json-sideload

A deserializer for JSON payloads that comply to the ActiveModel::Serializer spec in go.

Installation

go get github.com/vickyramachandra/json-sideload

Introduction

json-sideload uses StructField tags to annotate the structs fields that you already have and use in your app and then reads and writes ActiveModel::Serializer output based on the instructions you give the library in your json-sideload tags. Let's take an example. In your app, you most likely have structs that look similar to these:

type PersonResponse struct {
	Persons []*Person `json:"persons"`
}

type Person struct {
	ID          json.Number   `json:"id"`
	Name        string        `json:"name"`
	CurrentCity *City         `json:"city"`
	LivedCities []*City       `json:"lived_cities"`
	Dob         *time.Time    `json:"dob"`
}

type City struct {
	ID   float64 `json:"id"`
	Name string  `json:"name"`
}

These structs may or may not resemble the layout of your database. But these are the ones that you want to use right? You wouldn't want to use structs like those that ActiveModel::Serializer with sideload sends because it is difficult to get at all of your data easily.

Example

The json-sideload StructTags tells this library how to unmarshal JSON with sideload payloads to your structs. Here's an example of the structs above using jsonsideload tags:

type PersonResponse struct {
	Persons []*Person `json:"persons" jsonsideload:"includes,persons"`
}

type Person struct {
	ID          json.Number   `json:"id"`
	Name        string        `json:"name"`
	CurrentCity *City         `json:"city" jsonsideload:"hasone,cities,current_city_id" json:"city"`
	LivedCities []*City       `json:"lived_cities" jsonsideload:"hasmany,cities,lived_city_ids"`
	Dob         *time.Time    `json:"dob"`
	ShortDob    *mytime.Ctime `json:"short_dob"` // custom types unmarshalling also works!
}

type City struct {
	ID   float64 `json:"id"`
	Name string  `json:"name"`
}

Permitted Tag Values

include

`jsonsideload:"include,<relationship>"`

This indicates that the relationship is already included in the JSON. Tag value arguments are comma separated. The first argument must be, includeand the second must be the name of the relationship as it appears in the JSON.

includes

`jsonsideload:"includes,<relationship>"`

Here the included relationship is an array. Tag value arguments are comma separated. The first argument must be, includeand the second must be the name of the relationship as it appears in the JSON.

hasone

`jsonsideload:"hasone,<array name in which the relationship is sideloaded>,
<key name with which the relationship should be searched in the sideloaded array>"`

The first argument must be, hasone, and the second should be the array name in which the relationship is sideloaded. The third argument is key name with which the relationship should be searched in the sideloaded array.

hasmany

`jsonsideload:"hasmany,<array name in which the relationship is sideloaded>,
<array of keys with which the relationship should be searched in the sideloaded array>"`

The first argument must be, hasone, and the second should be the array name in which the relationship is sideloaded. The third argument is an array of keys with which the relationship should be searched in the sideloaded array.

Methods Reference

Unmarshal

Method expect pointers to struct instance or array of pointers of the same contained with the interface{}s

Unmarshal(jsonPayload []byte, model interface{}) error

Example Code

func parseResponse(data []byte) {
	personResp := new(PersonResponse)
	if err := Unmarshal(data, personResp); err != nil {
		fmt.Println(err)
		return
	}
  fmt.Println("Parsed person response", personResp)
}

TODO

• Extensive code coverage
• Exhaustive unit tests
• Marshaller implementation

Contributing

Fork, Change, Pull Request with tests.