3

Ok I know the title is a bit confusing as I can't think of a good way to explain it. There is this function which I don't have access to and it looks something like this:

<?php function myFunction() {
?> '<img src="one.jpg" />';
<?php } ?>

Ok so everytime that function is called, it echo's the img tag. But what if I want to manipulate the img tag before it echos to the screen? Is it possible?

I want to assign it to a variable first, manipulate it and then I will echo it out. Something like this:

$image_src = myFunction();
$image_src = preg_replace('/s.*"/', $image_src);
echo $image_src;

Something like this possible?

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2 Answers 2

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13

Use output buffering:

ob_start();
myFunction();
$output = ob_get_clean();

after that, $output will contain the html that was echoed inside the function.

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5 Comments

also check ob_get_contents() and what happens when you give a callback argument to ob_start()
Thanks for the reply but is output buffering the only way?
@Rick Yes, since you don't have access to the function (and therefore can't change echo to return), it is the only way.
Sorry - what if the statement inside the function wasn't an echo? Then would this still work?
You could do it without output buffering, by making a little PHP script to perform the function, then calling that script from the first with exec. That would be inefficient, but it would work without output buffering.
1

I am new to php and the first thing I did was create a generic function to echo a line to html:

function html_line ( $string ) // echo line to browser
{
  echo PHP_EOL . $string . PHP_EOL;
}

Then I made functions for simple paragraphs and images that add html tags, for example:

function html_pp ( $string ) // echo paragraph to browser
{
  html_line ( '<p>' . $string . '</p>' );
}

Other functions and variables can be used to manipulate the content any way you wish before these are called:

function html_page ( $str_title, $str_content ) // simple page with title and body
{
  html_line ( '<html>' );
  html_line ( '<head>' );
  html_line ( '<title>' . $str_title . '</title>' );
  html_line ( '</head>' );
  html_line ( '<body>' );
  html_pp ( $str_content );
  html_line ( '</body>' );
  html_line ( '</html>' );
}

function html_test () // set some variables and create a test page
{
  $test_title = 'PHP Test';
  $test_msg = 'Hello World!';
  html_page ( $test_title, $test_msg );
}

I don't know if this answers your question but it is working well for me and could be a good starting point. If you decide to separate your functions out to a different file like I did just be sure to have correct include calls and the functions will have global scope from the caller.

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