rubenfonseca / fastimage

Finds the type and/or size of a remote image given its uri, by fetching as little as needed.

fastimage

by Ruben Fonseca (@rubenfonseca)

Golang implementation of fastimage. Finds the type and/or size of an image given its uri by fetching as little as needed.

How?

fastimage parses the image data as it is downloaded. As soon as it finds out the size and type of the image, it stops the download.

Install

$ go get github.com/rubenfonseca/fastimage

Usage

For instance, this is a big 10MB JPEG image on wikipedia:

url := "http://upload.wikimedia.org/wikipedia/commons/9/9a/SKA_dishes_big.jpg"

fastimage.Debug()
imagetype, size, err := fastimage.DetectImageType(url)
if err != nil {
	// Something went wrong, http failed? not an image?
	panic(err)
}

switch imagetype {
case fastimage.JPEG:
	log.Printf("JPEG")
case fastimage.PNG:
	log.Printf("PNG")
case fastimage.GIF:
	log.Printf("GIF")
}

log.Printf("Image type: %s", imagetype.String())
log.Printf("Image size: %v", size)

At the end, you can read something like this:

Closed after reading just 17863 bytes out of 10001439 bytes

If you want to set request timeout for url:

// the second argument is request timeout (milliseconds).
// FYI, DetectImageType() uses default timeout 5000ms.
imagetype, size, err := fastimage.DetectImageTypeWithTimeout(url, 2000)

Supported file types

File type	Can detect type?	Can detect size?
PNG	Yes	Yes
JPEG	Yes	Yes
GIF	Yes	Yes
BMP	Yes	No
TIFF	Yes	No

Project details

License

fastimage is under MIT license. See the LICENSE file for details.