| // Copyright 2015 xeipuuv ( https://github.com/xeipuuv ) |
| // |
| // 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. |
| |
| // author xeipuuv |
| // author-github https://github.com/xeipuuv |
| // author-mail xeipuuv@gmail.com |
| // |
| // repository-name gojsonpointer |
| // repository-desc An implementation of JSON Pointer - Go language |
| // |
| // description Main and unique file. |
| // |
| // created 25-02-2013 |
| |
| package gojsonpointer |
| |
| import ( |
| "errors" |
| "fmt" |
| "reflect" |
| "strconv" |
| "strings" |
| ) |
| |
| const ( |
| const_empty_pointer = `` |
| const_pointer_separator = `/` |
| |
| const_invalid_start = `JSON pointer must be empty or start with a "` + const_pointer_separator + `"` |
| ) |
| |
| type implStruct struct { |
| mode string // "SET" or "GET" |
| |
| inDocument interface{} |
| |
| setInValue interface{} |
| |
| getOutNode interface{} |
| getOutKind reflect.Kind |
| outError error |
| } |
| |
| type JsonPointer struct { |
| referenceTokens []string |
| } |
| |
| // NewJsonPointer parses the given string JSON pointer and returns an object |
| func NewJsonPointer(jsonPointerString string) (p JsonPointer, err error) { |
| |
| // Pointer to the root of the document |
| if len(jsonPointerString) == 0 { |
| // Keep referenceTokens nil |
| return |
| } |
| if jsonPointerString[0] != '/' { |
| return p, errors.New(const_invalid_start) |
| } |
| |
| p.referenceTokens = strings.Split(jsonPointerString[1:], const_pointer_separator) |
| return |
| } |
| |
| // Uses the pointer to retrieve a value from a JSON document |
| func (p *JsonPointer) Get(document interface{}) (interface{}, reflect.Kind, error) { |
| |
| is := &implStruct{mode: "GET", inDocument: document} |
| p.implementation(is) |
| return is.getOutNode, is.getOutKind, is.outError |
| |
| } |
| |
| // Uses the pointer to update a value from a JSON document |
| func (p *JsonPointer) Set(document interface{}, value interface{}) (interface{}, error) { |
| |
| is := &implStruct{mode: "SET", inDocument: document, setInValue: value} |
| p.implementation(is) |
| return document, is.outError |
| |
| } |
| |
| // Uses the pointer to delete a value from a JSON document (only works on maps/objects right now, not arrays) |
| func (p *JsonPointer) Delete(document interface{}) (interface{}, reflect.Kind, error) { |
| is := &implStruct{mode: "DEL", inDocument: document} |
| p.implementation(is) |
| return is.getOutNode, is.getOutKind, is.outError |
| } |
| |
| // Both Get and Set functions use the same implementation to avoid code duplication |
| func (p *JsonPointer) implementation(i *implStruct) { |
| |
| kind := reflect.Invalid |
| |
| // Full document when empty |
| if len(p.referenceTokens) == 0 { |
| i.getOutNode = i.inDocument |
| i.outError = nil |
| i.getOutKind = kind |
| i.outError = nil |
| return |
| } |
| |
| node := i.inDocument |
| |
| for ti, token := range p.referenceTokens { |
| |
| isLastToken := ti == len(p.referenceTokens)-1 |
| |
| switch v := node.(type) { |
| |
| case map[string]interface{}: |
| decodedToken := decodeReferenceToken(token) |
| if _, ok := v[decodedToken]; ok { |
| node = v[decodedToken] |
| if isLastToken && i.mode == "SET" { |
| v[decodedToken] = i.setInValue |
| } else if isLastToken && i.mode =="DEL" { |
| delete(v,decodedToken) |
| } |
| } else { |
| i.outError = fmt.Errorf("Object has no key '%s'", decodedToken) |
| i.getOutKind = reflect.Map |
| i.getOutNode = nil |
| return |
| } |
| |
| case []interface{}: |
| tokenIndex, err := strconv.Atoi(token) |
| if err != nil { |
| i.outError = fmt.Errorf("Invalid array index '%s'", token) |
| i.getOutKind = reflect.Slice |
| i.getOutNode = nil |
| return |
| } |
| if tokenIndex < 0 || tokenIndex >= len(v) { |
| i.outError = fmt.Errorf("Out of bound array[0,%d] index '%d'", len(v), tokenIndex) |
| i.getOutKind = reflect.Slice |
| i.getOutNode = nil |
| return |
| } |
| |
| node = v[tokenIndex] |
| if isLastToken && i.mode == "SET" { |
| v[tokenIndex] = i.setInValue |
| } |
| |
| default: |
| i.outError = fmt.Errorf("Invalid token reference '%s'", token) |
| i.getOutKind = reflect.ValueOf(node).Kind() |
| i.getOutNode = nil |
| return |
| } |
| |
| } |
| |
| i.getOutNode = node |
| i.getOutKind = reflect.ValueOf(node).Kind() |
| i.outError = nil |
| } |
| |
| // Pointer to string representation function |
| func (p *JsonPointer) String() string { |
| |
| if len(p.referenceTokens) == 0 { |
| return const_empty_pointer |
| } |
| |
| pointerString := const_pointer_separator + strings.Join(p.referenceTokens, const_pointer_separator) |
| |
| return pointerString |
| } |
| |
| // Specific JSON pointer encoding here |
| // ~0 => ~ |
| // ~1 => / |
| // ... and vice versa |
| |
| func decodeReferenceToken(token string) string { |
| step1 := strings.Replace(token, `~1`, `/`, -1) |
| step2 := strings.Replace(step1, `~0`, `~`, -1) |
| return step2 |
| } |
| |
| func encodeReferenceToken(token string) string { |
| step1 := strings.Replace(token, `~`, `~0`, -1) |
| step2 := strings.Replace(step1, `/`, `~1`, -1) |
| return step2 |
| } |