added planefinder as a destination finder

destinationfinder/destinationfinder.go

@@ -18,10 +18,12 @@ type DestinationFinder interface {
 func GetDestinationFinder() DestinationFinder {
 	findername := os.Getenv("WATFT_FINDER")
 	switch findername {
+	case "planefinder":
+		return PlaneFinderDestinationFinder{}
 	case "holidayextras":
 		return HolidayExtrasDestinationFinder{}
 	default:
-		return HolidayExtrasDestinationFinder{}
+		return PlaneFinderDestinationFinder{}
 	}
 	return nil
 }

destinationfinder/destinationfinder_planefinder.go

@@ -0,0 +1,89 @@
+// Package destinationfinder provides functionality for
+// determining where a flight with a given callsign is
+// destined.
+package destinationfinder
+
+import (
+	"errors"
+	"io/ioutil"
+	"net/http"
+	"os"
+	"strings"
+)
+
+type PlaneFinderDestinationFinder struct {
+}
+
+/**
+ * Retrieves the lat long of the destination (as a simple string, we're not interested in doing
+ * any real processing with this, just using it as an index. Uses the flightaware website as
+ * a datasource, and parses some js embedded in the page. As such this is potentially
+ * brittle, but the function defintion should stand, even if we were to plugin a different
+ * data source.
+ **/
+func (destination_finder PlaneFinderDestinationFinder) GetDestinationFromCallsign(callsign string) (lat_long string, err error) {
+	if callsign == "" {
+		return "", errors.New("Not going to get latlong from an empty callsign")
+	}
+	flight_url := "http://www.planefinder.net/data/flight/" + callsign
+
+	resp, err := http.Get(flight_url)
+	if err != nil {
+		return "", errors.New("Failed to retrieve flight details from " + flight_url)
+	}
+	defer resp.Body.Close()
+
+	planefinder_html, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return "", errors.New("Failed to retrieve flight details from " + flight_url)
+	}
+
+	return destination_finder.ExtractDestinationFromHTML(planefinder_html)
+}
+
+func (destination_finder *PlaneFinderDestinationFinder) ExtractDestinationFromHTML(html []byte) (lat_long string, err error) {
+	if strings.Index(string(html), "/data/airport") == -1 {
+		return "", errors.New("Failed to arrival airport in html ")
+	}
+
+	tmp_strings := strings.Split(string(html), "/data/airport/")
+	airport_code := strings.Split(tmp_strings[2], "\"")[0]
+	return destination_finder.getLatLongFromAirportCode(airport_code)
+}
+
+func (destination_finder *PlaneFinderDestinationFinder) getLatLongFromAirportCode(airport_code string) (lat_long string, err error) {
+	if airport_code == "" {
+		return "", errors.New("Not going to get latlong from an empty airport code")
+	}
+
+	airport_html, err := ioutil.ReadFile("./airport_" + airport_code + ".cache")
+	if err != nil {
+		airport_code_url := "http://www.planefinder.net/data/airport/" + airport_code
+
+		resp, err := http.Get(airport_code_url)
+		if err != nil {
+			return "", errors.New("Failed to retrieve airport details from " + airport_code_url)
+		}
+		defer resp.Body.Close()
+
+		airport_html, err = ioutil.ReadAll(resp.Body)
+		if err != nil {
+			return "", errors.New("Failed to retrieve airport details from " + airport_code_url)
+		}
+		cache_file, err := os.Create("./airport_" + airport_code + ".cache")
+		if err == nil {
+			cache_file.Write(airport_html)
+			cache_file.Sync()
+			cache_file.Close()
+		}
+	}
+
+	if strings.Index(string(airport_html), "location=") == -1 {
+		return "", errors.New("Failed to arrival airport in html ")
+	}
+
+	tmp_strings := strings.Split(string(airport_html), "location=")
+	airport_lat_lng := strings.Split(tmp_strings[1], ",13")[0]
+
+	return airport_lat_lng, nil
+}

destinationfinder/destinationfinder_test.go

@@ -22,3 +22,22 @@ func TestHolidayExtrasExtraction(t *testing.T) {
 		t.Fail()
 	}
 }
+
+func TestPlaneFinderExtraction(t *testing.T) {
+	var df PlaneFinderDestinationFinder
+	data, err := ioutil.ReadFile("./testdata/planefinder.html")
+	if err != nil {
+		fmt.Println(err)
+		t.Error("Failed to open planefinder.html")
+		return
+	}
+	latlong, err := df.ExtractDestinationFromHTML(data)
+	if err != nil {
+		fmt.Println("ExtractDestinationFromHTML errored with")
+		fmt.Println(err)
+		t.Fail()
+	} else if latlong != "63.985,-22.6056" {
+		fmt.Println("Failed to extract correct lat-long: " + latlong)
+		t.Fail()
+	}
+}