/
image.go
478 lines (399 loc) · 10.8 KB
/
image.go
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// Townsourced
// Copyright 2015 Tim Shannon. All rights reserved.
package app
import (
"bytes"
"errors"
"image"
"image/gif"
"image/jpeg"
"image/png"
"io"
"io/ioutil"
"net/http"
"time"
"git.townsourced.com/townsourced/goexif/exif"
"git.townsourced.com/townsourced/imaging"
log "git.townsourced.com/townsourced/logrus"
"github.com/timshannon/townsourced/data"
"github.com/timshannon/townsourced/fail"
)
const (
imageMaxSize = int64(10 << 20) //10MB
imageMaxWidth = 2048
imageMaxHeight = 2048
imageMaxThumbHeight = 300
imageMaxThumbWidth = 300
imageMaxPlaceholderWidth = 30
imageMaxPlaceholderHeight = 30
)
var (
// ErrImageNotFound is the error returned when an image is not found
ErrImageNotFound = &fail.Fail{
Message: "Image not found",
HTTPStatus: http.StatusNotFound,
}
// ErrImageTooLarge is returned with the passed in image is too large
ErrImageTooLarge = &fail.Fail{
Message: "The uploaded image is too large. The max size is 5 MB",
HTTPStatus: http.StatusRequestEntityTooLarge,
}
// ErrImageInvalidType is when the content type of the image is not supported
ErrImageInvalidType = fail.New("Unsupported image type, please use a jpeg, png, or gif")
// ErrImageNotOwner is when someone who is not the owner of the image is trying to modify it
ErrImageNotOwner = fail.New("You cannot update an image you are not the owner of")
// ErrImageDecodeError is when the image data can't be decoded properly
ErrImageDecodeError = fail.New("The uploaded image cannot be decoded properly based on the content type")
)
var imageValidContentTypes = []string{"image/gif", "image/jpeg", "image/png"}
// Image is a user uploaded image for use in posts, or other items
type Image struct {
Key data.UUID `json:"key,omitempty" gorethink:",omitempty"`
OwnerKey data.Key `json:"ownerKey,omitempty" gorethink:",omitempty"`
ContentType string `json:"contentType,omitempty" gorethink:",omitempty"`
// whether or not the image is used by a post or elsewhere
// images not in use will be cleaned up by a task
InUse bool `json:"-"`
data.Version
Data []byte `json:"-" gorethink:",omitempty"` // full image
ThumbData []byte `json:"-" gorethink:",omitempty"` // thumbnail image
PlaceholderData []byte `json:"-" gorethink:",omitempty"` // Placeholder image small, and downloads quick
image image.Image
}
// ImageNew inserts a new image into the database
// closes the reader when finished
func ImageNew(owner *User, contentType string, reader io.ReadCloser) (img *Image, err error) {
defer func() {
if cerr := reader.Close(); cerr != nil && err == nil {
err = cerr
}
}()
lr := &io.LimitedReader{R: reader, N: (imageMaxSize + 1)}
buff, err := ioutil.ReadAll(lr)
if err != nil {
return nil, err
}
if lr.N == 0 {
return nil, ErrImageTooLarge
}
img, err = imageNew(owner, contentType, buff, false)
return
}
func imageNew(owner *User, contentType string, imgData []byte, inUse bool) (*Image, error) {
i := &Image{
OwnerKey: owner.Username,
ContentType: contentType,
Data: imgData,
InUse: inUse,
}
err := i.validate()
if err != nil {
return nil, err
}
err = i.prep()
if err != nil {
