1[](https://godoc.org/github.com/exponent-io/jsonpath)
2[](https://travis-ci.org/exponent-io/jsonpath)
3
4# jsonpath
5
6This package extends the [json.Decoder](https://golang.org/pkg/encoding/json/#Decoder) to support navigating a stream of JSON tokens. You should be able to use this extended Decoder places where a json.Decoder would have been used.
7
8This Decoder has the following enhancements...
9 * The [Scan](https://godoc.org/github.com/exponent-io/jsonpath/#Decoder.Scan) method supports scanning a JSON stream while extracting particular values along the way using [PathActions](https://godoc.org/github.com/exponent-io/jsonpath#PathActions).
10 * The [SeekTo](https://godoc.org/github.com/exponent-io/jsonpath#Decoder.SeekTo) method supports seeking forward in a JSON token stream to a particular path.
11 * The [Path](https://godoc.org/github.com/exponent-io/jsonpath#Decoder.Path) method returns the path of the most recently parsed token.
12 * The [Token](https://godoc.org/github.com/exponent-io/jsonpath#Decoder.Token) method has been modified to distinguish between strings that are object keys and strings that are values. Object key strings are returned as the [KeyString](https://godoc.org/github.com/exponent-io/jsonpath#KeyString) type rather than a native string.
13
14## Installation
15
16 go get -u github.com/exponent-io/jsonpath
17
18## Example Usage
19
20#### SeekTo
21
22```go
23import "github.com/exponent-io/jsonpath"
24
25var j = []byte(`[
26 {"Space": "YCbCr", "Point": {"Y": 255, "Cb": 0, "Cr": -10}},
27 {"Space": "RGB", "Point": {"R": 98, "G": 218, "B": 255}}
28]`)
29
30w := json.NewDecoder(bytes.NewReader(j))
31var v interface{}
32
33w.SeekTo(1, "Point", "G")
34w.Decode(&v) // v is 218
35```
36
37#### Scan with PathActions
38
39```go
40var j = []byte(`{"colors":[
41 {"Space": "YCbCr", "Point": {"Y": 255, "Cb": 0, "Cr": -10, "A": 58}},
42 {"Space": "RGB", "Point": {"R": 98, "G": 218, "B": 255, "A": 231}}
43]}`)
44
45var actions PathActions
46
47// Extract the value at Point.A
48actions.Add(func(d *Decoder) error {
49 var alpha int
50 err := d.Decode(&alpha)
51 fmt.Printf("Alpha: %v\n", alpha)
52 return err
53}, "Point", "A")
54
55w := NewDecoder(bytes.NewReader(j))
56w.SeekTo("colors", 0)
57
58var ok = true
59var err error
60for ok {
61 ok, err = w.Scan(&actions)
62 if err != nil && err != io.EOF {
63 panic(err)
64 }
65}
66```
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