PHP - repeat retrieve XML if value is not correct

Question

I have a code in PHP to works with XML:

    $data_measuranment = file_get_contents($value, false, $context);
    $xml=simplexml_load_string($data_measuranment);
    $json = json_encode($xml);
    $array[] = json_decode($json,TRUE);

The values of my array ($array[]) depend on the time:

[1] => Array
        (
            [@attributes] => Array
                (
                    [end] => 1520439534044
                    [start] => 1520439300000
                    [step] => 300000
                )

            [columns] => Array
                (
                    [values] => Array
                        (
                            [0] => NaN
                            [1] => NaN
                        )

                )

            [timestamps] => Array
                (
                    [0] => 1520439300000
                    [1] => 1520439600000
                )

        )
 ...

If I execute the code some seconds ago. My array works:

[1] => Array
        (
            [@attributes] => Array
                (
                    [end] => 1520439565293
                    [start] => 1520439300000
                    [step] => 300000
                )

            [columns] => Array
                (
                    [values] => Array
                        (
                            [0] => 12
                            [1] => NaN
                        )

                )

            [timestamps] => Array
                (
                    [0] => 1520439300000
                    [1] => 1520439600000
                )

        )
...

The only value important for my is array[key][columns][values][0]=12

So, I need a code to wait some seconds and execute again the pull for the API and finish when the value array[1][columns][values][0] is different to NaN. I tried to do that with this code but not works:

do
{
    foreach ($array as $valor)
    {
        $term= $valor['columns']['values']['0'] ;
        if ($term === 'NaN')
        {
            unset($array);
            sleep(10);
            $data_measuranment = file_get_contents($value, false, $context);
            $xml=simplexml_load_string($data_measuranment);
            $json = json_encode($xml);
            $array[] = json_decode($json,TRUE);
        }
    }

}while (isset($array))

I need this: When the foreach read the value "$valor['columns']['values']['0']" and check is NaN. The code wait 10 seconds and retreive new array with file_get_contents, then check the condition again. If all values of $valor['columns']['values']['0'] are different of NaN continue the script.

Thank you.

Welcome to Stackoverflow. What is your actual question? You state what you have done, but not what the problem is you have encountered. — fred2, Mar 07 '18 at 20:37
What does "not works" mean - Did you get an error? Did it sleep the wrong amount of time? Did the loop carry on forever? Did your computer pop up a message saying "Guru Meditation"? Please [edit] the question to be as specific as possible. — IMSoP, Mar 08 '18 at 11:29
As a side note, converting the XML to an array via SimpleXML and JSON is a horrible hack which will make your life harder later; you will be much better off [learning how SimpleXML is intended to be used](http://php.net/manual/en/simplexml.examples-basic.php). In this case, you could rewrite your code as `foreach ( $xml->children() as $valor ) { $term = (string)$valor->columns->values[0]; ...` — IMSoP, Mar 08 '18 at 11:32

score 0 · Accepted Answer · answered Mar 09 '18 at 12:59

Let's restate your requirements:

Fetch the XML from the remote server.
If all values of $valor['columns']['values']['0'] are not equal to NaN, continue the script.
Else, wait 10 seconds and try again.

You have correctly identified step 3 as requiring a do ... while loop to go back to the beginning, and step 2 as requiring a foreach loop to examine each value in the result.

The problem is that you've added too much logic into the foreach loop, so that steps 1 and 3 are happening inside step 2. Instead, you need to perform step 2 in its entirety, and then decide whether to continue with the code, or sleep and try again.

You may find it helpful to break the code up into separate functions - step 2 should just be examining the data and returning an indication of whether it is "good" or "bad", and step 1 should just be fetching the data and parsing it with SimpleXML:

# Variable to control do...while loop
$have_good_data = false;
do
{
    # Step 1
    $data_measuranment = file_get_contents($value, false, $context);
    $xml = simplexml_load_string($data_measuranment);

    # Step 2; this could be moved into a function that returns $have_nans
    $have_nans = does_data_contain_nan($xml);

    # Step 3
    if ( $have_nans ) {
       sleep(10);
    } else {
       $have_good_data = true;
    }
} while ($have_good_data)

The function for step 2 might look something like this:

function does_data_contain_nan(\SimpleXMLElement $xml) {
    foreach ($xml->children() as $valor)
    {
        $term = (string)$valor->columns->values[0];
        if ($term === 'NaN')
        {
             // once we find a NaN, we don't need to look at the other values
             return true;
        }
    }
    // We got to the end of the loop without finding a NaN!
    return false;
}

PHP - repeat retrieve XML if value is not correct

1 Answers1