those teaching there — the content is usually top notch and cover their topics well. And they cover a vast range of topics as well. If you need a specific lesson, this is where you should begin.
Assignment #5: Read a Few, Good Books
The videos should give you an very good springboard, but, hopefully, hungry for more knowledge. The below books should give you a more elaborate introduction and lots of varied topics for you to devour.
If you feel bored reading the initial portions, good, just skip ahead to the portions where your head hurts.
“So why another PHP book? Well, not everyone who uses PHP is a programmer. PHP is the most common dynamic web language used by designers, if their web sites require dynamic functionality, and there are hordes of novice users who want to set up dynamic web sites.”
“PHP for Absolute Beginners starts at the very beginning stages of web programming, showing even the most inexperienced web developer, through examples, how to build a basic content management system. The book dives directly into writing web applications with accompanying explanation rather than explaining elements of the language and then showing examples.”
“PHP Cookbook has a wealth of solutions for problems that you’ll face regularly. With topics that range from beginner questions to advanced web programming techniques, this guide contains practical examples — or “recipes” — for anyone who uses this scripting language to generate dynamic web content.”
Assignment #6: Create Something Simple
This is the perfect time to build something simple with your new found knowledge.
Alright! With all those information swirling inside, you should feel like a rockstar. If not, don’t worry, it’s completely normal. Talk to me later so we can share notes about how daft we feel.
This is the perfect time to try and build something simple with your new found knowledge. It’s best to not try to build something too complicated and fail though — it’s a lot more disheartening than you’d think. Imagine being rejected for the first time. Now multiply it by a few hundred and you’ll be close.
Since you’re just starting out, play it safe and build something absolutely basic like a CRUD app. Nothing major — a few inputs and an ‘uncool’ table to display saved results. This tiny exercise will test your knowledge of a lot of PHP basics including the much vaunted ‘interfacing with a database’ skill.
Assignment #7: Create Something a Little More Complicated
Feeling better now? You should! You gazed upon where there was naught and said ‘This won’t do!’ and created something from scratch. If it were me, I’d be pumped. Let’s use it to extend our knowledge a little more.
While a simple CRUD app is a great start, you’d ideally need more complicated. A simple login/user system is absolutely great for this.
You get to learn how sessions work, how basic authentication is done, how to implement basic security measure and a ton more.
Note: If you’re in need of a little guidance, start here.
Assignment #8: Try out a Lean, Lightweight Framework
At this point, after creating a non-trivial system, you probably have noticed how repetitive some of the work is. Why the heck do you need to write your own sessions class or work on hashing passwords yourself? The answer, my friends, is to go with a lightweight framework.
A framework abstracts a lot of the repetitive, boilerplate features in your typical application thus freeing up your brain to actually getting things done.
Note: CodeIgniter, a very lightweight, yet powerful framework. If you prefer Kohana, we do that too!
Assignment #9: Try out a Full Stack Framework
Now that you’ve been with a lightweight framework, you can now check out the alternate path — a full stack framework. A full stack framework typically ships with a lot more features including code generators, ORMs and an inbuilt server. An excellent choice would be CakePHP — the PHP equivalent of Rails.
The reason you need to check these out later is because there is a lot of ‘magic’ going on. Without a solid understanding of how lightweight frameworks work, it’s hard to really dig into the better featured ones since you’ll mostly be lost and won’t understand how things work.
Note: I recommends both FuelPHP and Laravel as top-notch, modern PHP frameworks.
Assignment #10: Build Something Awesome
With all that information behind you, giving you Indiana’s swagger, now is the time to build something truly awesome. This is the final destination for PHP nirvana — and the choice is up to you.
So what exactly should you be building? Here are a few ideas:
A blog is always a safe option. There are a ton of open source solutions for you to get inspiration for the software architecture and the functionality requirements are unambiguous.
It’s a little old school but a discussion board is another excellent choice. Moderator rights and post counts, ahoy! If you need a little guidance, this tutorial is a great place to start.
Or if you’re too hip for any of these, build yourself a project management application or even just a todo list. They’re always fun to build and you’ll almost always end up using it personally.
Of course, there are just suggestions. No one is stopping you from building a multi-user, realtime chatroom or a service which receives input from random internet strangers and lights up stuff in your room. No one’s judging, go crazy!
