1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
|
jsonquery
====
[](https://travis-ci.org/antchfx/jsonquery)
[](https://coveralls.io/github/antchfx/jsonquery?branch=master)
[](https://godoc.org/github.com/antchfx/jsonquery)
[](https://goreportcard.com/report/github.com/antchfx/jsonquery)
Overview
===
jsonquery is an XPath query package for JSON document, lets you extract data from JSON documents through an XPath expression. Built-in XPath expression cache avoid re-compile XPath expression each query.
Getting Started
===
### Install Package
```
go get github.com/antchfx/jsonquery
```
#### Load JSON document from URL.
```go
doc, err := jsonquery.LoadURL("http://www.example.com/feed?json")
```
#### Load JSON document from string.
```go
s :=`{
"name":"John",
"age":31,
"city":"New York"
}`
doc, err := jsonquery.Parse(strings.NewReader(s))
```
#### Load JSON document from io.Reader.
```go
f, err := os.Open("./books.json")
doc, err := jsonquery.Parse(f)
```
#### Find authors of all books in the store.
```go
list := jsonquery.Find(doc, "store/book/*/author")
// or equal to
list := jsonquery.Find(doc, "//author")
// or by QueryAll()
nodes, err := jsonquery.QueryAll(doc, "//a")
```
#### Find the third book.
```go
book := jsonquery.Find(doc, "//book/*[3]")
```
#### Find the last book.
```go
book := jsonquery.Find(doc, "//book/*[last()]")
```
#### Find all books that have an isbn number.
```go
list := jsonquery.Find(doc, "//book/*[isbn]")
```
#### Find all books priced less than 10.
```go
list := jsonquery.Find(doc, "//book/*[price<10]")
```
Examples
===
```go
func main() {
s := `{
"name": "John",
"age" : 26,
"address" : {
"streetAddress": "naist street",
"city" : "Nara",
"postalCode" : "630-0192"
},
"phoneNumbers": [
{
"type" : "iPhone",
"number": "0123-4567-8888"
},
{
"type" : "home",
"number": "0123-4567-8910"
}
]
}`
doc, err := jsonquery.Parse(strings.NewReader(s))
if err != nil {
panic(err)
}
name := jsonquery.FindOne(doc, "name")
fmt.Printf("name: %s\n", name.InnerText())
var a []string
for _, n := range jsonquery.Find(doc, "phoneNumbers/*/number") {
a = append(a, n.InnerText())
}
fmt.Printf("phone number: %s\n", strings.Join(a, ","))
if n := jsonquery.FindOne(doc, "address/streetAddress"); n != nil {
fmt.Printf("address: %s\n", n.InnerText())
}
}
```
Implement Principle
===
If you are familiar with XPath and XML, you can easily figure out how to
write your XPath expression.
```json
{
"name":"John",
"age":30,
"cars": [
{ "name":"Ford", "models":[ "Fiesta", "Focus", "Mustang" ] },
{ "name":"BMW", "models":[ "320", "X3", "X5" ] },
{ "name":"Fiat", "models":[ "500", "Panda" ] }
]
}
```
The above JSON document will be convert to similar to XML document by the *JSONQuery*, like below:
```XML
<name>John</name>
<age>30</age>
<cars>
<element>
<name>Ford</name>
<models>
<element>Fiesta</element>
<element>Focus</element>
<element>Mustang</element>
</models>
</element>
<element>
<name>BMW</name>
<models>
<element>320</element>
<element>X3</element>
<element>X5</element>
</models>
</element>
<element>
<name>Fiat</name>
<models>
<element>500</element>
<element>Panda</element>
</models>
</element>
</cars>
```
Notes: `element` is empty element that have no any name.
List of XPath query packages
===
|Name |Description |
|--------------------------|----------------|
|[htmlquery](https://github.com/antchfx/htmlquery) | XPath query package for the HTML document|
|[xmlquery](https://github.com/antchfx/xmlquery) | XPath query package for the XML document|
|[jsonquery](https://github.com/antchfx/jsonquery) | XPath query package for the JSON document|
|
