如何检查我的功能是否打印/回声？

Question

I am often using echo to debug function code:

public function MyFunc() {

    // some code...
    echo "OK";
    // some code...

}

How can I check that my function print's/echo's something?

(pseudo code):

MyFunc();

if (<when something was printed>){
    echo "You forgot to delete echo calls in this function";
}

Answer 1

This should work for you:

Just call your functions, while you have output buffering on and check if the content then is empty, eg

ob_start();

//function calls here
MyFunc();

$content = ob_get_contents();

ob_end_clean();

if(!empty($content))
    echo "You forgot to delete echos for this function";

Answer 2

You could create a $debug flag and a debuglog() function, which checks for the debug flag and only then echos the message. Then you can toggle your debug messages on and off from one location.

define('DEBUGMODE', true); // somewhere high up in a config

function debuglog($msg){
    if( DEBUGMODE ){ echo $msg; }
}

Should you ever want to get rid of your debug echos, you can search for "debuglog(" and delete those lines of code. This way you won't accidentally delete any echo statements that are required in normal execution or miss any debug echo statements that should really have been removed.

Answer 3

It's the bad way checking if something is echoed.

You can set a variable named is_echoed to 1 or you can return the value

public $is_echoed = 0;
//rest
$this->is_echoed = 1;

or

function myFunc()
{
  return "OK";
}
if(myFunc() == 'OK')
     //rest

Answer 4

You can use var_dump() and die() to debug your code more efficiently.

$test = "debud test";
public function MyFunc($test)
{
// some code...
var_dump($test); die();
// some code...
}

Reference: http://php.net/manual/en/function.var-dump.php

http://php.net/manual/en/function.die.php

Answer 5

Why do you want to try such an extensive process of seeing if something has been echoed or not?

For debugging you can definitely use echo to see if the particular block is being hit during a particular use-case. But I would suggest you use flags and return the values to the calling function.

function xyz () {

     if (something) return some_value;
     else return some_other_value;
}

There is no particular need to have variables and use space in storing a 0 or 1 when you can just return a hard-coded literal.

Answer 6

I would suggest to you to use something like log4php [1]

But if not, I use a function like this:

define('DEBUG', true);
function debug($msg){
    if(DEBUG){ echo $msg; }
}

Or something like this to see the log in the browser console:

function debug_to_console( $data ) {

    if ( is_array( $data ) )
        $output = "<script>console.log( 'Debug Objects: " . implode( ',', $data) . "' );</script>";
    else
        $output = "<script>console.log( 'Debug Objects: " . $data . "' );</script>";

    echo $output;
}