gopdf/contrib/httpimg/httpimg.go

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2021-03-02 13:27:45 +01:00
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)
}