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PHP

Posted by fabrciojardimferreira
fabrciojardimferreira
8,100 Points

include() and blank lines before header()?

In the PHP Manual page for header():

Remember that header() must be called before any actual output is sent, either by normal HTML tags, blank lines in a file, or from PHP. It is a very common error to read code with include, or require, functions, or another file access function, and have spaces or empty lines that are output before header() is called. The same problem exists when using a single PHP/HTML file.

Well, in the code block from this video there are both include() and blank lines before the header() function:

<?php 
include("inc/data.php");
include("inc/functions.php");

if (isset($_GET["id"])) { 
    $id = $_GET["id"];
    if (isset($catalog[$id])) {
        $item = $catalog[$id];
    }
}

if (!isset($item)) {
    header("location:catalog.php");
    exit;
}

Is this lesson an example of bad code or am I misunderstanding something? Thanks for any insight.

2 Answers

Henrik Christensen
seal-mask
.a{fill-rule:evenodd;}techdegree
Henrik Christensen
Python Web Development Techdegree Student 38,322 Points
Henrik Christensen
.a{fill-rule:evenodd;}techdegree
Henrik Christensen
Python Web Development Techdegree Student 38,322 Points

before any actual output is sent - if you look in the code you have shared you can see that there is not being outputted any data to the screen (i.e. echo something).

fabrciojardimferreira
fabrciojardimferreira
8,100 Points

Thanks.

fabrciojardimferreira
fabrciojardimferreira
8,100 Points
fabrciojardimferreira
fabrciojardimferreira
8,100 Points

Thanks @Henrik Christensen

This is the sentence that confused me most so let me check if I understood it now:

It is a very common error to read code with include, or require, functions, or another file access function, and have spaces or empty lines that are output before header() is called.

The mention of the include and require functions is not because of those functions per se. Its because the external files might contain output in one of those forms.

Empty lines and spaces between PHP statements have no meaning, so they're not the problem. The problem, for instance, would be an empty space left after a PHP closing tag, that would be html output.

This is right?