如何仅在PHP函数中仅在页面上回显？

Question

Here is my function:

curl_setopt( $curl, CURLOPT_PROGRESSFUNCTION, function ( $resource, $download_size, $downloaded_size, $upload_size, $uploaded_size) use ($array)
{
static $previousProgress = 0;

    if ( $download_size == 0 ) {
        $progress = 0;
    } else {
        $progress = round( $downloaded_size * 100 / $download_size );
    }

As you can see I'm inserting my own variables with use at the end of the function.

What I'm trying to do is simply echo this line ONCE after the else condition

echo ' ' . $progress . '%' . ' (' . bytes($downloaded_size) . ' of ' . bytes($download_size) . ') ';

I've tried things such as

static $previousProgress = 0;
$count = $previousProgress++;

    } else {
    if ($count == 1) { echo echo ' ' . $progress . '%' . ' (' . bytes($downloaded_size) . ' of ' . bytes($download_size) . ') '; }
        $progress = round( $downloaded_size * 100 / $download_size );
    }

But at this point the function has already ran an unknown amount of times (50, or 60 sometimes), before it hits the else condition.

I can of course do this

static $previousProgress = 0;
    $count = $previousProgress++;
    if ($count == 1) { echo ' ' . $progress . '%' . ' (' . bytes($downloaded_size) . ' of ' . bytes($download_size) . ') '; }

And it works to only echo once.. but the issue is CURL does not have the $downloaded_size or $download_size variables set and display as 0 bytes - therefore it needs to be in the else condition.

I've tried using true / false variables as one would normally do to output something once in a for or foreach loop, but since the function is just recursively running until it times out, the function starts over again and this does not work.

As I said, I can insert an array of variables into this function to help me... but I'm not sure how I can do this considering the function starts over and is re-run everytime..

Tried other random things but I am apparently missing something. How can I echo the download size only once in the repeating function?

Answer 1

A static boolean variable should do what you want.

static $firstTime = true;
if ($firstTime) {
    echo "something";
    $firstTime = false;
}

The problem with your code is probably because you were using post-increment. If $previousProgress is 0 , the line:

$count = $previousProgress++;

will set $count to 0 (the old value) while incrementing $previousProgress to 1 . So the if ($count == 1) condition wasn't true until the second iteration. If you used ++$previousProgress it would set them both to 1 . That's the difference between pre-increment and post-increment.