将PHP API调用转换为cron作业并访问返回的值

Question

My goal is to run the below php script every 10 minutes and then be able to access the $temp and $icon values in a website front-end:

$api_endpoint = 'https://api.forecast.io/forecast/';
$api_key = get_field('forecast_api_key', 'option');
$latitude = get_field('latitude', 'option');
$longitude = get_field('longitude', 'option');
$units = 'auto';
$lang = 'en';
$exclude = 'minutely,hourly,daily,alerts,flags';

// Build API call and parse data

$url = $api_endpoint.$api_key.'/'.$latitude.','.$longitude.'?units='.$units.'&exclude='.$exclude;
$response = file_get_contents($url);
$weather_data = json_decode($response, true);

// Output to front-end

$temp = round($weather_data['currently']['temperature']);
$icon = $weather_data['currently']['icon'];

Could someone please explain on a high level what the best approach would be to do this? I need to limit the number of API calls per day to the endpoint and as far as I understand, this script should be executed as a cron task, but am not sure how to get at the variable values from a website in /var/www/.

If I have overlooked a simpler way (i.e. not using cron) to limit the number of calls per period time, I would be interested in alternative suggestions too.

The server environment is an Ubuntu 14.04 LTS VPS.

Many thanks for your help.

Answer 1

I don't think you need a cron task at all, unless you need the returned value for other purposes (conducting some calculations in background process for example)

What I suggest is to write a function, which makes the API call and stores the result in to the database. You can implement a simple caching logic to avoid the API call on every page load. Pseudo code might look like this:

function getAPIresult(){
   //Idea is to check for record in local db, before making the API call
   //you can define the time schedule, AKA cache validity time as you want
   $result = mysql_query("select from api_results where date='today'");
   if($result){
      return $result; // if valid record is found, use it on your website
   }
   else{
     return setAPIResult();
   }
}

function setAPIResult(){
   //API CALL goes here and inserts the result into the database
   .....
   $weather_data = json_decode($response, true);
   $result = mysql_insert('inserto into api_results ... values($weather_data)');
   return $result; // insert and return the value
}