Assignment #11: Advance into Development Eliteness
Development is as much about the workflow as much as it is about the code.
Development is as much about the workflow as much as it is about the code. Recently, a typical developer’s workflow has been massively improved by version control as well as platform as a service solutions.
Version control, as expected, frees you up from having to manage revisions manually while PaaS solutions save you from having to do a lot of sys admin work just to get your app to scale.
You can getting started with Git.
Assignment #12: Get Involved and Be Up to Date
New techniques and tools are being introduced everyday.
The web development industry is rarely in a state of equilibrium — everything is changing all the time. New techniques and tools are being introduced everyday and it’s important that you not only read about them but also start contributing.
Find a little glitch in some framework? Submit a patch. Added some new functionality? Patch away! These not only earn you good karma but also valuable points on your resume.
And, oh, about the keeping up to date stuff? Subscribe to our feed and follow us and I promise you’ll know all you need to know!
Assignment #13: Keep an Open Mind and Explore
Even though that you are a master of the PHP domain, you can’t afford to, or shouldn’t, rest. PHP is a grand language but that doesn’t mean that it does absolutely everything perfectly.
There is an ever increasing number of new languages out there each adding their own spin to solving a very specific problem that you simply can’t afford to miss out on. And learning something new something doesn’t really wipe out knowledge gained earlier does it? Well, except Star Wars, of course. Those new movies were a crapshoot.
Ruby, Python and Clojure are some of the languages that I’m constantly amazed by and I think they deserve your attention as well. Neither of these languages are necessarily ‘better’ than PHP but each of them do things their own unique way and you owe yourself a chance to take a look and find out whether that approach is for you.
Well, this is the end of the road, partner! Hopefully, this plan can help you become a PHP master and, indeed, take over the world.
If you feel that I’m missing some obvious resources here, feel free to yell at me in the comments section below and I’ll update this article whilst crying silently. Thank you so much for reading!
Why? How can this code be fixed to work correctly?
The problem here is that strpos() returns the starting position index of $str1 in $str2 (if found), otherwise it returns false. So in this example, strpos() returns 0 (which is then coerced to false when referenced in the if statement). That’s why the code doesn’t work properly.
The correct solution would be to explicitly compare the value returned by strpos() to false as follows:
Note that we used the !== operator, not just the != operator. If we use !=, we’ll be back to the problem that 0 is coerced to false when referenced in a boolean expression, so 0 != false will evaluate to false.
What will be the output of the code below and why?
The term $x++ says to use the current value of $x and then increment it. Similarly, the term $x-- says to use the current value of $x and then decrement it.
The increment operator (++) has higher precedence then the sum operator (+) in order of operations.
With these points in mind, we can understand that $x+++$x++ is evaluated as follows: The first reference to $x is when its value is still 5 (i.e., before it is incremented) and the second reference to $x is then when its value is 6 (i.e., before it is again incremented), so the operation is 5 + 6 which yields 11. After this operation, the value of $x is 7 since it has been incremented twice.
Similarly, we can understand that $x---$x-- is evaluated as follows: The first reference to $x is when its value is still 7 (i.e., before it is decremented) and the second reference to $x is then when its value is 6 (i.e., before it is again decremented), so the operation is 7 - 6 which yields 1. After this operation, the value of $x is back to its original value of 5, since it has been incremented twice and then decremented twice.
What will be the values of $a and $b after the code below is executed? Explain your answer.
$a = '1';
$b = &$a;
$b = "2$b";
Both $a and $b will be equal to the string "21" after the above code is executed.
The statement $b = &$a; sets $b equal to a reference to $a (as opposed to setting $b to the then-current value of $a). Thereafter, as long as $b remains a reference to $a, anything done to $a will affect $b and vice versa.
So when we subsequently execute the statement $b = "2$b", $b is set equal to the string "2" followed by the then-current value of $b (which is the same as $a) which is 1, so this results in $b being set equal to the string "21" (i.e., the concatenation of "2" and "1"). And, since $b is a reference to $a, this has the same affect on the value of $a, so both end up equal to "21".
