// FileTime returns the best guess of the file's creation time (or modtime).
// If the file doesn't have its own metadata indication the creation time (such as in EXIF),
// FileTime uses the modification time from the file system.
// It there was a valid EXIF but an error while trying to get a date from it,
// it logs the error and tries the other methods.
func FileTime(f io.ReaderAt) (time.Time, error) {
var ct time.Time
defaultTime := func() (time.Time, error) {
if osf, ok := f.(*os.File); ok {
fi, err := osf.Stat()
if err != nil {
return ct, fmt.Errorf("Failed to find a modtime: lstat: %v", err)
}
return fi.ModTime(), nil
}
return ct, errors.New("All methods failed to find a creation time or modtime.")
}
size, ok := findSize(f)
if !ok {
size = 256 << 10 // enough to get the EXIF
}
r := io.NewSectionReader(f, 0, size)
ex, err := exif.Decode(r)
if err != nil {
return defaultTime()
}
ct, err = ex.DateTime()
if err != nil {
return defaultTime()
}
return ct, nil
}
func showEXIF(file string) {
f, err := os.Open(file)
if err != nil {
panic(err.Error())
}
defer f.Close()
ex, err := exif.Decode(f)
if err != nil {
log.Fatalf("exif.Decode: %v", err)
}
fmt.Printf("exif.Decode = %#v\n", ex)
ct, err := ex.DateTime()
fmt.Printf("exif.DateTime = %v, %v\n", ct, err)
}
func main() {
flag.Parse()
fname := flag.Arg(0)
f, err := os.Open(fname)
if err != nil {
log.Fatal(err)
}
x, err := exif.Decode(f)
if err != nil {
log.Fatal(err)
}
x.Walk(Walker{})
}
func ExampleDecode() {
fname := "sample1.jpg"
f, err := os.Open(fname)
if err != nil {
log.Fatal(err)
}
x, err := exif.Decode(f)
if err != nil {
log.Fatal(err)
}
camModel, _ := x.Get("Model")
date, _ := x.Get("DateTimeOriginal")
fmt.Println(camModel.StringVal())
fmt.Println(date.StringVal())
focal, _ := x.Get("FocalLength")
numer, denom := focal.Rat2(0) // retrieve first (only) rat. value
fmt.Printf("%v/%v", numer, denom)
}
// TODO(mpl): move this test to the goexif lib if/when we contribute
// back the DateTime stuff to upstream.
func TestDateTime(t *testing.T) {
f, err := os.Open(path.Join(datadir, "f1-exif.jpg"))
if err != nil {
t.Fatal(err)
}
defer f.Close()
ex, err := exif.Decode(f)
if err != nil {
t.Fatal(err)
}
got, err := ex.DateTime()
if err != nil {
t.Fatal(err)
}
exifTimeLayout := "2006:01:02 15:04:05"
want, err := time.Parse(exifTimeLayout, "2012:11:04 05:42:02")
if err != nil {
t.Fatal(err)
}
if got != want {
t.Fatalf("Creation times differ; got %v, want: %v\n", got, want)
}
}
// DecodeConfig returns the image Config similarly to
// the standard library's image.DecodeConfig with the
// addition that it also checks for an EXIF orientation,
// and sets the Width and Height as they would visibly
// be after correcting for that orientation.
func DecodeConfig(r io.Reader) (Config, error) {
var c Config
var buf bytes.Buffer
tr := io.TeeReader(io.LimitReader(r, 2<<20), &buf)
swapDimensions := false
ex, err := exif.Decode(tr)
if err != nil {
imageDebug("No valid EXIF.")
} else {
tag, err := ex.Get(exif.Orientation)
if err != nil {
imageDebug("No \"Orientation\" tag in EXIF.")
} else {
orient := tag.Int(0)
switch orient {
// those are the orientations that require
// a rotation of ±90
case leftSideTop, rightSideTop, rightSideBottom, leftSideBottom:
swapDimensions = true
}
}
}
conf, format, err := image.DecodeConfig(io.MultiReader(&buf, r))
if err != nil {
imageDebug(fmt.Sprintf("Image Decoding failed: %v", err))
return c, err
}
c.Format = format
if swapDimensions {
c.Width, c.Height = conf.Height, conf.Width
} else {
c.Width, c.Height = conf.Width, conf.Height
}
return c, err
}
func indexEXIF(wholeRef blob.Ref, header []byte, mm *mutationMap) {
ex, err := exif.Decode(bytes.NewReader(header))
if err != nil {
return
}
defer func() {
// The EXIF library panics if you access a field past
// what the file contains. Be paranoid and just
// recover here, instead of crashing on an invalid
// EXIF file.
