Parsing JSON using php jsonpath

Question

I'm trying to parse a JSON in PHP using jsonpath ....

My JSON is coming from this

https://servizionline.sanita.fvg.it/tempiAttesaService/tempiAttesaPs

(it's quite too long to cut/paste here but you can see it in a browser session ....)

The JSON is a valid JSON (I've verified it using https://jsonlint.com/ ... ).

I've tried the jsonpath expression using http://www.jsonquerytool.com/ and all seems works fine, but when I put all in my PHP code sample below ....

<?php  
    ini_set('display_errors', 'On');
    error_reporting(E_ALL);

    require_once('json.php');      // JSON parser
    require_once('jsonpath-0.8.0.php');  // JSONPath evaluator

    $url = 'https://servizionline.sanita.fvg.it/tempiAttesaService/tempiAttesaPs';

    $ch = curl_init();
    curl_setopt($ch, CURLOPT_AUTOREFERER, TRUE);
    curl_setopt($ch, CURLOPT_HEADER, 0);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, TRUE);
    curl_setopt($ch, CURLOPT_PROXY, '');
    $data = curl_exec($ch);
    curl_close($ch);

    $parser = new Services_JSON(SERVICES_JSON_LOOSE_TYPE);
    $o = $parser->decode($data);

    $xpath_for_parsing = '$..aziende[?(@.descrizione=="A.S.U.I. - Trieste")]..prontoSoccorsi[?(@.descrizione=="Pronto Soccorso e Terapia Urgenza Trieste")]..dipartimenti[?(@.descrizione=="Pronto Soccorso Maggiore")]..codiciColore[?(@.descrizione=="Bianco")]..situazionePazienti..numeroPazientiInAttesa';

    $match1 = jsonPath($o, $xpath_for_parsing);
    //print_r($match1);
    $match1_encoded = $parser->encode($match1);
    print_r($match1_encoded);

    $match1_decoded = json_decode($match1_encoded);

    //print_r($match1_decoded);

    if ($match1_decoded[0] != '') {
     return  $match1_decoded[0];
    }
    else {
     return  "N.D.";
   } 
?>

... no values are printed .. only a "false" value.

Something goes wrong in my jsonpath expression when I put it in my PHP code: ths error that coming out is the follow

Warning: Missing argument 3 for JsonPath::evalx(), called in /var/www/html/OpenProntoSoccorso/Test/jsonpath-0.8.0.php on line 84 and defined in /var/www/html/OpenProntoSoccorso/Test/jsonpath-0.8.0.php on line 101

Notice: Use of undefined constant descrizione - assumed 'descrizione' in /var/www/html/OpenProntoSoccorso/Test/jsonpath-0.8.0.php(104) : eval()'d code on line 1

Probably I've to escape / quoting my jsonpath to use it in PHP but I don't know how ... any suggestion is appreciated ...

NOTE: I need to use jsonpath expressions like ?(@.descrizione=="A.S.U.I. - Trieste") and I can't use "positional" json path ...

I've also tried to use jsonpath-0.8.3.php coming from here https://github.com/ITS-UofIowa/jsonpath/blob/master/jsonpath.php, but nothing change ...

Suggestions?

Thank you in advance ...

Answer 1

I would suggest trying to use a different library for JsonPath, if the one you are working with has a bug and the 3rd party service states no error in query.

Here are a few:

• FlowCommunications/JSONPath
• Peekmo/JsonPath
• mtdowling/JmesPath

I am pretty sure there are more. Hope that helps.