lxPdf/contrib/httpimg/httpimg.go

package httpimg

import (
	"io"
	"net/http"

	"github.com/jung-kurt/gofpdf"
)

// httpimgPdf is a partial interface that only implements the functions we need
// from the PDF generator to put the HTTP images on the PDF.
type httpimgPdf interface {
	GetImageInfo(imageStr string) *gofpdf.ImageInfoType
	ImageTypeFromMime(mimeStr string) string
	RegisterImageReader(imgName, tp string, r io.Reader) *gofpdf.ImageInfoType
	SetError(err error)
}

// Register registers a HTTP image. Downloading the image from the provided URL
// and adding it to the PDF but not adding it to the page. Use Image() with the
// same URL to add the image to the page.
func Register(f httpimgPdf, urlStr, tp string) (info *gofpdf.ImageInfoType) {
	info = f.GetImageInfo(urlStr)

	if info != nil {
		return
	}

	resp, err := http.Get(urlStr)

	if err != nil {
		f.SetError(err)
		return
	}

	defer resp.Body.Close()

	if tp == "" {
		tp = f.ImageTypeFromMime(resp.Header["Content-Type"][0])
	}

	return f.RegisterImageReader(urlStr, tp, resp.Body)
}