README
¶
Image resizer
Created as part of inspishop e-commerce platform by inspirum team.
On-demand image resizing, format converting and size optimization with the best CLI tools. Prepared to be used as Docker image with cloud storage as Amazon S3.
- image resizing, format converting and optimization
- support for jpeg, png, webp, bmp, gif, tiff, svg image formats
- file-cache for resized images on local disk (temporary cache) and cloud storage (persistent cache)
Usage example
Resizing
Application handle route with dynamic template (parameters divided by dash) and filepath parameters.
GET /image/{template}/{filepath}
Template
Options for resizing are specified as a dash delimited list of parameters, which can be supplied in any order. Duplicate parameters overwrite last values.
| Name | Template | Example | Description |
|---|---|---|---|
| width | w[X] |
w200 |
Resize to 200px width with proportional height |
| height | h[X] |
h100 |
Resize to 100px height with proportional width |
| ratio | [X]x[X] |
1x2 |
Resize to ratio to 1:2 (width : height) |
| crop | crop |
crop |
Image fill whole canvas (no addition background added) |
| upscale | upscale |
upscale |
Image can be larger than original |
There are special template string original. This will return optimized image with original dimensions.
It is helpful to show image with maximal resolution without knowing its dimension.
When there are set both height and width then ratio parameter will be ignored.
If output image has a different ratio than an original, image will be centered on transparent canvas (jpg has white background because it doesn't support transparent color).
Examples
Values are for an image with dimension 200x400px (width : height).
| Template string | Output dimension |
|---|---|
original |
200x400 |
h100 |
50x100 |
w100 |
100x200 |
w50-w200 |
100x200 |
w100-h300 |
100x300 |
w200-1x1 |
200x200 |
w200-1x3 |
200x600 |
w100-h300-2x1 |
100x300 |
w1000-1x1 |
1000x1000 |
w1000-1x1-crop |
200x200 |
w1000-1x1-crop-upscale |
1000x1000 |
Width & height
Examples use jpg format because canvas background is white (for better visibility)
h200 |
w200 |
w188-h233 |
|---|---|---|
| (300x200) | (200x134) | (188x233) |
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 |
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Ratio
h200-1x1 |
h200-1x2 |
h200-2x1 |
|---|---|---|
| (200x200) | (100x200) | (400x200) |
 |
 |
 |
Crop
cropparameter will crop image to fill whole canvas
h200-1x1-crop |
h200-1x2-crop |
h200-2x1-crop |
|---|---|---|
| (200x200) | (100x200) | (400x200) |
 |
 |
 |
Upscale
By default, image can't up-size (be larger than original)
original |
w250-h300 |
w250-h300-upscale |
w250-h300-crop |
w250-h300-crop-upscale |
|---|---|---|---|---|
| (200x200) | (250x300) | (250x300) | (167x200) | (250x300) |
 |
 |
 |
 |
 |
original |
w500-h300-crop |
w500-h300-crop |
w500-h300-crop-upscale |
|---|---|---|---|
| (200x200) | (500x300) | (200x120) | (500x300) |
|
 |
 |
 |
Format encoding
Image can be encoded to any supported format simple by changing file extension in URL.
Original image extension is specified in original query parameter.
This is typically used to encode image as web-friendly webp format
http://localhost:3000/image/custom-w400-1x1-upscale/data/products/0/1/background.webp?original=png
Optimization
The package will use these optimizers if they are present on your system:
By setting environment variable you can change default path to binary file or default arguments.
| Environment variable | Default value |
|---|---|
CMD_OPTIMIZER_PNG |
pngquant --force --ext .png --skip-if-larger --quality 0-75 --speed 4 --strip -- |
CMD_OPTIMIZER_JPG |
jpegoptim --force --strip-all --max 75 --quiet --all-progressive |
CMD_OPTIMIZER_GIF |
gifsicle --batch --optimize=3 |
CMD_OPTIMIZER_SVG |
svgcleaner |
CMD_OPTIMIZER_WEBP |
cwebp -m 6 -pass 10 -mt -q 75 -quiet |
Examples
| 64 kB | 28 kB (43 %) | 22 kB (34 %) |
|---|---|---|
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| 421 kB | 91 kB (21 %) | 23 kB (5 %) |
|---|---|---|
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System requirements
Installation
Testing
Contributing
Please see CONTRIBUTING and CODE_OF_CONDUCT for details.
Security
If you discover any security related issues, please email tomas.novotny@inspirum.cz instead of using the issue tracker.
Credits
License
The MIT License (MIT). Please see License File for more information.
Documentation
¶
Index ¶
- func ConvertFile(inputFilePath string, inputWidth int, inputHeight int, outputFilePath string, ...) (err error)
- func CopyFile(src, dst string) (err error)
- func CreateTempFileFromReader(c io.Reader, ext string) (f *os.File, err error)
- func GetEnv(key string, fallback string) string
- func GetEnvAsBool(key string, fallback bool) bool
- func GetEnvAsInt(key string, fallback int) int
- func GetImageDimensions(p string) (w int, h int, err error)
- func GetReaderContentType(c io.ReadSeeker) (mime string, err error)
- func NewS3Client(endpoint string, bucket string, key string, secret string, region string) *s3client
- func OpenFileWithModTime(p string) (*os.File, *time.Time, error)
- func OptimizeFile(filePath string) (err error)
- func ReplacePathExt(p string, r *http.Request) string
- func ShouldNotResize(template string, filePath string) bool
- func ValidateFilename(filePath string) error
- func ValidateTemplate(template string) error
- func WriteFileFromReader(p string, c io.Reader) (bool, error)
- type HttpError
- type Storage
- type Template
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func ConvertFile ¶
func GetEnvAsBool ¶
func GetEnvAsInt ¶
func GetReaderContentType ¶
func GetReaderContentType(c io.ReadSeeker) (mime string, err error)
func NewS3Client ¶
func OptimizeFile ¶
func ShouldNotResize ¶
func ValidateFilename ¶
func ValidateTemplate ¶
Types ¶
type Storage ¶
type Storage interface {
DownloadFile(path string, outputPath string) (f *os.File, err error)
DownloadFileWithModTime(path string, outputPath string) (f *os.File, t *time.Time, err error)
UploadContentReaderIfNewer(path string, time time.Time, content io.ReadSeeker) (bool, error)
UploadContentReader(path string, content io.ReadSeeker) error
}
Source Files
Directories