if e := recover(); e != nil {
log.Printf("Ignoring invalid EXIF file. Caught panic: %v", e)
}
}()
ex.Walk(exifWalkFunc(func(name exif.FieldName, tag *tiff.Tag) error {
tagFmt := tagFormatString(tag)
if tagFmt == "" {
return nil
}
key := keyEXIFTag.Key(wholeRef, fmt.Sprintf("%04x", tag.Id))
numComp := int(tag.Ncomp)
if tag.Format() == tiff.StringVal {
numComp = 1
}
var val bytes.Buffer
val.WriteString(keyEXIFTag.Val(tagFmt, numComp, ""))
if tag.Format() == tiff.StringVal {
str := tag.StringVal()
if containsUnsafeRawStrByte(str) {
val.WriteString(urle(str))
} else {
val.WriteString(str)
}
} else {
for i := 0; i < int(tag.Ncomp); i++ {
if i > 0 {
val.WriteByte('|')
}
switch tagFmt {
case "int":
fmt.Fprintf(&val, "%d", tag.Int(i))
case "rat":
n, d := tag.Rat2(i)
fmt.Fprintf(&val, "%d/%d", n, d)
case "float":
fmt.Fprintf(&val, "%v", tag.Float(i))
default:
panic("shouldn't get here")
}
}
}
valStr := val.String()
mm.Set(key, valStr)
return nil
}))
longTag, err := ex.Get(exif.FieldName("GPSLongitude"))
if err != nil {
return
}
ewTag, err := ex.Get(exif.FieldName("GPSLongitudeRef"))
if err != nil {
return
}
latTag, err := ex.Get(exif.FieldName("GPSLatitude"))
if err != nil {
return
}
nsTag, err := ex.Get(exif.FieldName("GPSLatitudeRef"))
if err != nil {
return
}
long := tagDegrees(longTag)
lat := tagDegrees(latTag)
if ewTag.StringVal() == "W" {
long *= -1.0
}
if nsTag.StringVal() == "S" {
lat *= -1.0
}
mm.Set(keyEXIFGPS.Key(wholeRef), keyEXIFGPS.Val(fmt.Sprint(lat), fmt.Sprint(long)))
}
// Decode decodes an image from r using the provided decoding options.
// The string returned is the format name returned by image.Decode.
// If opts is nil, the defaults are used.
func Decode(r io.Reader, opts *DecodeOpts) (image.Image, string, error) {
var buf bytes.Buffer
tr := io.TeeReader(io.LimitReader(r, 2<<20), &buf)
angle := 0
flipMode := FlipDirection(0)
if opts.useEXIF() {
ex, err := exif.Decode(tr)
if err != nil {
imageDebug("No valid EXIF; will not rotate or flip.")
return image.Decode(io.MultiReader(&buf, r))
}
tag, err := ex.Get(exif.Orientation)
if err != nil {
imageDebug("No \"Orientation\" tag in EXIF; will not rotate or flip.")
return image.Decode(io.MultiReader(&buf, r))
}
orient := tag.Val[1]
switch orient {
case 1:
// do nothing
case 2:
flipMode = 2
case 3:
angle = 180
case 4:
angle = 180
flipMode = 2
case 5:
angle = -90
flipMode = 2
case 6:
angle = -90
case 7:
angle = 90
flipMode = 2
case 8:
angle = 90
}
} else {
if opts.forcedRotate() {
var ok bool
angle, ok = opts.Rotate.(int)
if !ok {
return nil, "", fmt.Errorf("Rotate should be an int, not a %T", opts.Rotate)
}
}
if opts.forcedFlip() {
var ok bool
flipMode, ok = opts.Flip.(FlipDirection)
if !ok {
return nil, "", fmt.Errorf("Flip should be a FlipDirection, not a %T", opts.Flip)
}
}
}
im, err := jpeg.Decode(io.MultiReader(&buf, r))
if err != nil {
return nil, "", err
}
return flip(rotate(im, angle), flipMode), "jpeg", nil
}
// Decode decodes an image from r using the provided decoding options.
// The Config returned is similar to the one from the image package,
// with the addition of the Modified field which indicates if the
// image was actually flipped or rotated.
