func writeAndCacheImg(w io.Writer, img image.Image, opts optimizer.Options, fileName string) {
f, cacheWriter := fileCacheWriter(fileName)
defer f.Close()
multi := io.MultiWriter(w, cacheWriter)
// Write image response.
optimizer.Encode(multi, img, opts)
cacheWriter.Flush()
return
}
func optimizeAndServeImg(w http.ResponseWriter, r *http.Request, opts optimizer.Options, domain string, imagePath string, body []byte) (err error) {
img, _, err := image.Decode(bytes.NewReader(body))
if err != nil || img == nil {
log.Errorf("Could not decode %s/%s: %s", domain, imagePath, err.Error())
return
}
// If decoding succeeds, cache it.
go cacheDomainFile(domain, imagePath, body)
// If cache enabled, cache the file.
imgHeaders(&w, r)
if useFileCache {
writeAndCacheImg(w, img, opts, getOptimizedImgCachePath(domain, imagePath, opts))
return
}
// If cache disabled, just serve
optimizer.Encode(w, img, opts)
return
}
func main() {
var img image.Image
var err error
var origFmt string
// Process flags.
mimeFlag := flag.String("format", "", "The mime type to output. If none specified, will default to the output file format or original format.")
qualityFlag := flag.Int("quality", 0, "The quality level for the final image")
widthFlag := flag.Uint("width", 0, "The width of the final image")
heightFlag := flag.Uint("height", 0, "The height of the final image")
dprFlag := flag.Float64("dpr", 1.0, "The Viewport DPR to optimize for")
downlinkFlag := flag.Float64("downlink", 0.384, "The downlink speed to optimize for")
saveDataFlag := flag.Bool("savedata", false, "Optimize to save data")
flag.Parse()
args := flag.Args()
numArgs := len(args)
stat, _ := os.Stdin.Stat()
// @todo If using stdin, decode stdin into image, otherwise decode file into image.
if (stat.Mode() & os.ModeCharDevice) == 0 {
img, origFmt, err = image.Decode(bufio.NewReader(os.Stdin))
} else {
// If no stdin and no file, return error.
if numArgs < 1 {
fmt.Println("You must supply a file via stdin or the first argument")
os.Exit(1)
}
// Try to open and read the file.
f, e := os.Open(args[0])
if e != nil {
fmt.Printf("Error reading file: %s\n", e)
os.Exit(1)
}
defer f.Close()
img, origFmt, err = image.Decode(bufio.NewReader(f))
}
// Check to see decoding suceeded.
if err != nil {
fmt.Printf("Could not decode image from stdin: %s\n", err)
os.Exit(1)
}
// Check for mime output flag.
target := ""
mimeType := *mimeFlag
if mimeType == "" {
// If using output file, get from extension.
if numArgs > 1 {
target = args[1]
} else if numArgs > 1 {
target = args[0]
}
if target != "" {
mimeType = mime.TypeByExtension(path.Ext(target))
} else {
// Still no mime? Set to input image.
mimeType = origFmt
}
}
// Output. Check if target out, otherwise write to stdout.
var w io.Writer
if numArgs > 1 {
// Output to file.
f, err := os.Create(args[1])
if err != nil {
fmt.Printf("Could not write to %s\n", args[1])
os.Exit(1)
}
defer f.Close()
w = bufio.NewWriter(f)
} else {
// Output to stdout.
w = bufio.NewWriter(os.Stdout)
}
// If here, have an io.Writer in w and are read to rock.
o := optimizer.Options{
Mime: mimeType,
Width: *widthFlag,
Height: *heightFlag,
Dpr: *dprFlag,
Quality: *qualityFlag,
SaveData: *saveDataFlag,
Downlink: *downlinkFlag,
}
err = optimizer.Encode(w, img, o)
if err != nil {
fmt.Printf("Error encoding image: %s", err)
os.Exit(1)
}
}