mirror of
https://github.com/superseriousbusiness/gotosocial.git
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414 lines
9.7 KiB
Go
414 lines
9.7 KiB
Go
/*
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* MinIO Go Library for Amazon S3 Compatible Cloud Storage
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* Copyright 2020-2022 MinIO, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package tags
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import (
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"encoding/xml"
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"io"
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"net/url"
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"regexp"
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"sort"
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"strings"
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"unicode/utf8"
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)
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// Error contains tag specific error.
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type Error interface {
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error
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Code() string
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}
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type errTag struct {
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code string
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message string
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}
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// Code contains error code.
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func (err errTag) Code() string {
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return err.code
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}
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// Error contains error message.
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func (err errTag) Error() string {
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return err.message
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}
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var (
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errTooManyObjectTags = &errTag{"BadRequest", "Tags cannot be more than 10"}
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errTooManyTags = &errTag{"BadRequest", "Tags cannot be more than 50"}
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errInvalidTagKey = &errTag{"InvalidTag", "The TagKey you have provided is invalid"}
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errInvalidTagValue = &errTag{"InvalidTag", "The TagValue you have provided is invalid"}
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errDuplicateTagKey = &errTag{"InvalidTag", "Cannot provide multiple Tags with the same key"}
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)
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// Tag comes with limitation as per
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// https://docs.aws.amazon.com/AmazonS3/latest/dev/object-tagging.html amd
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// https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/Using_Tags.html#tag-restrictions
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const (
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maxKeyLength = 128
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maxValueLength = 256
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maxObjectTagCount = 10
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maxTagCount = 50
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)
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// https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/Using_Tags.html#tag-restrictions
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// borrowed from this article and also testing various ASCII characters following regex
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// is supported by AWS S3 for both tags and values.
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var validTagKeyValue = regexp.MustCompile(`^[a-zA-Z0-9-+\-._:/@ ]+$`)
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func checkKey(key string) error {
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if len(key) == 0 {
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return errInvalidTagKey
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}
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if utf8.RuneCountInString(key) > maxKeyLength || !validTagKeyValue.MatchString(key) {
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return errInvalidTagKey
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}
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return nil
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}
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func checkValue(value string) error {
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if value != "" {
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if utf8.RuneCountInString(value) > maxValueLength || !validTagKeyValue.MatchString(value) {
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return errInvalidTagValue
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}
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}
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return nil
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}
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// Tag denotes key and value.
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type Tag struct {
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Key string `xml:"Key"`
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Value string `xml:"Value"`
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}
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func (tag Tag) String() string {
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return tag.Key + "=" + tag.Value
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}
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// IsEmpty returns whether this tag is empty or not.
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func (tag Tag) IsEmpty() bool {
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return tag.Key == ""
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}
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// Validate checks this tag.
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func (tag Tag) Validate() error {
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if err := checkKey(tag.Key); err != nil {
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return err
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}
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return checkValue(tag.Value)
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}
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// MarshalXML encodes to XML data.
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func (tag Tag) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
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if err := tag.Validate(); err != nil {
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return err
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}
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type subTag Tag // to avoid recursively calling MarshalXML()
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return e.EncodeElement(subTag(tag), start)
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}
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// UnmarshalXML decodes XML data to tag.
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func (tag *Tag) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
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type subTag Tag // to avoid recursively calling UnmarshalXML()
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var st subTag
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if err := d.DecodeElement(&st, &start); err != nil {
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return err
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}
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if err := Tag(st).Validate(); err != nil {
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return err
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}
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*tag = Tag(st)
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return nil
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}
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// tagSet represents list of unique tags.
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type tagSet struct {
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tagMap map[string]string
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isObject bool
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}
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func (tags tagSet) String() string {
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if len(tags.tagMap) == 0 {
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return ""
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}
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var buf strings.Builder
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keys := make([]string, 0, len(tags.tagMap))
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for k := range tags.tagMap {
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keys = append(keys, k)
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}
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sort.Strings(keys)
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for _, k := range keys {
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keyEscaped := url.QueryEscape(k)
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valueEscaped := url.QueryEscape(tags.tagMap[k])
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if buf.Len() > 0 {
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buf.WriteByte('&')
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}
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buf.WriteString(keyEscaped)
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buf.WriteByte('=')
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buf.WriteString(valueEscaped)
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}
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return buf.String()
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}
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func (tags *tagSet) remove(key string) {
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delete(tags.tagMap, key)
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}
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func (tags *tagSet) set(key, value string, failOnExist bool) error {
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if failOnExist {
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if _, found := tags.tagMap[key]; found {
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return errDuplicateTagKey
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}
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}
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if err := checkKey(key); err != nil {
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return err
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}
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if err := checkValue(value); err != nil {
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return err
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}
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if tags.isObject {
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if len(tags.tagMap) == maxObjectTagCount {
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return errTooManyObjectTags
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}
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} else if len(tags.tagMap) == maxTagCount {
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return errTooManyTags
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}
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tags.tagMap[key] = value
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return nil
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}
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func (tags tagSet) count() int {
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return len(tags.tagMap)
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}
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func (tags tagSet) toMap() map[string]string {
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m := make(map[string]string, len(tags.tagMap))
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for key, value := range tags.tagMap {
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m[key] = value
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}
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return m
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}
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// MarshalXML encodes to XML data.
