gotosocial/internal/media/util.go

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Api/v1/accounts (#8) * start work on accounts module * plodding away on the accounts endpoint * groundwork for other account routes * add password validator * validation utils * require account approval flags * comments * comments * go fmt * comments * add distributor stub * rename api to federator * tidy a bit * validate new account requests * rename r router * comments * add domain blocks * add some more shortcuts * add some more shortcuts * check email + username availability * email block checking for signups * chunking away at it * tick off a few more things * some fiddling with tests * add mock package * relocate repo * move mocks around * set app id on new signups * initialize oauth server properly * rename oauth server * proper mocking tests * go fmt ./... * add required fields * change name of func * move validation to account.go * more tests! * add some file utility tools * add mediaconfig * new shortcut * add some more fields * add followrequest model * add notify * update mastotypes * mock out storage interface * start building media interface * start on update credentials * mess about with media a bit more * test image manipulation * media more or less working * account update nearly working * rearranging my package ;) ;) ;) * phew big stuff!!!! * fix type checking * *fiddles* * Add CreateTables func * account registration flow working * tidy * script to step through auth flow * add a lil helper for generating user uris * fiddling with federation a bit * update progress * Tidying and linting
2021-04-01 18:46:45 +00:00
/*
GoToSocial
Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package media
import (
"bytes"
"errors"
"fmt"
"image"
"image/gif"
"image/jpeg"
"image/png"
"github.com/buckket/go-blurhash"
"github.com/h2non/filetype"
"github.com/nfnt/resize"
"github.com/superseriousbusiness/exifremove/pkg/exifremove"
)
// parseContentType parses the MIME content type from a file, returning it as a string in the form (eg., "image/jpeg").
// Returns an error if the content type is not something we can process.
func parseContentType(content []byte) (string, error) {
head := make([]byte, 261)
_, err := bytes.NewReader(content).Read(head)
if err != nil {
return "", fmt.Errorf("could not read first magic bytes of file: %s", err)
}
kind, err := filetype.Match(head)
if err != nil {
return "", err
}
if kind == filetype.Unknown {
return "", errors.New("filetype unknown")
}
return kind.MIME.Value, nil
}
// supportedImageType checks mime type of an image against a slice of accepted types,
// and returns True if the mime type is accepted.
func supportedImageType(mimeType string) bool {
acceptedImageTypes := []string{
"image/jpeg",
"image/gif",
"image/png",
}
for _, accepted := range acceptedImageTypes {
if mimeType == accepted {
return true
}
}
return false
}
// purgeExif is a little wrapper for the action of removing exif data from an image.
// Only pass pngs or jpegs to this function.
func purgeExif(b []byte) ([]byte, error) {
if len(b) == 0 {
return nil, errors.New("passed image was not valid")
}
clean, err := exifremove.Remove(b)
if err != nil {
return nil, fmt.Errorf("could not purge exif from image: %s", err)
}
if len(clean) == 0 {
return nil, errors.New("purged image was not valid")
}
return clean, nil
}
func deriveImage(b []byte, extension string) (*imageAndMeta, error) {
var i image.Image
var err error
switch extension {
case "image/jpeg":
i, err = jpeg.Decode(bytes.NewReader(b))
if err != nil {
return nil, err
}
case "image/png":
i, err = png.Decode(bytes.NewReader(b))
if err != nil {
return nil, err
}
case "image/gif":
i, err = gif.Decode(bytes.NewReader(b))
if err != nil {
return nil, err
}
default:
return nil, fmt.Errorf("extension %s not recognised", extension)
}
width := i.Bounds().Size().X
height := i.Bounds().Size().Y
size := width * height
aspect := float64(width) / float64(height)
bh, err := blurhash.Encode(4, 3, i)
if err != nil {
return nil, fmt.Errorf("error generating blurhash: %s", err)
}
out := &bytes.Buffer{}
if err := jpeg.Encode(out, i, nil); err != nil {
return nil, err
}
return &imageAndMeta{
image: out.Bytes(),
width: width,
height: height,
size: size,
aspect: aspect,
blurhash: bh,
}, nil
}
// deriveThumbnailFromImage returns a byte slice and metadata for a 256-pixel-width thumbnail
// of a given jpeg, png, or gif, or an error if something goes wrong.
//
// Note that the aspect ratio of the image will be retained,
// so it will not necessarily be a square.
func deriveThumbnail(b []byte, extension string) (*imageAndMeta, error) {
var i image.Image
var err error
switch extension {
case "image/jpeg":
i, err = jpeg.Decode(bytes.NewReader(b))
if err != nil {
return nil, err
}
case "image/png":
i, err = png.Decode(bytes.NewReader(b))
if err != nil {
return nil, err
}
case "image/gif":
i, err = gif.Decode(bytes.NewReader(b))
if err != nil {
return nil, err
}
default:
return nil, fmt.Errorf("extension %s not recognised", extension)
}
thumb := resize.Thumbnail(256, 256, i, resize.NearestNeighbor)
width := thumb.Bounds().Size().X
height := thumb.Bounds().Size().Y
size := width * height
aspect := float64(width) / float64(height)
out := &bytes.Buffer{}
if err := jpeg.Encode(out, thumb, nil); err != nil {
return nil, err
}
return &imageAndMeta{
image: out.Bytes(),
width: width,
height: height,
size: size,
aspect: aspect,
}, nil
}
type imageAndMeta struct {
image []byte
width int
height int
size int
aspect float64
blurhash string
}