This example contains a state machine called weather that demonstrates how to use the detect plug-in. The state machine queries the Yahoo! Weather RSS feed for the locations in a list of major cities and finds the first location with weather conditions satisfying a simple temperature test criteria.

The state machine has a single state, DetectTemperature. This state uses the detect plug-in to iterate over a list of WOEID (Where On Earth ID) codes, calling the binary asynchronous function aboveTemperature for each. The first code to return true is returned.

The aboveTemperature function is defined directly in the imports object. It wraps the yahooapis.request asynchronous function, providing it with a callback function to call its own callback with true or false depending on the result of the temperature test.

var yahooapis = require('../../weather_yahooapis');

function weather (fire, woeidArray, temperature) {
  this.startState = 'DetectTemperature';
  this.states = {
    DetectTemperature: {
      detect: {
        fn: 'aboveTemperature',
        fnArgs: function (woied) {
          return [temperature, { 'w': woied, 'u': 'c' }];
        },
        par: 5
      },
      actions: {
        'detect.done': function (result) {
          if (result) {
            console.log('woied:%s has temperature > %s', 
                result, temperature);
          } else {
            console.log('no woied found.');
          }
          return '@exit';
        }
      }
    }
  };
};

weather.defaults = {
  imports: {
    aboveTemperature: function (temperature, options, cb) {
      yahooapis.request(options, function (err, weather) {
        if (err) {
          cb(false);
        } else {
          cb(weather.condition.temp > temperature);
        }
      });
    }
  },
  args: [ yahooapis.majorCities, 25 ]
};

module.exports = weather;

 $ ./bin/ignite examples/plugins/detect/weather.js
 Running examples/plugins/detect/weather.js
 woied:2151330 has temperature > 25
 run: examples/plugins/detect/weather.js Exited with no error.
 $ _