What will be the output of each of the statements below and why?
var_dump(0123 == 123) will output bool(false) because the leading 0 in 0123 tells the PHP interpreter to treat the value as octal (rather than decimal) value, and 123 octal is equal to 83 decimal, so the values are not equal.
var_dump('0123' == 123) will output bool(true) since the string 0123 will automatically be coerced to an integer when being compared with an integer value. Interestingly, when this conversion is performed, the leading 0 is ignored and the value is treated as a decimal (rather than octal) value, so the values are bother 123 (decimal) and are therefore equal.
var_dump('0123' === 123) outputs bool(false) since it performs a more strict comparison and does not do the automatic type coercion of the string to an integer.
What is the problem with the code below? What will it output? How can it be fixed?
You may also see two warnings generated, similar to the following:
Warning: array_merge(): Argument #2 is not an array
Warning: array_merge(): Argument #1 is not an array
The issue here is that, if either the first or second argument to array_merge() is not an array, the return value will be NULL. For example, although one might reasonably expect that a call such as array_merge($someValidArray, NULL) would simply return $someValidArray, it instead returns NULL! (And to make matters worse, this is not documented well at all in the PHP documentation.)
As a result, the call to $testArray = array_merge($testArray, $referenceTable['val2']) evaluates to $testArray = array_merge($testArray, 3) and, since 3 is not of type array, this call to array_merge() returns NULL, which in turn ends up setting $testArray equal to NULL. Then, when we get to the next call to array_merge(), $testArray is now NULL so array_merge() again returns NULL. (This also explains why the first warning complains about argument #2 and the second warning complains about argument #1.)
The fix for this is straightforward. If we simply typecast the second argument to an array, we will get the desired results. The corrected array_merge() calls would therefore be as follows:
Surprisingly to many, the above code will output bool(true) seeming to imply that the and operator is behaving instead as an or.
The issue here is that the = operator takes precedence over the and operator in order of operations, so the statement $x = true and false ends up being functionally equivalent to:
$x = true; // sets $x equal to true
true and false; // results in false, but has no affect on anything
This is, incidentally, a great example of why using parentheses to clearly specify your intent is generally a good practice, in any language. For example, if the above statement $x = true and false were replaced with $x = (true and false), then $x would be set to false as expected.
What will $x be equal to after the statement $x = 3 + "15%" + "$25"?
If you perform an arithmetic operation on an expression that contains a string, that string will be interpreted as the appropriate numeric type for the purposes of evaluating the expression. So, if the string begins with one or more numeric characters, the remainder of the string (if any) will be ignored and the numeric value is interpreted as the appropriate numeric type. On the other hand, if the string begins with a non-numeric character, then it will evaluate to zero.
With that understanding, we can see that "15%" evaluates to the numeric value 15 and "$25" evaluates to the numeric value zero, which explains why the result of the statement $x = 3 + "15%" + "$25" is 18 (i.e., 3 + 15 + 0).
After the code below is executed, what will be the value of $text and what will strlen($text) return? Explain your answer.
$text = 'John ';
$text = 'Doe';
After the above code is executed, the value of $text will be the string “John D” (i.e., “John”, followed by 5 spaces, followed by “D”) and strlen($text) will return 11.
There are two things going on here.
First of all, since $text is a string, setting a single element of $text simply sets that single character to the value specified. The statement $text = 'Doe' therefore sets that single character to 'D' (i.e., the first character in the string "Doe", since an element of a string can only be a single character).
Secondly, $text = 'Doe' says to set the 11th character of the string (remember that indices are zero-based) to 'D'. Prior to that statement, though, the length of the string $text ("John ") was only 5. Whereas compilers or interpreters in other languages might barf (with something akin to an out-of-bounds-index error) when you then attempt to set the 11th character of a 5 character string, PHP instead is very “accommodating” and instead allows this and sets all intermediate characters to blanks.
PHP_INT_MAX is a PHP constant that corresponds to the largest supported integer value (value is based on the version of PHP being run and the platform it is running on).
Assume that var_dump(PHP_INT_MAX) will yield int(9223372036854775807).
In that case, what will be the result of var_dump(PHP_INT_MAX + 1)? Also, what will be the result of var_dump((int)(PHP_INT_MAX + 1))?
NOTE: It’s not important to supply the exact value when answering the question, but rather to explain what will happen and why.
The result of var_dump(PHP_INT_MAX + 1) will be displayed as a double (in the case of this specific example, it will display double(9.2233720368548E+18)). The key here is for the candidate to know that PHP handles large integers by converting them to doubles (which can store larger values).
