requires Date.js, parses jhead output to array of objects

node-jhead.coffee

# This is a simple little wrapper around the jhead exif reader.
# See http://www.sentex.net/~mwandel/jhead/

# Date.js (http://datejs.org).  Remove and the below lines if you don't need js dates
require "./date"
sys: require "sys"
path: require "path"
PATH_TO_JHEAD: "./external/jhead"

jhead_parse: (image_file_or_dir, callback) ->
	image_file_or_dir: image_file_or_dir.replace(" ", "\\ ")
	cmd: "${PATH_TO_JHEAD} ${image_file_or_dir}"
	sys.exec cmd, (err, stdout, stderr) ->
		callback(err) if err?
		callback(stderr) if stderr?
		
		exifs_raw: stdout.split("\n\n")
		exifs: []
		for exif_raw in exifs_raw
			lines: exif_raw.split("\n")
			exif: {}
			for line in lines
				if line.length <=1 then continue
				name_val: line.split(": ")
				name: name_val[0].trim()
				value: name_val[1].trim()
				switch name
					when "GPS Latitude" then exif.gps_lat: value
					when "GPS Longitude" then exif.gps_long: value
					when "File name"
						exif.file_name: path.basename(value)
						exif.path: value
					when "File size" then exif.file_size: value
					when "File date" then exif.file_date: parse_jhead_date(value)
					when "Camera make" then exif.camera_make: value
					when "Camera model" then exif.camera_model: value
					when "Date/Time" then exif.date_time: parse_jhead_date(value) 
					when "Resolution" then exif.resolution: value
					when "Orientation" then exif.orientation: value
					when "Flash used" then exif.flash_used: value
					when "Focal length" then exif.focal_length: value
					when "Exposure time" then exif.exposure_time: value
					when "Aperture" then exif.aperture: value
					when "ISO equiv." then exif.iso_equiv: value
					when "Whitebalance" then exif.white_balance: value
					when "Metering Mode" then exif.metering_mode: value
					when "Exposure" then exif.exposure: value
			exifs.push(exif)
		callback(null, exifs) if callback?
			
#parse (e.g. 2010:02:07 11:40:33) into a JS Date
parse_jhead_date: (value) ->
	date_str: value[0..3] + " " + value[5..6] + " " + value[8..9] +  " " + value[12..18]
	return new Date.parse(date_str)
		
	
# callback with an error or an array of exif objects with the above properties on them				
exports.parse: (image_file_or_dir, callback) ->
	jhead_parse(image_file_or_dir, callback)