Turning a web folder with data into an API using YQL execute

Yesterday Johan Bouveng challenged me on Facebook with another brain teaser. Johan had found a nice resource for weather forecasts for airports. The data came back in TAF or METAR formats and he already had a parser for this (thank f*** – what a mess these formats). Now, what he wanted to have is an API to get the weather forecast data from the following resources:

• http://weather.noaa.gov/pub/data/forecasts/taf/stations/
• http://weather.noaa.gov/pub/data/observations/metar/stations/

Using YQL and YQL execute this was pretty easy. All I had to do was to write an open table that reads the correct file.

// check if taf or metar was requested or return an error

if(datatype  'taf' || datatype  ‘metar’){

var returnobj,url;


	
// get the correct url using the airport ID and format

if(datatype==’metar’){

url = ‘http://weather.noaa.gov/pub/data/observations/’ +

‘metar/stations/’ + airportid + ‘.TXT’

} else {

url = ‘http://weather.noaa.gov/pub/data/forecasts/’+

‘taf/stations/’ + airportid +’.TXT’;

}

	
// do a REST call and get the response back

var out = y.rest(url).get().response;

	
// if there is no data returned, return an error.

if(out == ‘’){

returnobj = Airport {airportid} not found.;

	
// otherwise return the data in the TXT file

} else {

returnobj = {out};

}
	
} else{

// error condition for wrong datatype

returnobj = Datatype must be either taf or metar.;

}

	
// give back the data to YQL

response.object = returnobj;

Having done this you can now use it as a table in YQL:

use “http://isithackday.com/hacks/airportweather/airportweather.xml” as aw;

select * from aw where airportid=”AAXX” and datatype=”taf”;

As you can see, you don’t have to be a genius to build your own API :)

Tags: api, execute, noaa, table, weather, yql