Consume a nested array inside JSON request in Go

Question

How do I go about consuming the following json post in Go?

{
    "notificationType": "email",
    "client": "The CLient",
    "content": "Hellow World",
    "recipients": [
        {
            "address": "[email protected]"
        },
        {
            "address": "[email protected]"
        }
    ]
}

I've managed to get the string types but I really don't know enough about Go to deal with the recipients array.

My code looks like this:

package handlers

import (
    "net/http"
    "encoding/json"
    "notificationservice/src/validation"
    "io/ioutil"
    "fmt"
)

func EmailHandler(w http.ResponseWriter, r *http.Request) {
    b, err := ioutil.ReadAll(r.Body)
    defer r.Body.Close()
    if err != nil {
        http.Error(w, err.Error(), 500)
        return
    }

    var postData validation.EmailValidator
    err = json.Unmarshal(b, &postData)
    if err != nil {
        http.Error(w, err.Error(), 500)
        return
    }

    fmt.Println(postData.Client)
    fmt.Println(postData.Content)
}

My struct:

package validation

import "fmt"

type EmailValidator struct {
    Client  string `json:"client"`
    Content string `json:"content"`
    //Recipients []string `json:"recipients"`
}

func (validator * EmailValidator) ValidateEmail() (bool) {

    var required = []string {validator.Client, validator.Content, validator.Stuff}

    for _, param := range required {
        fmt.Println(param)
    }
    return true;
}

I've tried setting Recipients to []string and [][]string but I really don't know what I'm doing.

In PHP I would use the var_dump command to print out the entire object and debug step by step from there, but Go doesn't appear to have that functionality.

cn0047 · Accepted Answer · 2018-07-03 12:19:03Z

4

You can try something like this:

package main

import (
    "encoding/json"
    "fmt"
)

type Email struct {
    Adress string `json:"address"`
}

type EmailValidator struct {
    Client  string `json:"client"`
    Content string `json:"content"`
    Recipients []Email `json:"recipients"`
}

func main() {
    j := `{
    "notificationType": "email",
    "client": "The CLient",
    "content": "Hellow World",
    "recipients": [
        {
            "address": "[email protected]"
        },
        {
            "address": "[email protected]"
        }
    ]
    }`
    result := EmailValidator{}
    json.Unmarshal([]byte(j), &result)
    fmt.Printf("%+v", result) // something like var_dump in PHP
}

answered Jul 3, 2018 at 12:19

cn0047

17.2k7 gold badges61 silver badges75 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

user1894292 Over a year ago

Thanks for your answers, but this is still not working. Could it be because 'address' is in it's own anonymous object?

cn0047 Over a year ago

@user1894292 If you run code from my answer you receive: {Client:The CLient Content:Hellow World Recipients:[{Adress:[email protected]} {Adress:[email protected]}]}. Isn't result correct? What do you mean by 'address' is in it's own anonymous object? Do you have another JSON format?

cd1 · Accepted Answer · 2018-07-03 12:16:34Z

2

You need an array of "things with an address":

type EmailValidator struct {
    Client  string `json:"client"`
    Content string `json:"content"`
    Recipients []Recipient `json:"recipients"`
}


type Recipient struct {
    Address string `json:"address"`
}

answered Jul 3, 2018 at 12:16

cd1

16.6k12 gold badges50 silver badges52 bronze badges

4 Comments

user1894292 Over a year ago

Thanks for your answers, but this is still not working. Could it be because 'address' is in it's own anonymous object?

cd1 Over a year ago

So maybe your JSON data isn't how you expect it to be. Try to print your HTTP response body to make sure it looks the way you expect. For the JSON example you mentioned, this code does work.

user1894292 Over a year ago

How would you print HTTP response body? When I try to print the raw response, I get what looks like a hex string.

cd1 Over a year ago

When you used ioutil.ReadAll, you got a byte slice. Convert it to string with string(b).

Zak · Accepted Answer · 2018-07-03 12:16:09Z

1

You can nest objects, and Unmarshal will handle the entire tree for you.

type Recipient struct {
    Address string `json:"address"`
}

type EmailValidator struct {
    Client  string `json:"client"`
    Content string `json:"content"`
    Recipients []Recipient `json:"recipients"`
}

The rest of your code looks good.

answered Jul 3, 2018 at 12:16

Zak

5,90825 silver badges36 bronze badges

Collectives™ on Stack Overflow

Consume a nested array inside JSON request in Go

3 Answers 3

2 Comments

4 Comments

Comments

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

2 Comments

4 Comments

Comments

Related