Empty string element in a slice disappears after decoding

[mariaefi29]

For example, I have a struct:

type Post struct { Images []string }

If I want to put in the struct values like (contains three elements, including empty string):

["a", "", "b"]

After decoding I have a slice with two elements excluding an empty string as a result.

Could you please tell me if it Is a bug or a way it works? Thank you!

[kisielk]

Can you please provide a full code sample to reproduce this?

…

On May 16, 2018, at 04:18, Maria Efimenko ***@***.***> wrote: For example, I have a struct: type Post struct { Images []string } If I want to put in the struct values like (contains three elements, including empty string): ["a", "", ""b] After decoding I have a slice with two elements excluding an empty string as a result. Could you please tell me if it Is a bug or a way it works? Thank you! — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#105>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AADk-ubU3UQmTlNi6a_vNZR0CgS-n4HHks5tzAsWgaJpZM4UBHkr>.

[mariaefi29]

package main

import (
	"fmt"
	"github.com/gorilla/schema"
	"net/url"
)

func main() {

	type Images struct {
		Images []string
	}

	decoder := schema.NewDecoder()

	values := url.Values{}
	values.Add("Images", "a")
	values.Add("Images", "")
	values.Add("Images", "b")

	images := Images{}

	fmt.Println("Values are --->", values)
	fmt.Println("The length of values is --->", len(values["Images"]))

	err := decoder.Decode(&images, values)
	if err != nil {
		fmt.Println(err)
	}
	fmt.Println("Images after decoding are --->", images)
	fmt.Println("The length of Images after decoding is --->", len(images.Images))

}

[kisielk]

Hi @mariaefi29

Sorry for taking a while back to you. What you need to do is call decoder.ZeroEmpty(true) before calling the Decode method. That will cause empty strings to produce the zero value of the decoded type, otherwise they are ignored.

[mariaefi29]

Thank you very much for your help!

[novikov1337danil]

Hi @mariaefi29

Sorry for taking a while back to you. What you need to do is call decoder.ZeroEmpty(true) before calling the Decode method. That will cause empty strings to produce the zero value of the decoded type, otherwise they are ignored.

Hello! For me ZeroEmpty still not working. I still get an empty string instead of nil

Here is my code:
var user models.User
d := schema.NewDecoder()
d.ZeroEmpty(true)
err = d.Decode(&user, r.PostForm)

[elithrar]

The zero value in Go for a string is “”. You may want [][]byte instead, if dealing with image data.

…

On Tue, Apr 9, 2019 at 2:43 AM novikov1337danil ***@***.***> wrote: Hi @mariaefi29 <https://github.com/mariaefi29> Sorry for taking a while back to you. What you need to do is call decoder.ZeroEmpty(true) before calling the Decode method. That will cause empty strings to produce the zero value of the decoded type, otherwise they are ignored. Hello! For me ZeroEmpty still not working. I still get an empty string instead of nil — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#105 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AABIcLwXTMGD67edIPQJt41R5NEoE98Lks5vfGDZgaJpZM4UBHkr> .