Fasthttp: How to work with uploads

[ghost]

Hello,

i am morely new to _Go_ and build some things for my backend these days with net/http. Now, i tried fasthttp which works awesome - as known 😊 But, it's a very wide topic and a very complex API.

I want to work with uploaded POST form values and multipart/form-data, which seems confusing. In most languages and frameworks one can iterate over this data, like an _array_ or _map_ (practically without knowing all their names itself). I did not found some samples how to parse uploads in fasthttp.

---

Given is my _upload-script-dummy_ as simple function:

func upload(ctx *fasthttp.RequestCtx) {
  // ...
}

This function in this case is called via https://domain.tld/upload with the following _dummy-forms_

---

1: simple data

<form action="upload" method="post">
    <input type="text" name="name">
    <input type="email" name="mail">
    <textarea name="message"></textarea>
</form>

How to iterate over those _pairs_? (name=max, [email protected], message=Hi!)

2: single file

<form method="upload" enctype="multipart/form-data">
    <input name="file" type="file"> 
</form>

How do i get/save (move) this (temp-)file? (file=name.jpg)
How to access extended data, like size etc.?

3: multiple files

<form method="upload" enctype="multipart/form-data">
    <input name="files[]" type="file" multiple> 
</form>

How to iterate over multiple files in files[]?
(files=[1=[name=a.jpg, size=12345, ...], 2=[name=b.png, size=...], 3=[name=c.txt, ...]])
How to access their extended data, like size, tempname or whatever is in there?

---

Can someone give me reduced examples (just the needed lines) to handle that?

Thank you very much ☺️

(i am happy too if it's only a sample for one of that 😊 )

[dgrr]

Multipart forms are so easy to use in fasthttp. I think than are more easy than net/http. I won't provide you a full example only some utils functions.

You can use MultipartForm to interact with the multipart form (obviously).

form, err := ctx.MultipartForm()
if err != nil {
  ctx.Error(...)
  return
}
// We got the form!

Given the first html form we will make the following to get text, email and message (do not forget form.Value is a map[string][]string, so given a key the value will be a string slice):

texts := form.Value["text"]
if len(texts) == 0 {
  ctx.Error(...)
}
text := texts[0]
emails := form.Value["email"]
if len(emails) == 0 {
  ctx.Error(...)
}
email := emails[0]
...

Given the second form we will get the file using FormFile and store it in disk using SaveMultipartFile.

header, err := ctx.FormFile("file")
if err != nil {
  ctx.Error(...)
}
fasthttp.SaveMultipartFile(header, fmt.Sprintf("/tmp/%s", header.Filename))

Given the third form we will get the files walking along form.Files map.

form, err := ctx.MultipartForm()
if err != nil {
  ctx.Error(...)
  return
}
for k, v := range form.File {
  for _, header := range v {
    fasthttp.SaveMultipartFile(header, fmt.Sprintf("/tmp/%s", header.Filename))
  }
}

[ghost]

@dgrr thank you very much :100: