How to send POST request multipart/form-data field as array for unit testing?

Question

I'm trying to make unit testing for my Go application that handles form data in multipart/form-data content type using gin (PostForm and PostFormArray) like

x, y := c.PostForm("x"), c.PostFormArray("y")

I have no problem on making a form field which have non-array value (PostForm) with mime/multipart library which Go provides like this

buf := new(bytes.Buffer)
w := multipart.NewWriter(buf)

x, _ := w.CreateFormField("x")
x.Write([]byte("This is x value"))

w.Close()

which PostForm handles perfectly, now I'm wondering if there is any way to send a multipart/form-data field with an array as its value like []string{"this is y 1", "this is y 2"} for it to work with gin's PostFormArray. Is it possible and how do I do it? Any help would be greatly appreciated. Thanks in advance!

"send a multipart/form-data field with an array as its value" this is not how multipart works. multipart has no notion of "array". What exactly do you want to send? — Volker
– Volker, Commented Aug 11, 2020 at 12:32
Have you tried y1, _ := w.CreateFormField("y") then y1.Write([]byte("this is y 1")), and y2, _ := w.CreateFormField("y") then y2.Write([]byte("this is y 2"))? — mkopriva
– mkopriva, Commented Aug 11, 2020 at 12:38
@Volker I want to send a form field which can work with gin's PostFormArray, which basically means a key with multiple values I guess — KKrome
– KKrome, Commented Aug 12, 2020 at 3:20
@mkopriva Thanks, that does the trick! Can't believe I missed this hahahaha, if you want you can post your answer and I'll accept your answer — KKrome
– KKrome, Commented Aug 12, 2020 at 3:21

mkopriva · Accepted Answer · 2020-08-12 03:39:41Z

3

You can create multiple fields with the same name, e.g.

buf := new(bytes.Buffer)
w := multipart.NewWriter(buf)

x, _ := w.CreateFormField("x")
x.Write([]byte("This is x value"))

y1, _ := w.CreateFormField("y")
y1.Write([]byte("this is y 1"))

y2, _ := w.CreateFormField("y")
y2.Write([]byte("this is y 2"))

w.Close()

answered Aug 12, 2020 at 3:39

mkopriva

38.7k4 gold badges73 silver badges86 bronze badges

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

1 Comment

Muhammad Hewedy Over a year ago

The simplest and to the point solution

Collectives™ on Stack Overflow

How to send POST request multipart/form-data field as array for unit testing?

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related