And interestingly, the result of var_dump((int)(PHP_INT_MAX + 1)) will be displayed as a negative number (in the case of this specific example, it will display int(-9223372036854775808)). Again, the key here is for the candidate to know that the value will be displayed as a negative number, not to know the precise value.
How would you sort an array of strings to their natural case-insensitive order, while maintaing their original index association?
The function asort() is a variant of the standard function sort() that preserves the index association. The three flags used above SORT_STRING, SORT_FLAG_CASE and SORT_NATURAL forces the sort function to treat the items as strings, sort in a case-insensitive way and maintain natural order respectively.
Note: Using the natcasesort() function would not be a correct answer, since it would not maintain the original index association of the elements of the array.
What is PEAR in php?
PEAR (PHP Extension and Application Repository) is a framework and repository for reusable PHP components. PEAR is a code repository containing all kinds of php code snippets and libraries.
PEAR also offers a command-line interface that can be used to automatically install packages.
What are the differences between echo and print in PHP?
echo and print are largely the same in PHP. Both are used to output data to the screen.
The only differences are as follows:
echo does not return a value whereas print does return a value of 1 (this enables print to be used in expressions).
echo can accept multiple parameters (although such usage is rare) while print can only take a single argument.
What will be the value of $x after this code executes? Explain your answer.
Perhaps surprisingly, the answer is neither NULL nor 255. Rather, the answer is that $x will equal 0 (zero).
First, let’s consider whether '0xFF' == 255 will evaluate to true or false. When a hex string is loosely compared to an integer, it is converted to an integer. Internally, PHP uses is_numeric_string to detect that the string contains a hex value and converts it to an integer (since the other operand is an integer). So in this case, ‘0xFF’ is converted to its integer equivalent which is 255. Since 255 = 255, this condition evaluates to true. (Note that this only works for hex strings, not for octal or binary strings.)
But if that’s the case, shouldn’t the statement $x = (int)'0xFF'; execute and result in $x being set equal to 255?
Well, the statement does execute, but it results in $x being set equal to 0, not 255 (i.e., it is not set to the integer equivalent of ‘0xFF’). The reason is that the explicit type cast of the string to an integer uses convert_to_long (which works differently than the is_numeric_string function that was used in evaluating the conditional expression, as explained above). convert_to_long processes the string one character at a time from left to right and stops at the first non-numeric character that it reaches. In the case of ‘0xFF’, the first non-numeric character is ‘x’, so the only part of the string processed is the initial ‘0’. As a result, the value returned by (int)'0xFF' is 0, so when the code completes, $x will be equal to 0.
What is use of the header() function in PHP?
header() is used to redirect from one page to another: header("Location: index.php");
header() is used to send an HTTP status code: header("HTTP/1.0 this Not Found");
header() is used to send a raw HTTP header: header('Content-Type: application/json');
What is the difference between include_once() and require_once(), which one would you use in circumstances where you need to connect to a database, and why?
include_once() or include allows a file to be included, and in cases where the file is missing or has the wrong name, we receive an error message and execution will still continue regardless.
On the other hand, require_once() or require would be suitable in cases where a file needs to be included once and if it is missing or has a wrong name then we receive a fatal error and the execution of the program stops.
require_once or require is a suitable method in cases where a database connection file is involved and helps alleviate the possibility of multiple instances of the same file being included several times.
How can you tell if a number is even or odd without using any condition or loop?
echo"Your number is: ".$arr[$check%2];
What is the difference between session and quickies?
Session stores the value on the server and quickies stores the value on the user’s browser.
Here we are assigning different strings to the number_class variable based on a numeric value ($number).
What are Traits?
Traits are a mechanism that provides some of the reuse advantages of multiple inheritance in languages like PHP where multiple inheritance is not supported. Traits enable developers to reuse combinations of methods from different class hierarchies.
LAMP is an open-source solution stack that contains everything you need to create a complete, stand-alone platform for your web application—Linux, Apache, MySQL, and PHP. This question is a good opportunity for your prospective programmer to detail any experience they have taking a web project from conception to completion.
What are PHP sessions and how do they work?