// If opts is nil, the defaults are used.
func Decode(r io.Reader, opts *DecodeOpts) (image.Image, Config, error) {
var c Config
var buf bytes.Buffer
tr := io.TeeReader(io.LimitReader(r, 2<<20), &buf)
angle := 0
flipMode := FlipDirection(0)
if opts.useEXIF() {
ex, err := exif.Decode(tr)
maybeRescale := func() (image.Image, Config, error) {
im, format, err := image.Decode(io.MultiReader(&buf, r))
if err == nil && opts.wantRescale(im.Bounds()) {
im = rescale(im, opts)
c.Modified = true
}
c.Format = format
c.setBounds(im)
return im, c, err
}
if err != nil {
imageDebug("No valid EXIF; will not rotate or flip.")
return maybeRescale()
}
tag, err := ex.Get(exif.Orientation)
if err != nil {
imageDebug("No \"Orientation\" tag in EXIF; will not rotate or flip.")
return maybeRescale()
}
orient := tag.Int(0)
switch orient {
case topLeftSide:
// do nothing
case topRightSide:
flipMode = 2
case bottomRightSide:
angle = 180
case bottomLeftSide:
angle = 180
flipMode = 2
case leftSideTop:
angle = -90
flipMode = 2
case rightSideTop:
angle = -90
case rightSideBottom:
angle = 90
flipMode = 2
case leftSideBottom:
angle = 90
}
} else {
if opts.forcedRotate() {
var ok bool
angle, ok = opts.Rotate.(int)
if !ok {
return nil, c, fmt.Errorf("Rotate should be an int, not a %T", opts.Rotate)
}
}
if opts.forcedFlip() {
var ok bool
flipMode, ok = opts.Flip.(FlipDirection)
if !ok {
return nil, c, fmt.Errorf("Flip should be a FlipDirection, not a %T", opts.Flip)
}
}
}
im, format, err := image.Decode(io.MultiReader(&buf, r))
if err != nil {
return nil, c, err
}
rescaled := false
if opts.wantRescale(im.Bounds()) {
im = rescale(im, opts)
rescaled = true
}
im = flip(rotate(im, angle), flipMode)
modified := true
if angle == 0 && flipMode == 0 && !rescaled {
modified = false
}
c.Format = format
c.Modified = modified
c.setBounds(im)
return im, c, nil
}
// Decode decodes an image from r using the provided decoding options.
// The Config returned is similar to the one from the image package,
// with the addition of the Modified field which indicates if the
// image was actually flipped or rotated.
// If opts is nil, the defaults are used.
func Decode(r io.Reader, opts *DecodeOpts) (image.Image, Config, error) {
var c Config
var buf bytes.Buffer
tr := io.TeeReader(io.LimitReader(r, 2<<20), &buf)
angle := 0
flipMode := FlipDirection(0)
if opts.useEXIF() {
ex, err := exif.Decode(tr)
if err != nil {
imageDebug("No valid EXIF; will not rotate or flip.")
im, format, err := image.Decode(io.MultiReader(&buf, r))
c.Format = format
c.setBounds(im)
return im, c, err
}
tag, err := ex.Get(exif.Orientation)
if err != nil {
imageDebug("No \"Orientation\" tag in EXIF; will not rotate or flip.")
im, format, err := image.Decode(io.MultiReader(&buf, r))
c.Format = format
c.setBounds(im)
return im, c, err
}
orient := tag.Int(0)
switch orient {
case 1:
// do nothing
case 2:
flipMode = 2
case 3:
angle = 180
case 4:
angle = 180
flipMode = 2
case 5:
angle = -90
flipMode = 2
case 6:
angle = -90
case 7:
angle = 90
flipMode = 2
case 8:
angle = 90
}
} else {
if opts.forcedRotate() {
var ok bool
angle, ok = opts.Rotate.(int)
if !ok {
return nil, c, fmt.Errorf("Rotate should be an int, not a %T", opts.Rotate)
}
}
if opts.forcedFlip() {
var ok bool
flipMode, ok = opts.Flip.(FlipDirection)
if !ok {
return nil, c, fmt.Errorf("Flip should be a FlipDirection, not a %T", opts.Flip)
}
}
}
im, err := jpeg.Decode(io.MultiReader(&buf, r))
if err != nil {
return nil, c, err
}
im = flip(rotate(im, angle), flipMode)
modified := true
if angle == 0 && flipMode == 0 {
modified = false
}
c.Format = "jpeg"
c.Modified = modified
c.setBounds(im)
return im, c, nil
}