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func (tags tagSet) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
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tagList := struct {
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Tags []Tag `xml:"Tag"`
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}{}
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tagList.Tags = make([]Tag, 0, len(tags.tagMap))
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for key, value := range tags.tagMap {
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tagList.Tags = append(tagList.Tags, Tag{key, value})
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}
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return e.EncodeElement(tagList, start)
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}
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// UnmarshalXML decodes XML data to tag list.
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func (tags *tagSet) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
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tagList := struct {
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Tags []Tag `xml:"Tag"`
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}{}
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if err := d.DecodeElement(&tagList, &start); err != nil {
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return err
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}
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if tags.isObject {
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if len(tagList.Tags) > maxObjectTagCount {
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return errTooManyObjectTags
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}
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} else if len(tagList.Tags) > maxTagCount {
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return errTooManyTags
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}
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m := make(map[string]string, len(tagList.Tags))
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for _, tag := range tagList.Tags {
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if _, found := m[tag.Key]; found {
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return errDuplicateTagKey
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}
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m[tag.Key] = tag.Value
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}
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tags.tagMap = m
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return nil
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}
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type tagging struct {
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XMLName xml.Name `xml:"Tagging"`
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TagSet *tagSet `xml:"TagSet"`
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}
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// Tags is list of tags of XML request/response as per
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// https://docs.aws.amazon.com/AmazonS3/latest/API/API_GetBucketTagging.html#API_GetBucketTagging_RequestBody
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type Tags tagging
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func (tags Tags) String() string {
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return tags.TagSet.String()
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}
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// Remove removes a tag by its key.
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func (tags *Tags) Remove(key string) {
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tags.TagSet.remove(key)
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}
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// Set sets new tag.
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func (tags *Tags) Set(key, value string) error {
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return tags.TagSet.set(key, value, false)
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}
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// Count - return number of tags accounted for
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func (tags Tags) Count() int {
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return tags.TagSet.count()
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}
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// ToMap returns copy of tags.
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func (tags Tags) ToMap() map[string]string {
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return tags.TagSet.toMap()
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}
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// MapToObjectTags converts an input map of key and value into
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// *Tags data structure with validation.
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func MapToObjectTags(tagMap map[string]string) (*Tags, error) {
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return NewTags(tagMap, true)
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}
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// MapToBucketTags converts an input map of key and value into
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// *Tags data structure with validation.
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func MapToBucketTags(tagMap map[string]string) (*Tags, error) {
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return NewTags(tagMap, false)
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}
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// NewTags creates Tags from tagMap, If isObject is set, it validates for object tags.
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func NewTags(tagMap map[string]string, isObject bool) (*Tags, error) {
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tagging := &Tags{
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TagSet: &tagSet{
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tagMap: make(map[string]string),
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isObject: isObject,
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},
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}
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for key, value := range tagMap {
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if err := tagging.TagSet.set(key, value, true); err != nil {
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return nil, err
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}
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}
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return tagging, nil
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}
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func unmarshalXML(reader io.Reader, isObject bool) (*Tags, error) {
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tagging := &Tags{
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TagSet: &tagSet{
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tagMap: make(map[string]string),
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isObject: isObject,
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},
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}
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if err := xml.NewDecoder(reader).Decode(tagging); err != nil {
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return nil, err
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}
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return tagging, nil
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}
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// ParseBucketXML decodes XML data of tags in reader specified in
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// https://docs.aws.amazon.com/AmazonS3/latest/API/API_PutBucketTagging.html#API_PutBucketTagging_RequestSyntax.
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func ParseBucketXML(reader io.Reader) (*Tags, error) {
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return unmarshalXML(reader, false)
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}
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// ParseObjectXML decodes XML data of tags in reader specified in
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// https://docs.aws.amazon.com/AmazonS3/latest/API/API_PutObjectTagging.html#API_PutObjectTagging_RequestSyntax
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func ParseObjectXML(reader io.Reader) (*Tags, error) {
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return unmarshalXML(reader, true)
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}
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// stringsCut slices s around the first instance of sep,
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// returning the text before and after sep.
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// The found result reports whether sep appears in s.
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// If sep does not appear in s, cut returns s, "", false.
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func stringsCut(s, sep string) (before, after string, found bool) {
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if i := strings.Index(s, sep); i >= 0 {
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return s[:i], s[i+len(sep):], true
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}
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return s, "", false
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}
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func (tags *tagSet) parseTags(tgs string) (err error) {
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for tgs != "" {
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var key string
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key, tgs, _ = stringsCut(tgs, "&")
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if key == "" {
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continue
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}
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key, value, _ := stringsCut(key, "=")
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key, err1 := url.QueryUnescape(key)
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if err1 != nil {
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if err == nil {
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err = err1
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}
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continue
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}
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value, err1 = url.QueryUnescape(value)
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if err1 != nil {
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if err == nil {
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err = err1
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}
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continue
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}
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if err = tags.set(key, value, true); err != nil {
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return err
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}
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}
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return err
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}
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// Parse decodes HTTP query formatted string into tags which is limited by isObject.
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// A query formatted string is like "key1=value1&key2=value2".
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func Parse(s string, isObject bool) (*Tags, error) {
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tagging := &Tags{
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TagSet: &tagSet{
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tagMap: make(map[string]string),
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isObject: isObject,
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},
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}
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if err := tagging.TagSet.parseTags(s); err != nil {
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return nil, err
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}
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return tagging, nil
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}
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// ParseObjectTags decodes HTTP query formatted string into tags. A query formatted string is like "key1=value1&key2=value2".
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func ParseObjectTags(s string) (*Tags, error) {
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return Parse(s, true)
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}
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