return nil, err
}
i.Rev()
key, err := data.ImageInsert(i)
if err != nil {
return nil, err
}
i.Key = key
return i, nil
}
// ImageGet retrieves an image by it's key
func ImageGet(key data.UUID) (*Image, error) {
return imageGet(key, false, false)
}
// ImageGetThumb retrieves an image by it's key
func ImageGetThumb(key data.UUID) (*Image, error) {
return imageGet(key, true, false)
}
// ImageGetPlaceholder retrieves an image by it's key
func ImageGetPlaceholder(key data.UUID) (*Image, error) {
return imageGet(key, false, true)
}
func imageGet(key data.UUID, thumb, placeholder bool) (*Image, error) {
i := &Image{}
err := data.ImageGet(i, key, thumb, placeholder)
if err == data.ErrNotFound {
return nil, ErrImageNotFound
}
if err != nil {
return nil, err
}
return i, nil
}
// Etag returns an appropriate string to use as an HTTP etag, or database version
func (i *Image) Etag() string {
return i.Version.Ver()
}
func (i *Image) update() error {
if i.image != nil {
err := i.encode()
if err != nil {
return err
}
}
return data.ImageUpdate(i, i.Key)
}
func (i *Image) delete() error {
return data.ImageDelete(i.Key)
}
//imageSetUsed updates an image as inUse and updates it in the
// database
func imageSetUsed(imageKey data.UUID) error {
return data.ImageUpdate(struct {
InUse bool
}{
InUse: true,
}, imageKey)
}
func (i *Image) validate() error {
if len(i.Data) == 0 {
return errors.New("Image not loaded properly")
}
//check content type
found := false
for j := range imageValidContentTypes {
if i.ContentType == imageValidContentTypes[j] {
found = true
break
}
}
if !found {
return ErrImageInvalidType
}
return nil
}
// fit the image into the proper size and build thumbnail and placeholders
func (i *Image) prep() error {
orientation := 1
if i.ContentType == "image/jpeg" {
// rotate based on exif data if applicable
ex, err := exif.Decode(bytes.NewReader(i.Data))
// if at any point we can't parse exif data properly, then we stick to default orientation
if err == nil {
//lookup orientation
tag, err := ex.Get(exif.Orientation)
if err == nil {
orientation, _ = tag.Int(0)
}
}
}
//resize to max allowable image size
err := i.decode()
if err != nil {
return err
}
//0 will preserve the ratio
newWidth := 0
newHeight := 0
if i.image.Bounds().Dx() > imageMaxWidth {
newWidth = imageMaxWidth
} else if i.image.Bounds().Dy() > imageMaxHeight {
newHeight = imageMaxHeight
}
if newWidth != 0 || newHeight != 0 {
err = i.resize(&User{Username: i.OwnerKey}, newWidth, newHeight)
if err != nil {
return err
}
}
switch orientation {
case 2:
i.image = imaging.FlipH(i.image)
case 3:
i.image = imaging.Rotate180(i.image)
case 4:
i.image = imaging.FlipV(i.image)
case 5:
i.image = imaging.Rotate90(imaging.FlipH(i.image))
case 6:
i.image = imaging.Rotate270(i.image)
case 7:
i.image = imaging.FlipH(imaging.Rotate90(i.image))
case 8:
i.image = imaging.Rotate90(i.image)
}
err = i.encode()
if err != nil {
return err
}
return nil
}
// decode decodes the image data into the go Image format for processing
func (i *Image) decode() error {
if i.image != nil {
//image is already decoded
return nil
}
if len(i.Data) == 0 {
return errors.New("Image not loaded properly.")
