Upload Image from url (#1193)

pkg/utils/image.go

@@ -4,11 +4,66 @@ import (
 	"crypto/md5"
 	"encoding/base64"
 	"fmt"
+	"io/ioutil"
 	"net/http"
 	"regexp"
 	"strings"
+	"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(imageInput string) ([]byte, error) {
+	regex := regexp.MustCompile(base64RE)
+	if regex.MatchString(imageInput) {
+		_, d, err := ProcessBase64Image(imageInput)
+		return d, err
+	}
+
+	// assume input is a URL. Read it.
+	return ReadImageFromURL(imageInput)
+}
+
+// ReadImageFromURL returns image data from a URL
+func ReadImageFromURL(url string) ([]byte, error) {
+	client := &http.Client{
+		Timeout: imageGetTimeout,
+	}
+
+	req, err := http.NewRequest("GET", 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+"/")
+	}
+
+	resp, err := client.Do(req)
+
+	if err != nil {
+		return nil, err
+	}
+
+	defer resp.Body.Close()
+
+	body, err := ioutil.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 MD5 hash of the data and the
 // image itself as a byte slice.
 func ProcessBase64Image(imageString string) (string, []byte, error) {
@@ -16,7 +71,7 @@ func ProcessBase64Image(imageString string) (string, []byte, error) {
 		return "", nil, fmt.Errorf("empty image string")
 	}
 
-	regex := regexp.MustCompile(`^data:.+\/(.+);base64,(.*)$`)
+	regex := regexp.MustCompile(base64RE)
 	matches := regex.FindStringSubmatch(imageString)
 	var encodedString string
 	if len(matches) > 2 {