1// Copyright 2015 go-swagger maintainers
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
15package spec
16
17import (
18	"bytes"
19	"encoding/gob"
20	"encoding/json"
21	"net/http"
22	"os"
23	"path/filepath"
24
25	"github.com/go-openapi/jsonreference"
26)
27
28// Refable is a struct for things that accept a $ref property
29type Refable struct {
30	Ref Ref
31}
32
33// MarshalJSON marshals the ref to json
34func (r Refable) MarshalJSON() ([]byte, error) {
35	return r.Ref.MarshalJSON()
36}
37
38// UnmarshalJSON unmarshalss the ref from json
39func (r *Refable) UnmarshalJSON(d []byte) error {
40	return json.Unmarshal(d, &r.Ref)
41}
42
43// Ref represents a json reference that is potentially resolved
44type Ref struct {
45	jsonreference.Ref
46}
47
48// RemoteURI gets the remote uri part of the ref
49func (r *Ref) RemoteURI() string {
50	if r.String() == "" {
51		return ""
52	}
53
54	u := *r.GetURL()
55	u.Fragment = ""
56	return u.String()
57}
58
59// IsValidURI returns true when the url the ref points to can be found
60func (r *Ref) IsValidURI(basepaths ...string) bool {
61	if r.String() == "" {
62		return true
63	}
64
65	v := r.RemoteURI()
66	if v == "" {
67		return true
68	}
69
70	if r.HasFullURL {
71		//nolint:noctx,gosec
72		rr, err := http.Get(v)
73		if err != nil {
74			return false
75		}
76		defer rr.Body.Close()
77
78		return rr.StatusCode/100 == 2
79	}
80
81	if !(r.HasFileScheme || r.HasFullFilePath || r.HasURLPathOnly) {
82		return false
83	}
84
85	// check for local file
86	pth := v
87	if r.HasURLPathOnly {
88		base := "."
89		if len(basepaths) > 0 {
90			base = filepath.Dir(filepath.Join(basepaths...))
91		}
92		p, e := filepath.Abs(filepath.ToSlash(filepath.Join(base, pth)))
93		if e != nil {
94			return false
95		}
96		pth = p
97	}
98
99	fi, err := os.Stat(filepath.ToSlash(pth))
100	if err != nil {
101		return false
102	}
103
104	return !fi.IsDir()
105}
106
107// Inherits creates a new reference from a parent and a child
108// If the child cannot inherit from the parent, an error is returned
109func (r *Ref) Inherits(child Ref) (*Ref, error) {
110	ref, err := r.Ref.Inherits(child.Ref)
111	if err != nil {
112		return nil, err
113	}
114	return &Ref{Ref: *ref}, nil
115}
116
117// NewRef creates a new instance of a ref object
118// returns an error when the reference uri is an invalid uri
119func NewRef(refURI string) (Ref, error) {
120	ref, err := jsonreference.New(refURI)
121	if err != nil {
122		return Ref{}, err
123	}
124	return Ref{Ref: ref}, nil
125}
126
127// MustCreateRef creates a ref object but panics when refURI is invalid.
128// Use the NewRef method for a version that returns an error.
129func MustCreateRef(refURI string) Ref {
130	return Ref{Ref: jsonreference.MustCreateRef(refURI)}
131}
132
133// MarshalJSON marshals this ref into a JSON object
134func (r Ref) MarshalJSON() ([]byte, error) {
135	str := r.String()
136	if str == "" {
137		if r.IsRoot() {
138			return []byte(`{"$ref":""}`), nil
139		}
140		return []byte("{}"), nil
141	}
142	v := map[string]interface{}{"$ref": str}
143	return json.Marshal(v)
144}
145
146// UnmarshalJSON unmarshals this ref from a JSON object
147func (r *Ref) UnmarshalJSON(d []byte) error {
148	var v map[string]interface{}
149	if err := json.Unmarshal(d, &v); err != nil {
150		return err
151	}
152	return r.fromMap(v)
153}
154
155// GobEncode provides a safe gob encoder for Ref
156func (r Ref) GobEncode() ([]byte, error) {
157	var b bytes.Buffer
158	raw, err := r.MarshalJSON()
159	if err != nil {
160		return nil, err
161	}
162	err = gob.NewEncoder(&b).Encode(raw)
163	return b.Bytes(), err
164}
165
166// GobDecode provides a safe gob decoder for Ref
167func (r *Ref) GobDecode(b []byte) error {
168	var raw []byte
169	buf := bytes.NewBuffer(b)
170	err := gob.NewDecoder(buf).Decode(&raw)
171	if err != nil {
172		return err
173	}
174	return json.Unmarshal(raw, r)
175}
176
177func (r *Ref) fromMap(v map[string]interface{}) error {
178	if v == nil {
179		return nil
180	}
181
182	if vv, ok := v["$ref"]; ok {
183		if str, ok := vv.(string); ok {
184			ref, err := jsonreference.New(str)
185			if err != nil {
186				return err
187			}
188			*r = Ref{Ref: ref}
189		}
190	}
191
192	return nil
193}
194