Understanding ob_start() in PHP Coding Language | Coding Like a Pro
Understanding ob_start() in PHP Coding Language

Understanding ob_start() in PHP Coding Language

Introduction

We will begin this lesson on a soft note. If you are reading this lesson, it is believed you have a considerable knowledge of PHP.

However, it is equally possible you may not know even the simplest thing about the concept – like, what it means. Oh, that could be embarrassing pretty much. But, hey, you can start learning it now. It’s never too late.

So, for the sake of emphasis, we are going to briefly look at what PHP means before we delve into the main subject of discussion.

What is PHP?

PHP Hypertext Processor. We only use PHP as the abbreviation; to keep it short. It is a comprehensive programming language which was initially built for web development. But now, it has broadened. It isn’t only used to build dynamic and static sites only like it was when it was called Personal Home Pages. Rather, it has advanced to include the development of Apps for the web.

Did you learn a thing or two from that? Ok, let’s get into the lesson proper.

Meaning of ob_start()

bool ob_start ([ callable $output_callback = NULL [, int $chunk_size = 0 [, int $flags = PHP_OUTPUT_HANDLER_STDFLAGS ]]] )

We can’t deny the fact that not everyone knows about this feature in PHP. In fact, it may not be surprising that even some pro programmers don’t have good knowledge of the feature.

However, most people that use the PHP language for their coding may have in one way or the other come across the tool. You may equally know a bit about it yourself.

You ask, what is this ob_start()? We’ll answer it together. Ob_start is one of the output buffering in PHP. Did that sink?

Let’s discuss it further. Actually, we use the feature to put on the output buffering. You still wonder what this means?

Ok. Imagine we need to influence the attribute of specific elements over our code into different values. Now, what helps us to achieve this purpose is ob_start().

Therefore, whenever we get to put on the output buffering of the programming language, what it means in essence is that we are sending a message to it. And what is that message? We’re telling it to “collect anything we write at this place, then preserve it as an item for us to employ or influence at will.”

To break it down, we can explain it as a type of keeper for strings that we need to output to the web browser and our screen. In essence, what it does is to collect whatever that is required to be produced to the screen and then goes ahead to preserve it as string. When it completes the task, you could see the message on the screen that reads “hold on a minute.”

What follows next after this is accessing the content. Yes, we need to access the content. I hear you ask; how can we access the content preserved in the output buffering of the Hypertex Processor? That’s a great question.

Now, to take care of this need, a function has been created in PHP already – ob_get_contents(). Got it?

What result do we get when we use ob_get_contents()?

This is indeed a very important question, and very necessary to understand in this lesson. So, pay close attention.

What the function does is to collect and preserve the data strings. What we do is to name the function to deliver every string which had been saved in the recent buffering order.

However, if you so desire while working on your own, you can jump the “call.” But this should be when you want to influence a copy or reproduce expression directly.

Oh, wait a minute!

How about when we have many ob_start() statements and calls over our code? What will happen then? Ok, your worry is clear and understood. But, hey, just listen to this:

Understand that ob_start() is much. What this means is that we can call it different times we wish. But, we can be smart about it. So, we get to apply the third item of the output buffering attributes in the Hypertex Processor which is known as ob_clean(). Now, when we are through doing that, we can go ahead and use it. Then, there is ob_end_clean(). And equally the third and last cleaning attribute which is ob_get_clean().

ob_get_clean() in Hypertex Processor

Now, when we reach the close of every ob_start() expression, we employ any of the cleaning attributes to help end the ongoing buffering and clean it. When this is done, we can then go ahead to reuse buffering on our code in a separate segment.

So, the function ob_get_clean() has about 3 roles it plays during our programming on PHP. And these roles it plays are explained below:

  1. Collect buffered the text
  2. Clean or wipe the buffered text
  3. Close buffering.

Did that sink?

That’s good. Now, we are going to take up some practical examples to illustrate what we have been discussing so far.

Let’s see…

ob_start();
the_ID();
$id = ob_get_clean();
echo $id + 5;

What did we do in the example above? Can you tell?

Well, we just resumed buffering employing ob_start(). We then run through a procedure (the procedure in this instance finds the ID and holds it for us). And then, the $id enables us to call the_ID() found for us. 10.

Here is what happens next. We run ob_get_clean(), the ID that’s restored gets preserved as a string, this is then followed by a duplicate text. The number 10 stays in our running buffer process. When we duplicate out the $id+, a fixed number which the duplicate outcome found becomes.15.

Thereafter, ob_get_clean() closes the buffer process.

To strengthen our understanding and give it a clearer perspective, we’ll consider another practical example.

Here we go:

ob_start();
print "Hello Dan";
ob_end_flush(); // end ob and print


ob_start();
print "Hello Sam";
ob_end_clean(); //  end ob and remove

Here are the outcomes:

  1. Hello Dan is reproduced, while OB is wiped.
  2. Hello Sam is not reproduced, and OB is ceased with the text wiped.

Another PHP function ob_end_flush()

There is still another function of the Hypertex Processor you need to know if you haven’t already – ob_end_flush(). Heard of it before now?

What this does is to draw the recent buffering ordered string, stores and ends the buffering. Mostly, we encounter it but apply it less often.

Wrap Up

Oh, yeah. We can now hiss a sigh of relief. We have finally come to the end of the tutorial. Sure, it wasn’t so stressful and difficult to understand.

We have really covered a lot about the topic and even went further to discuss, though briefly, another function of Hypertex Processor which is available for our use.

However, it is best you do a little more research on your to better understand the topic in case you have any little confusion or need for clarification.

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