Gophercises - 18 - Image Transformer

Problem

• https://github.com/gophercises/transform
• https://gophercises.com/exercises/transform

Solution

• main.go: Main functionality.
• primitive/primitive.go: Primitive package.

Lessons Learned

HTML Input type File

We can use something like this

<input type="file"
    id="upload" name="upload"
    accept="image/jpeg,image/png" />

This only shows files of type jpeg and png. We can also do image/* to show all images.

Int to Enum

Assuming we have this enum:

type EnumType int

const (
	Zero Enum = iota
	One
	Two
	Three
)

We can convert an int to this type with EnumType(2).

http.Request.FormFile

Gets the first file in the param (usually POST body).

• https://golang.org/pkg/net/http/?#Request.FormFile

file, header, err := r.FormFile("upload")

• file can be used like any other file (hint: implements io.Reader).
  • https://golang.org/pkg/mime/multipart/#File
• header has info about the file like name and size.
  • https://golang.org/pkg/mime/multipart/#FileHeader

Response.PostForm is a map of url.Values (map[string][]string).