What you’re really asking is whether they know how to use session_start(). It either creates or resumes a session based on an identifier that is sent to the server via a GET or POST request or a cookie. The most common use case scenario on the web is when a website won’t let you comment or post without first prompting a login. How does it know whether you’re logged in? One way would be to place a cookie in the user’s browser; on every request the cookie is sent server-side, where PHP can be used to determine which information is sent back and displayed to the client. While session_start() saves session data in files by default, it is also possible to store sessions directly in the database.
How are classes loaded in PHP?
This is a good way to gauge a developer’s understanding of autoloading. Whenever a class is instantiated, a function is triggered. You can register a function with the spl_autoload que detailed below, courtesy of php.net:
This question reveals a few interesting things about the way PHP interprets code. The value of $pear in the code above will be the string “PEAR P” or the string “PEAR ” followed by seven spaces, followed by “P,” which is the first character in the string “PHP Extension and Application Repository.” The value returned by strlen($pear) will thus be 13. Since an element of a string can only consist of one character, and the count of elements within a string starts with 0, $pear sets the 13th character of the string to the letter “P.” Interestingly enough, we chose to set the 13th value of a string that only has five characters. While other language interpreters might have thrown an out-of-bounds index error, PHP is more forgiving and fills in the blanks with empty spaces.
Determine the output of the code below. Explain your answer.
This question quizzes the coder on how the PHP interpreter handles numbers and strings.
i. var_dump(42 == 042); will output bool(false) because the PHP interpreter treats leading zeroes as octals. 042 is 32 in decimal, which does not equal 42.
ii. var_dump(‘042’ == 42); will output bool(true) because PHP interpreter will coerce the string into an integer but ignore the leading zero. 42 is equal to 42.
iii. var_dump(‘042’ === 42); will output bool(false) because the === operator performs a stricter comparison and will not coerce the integer into a string.
Explain why the two code snippets below will evaluate to the same output.
$x = true or false; $x = true and false;
This question is designed to test a coder’s knowledge of the order of operations. The first block of code is more straightforward, evaluating to true because of the “or” operator. The second code block, however, would typically be expected to evaluate to false. Instead, it evaluates to true because of how the PHP interpreter handles the order of operations: “=” is prioritized leading to the following equivalent code snippet:
$x = true; // sets $x equal to true
True and false; // evaluates to false, but does not affect anything
If $x = 100 + “25%” + “$40” what is the value of $x and why?
The answer is $x = 125, because PHP uses automatic type conversion in deciding how to treat variables and values depending on how they are used. When PHP encounters a string during an arithmetic operation, it will interpret any numerical value and ignore the remainder in order from left to right. Strings that don’t start with numbers are evaluated to zero.
$x = 100 + 25 + 0 = 125.
Explain the difference between classes and interfaces.
In layman’s terms, an interface is a class without all the business logic. In an interface, all methods must be public and multiple inheritance is supported. However, all methods must be defined within the class that implements them. Abstract classes, on the other hand, can be declared with modifiers like public or internal, and can define properties or variables. Abstract classes do not support multiple inheritance and can only be extended by one abstract class.
Predict the output of the code below. Explain your answer.
At first glance, one would expect the boolean to evaluate to “true” because 6 > 4 > 2. However, the correct answer is “false” because PHP will first evaluate $z > $y, which returns a boolean value of 1 or true. It is this boolean value of 1 that is compared to the next integer in the chain, bool(1) > $z, which will result in NULL and echo “false.”
Clean Code PHP (jupeter/clean-code-php), is a guide based on the book Clean Code: A Handbook of Agile Software Craftmanship, a classic programming book about writing maintainable code by Uncle Bob Martin.
Here are a few of my favorite adaptations from the clean-code-php repository:
Don’t add unneeded context
The author outlines the following about the purpose of the guide:
Not every principle herein has to be strictly followed, and even fewer will be universally agreed upon. These are guidelines and nothing more, but they are ones codified over many years of collective experience by the authors of Clean Code.
In a dynamic language like PHP (or any language for that matter), developers will disagree with some (or many) of the points made about the concepts demonstrated. I think the point I’d make is not to write off all ideas contained in the guide if you disagree with one or more ideas.
Learn More about Clean Code
I highly recommend that you read the Clean Code book to get a deeper understanding of the guidelines demonstrated in the PHP adaptation. On its own, the PHP guide is a good read, but part of the journey is learning how to spot code that needs some work and then adapting it.