Question 40002 in PHP Question posted in
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PHP retry the loop once

This is really not elegant:

$retry = 0;
do {
  try {
    $this->foo();
    $retry = 0;
  }
  catch (FooException $e) {
    $retry++;
  }
} while ((!$retry && $fooCondition()) || ($retry === 1))

This is to say, do something, if succeeded then reset retries to 0, if it failed increase the number of retries. If this is not a retry, check the normal loop condition. But even if the normal loop condition fails, if this is a retry, loop.

Is there really not a more elegant construct to express this?

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3

Answers


  1. Chosen as BEST ANSWER
    0

    I changed the counter to a boolean and added one more variable and it became a lot more readable:

    $last_try_succeeded = TRUE;
$needs_more = TRUE;
while ($needs_more) {
  try {
    $this->foo();
    $last_try_succeeded = TRUE;
    $needs_more = $fooCondition();
  }
  catch (FooException $e) {
    if ($last_try_succeeded) {
      $last_try_succeeded = FALSE;
      $needs_more = TRUE;
    }
    else {
      $needs_more = FALSE;
    }
  }
}

    The original version expressed this by saying "if the try section executed successful then retries is zero and then $fooCondition() decides whether to loop. Otherwise retries is not zero and then we need to loop if this is the first retry." But there is no need for such a complex expression, we can just simply set the loop condition itself in the try and the catch sections. A good IDE -- like PhpStorm -- will highlight the places where $needs_more is set, making it rather easy to see and comprehend.


  2. 0

    Simplify.

    $retries = 1;
for( $i=0; $i<=$retries || someCondition(); ++$i ) {
    try {
        thing();
        break;
    } catch( SomeException $e ) {}
}
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  3. 0

    Try this? Look a bit more elegant.

    $retry = 0;
$max_tries = 2; // Including the first one
do {
  try {
    $this->foo();
    break;
  }
  catch (FooException $e) {}
} while ( $fooCondition() and ++$retry < $max_tries );
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