PHP read weather feed from api.met.no

Question

I am trying to read JSON from this https://api.met.no/weatherapi/locationforecast/2.0/compact?lat=-16.516667&lon=-68.166667

$options = array(
    'http'=>array(
      'method'=>"GET",
      'header'=>"Accept-language: en\r\n" .
                "User-Agent: Mozilla/5.0 (iPad; U; CPU OS 3_2 like Mac OS X; en-us) AppleWebKit/531.21.10 (KHTML, like Gecko) Version/4.0.4 Mobile/7B334b Safari/531.21.102011-10-16 20:23:10\r\n" // i.e. An iPad 
    )
);  

$context = stream_context_create($options);
$data_url = "https://api.met.no/weatherapi/locationforecast/2.0/compact?lat=-16.516667&lon=-68.166667";

$json = file_get_contents($data_url,false,$context);

$data = new RecursiveIteratorIterator(
    new RecursiveArrayIterator(json_decode($json, TRUE)),
    RecursiveIteratorIterator::SELF_FIRST);


foreach ($data as $key => $val) {
    if(is_array($val)) {
        echo "$key:\n<br>";
    } else {
        echo "$key => $val\n<br>";
    }
}

This works fine, but I need to select specific values according to the key, something like:

foreach ($data as $key) {
      echo $key["properties"] ["timeseries"] ["0-x"] ["data"] ["instant"] ["details"];
}

But of course that doesn't work for me. Please don't know how to do it? Thanks

Answer 1

Looking at the raw json return, the item you are trying to get is fairly buried, but you can still get to it easy enough. Example data return:

{
  "type": "Feature",
  "geometry": {
     ...
  },
  "properties": {
    "meta": {
       ...
    },
    "timeseries": [
        {
        "time": "2020-08-18T12:00:00Z",
        "data": {
          "instant": {
            "details": {
              "air_pressure_at_sea_level": 1018.4,
              "air_temperature": 4.7,
              "cloud_area_fraction": 92.2,
              "relative_humidity": 59.3,
              "wind_from_direction": 308.4,
              "wind_speed": 3.8
            }
         },
    ...

You can access that specific data with:

$json = file_get_contents($data_url,false,$context);

// This is all you need to turn json into a usable array
$data = json_decode($json,true); 

// Loop on the nested timeseries group:
foreach($data['properties']['timeseries'] as $ts) {
    
    // the time part of it
    $time    = $ts['time'];
    
    // get at it direct
    $var     = $ts['data']['instant']['details']['air_temperature'];

    // shorthand it if you wish:
    $details = $ts['data']['instant']['details'];
    $var     = $details['air_temperature'];
    
    // do whatever else you need to do with it
    echo $var;
    $array_of_temps[] = $var;
    // etc ...

}