Merge pull request #63 from AndreyKostov/add-urlfor-method-param

Add functionality to make a url signed for a HEAD request to S4 driver

storagedriver/s3/s3.go

@@ -642,6 +642,15 @@ func (d *Driver) URLFor(path string, options map[string]interface{}) (string, er
 		return "", storagedriver.InvalidPathError{Path: path}
 	}
 
+	methodString := "GET"
+	method, ok := options["method"]
+	if ok {
+		methodString, ok = method.(string)
+		if !ok || (methodString != "GET" && methodString != "HEAD") {
+			return "", storagedriver.ErrUnsupportedMethod
+		}
+	}
+
 	expiresTime := time.Now().Add(20 * time.Minute)
 	expires, ok := options["expiry"]
 	if ok {
@@ -651,7 +660,7 @@ func (d *Driver) URLFor(path string, options map[string]interface{}) (string, er
 		}
 	}
 
-	return d.Bucket.SignedURL(d.s3Path(path), expiresTime), nil
+	return d.Bucket.SignedURLWithMethod(methodString, d.s3Path(path), expiresTime, nil, nil), nil
 }
 
 func (d *Driver) s3Path(path string) string {

storagedriver/testsuites/testsuites.go

@@ -605,6 +605,16 @@ func (suite *DriverSuite) TestURLFor(c *check.C) {
 	read, err := ioutil.ReadAll(response.Body)
 	c.Assert(err, check.IsNil)
 	c.Assert(read, check.DeepEquals, contents)
+
+	url, err = suite.StorageDriver.URLFor(filename, map[string]interface{}{"method": "HEAD"})
+	if err == storagedriver.ErrUnsupportedMethod {
+		return
+	}
+	c.Assert(err, check.IsNil)
+
+	response, err = http.Head(url)
+	c.Assert(response.StatusCode, check.Equals, 200)
+	c.Assert(response.ContentLength, check.Equals, int64(32))
 }
 
 // TestDeleteNonexistent checks that removing a nonexistent key fails.