jsonq

package module
Version: v0.0.0-...-e874b16 Latest Latest
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Published: May 11, 2015 License: MIT Imports: 2 Imported by: 127

README

jsonq

Build Status Godoc license

Simplify your golang json usage by extracting fields or items from arrays and objects with a simple, hierarchical query. API Documentation on godoc.org.

This package is meant to make working with complex feeds a bit more easy. If you have simple feeds you want to model with struct types, check out jflect, which will create struct definitions given a json document.

installing

go get github.com/jmoiron/jsonq

usage

Given some json data like:

{
	"foo": 1,
	"bar": 2,
	"test": "Hello, world!",
	"baz": 123.1,
	"array": [
		{"foo": 1},
		{"bar": 2},
		{"baz": 3}
	],
	"subobj": {
		"foo": 1,
		"subarray": [1,2,3],
		"subsubobj": {
			"bar": 2,
			"baz": 3,
			"array": ["hello", "world"]
		}
	},
	"bool": true
}

Decode it into a map[string]interface{}:

import (
	"strings"
	"encoding/json"
	"github.com/jmoiron/jsonq"
)

data := map[string]interface{}{}
dec := json.NewDecoder(strings.NewReader(jsonstring))
dec.Decode(&data)
jq := jsonq.NewQuery(data)

From here, you can query along different keys and indexes:

// data["foo"] -> 1
jq.Int("foo")

// data["subobj"]["subarray"][1] -> 2
jq.Int("subobj", "subarray", "1")

// data["subobj"]["subarray"]["array"][0] -> "hello"
jq.String("subobj", "subsubobj", "array", "0")

// data["subobj"] -> map[string]interface{}{"subobj": ...}
obj, err := jq.Object("subobj")

Missing keys, out of bounds indexes, and type failures will return errors. For simplicity, integer keys (ie, {"0": "zero"}) are inaccessible by jsonq as integer strings are assumed to be array indexes.

The Int and Float methods will attempt to parse numbers from string values to ease the use of many real world feeds which deliver numbers as strings.

Suggestions/comments please tweet @jmoiron

Documentation

Overview

Package jsonq simplify your json usage with a simple hierarchical query.

Given some json data like:

{
	"foo": 1,
	"bar": 2,
	"test": "Hello, world!",
	"baz": 123.1,
	"array": [
		{"foo": 1},
		{"bar": 2},
		{"baz": 3}
	],
	"subobj": {
		"foo": 1,
		"subarray": [1,2,3],
		"subsubobj": {
			"bar": 2,
			"baz": 3,
			"array": ["hello", "world"]
		}
	},
	"bool": true
}

Decode it into a map[string]interrface{}:

import (
	"strings"
	"encoding/json"
	"github.com/jmoiron/jsonq"
)

data := map[string]interface{}{}
dec := json.NewDecoder(strings.NewReader(jsonstring))
dec.Decode(&data)
jq := jsonq.NewQuery(data)

From here, you can query along different keys and indexes:

// data["foo"] -> 1
jq.Int("foo")

// data["subobj"]["subarray"][1] -> 2
jq.Int("subobj", "subarray", "1")

// data["subobj"]["subarray"]["array"][0] -> "hello"
jq.String("subobj", "subsubobj", "array", "0")

// data["subobj"] -> map[string]interface{}{"subobj": ...}
obj, err := jq.Object("subobj")

Notes:

Missing keys, out of bounds indexes, and type failures will return errors. For simplicity, integer keys (ie, {"0": "zero"}) are inaccessible by `jsonq` as integer strings are assumed to be array indexes.

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

This section is empty.

Types

type JsonQuery

type JsonQuery struct {
	// contains filtered or unexported fields
}

JsonQuery is an object that enables querying of a Go map with a simple positional query language.

func NewQuery

func NewQuery(data interface{}) *JsonQuery

NewQuery creates a new JsonQuery obj from an interface{}.

func (*JsonQuery) Array

func (j *JsonQuery) Array(s ...string) ([]interface{}, error)

Array extracts a []interface{} from the JsonQuery

func (*JsonQuery) ArrayOfArrays

func (j *JsonQuery) ArrayOfArrays(s ...string) ([][]interface{}, error)

ArrayOfArrays extracts an array of []interface{} (arrays) from some json

func (*JsonQuery) ArrayOfBools

func (j *JsonQuery) ArrayOfBools(s ...string) ([]bool, error)

ArrayOfBools extracts an array of bools from some json

func (*JsonQuery) ArrayOfFloats

func (j *JsonQuery) ArrayOfFloats(s ...string) ([]float64, error)

ArrayOfFloats extracts an array of float64s from some json

func (*JsonQuery) ArrayOfInts

func (j *JsonQuery) ArrayOfInts(s ...string) ([]int, error)

ArrayOfInts extracts an array of ints from some json

func (*JsonQuery) ArrayOfObjects

func (j *JsonQuery) ArrayOfObjects(s ...string) ([]map[string]interface{}, error)

ArrayOfObjects extracts an array of map[string]interface{} (objects) from some json

func (*JsonQuery) ArrayOfStrings

func (j *JsonQuery) ArrayOfStrings(s ...string) ([]string, error)

ArrayOfStrings extracts an array of strings from some json

func (*JsonQuery) Bool

func (j *JsonQuery) Bool(s ...string) (bool, error)

Bool extracts a bool the JsonQuery

func (*JsonQuery) Float

func (j *JsonQuery) Float(s ...string) (float64, error)

Float extracts a float from the JsonQuery

func (*JsonQuery) Int

func (j *JsonQuery) Int(s ...string) (int, error)

Int extracts an int from the JsonQuery

func (*JsonQuery) Interface

func (j *JsonQuery) Interface(s ...string) (interface{}, error)

Interface extracts an interface{} from the JsonQuery

func (*JsonQuery) Matrix2D

func (j *JsonQuery) Matrix2D(s ...string) ([][]interface{}, error)

Matrix2D is an alias for ArrayOfArrays

func (*JsonQuery) Object

func (j *JsonQuery) Object(s ...string) (map[string]interface{}, error)

Object extracts a json object from the JsonQuery

func (*JsonQuery) String

func (j *JsonQuery) String(s ...string) (string, error)

String extracts a string from the JsonQuery

Source Files

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