}
var err error
buffer := bytes.NewBuffer(i.Data)
switch i.ContentType {
case "image/gif":
i.image, err = gif.Decode(buffer)
case "image/jpeg":
i.image, err = jpeg.Decode(buffer)
case "image/png":
i.image, err = png.Decode(buffer)
default:
return ErrImageInvalidType
}
if err != nil {
log.WithField("imagekey", i.Key).Error(err)
return err
}
i.Data = nil
return nil
}
// encode encodes the image format data into image data
func (i *Image) encode() error {
if i.image == nil {
// image is already encoded
return nil
}
buffer := bytes.NewBuffer(i.Data)
err := imageEncode(i.image, i.ContentType, buffer)
if err != nil {
return err
}
i.Data = buffer.Bytes()
err = i.buildThumbAndPlaceholder()
if err != nil {
return err
}
i.image = nil
return nil
}
func imageEncode(image image.Image, contentType string, result *bytes.Buffer) error {
switch contentType {
case "image/gif":
return gif.Encode(result, image, nil)
case "image/jpeg":
return jpeg.Encode(result, image, nil)
case "image/png":
return png.Encode(result, image)
default:
return ErrImageInvalidType
}
}
func (i *Image) buildThumbAndPlaceholder() error {
//0 will preserve the ratio
newWidth := 0
newHeight := 0
var err error
// create thumb and placeholder seqeuentially to benefit from
// increasingly smaller images
//first thumb
//thumbnail rules are a bit different, resize so that the smallest
// dimension is resized instead of the largest, this is to prevent
// cases where really tall or really wide images create poor
// thumbnails
if i.image.Bounds().Dx() > i.image.Bounds().Dy() {
//wider than tall
newHeight = imageMaxThumbHeight
} else {
//taller than wide or same
newWidth = imageMaxThumbWidth
}
if newWidth != 0 || newHeight != 0 {
err = i.resize(&User{Username: i.OwnerKey}, newWidth, newHeight)
if err != nil {
return err
}
}
buffer := bytes.NewBuffer(i.ThumbData)
err = imageEncode(i.image, i.ContentType, buffer)
if err != nil {
return err
}
i.ThumbData = buffer.Bytes()
// then placeholder
newWidth = 0
newHeight = 0
if i.image.Bounds().Dx() > imageMaxPlaceholderWidth {
newWidth = imageMaxPlaceholderWidth
} else if i.image.Bounds().Dy() > imageMaxPlaceholderHeight {
newHeight = imageMaxPlaceholderHeight
}
if newWidth != 0 || newHeight != 0 {
err = i.resize(&User{Username: i.OwnerKey}, newWidth, newHeight)
if err != nil {
return err
}
}
buffer = bytes.NewBuffer(i.PlaceholderData)
err = imageEncode(i.image, i.ContentType, buffer)
if err != nil {
return err
}
i.PlaceholderData = buffer.Bytes()
return nil
}
func (i *Image) resize(who *User, width, height int) error {
if i.OwnerKey != who.Username {
return ErrImageNotOwner
}
err := i.decode()
if err != nil {
return err
}
i.image = imaging.Resize(i.image, width, height, imaging.Linear)
return nil
}
func (i *Image) crop(who *User, x0, y0, x1, y1 int) error {
if i.OwnerKey != who.Username {
return ErrImageNotOwner
}
err := i.decode()
if err != nil {
return err
}
i.image = imaging.Crop(i.image, image.Rect(x0, y0, x1, y1))
return nil
}
func (i *Image) cropCenter(who *User, width, height int) error {
if i.OwnerKey != who.Username {
return ErrImageNotOwner
}
err := i.decode()
if err != nil {
return err
}
i.image = imaging.CropCenter(i.image, width, height)
return nil
}
// ReadSeeker returns a ReadSeeker for the available image data
// uses the highest quality image data available
func (i *Image) ReadSeeker() io.ReadSeeker {
if len(i.Data) != 0 {
return bytes.NewReader(i.Data)
}
if len(i.ThumbData) != 0 {
return bytes.NewReader(i.ThumbData)
}
if len(i.PlaceholderData) != 0 {
return bytes.NewReader(i.PlaceholderData)
}
// No data available? Shouldn't happen
return bytes.NewReader([]byte{})
}
//Delete Unused Image Tasker
type taskerUnusedImages struct{}
func (d *taskerUnusedImages) Type() string { return "DeleteUnusedImages" }
func (d *taskerUnusedImages) Priority() uint { return priorityLow }
func (d *taskerUnusedImages) NextRun() time.Time { return time.Now().Add(15 * time.Minute) }
func (d *taskerUnusedImages) Retry() int { return -1 }
func (d *taskerUnusedImages) Do(variables ...interface{}) error {
// delete all images that aren't in use an hour after they were last updated
err := data.ImageDeleteOrphans(time.Now().Add(-1 * time.Hour))
if err == data.ErrNotFound {
return nil
}
return err
}