fix: fixes tagging string parsing for PutObject, CopyObject and CreateMultipartUpload

Fixes #1215
Fixes #1216

`PutObject`, `CopyObject` and `CreateMultipartUpload` accept tag string as an http request header which should be url-encoded. The tag string should be a valid url-encoded string and each key/value pair should be valid, otherwise they should fail with `APIError`.

If the provided tag set contains duplicate `keys` the calls should fail with the same `InvalidURLEncodedTagging` error.

Not all url-encoded characters are supported by `S3`. The tagging string should contain only `letters`, `digits` and the following special chars:
- `-`
- `.`
- `/`
- `_`
- `+`
- ` `(space)

And their url-encoded versions: e.g. `%2F`(/), `%2E`(.) ... .

If the provided tagging string contains invalid `key`/`value`, the calls should fail with the following errors respectively:
`invalid key` - `(InvalidTag) The TagKey you have provided is invalid`
`invalid value` - `(InvalidTag) The TagValue you have provided is invalid`

s3err/s3err.go

@@ -89,6 +89,7 @@ const (
 	ErrDuplicateTagKey
 	ErrBucketTaggingLimited
 	ErrObjectTaggingLimited
+	ErrInvalidURLEncodedTagging
 	ErrAuthHeaderEmpty
 	ErrSignatureVersionNotSupported
 	ErrMalformedPOSTRequest
@@ -335,6 +336,11 @@ var errorCodeResponse = map[ErrorCode]APIError{
 		Description:    "Object tags cannot be greater than 10",
 		HTTPStatusCode: http.StatusBadRequest,
 	},
+	ErrInvalidURLEncodedTagging: {
+		Code:           "InvalidArgument",
+		Description:    "The header 'x-amz-tagging' shall be encoded as UTF-8 then URLEncoded URL query parameters without tag name duplicates.",
+		HTTPStatusCode: http.StatusBadRequest,
+	},
 	ErrMalformedXML: {
 		Code:           "MalformedXML",
 		Description:    "The XML you provided was not well-formed or did not validate against our published schema.",