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Matthias Andreas Benkard832a54e2019-01-29 09:27:38 +01001// Copyright 2013 sigu-399 ( https://github.com/sigu-399 )
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7// http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15// author sigu-399
16// author-github https://github.com/sigu-399
17// author-mail sigu.399@gmail.com
18//
19// repository-name jsonreference
20// repository-desc An implementation of JSON Reference - Go language
21//
22// description Main and unique file.
23//
24// created 26-02-2013
25
26package jsonreference
27
28import (
29 "errors"
30 "net/url"
31 "strings"
32
33 "github.com/PuerkitoBio/purell"
34 "github.com/go-openapi/jsonpointer"
35)
36
37const (
38 fragmentRune = `#`
39)
40
41// New creates a new reference for the given string
42func New(jsonReferenceString string) (Ref, error) {
43
44 var r Ref
45 err := r.parse(jsonReferenceString)
46 return r, err
47
48}
49
50// MustCreateRef parses the ref string and panics when it's invalid.
51// Use the New method for a version that returns an error
52func MustCreateRef(ref string) Ref {
53 r, err := New(ref)
54 if err != nil {
55 panic(err)
56 }
57 return r
58}
59
60// Ref represents a json reference object
61type Ref struct {
62 referenceURL *url.URL
63 referencePointer jsonpointer.Pointer
64
65 HasFullURL bool
66 HasURLPathOnly bool
67 HasFragmentOnly bool
68 HasFileScheme bool
69 HasFullFilePath bool
70}
71
72// GetURL gets the URL for this reference
73func (r *Ref) GetURL() *url.URL {
74 return r.referenceURL
75}
76
77// GetPointer gets the json pointer for this reference
78func (r *Ref) GetPointer() *jsonpointer.Pointer {
79 return &r.referencePointer
80}
81
82// String returns the best version of the url for this reference
83func (r *Ref) String() string {
84
85 if r.referenceURL != nil {
86 return r.referenceURL.String()
87 }
88
89 if r.HasFragmentOnly {
90 return fragmentRune + r.referencePointer.String()
91 }
92
93 return r.referencePointer.String()
94}
95
96// IsRoot returns true if this reference is a root document
97func (r *Ref) IsRoot() bool {
98 return r.referenceURL != nil &&
99 !r.IsCanonical() &&
100 !r.HasURLPathOnly &&
101 r.referenceURL.Fragment == ""
102}
103
104// IsCanonical returns true when this pointer starts with http(s):// or file://
105func (r *Ref) IsCanonical() bool {
106 return (r.HasFileScheme && r.HasFullFilePath) || (!r.HasFileScheme && r.HasFullURL)
107}
108
109// "Constructor", parses the given string JSON reference
110func (r *Ref) parse(jsonReferenceString string) error {
111
112 parsed, err := url.Parse(jsonReferenceString)
113 if err != nil {
114 return err
115 }
116
117 r.referenceURL, _ = url.Parse(purell.NormalizeURL(parsed, purell.FlagsSafe|purell.FlagRemoveDuplicateSlashes))
118 refURL := r.referenceURL
119
120 if refURL.Scheme != "" && refURL.Host != "" {
121 r.HasFullURL = true
122 } else {
123 if refURL.Path != "" {
124 r.HasURLPathOnly = true
125 } else if refURL.RawQuery == "" && refURL.Fragment != "" {
126 r.HasFragmentOnly = true
127 }
128 }
129
130 r.HasFileScheme = refURL.Scheme == "file"
131 r.HasFullFilePath = strings.HasPrefix(refURL.Path, "/")
132
133 // invalid json-pointer error means url has no json-pointer fragment. simply ignore error
134 r.referencePointer, _ = jsonpointer.New(refURL.Fragment)
135
136 return nil
137}
138
139// Inherits creates a new reference from a parent and a child
140// If the child cannot inherit from the parent, an error is returned
141func (r *Ref) Inherits(child Ref) (*Ref, error) {
142 childURL := child.GetURL()
143 parentURL := r.GetURL()
144 if childURL == nil {
145 return nil, errors.New("child url is nil")
146 }
147 if parentURL == nil {
148 return &child, nil
149 }
150
151 ref, err := New(parentURL.ResolveReference(childURL).String())
152 if err != nil {
153 return nil, err
154 }
155 return &ref, nil
156}