What is header file in php

PHP Header header() function in PHP?

Original and detailed post of this tutorial is located at What is header() function in PHP? As per php.net documentation, the header function is mainly used to send a raw HTTP header. Well, in the beginning, it is confusing to know the term raw HTTP. In this tutorial, we’ll see what is header() function in PHP, its importance, and its uses.

Use of header() function in PHP

header() function in PHP is used to send raw HTTP header and it must be called before any output is sent to the requester, either by normal HTML tags, blank lines in a file, or from PHP. The main purpose of header() function is to redirect user from the current/certain page to another URL. Let’s understand the syntax first and then we’ll see individual parameters.

Where, $header: is the header string which has two special-case header calls. One is the “Location:” and another is the “HTTP/“.
$replace: Optional. It indicates whether the header should replace a previously sent similar header, or add another header of the same type.
$http_response_code: It forces the HTTP response code to the specified value.

Using “Location:”

With “HTTP/” parameter can contain any HTTP status code to send. For example, if we have configured Apache to use a PHP script to handle requests for missing files then we can redirect user to the specified file

 header("HTTP/1.0 404 Not Found"); 

This will show a 404 page not found page because we have added security restriction for accessing certain pages so that if the user tries to access those page then we’ll certainly show not found page.

Download file using header in PHP

The advantage of header function is that we can create and download files on the fly. This is a very important feature that is needed while working with files related operations in the project.

 // what kind of document to be downloaded header('Content-Type: application/pdf'); // name the file as document.pdf header('Content-Disposition: attachment; filename="document.pdf"'); // Read original.pdf file and output it readfile('original.pdf'); 

• Define type of file to be downloaded
• name that file
• read the content of the file/text

Besides other intermediate steps, these are the 3 basic steps which are used to download file on the fly.

Set HTTP headers to prevent page caching

PHP is quite famous for its dynamic data. But there are certain situations where we don’t client browser to cached those data (to load website faster of course )

We can use header() function to override such a situation and add certain parameters that will prevent webpages from being cached.

 header("expires: Wed, 11 Jan 1984 05:00:00 GMT"); header("cache-control: no-cache, must-revalidate, max-age=0"); ?> 

Here, we have added cache-control: no-cache to make sure that each time browser request for a particular webpage then server must send updated data rather than cached one.

We’ve also added expires parameter to past date represents that web-page is already expired and new data is expected from the client browser.

Conclusion:

Introduced in PHP 4, header function plays an important role while development. May modern frameworks used this function in the core to redirect users to a specific function. Downloading file at runtime, setting cache-control is the of the main features in header() function

I hope that I have covered all the related information about what is header() function in PHP and it’s related uses. If you have any questions Or you think any need for improvement then please comment.

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The header.php File: What Needs to Go in It and What Doesn’t

In this tutorial, let’s talk about the header.php file, an essential file for any WordPress theme. I’ll show you a header file example and give tips about what needs to go in it and what doesn’t.

Introduction

It’s important for you to know what exactly the header.php file should contain in a WordPress theme.

We have more than a logo and menu in this file—we also have the head tag and lots of other tags, like link , script , meta , and title .

In the course of this article, we’ll create a demo header.php file, and we’ll discuss each and every element in that file.

Remember that the header of your site is the content which is shown on all the pages of your site. For example, the logo and menu are shown on all the pages of your site, and thus, they should be included in the header.php file.

If an element is shown only on a specific page, then you should not include it the header.php file.

The Sample Code

In this section, we’ll build a demo header.php file. In the next section, we’ll go through each and every piece of code to understand what it does.

But before we implement the header, let’s paste the following code at the top of your wp-includes/functions.php file. Remember to modify the paths to your CSS and JavaScript files as needed.

remove_action('wp_head', 'wp_generator'); 

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Header in PHP: The Ultimate Guide to Header Function

PHP stands for Hypertext Preprocessor and is a server-side programming language that was created with web development in mind. It is open-source, which means you can download and use it for free. It’s incredibly easy to pick up and use. The files contain the “.php” extension.

Rasmus Lerdorf was the driving force behind the first version of PHP, as well as a contributor to succeeding versions. It is an interpreted language that does not necessitate the use of a compiler.

Many databases, including Oracle, Microsoft SQL Server, MySQL, PostgreSQL, Sybase, and Informix, can be combined with it.

It is used to regulate user access and hold a content management system like WordPress.

Example

Output

Stand Out From Your Peers this Appraisal Season

What Is a Header in PHP? Explain With Syntax

The header in PHP is a PHP built-in function for sending a raw HTTP header. The HTTP functions are those that manipulate information sent by the webserver to the client or browser before it sends any further output. The header() function in PHP sends a raw HTTP header to a client or browser. Before HTML, XML, JSON, or other output is given to a browser or client, the server sends raw data as header information with the request (particularly HTTP Request). Headers in PHP contain additional details about the object delivered in the message body, as well as the request and response.

Syntax

void header( $header, $replace = TRUE, $http_response_code )

It includes a header string in the string. There are two types of header calls in general. One is a header that begins with the string «HTTP/» and is used to determine the HTTP status code to send. Another is the «Location,» which is required.

• replace: This is an optional parameter that specifies whether the header should add a new header or replace the previous one.
• http response code is an optional parameter that sets the HTTP response code to a specific value (available in PHP 4.3 and higher).

The header() method is a built-in function that allows you to deliver a raw HTTP header to a client. HTTP functions allow you to manipulate data supplied to the browser by the webserver before it sends any additional output. You must call it before any actual output is sent, whether from HTML tags, blank lines in a file, or a PHP file.

Example

header(«Expires: Sun, 22 Jun 1997 04:00:00 GMT»);

header(«Cache-Control: no-cache, must-revalidate»);

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