stash/pkg/utils/image.go

123 lines
3.0 KiB
Go

package utils
import (
"context"
"crypto/tls"
"encoding/base64"
"fmt"
"io"
"net/http"
"regexp"
"time"
)
// Timeout to get the image. Includes transfer time. May want to make this
// configurable at some point.
const imageGetTimeout = time.Second * 60
const base64RE = `^data:.+\/(.+);base64,(.*)$`
// ProcessImageInput transforms an image string either from a base64 encoded
// string, or from a URL, and returns the image as a byte slice
func ProcessImageInput(ctx context.Context, imageInput string) ([]byte, error) {
if imageInput == "" {
return []byte{}, nil
}
regex := regexp.MustCompile(base64RE)
if regex.MatchString(imageInput) {
d, err := ProcessBase64Image(imageInput)
return d, err
}
// assume input is a URL. Read it.
return ReadImageFromURL(ctx, imageInput)
}
// ReadImageFromURL returns image data from a URL
func ReadImageFromURL(ctx context.Context, url string) ([]byte, error) {
client := &http.Client{
Transport: &http.Transport{ // ignore insecure certificates
TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
Proxy: http.ProxyFromEnvironment,
},
Timeout: imageGetTimeout,
}
req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
if err != nil {
return nil, err
}
// assume is a URL for now
// set the host of the URL as the referer
if req.URL.Scheme != "" {
req.Header.Set("Referer", req.URL.Scheme+"://"+req.Host+"/")
}
req.Header.Set("User-Agent", getUserAgent())
resp, err := client.Do(req)
if err != nil {
return nil, err
}
if resp.StatusCode >= 400 {
return nil, fmt.Errorf("http error %d", resp.StatusCode)
}
defer resp.Body.Close()
body, err := io.ReadAll(resp.Body)
if err != nil {
return nil, err
}
return body, nil
}
// ProcessBase64Image transforms a base64 encoded string from a form post and
// returns the image itself as a byte slice.
func ProcessBase64Image(imageString string) ([]byte, error) {
if imageString == "" {
return nil, fmt.Errorf("empty image string")
}
regex := regexp.MustCompile(base64RE)
matches := regex.FindStringSubmatch(imageString)
var encodedString string
if len(matches) > 2 {
encodedString = regex.FindStringSubmatch(imageString)[2]
} else {
encodedString = imageString
}
imageData, err := GetDataFromBase64String(encodedString)
if err != nil {
return nil, err
}
return imageData, nil
}
// GetDataFromBase64String returns the given base64 encoded string as a byte slice
func GetDataFromBase64String(encodedString string) ([]byte, error) {
return base64.StdEncoding.DecodeString(encodedString)
}
// GetBase64StringFromData returns the given byte slice as a base64 encoded string
func GetBase64StringFromData(data []byte) string {
return base64.StdEncoding.EncodeToString(data)
}
func ServeImage(w http.ResponseWriter, r *http.Request, image []byte) {
contentType := http.DetectContentType(image)
if contentType == "text/xml; charset=utf-8" || contentType == "text/plain; charset=utf-8" {
contentType = "image/svg+xml"
}
w.Header().Set("Content-Type", contentType)
ServeStaticContent(w, r, image)
}