diff --git a/pkg/tags/tags.go b/pkg/tags/tags.go new file mode 100644 index 000000000..cfbaddbcd --- /dev/null +++ b/pkg/tags/tags.go @@ -0,0 +1,324 @@ +/* + * MinIO Cloud Storage, (C) 2020 MinIO, Inc. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package tags + +import ( + "encoding/xml" + "io" + "net/url" + "strings" + "unicode/utf8" +) + +// Error contains tag specific error. +type Error interface { + error + Code() string +} + +type errTag struct { + code string + message string +} + +// Code contains error code. +func (err errTag) Code() string { + return err.code +} + +// Error contains error message. +func (err errTag) Error() string { + return err.message +} + +var ( + errTooManyObjectTags = &errTag{"BadRequest", "Tags cannot be more than 10"} + errTooManyTags = &errTag{"BadRequest", "Tags cannot be more than 50"} + errInvalidTagKey = &errTag{"InvalidTag", "The TagKey you have provided is invalid"} + errInvalidTagValue = &errTag{"InvalidTag", "The TagValue you have provided is invalid"} + errDuplicateTagKey = &errTag{"InvalidTag", "Cannot provide multiple Tags with the same key"} +) + +// Tag comes with limitation as per +// https://docs.aws.amazon.com/AmazonS3/latest/dev/object-tagging.html amd +// https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/Using_Tags.html#tag-restrictions +const ( + maxKeyLength = 128 + maxValueLength = 256 + maxObjectTagCount = 10 + maxTagCount = 50 +) + +func checkKey(key string) error { + if len(key) == 0 || utf8.RuneCountInString(key) > maxKeyLength || strings.Contains(key, "&") { + return errInvalidTagKey + } + + return nil +} + +func checkValue(value string) error { + if utf8.RuneCountInString(value) > maxValueLength || strings.Contains(value, "&") { + return errInvalidTagValue + } + + return nil +} + +// Tag denotes key and value. +type Tag struct { + Key string `xml:"Key"` + Value string `xml:"Value"` +} + +func (tag Tag) String() string { + return tag.Key + "=" + tag.Value +} + +// IsEmpty returns whether this tag is empty or not. +func (tag Tag) IsEmpty() bool { + return tag.Key == "" +} + +// Validate checks this tag. +func (tag Tag) Validate() error { + if err := checkKey(tag.Key); err != nil { + return err + } + + return checkValue(tag.Value) +} + +// MarshalXML encodes to XML data. +func (tag Tag) MarshalXML(e *xml.Encoder, start xml.StartElement) error { + if err := tag.Validate(); err != nil { + return err + } + + type subTag Tag // to avoid recursively calling MarshalXML() + return e.EncodeElement(subTag(tag), start) +} + +// UnmarshalXML decodes XML data to tag. +func (tag *Tag) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error { + type subTag Tag // to avoid recursively calling UnmarshalXML() + var st subTag + if err := d.DecodeElement(&st, &start); err != nil { + return err + } + + if err := Tag(st).Validate(); err != nil { + return err + } + + *tag = Tag(st) + return nil +} + +// tagSet represents list of unique tags. +type tagSet struct { + tagMap map[string]string + isObject bool +} + +func (tags tagSet) String() string { + s := []string{} + for key, value := range tags.tagMap { + s = append(s, key+"="+value) + } + + return strings.Join(s, "&") +} + +func (tags *tagSet) remove(key string) { + delete(tags.tagMap, key) +} + +func (tags *tagSet) set(key, value string, failOnExist bool) error { + if failOnExist { + if _, found := tags.tagMap[key]; found { + return errDuplicateTagKey + } + } + + if err := checkKey(key); err != nil { + return err + } + + if err := checkValue(value); err != nil { + return err + } + + if tags.isObject { + if len(tags.tagMap) == maxObjectTagCount { + return errTooManyObjectTags + } + } else if