gopeg.go

package main

import (
	"fmt"
	"encoding/json"
	"time"
	"log"
	"os"
	"path/filepath"
	"flag"
	"github.com/rwcarlsen/goexif/exif"
)

type LocationEntry struct {
	Date time.Time
	Lat, Lng float64
}

func main() {
  flag.Parse()
  root := flag.Arg(0)
  list := make([]LocationEntry, 0, 10)
  walk := func (path string, info os.FileInfo, err error) error {
		if err != nil {
			fmt.Println(err)
			return nil
	  }

	  if info.IsDir() || filepath.Ext(path) != ".jpg" {
	  	return nil
	  }

		f, err := os.Open(path)

		if err != nil {
			log.Fatal(err)
		}

		x, err := exif.Decode(f)
		if err != nil {
			log.Fatal(err)
		}

		// Two convenience functions exist for date/time taken and GPS coords:
		tm, _ := x.DateTime()
		lat, long, _ := x.LatLong()

		f.Close()

		if lat == 0 || long == 0 {
			return nil
		}

		c := LocationEntry{tm, lat, long}
		list = append(list, c)
		return nil
	}

  err := filepath.Walk(root, walk)

  if err != nil {
  	fmt.Printf("walk error [%v]\n", err)
  }

  jsonString, err := json.Marshal(list)
  if err != nil {
  	fmt.Printf("json error [%v]\n", err)
  }

  fmt.Print(string(jsonString))
}