move NewRequest to data.go

proxy/data.go

@@ -18,6 +18,7 @@ package proxy
 import (
 	"bytes"
 	"fmt"
+	"net/http"
 	"net/url"
 	"strconv"
 	"strings"
@@ -116,6 +117,41 @@ type Request struct {
 	Options *Options // Image transformation to perform
 }
 
+// NewRequest parses an http.Request into an image request.
+func NewRequest(r *http.Request) (*Request, error) {
+	var err error
+	req := new(Request)
+
+	path := r.URL.Path[1:] // strip leading slash
+	req.URL, err = url.Parse(path)
+	if err != nil || !req.URL.IsAbs() {
+		// first segment is likely options
+		parts := strings.SplitN(path, "/", 2)
+		if len(parts) != 2 {
+			return nil, URLError{"too few path segments", r.URL}
+		}
+
+		req.URL, err = url.Parse(parts[1])
+		if err != nil {
+			return nil, URLError{fmt.Sprintf("unable to parse remote URL: %v", err), r.URL}
+		}
+
+		req.Options = ParseOptions(parts[0])
+	}
+
+	if !req.URL.IsAbs() {
+		return nil, URLError{"must provide absolute remote URL", r.URL}
+	}
+
+	if req.URL.Scheme != "http" && req.URL.Scheme != "https" {
+		return nil, URLError{"remote URL must have http or https URL", r.URL}
+	}
+
+	// query string is always part of the remote URL
+	req.URL.RawQuery = r.URL.RawQuery
+	return req, nil
+}
+
 // Image represents a remote image that is being proxied.  It tracks where
 // the image was originally retrieved from and how long the image can be cached.
 type Image struct {