jsonlogic

README

Go JSON Logic

Implementation of JSON Logic in Go Lang.

What's JSON Logic?

JSON Logic is a DSL to write logic decisions in JSON. It's has a great specification and is very simple to learn. The official website has a great documentation with examples.

How to use it

The use of this library is very straightforward. Here's a simple example:

package main

import (
	"bytes"
	"fmt"
	"strings"

	"github.com/diegoholiveira/jsonlogic"
)

func main() {
	logic := strings.NewReader(`{"==": [1, 1]}`)
	data := strings.NewReader(`{}`)

	var result bytes.Buffer

	jsonlogic.Apply(logic, data, &result)

	fmt.Println(result.String())
}

This will output true in your console.

Here's another example, but this time using variables passed in the data parameter:

package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"strings"

	"github.com/diegoholiveira/jsonlogic"
)

type (
	User struct {
		Name     string `json:"name"`
		Age      int    `json:"age"`
		Location string `json:"location"`
	}

	Users []User
)

func main() {
	logic := strings.NewReader(`{
        "filter": [
            {"var": "users"},
            {">=": [
                {"var": ".age"},
                18
            ]}
        ]
    }`)

	data := strings.NewReader(`{
        "users": [
            {"name": "Diego", "age": 33, "location": "Florianópolis"},
            {"name": "Jack", "age": 12, "location": "London"},
            {"name": "Pedro", "age": 19, "location": "Lisbon"},
            {"name": "Leopoldina", "age": 30, "location": "Rio de Janeiro"}
        ]
    }`)

	var result bytes.Buffer

	err := jsonlogic.Apply(logic, data, &result)
	if err != nil {
		fmt.Println(err.Error())

		return
	}

	var users Users

	decoder := json.NewDecoder(&result)
	decoder.Decode(&users)

	for _, user := range users {
		fmt.Printf("    - %s\n", user.Name)
	}
}

License

This project is licensed under the MIT License - see the LICENSE file for details

Documentation

Index

• func Apply(rule, data io.Reader, result io.Writer) error
• func ApplyInterface(rule, data interface{}) (interface{}, error)
• func ApplyRaw(rule, data json.RawMessage) (json.RawMessage, error)
• func IsValid(rule io.Reader) bool

Functions

func Apply

func Apply(rule, data io.Reader, result io.Writer) error

Apply read the rule and it's data from io.Reader, executes it and write back a JSON into an io.Writer result

func ApplyInterface

func ApplyInterface(rule, data interface{}) (interface{}, error)

func ApplyRaw

func ApplyRaw(rule, data json.RawMessage) (json.RawMessage, error)

func IsValid

func IsValid(rule io.Reader) bool

IsValid reads a JSON Logic rule from io.Reader and validates it