67 lines
2.4 KiB
Markdown
67 lines
2.4 KiB
Markdown
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[](https://godoc.org/github.com/exponent-io/jsonpath)
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[](https://travis-ci.org/exponent-io/jsonpath)
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# jsonpath
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This 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.
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This Decoder has the following enhancements...
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* 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).
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* 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.
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* The [Path](https://godoc.org/github.com/exponent-io/jsonpath#Decoder.Path) method returns the path of the most recently parsed token.
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* 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.
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## Installation
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go get -u github.com/exponent-io/jsonpath
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## Example Usage
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#### SeekTo
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```go
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import "github.com/exponent-io/jsonpath"
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var j = []byte(`[
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{"Space": "YCbCr", "Point": {"Y": 255, "Cb": 0, "Cr": -10}},
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{"Space": "RGB", "Point": {"R": 98, "G": 218, "B": 255}}
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]`)
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w := json.NewDecoder(bytes.NewReader(j))
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var v interface{}
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w.SeekTo(1, "Point", "G")
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w.Decode(&v) // v is 218
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```
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#### Scan with PathActions
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```go
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var j = []byte(`{"colors":[
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{"Space": "YCbCr", "Point": {"Y": 255, "Cb": 0, "Cr": -10, "A": 58}},
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{"Space": "RGB", "Point": {"R": 98, "G": 218, "B": 255, "A": 231}}
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]}`)
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var actions PathActions
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// Extract the value at Point.A
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actions.Add(func(d *Decoder) error {
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var alpha int
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err := d.Decode(&alpha)
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fmt.Printf("Alpha: %v\n", alpha)
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return err
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}, "Point", "A")
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w := NewDecoder(bytes.NewReader(j))
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w.SeekTo("colors", 0)
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var ok = true
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var err error
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for ok {
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ok, err = w.Scan(&actions)
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if err != nil && err != io.EOF {
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panic(err)
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}
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}
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```
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