revel image upload example

fotos.go

package controllers

import (
	"bytes"
	"image"
	"image/gif"
	"image/jpeg"
	"image/png"
	"io"
	"net/http"
	"strings"

	"github.com/nfnt/resize"
	"github.com/revel/revel"

	"corp/WebAdmin/app/routes"
	"corp/models"
)

type Fotos struct {
	App
}

func (c Fotos) Save(f models.Foto, imagefile io.Reader) revel.Result {
	headers, ok := c.Params.Files["imagefile"]
	if ok {

		if len(headers) != 1 {
			return c.RenderError(SaveFotoError{msg: "only one file at a time."})
		}

		var (
			err         error
			bildBuf     bytes.Buffer
			nameSplit   []string
			suffix      string
			uploadDaten image.Image
		)

		nameSplit = strings.Split(strings.ToLower(headers[0].Filename), ".")
		if len(nameSplit) <= 1 {
			return c.RenderError(SaveFotoError{msg: "no file suffix."})
		}
		suffix = nameSplit[len(nameSplit)-1]

		switch {
		case suffix == "jpg" || suffix == "jpeg":
			uploadDaten, err = jpeg.Decode(imagefile)
			if err != nil {
				return c.RenderError(SaveFotoError{"jpeg.Decode() failed", err})
			}

		case suffix == "png":
			uploadDaten, err = png.Decode(imagefile)
			if err != nil {
				return c.RenderError(SaveFotoError{"png.Decode() failed", err})
			}

		case suffix == "gif":
			uploadDaten, err = gif.Decode(imagefile)
			if err != nil {
				return c.RenderError(SaveFotoError{"gif.Decode() failed", err})
			}
		default:
			return c.RenderError(SaveFotoError{msg: "unsupported image suffix"})
		}

		resized := resize.Resize(500, 0, uploadDaten, resize.Lanczos3)

		err = png.Encode(&bildBuf, resized)
		if err != nil {
			return c.RenderError(SaveFotoError{"png.Encode() failed", err})
		}

		f.Data = bildBuf.Bytes()
		f.Width = resized.Bounds().Dx()
		f.Height = resized.Bounds().Dy()
		c.Flash.Success("Bild gespeichert")
	}

	f.Save(c.Txn)

	return c.Redirect(routes.Fotos.Index(false, f.HerstellerId))
}

struct Foto ???