Jeffail/gabs/README.md

![Gabs](gabs_logo.png "Gabs")

Gabs is a small utility for dealing with dynamic or unknown JSON structures in
golang. It's pretty much just a helpful wrapper around the golang
`json.Marshal/json.Unmarshal` behaviour and `map[string]interface{}` objects.
It does nothing spectacular except for being fabulous.

https://godoc.org/github.com/Jeffail/gabs

## Install

``` bash
go get github.com/Jeffail/gabs
```

## Use

### Parsing and searching JSON

``` go
jsonParsed, err := gabs.ParseJSON([]byte(`{
	"outter":{
		"inner":{
			"value1":10,
			"value2":22
		},
		"alsoInner":{
			"value1":20,
			"array1":[
				30, 40
			]
		}
	}
}`))

var value float64
var ok bool

value, ok = jsonParsed.Path("outter.inner.value1").Data().(float64)
// value == 10.0, ok == true

value, ok = jsonParsed.Search("outter", "inner", "value1").Data().(float64)
// value == 10.0, ok == true

gObj, err := jsonParsed.JSONPointer("/outter/alsoInner/array1/1")
if err != nil {
	panic(err)
}
value, ok = gObj.Data().(float64)
// value == 40.0, ok == true

value, ok = jsonParsed.Path("does.not.exist").Data().(float64)
// value == 0.0, ok == false

exists := jsonParsed.Exists("outter", "inner", "value1")
// exists == true

exists := jsonParsed.ExistsP("does.not.exist")
// exists == false
```

### Iterating objects

``` go
jsonParsed, _ := gabs.ParseJSON([]byte(`{"object":{ "first": 1, "second": 2, "third": 3 }}`))

// S is shorthand for Search
children, _ := jsonParsed.S("object").ChildrenMap()
for key, child := range children {
	fmt.Printf("key: %v, value: %v\n", key, child.Data().(string))
}
```

### Iterating arrays

``` go
jsonParsed, err := gabs.ParseJSON([]byte(`{"array":[ "first", "second", "third" ]}`))
if err != nil {
	panic(err)
}

// S is shorthand for Search
children, err := jsonParsed.S("array").Children()
if err != nil {
	panic(err)
}

for _, child := range children {
	fmt.Println(child.Data().(string))
}
```

Will print:

```
first
second
third
```

Children() will return all children of an array in order. This also works on
objects, however, the children will be returned in a random order.

### Searching through arrays

If your JSON structure contains arrays you can still search the fields of the
objects within the array, this returns a JSON array containing the results for
each element.

``` go
jsonParsed, err := gabs.ParseJSON([]byte(`{"array":[ {"value":1}, {"value":2}, {"value":3} ]}`))
if err != nil {
	panic(err)
}
fmt.Println(jsonParsed.Path("array.value").String())
```

Will print:

```
[1,2,3]
```

### Generating JSON

``` go
jsonObj := gabs.New()
// or gabs.Consume(jsonObject) to work on an existing map[string]interface{}

jsonObj.Set(10, "outter", "inner", "value")
jsonObj.SetP(20, "outter.inner.value2")
jsonObj.Set(30, "outter", "inner2", "value3")

fmt.Println(jsonObj.String())
```

Will print:

```
{"outter":{"inner":{"value":10,"value2":20},"inner2":{"value3":30}}}
```

To pretty-print:

``` go
fmt.Println(jsonObj.StringIndent("", "  "))
```

Will print:

```
{
  "outter": {
    "inner": {
      "value": 10,
      "value2": 20
    },
    "inner2": {
      "value3": 30
    }
  }
}
```

### Generating Arrays

``` go
jsonObj := gabs.New()

jsonObj.Array("foo", "array")
// Or .ArrayP("foo.array")

jsonObj.ArrayAppend(10, "foo", "array")
jsonObj.ArrayAppend(20, "foo", "array")
jsonObj.ArrayAppend(30, "foo", "array")

fmt.Println(jsonObj.String())
```

Will print:

```
{"foo":{"array":[10,20,30]}}
```

Working with arrays by index:

``` go
jsonObj := gabs.New()

// Create an array with the length of 3
jsonObj.ArrayOfSize(3, "foo")

jsonObj.S("foo").SetIndex("test1", 0)
jsonObj.S("foo").SetIndex("test2", 1)

// Create an embedded array with the length of 3
jsonObj.S("foo").ArrayOfSizeI(3, 2)

jsonObj.S("foo").Index(2).SetIndex(1, 0)
jsonObj.S("foo").Index(2).SetIndex(2, 1)
jsonObj.S("foo").Index(2).SetIndex(3, 2)

fmt.Println(jsonObj.String())
```

Will print:

```
{"foo":["test1","test2",[1,2,3]]}
```

### Converting back to JSON

This is the easiest part:

``` go
jsonParsedObj, _ := gabs.ParseJSON([]byte(`{
	"outter":{
		"values":{
			"first":10,
			"second":11
		}
	},
	"outter2":"hello world"
}`))

jsonOutput := jsonParsedObj.String()
// Becomes `{"outter":{"values":{"first":10,"second":11}},"outter2":"hello world"}`
```

And to serialize a specific segment is as simple as:

``` go
jsonParsedObj := gabs.ParseJSON([]byte(`{
	"outter":{
		"values":{
			"first":10,
			"second":11
		}
	},
	"outter2":"hello world"
}`))

jsonOutput := jsonParsedObj.Search("outter").String()
// Becomes `{"values":{"first":10,"second":11}}`
```

### Merge two containers

You can merge a JSON structure into an existing one, where collisions will be
converted into a JSON array.

``` go
jsonParsed1, _ := ParseJSON([]byte(`{"outter": {"value1": "one"}}`))
jsonParsed2, _ := ParseJSON([]byte(`{"outter": {"inner": {"value3": "three"}}, "outter2": {"value2": "two"}}`))

jsonParsed1.Merge(jsonParsed2)
// Becomes `{"outter":{"inner":{"value3":"three"},"value1":"one"},"outter2":{"value2":"two"}}`
```

Arrays are merged:

``` go
jsonParsed1, _ := ParseJSON([]byte(`{"array": ["one"]}`))
jsonParsed2, _ := ParseJSON([]byte(`{"array": ["two"]}`))

jsonParsed1.Merge(jsonParsed2)
// Becomes `{"array":["one", "two"]}`
```

### Parsing Numbers

Gabs uses the `json` package under the bonnet, which by default will parse all
number values into `float64`. If you need to parse `Int` values then you should
use a `json.Decoder` (https://golang.org/pkg/encoding/json/#Decoder):

``` go
sample := []byte(`{"test":{"int":10, "float":6.66}}`)
dec := json.NewDecoder(bytes.NewReader(sample))
dec.UseNumber()

val, err := gabs.ParseJSONDecoder(dec)
if err != nil {
    t.Errorf("Failed to parse: %v", err)
    return
}

intValue, err := val.Path("test.int").Data().(json.Number).Int64()
```