len(tags.tagMap) == maxTagCount { + return errTooManyTags + } + + tags.tagMap[key] = value + return nil +} + +func (tags tagSet) toMap() map[string]string { + m := make(map[string]string) + for key, value := range tags.tagMap { + m[key] = value + } + return m +} + +// MarshalXML encodes to XML data. +func (tags tagSet) MarshalXML(e *xml.Encoder, start xml.StartElement) error { + tagList := struct { + Tags []Tag `xml:"Tag"` + }{} + + for key, value := range tags.tagMap { + tagList.Tags = append(tagList.Tags, Tag{key, value}) + } + + return e.EncodeElement(tagList, start) +} + +// UnmarshalXML decodes XML data to tag list. +func (tags *tagSet) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error { + tagList := struct { + Tags []Tag `xml:"Tag"` + }{} + + if err := d.DecodeElement(&tagList, &start); err != nil { + return err + } + + if tags.isObject { + if len(tagList.Tags) > maxObjectTagCount { + return errTooManyObjectTags + } + } else if len(tagList.Tags) > maxTagCount { + return errTooManyTags + } + + m := map[string]string{} + for _, tag := range tagList.Tags { + if _, found := m[tag.Key]; found { + return errDuplicateTagKey + } + + m[tag.Key] = tag.Value + } + + tags.tagMap = m + return nil +} + +type tagging struct { + XMLName xml.Name `xml:"Tagging"` + TagSet *tagSet `xml:"TagSet"` +} + +// Tags is list of tags of XML request/response as per +// https://docs.aws.amazon.com/AmazonS3/latest/API/API_GetBucketTagging.html#API_GetBucketTagging_RequestBody +type Tags tagging + +func (tags Tags) String() string { + return tags.TagSet.String() +} + +// Remove removes a tag by its key. +func (tags *Tags) Remove(key string) { + tags.TagSet.remove(key) +} + +// Set sets new tag. +func (tags *Tags) Set(key, value string) error { + return tags.TagSet.set(key, value, false) +} + +// ToMap returns copy of tags. +func (tags Tags) ToMap() map[string]string { + return tags.TagSet.toMap() +} + +// NewTags creates Tags from tagMap, If isObject is set, it validates for object tags. +func NewTags(tagMap map[string]string, isObject bool) (*Tags, error) { + tagging := &Tags{ + TagSet: &tagSet{ + tagMap: make(map[string]string), + isObject: isObject, + }, + } + + for key, value := range tagMap { + if err := tagging.TagSet.set(key, value, true); err != nil { + return nil, err + } + } + + return tagging, nil +} + +func unmarshalXML(reader io.Reader, isObject bool) (*Tags, error) { + tagging := &Tags{ + TagSet: &tagSet{ + tagMap: make(map[string]string), + isObject: isObject, + }, + } + + if err := xml.NewDecoder(reader).Decode(tagging); err != nil { + return nil, err + } + + return tagging, nil +} + +// ParseBucketXML decodes XML data of tags in reader specified in +// https://docs.aws.amazon.com/AmazonS3/latest/API/API_PutBucketTagging.html#API_PutBucketTagging_RequestSyntax. +func ParseBucketXML(reader io.Reader) (*Tags, error) { + return unmarshalXML(reader, false) +} + +// ParseObjectXML decodes XML data of tags in reader specified in +// https://docs.aws.amazon.com/AmazonS3/latest/API/API_PutObjectTagging.html#API_PutObjectTagging_RequestSyntax +func ParseObjectXML(reader io.Reader) (*Tags, error) { + return unmarshalXML(reader, true) +} + +// ParseObjectTags decodes HTTP query formatted string into tags. A query formatted string is like "key1=value1&key2=value2". +func ParseObjectTags(s string) (*Tags, error) { + values, err := url.ParseQuery(s) + if err != nil { + return nil, err + } + + tagging := &Tags{ + TagSet: &tagSet{ + tagMap: make(map[string]string), + isObject: true, + }, + } + + for key := range values { + if err := tagging.TagSet.set(key, values.Get(key), true); err != nil { + return nil, err + } + } + + return tagging, nil +}