1 files changed, 204 insertions, 0 deletions
diff --git a/src/http/assets.go b/src/http/assets.go
new file mode 100644
index 0000000..2cbe7a2
--- /dev/null
+++ b/src/http/assets.go
@@ -0,0 +1,204 @@
+package http
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"image"
+	"image/jpeg"
+	"image/png"
+	"io"
+	"net/http"
+	"path/filepath"
+	"strings"
+
+	"github.com/mediocregopher/blog.mediocregopher.com/srv/http/apiutil"
+	"github.com/mediocregopher/blog.mediocregopher.com/srv/post"
+	"golang.org/x/image/draw"
+)
+
+func isImgResizable(id string) bool {
+	switch strings.ToLower(filepath.Ext(id)) {
+	case ".jpg", ".jpeg", ".png":
+		return true
+	default:
+		return false
+	}
+}
+
+func resizeImage(out io.Writer, in io.Reader, maxWidth float64) error {
+
+	img, format, err := image.Decode(in)
+	if err != nil {
+		return fmt.Errorf("decoding image: %w", err)
+	}
+
+	imgRect := img.Bounds()
+	imgW, imgH := float64(imgRect.Dx()), float64(imgRect.Dy())
+
+	if imgW > maxWidth {
+
+		newH := imgH * maxWidth / imgW
+		newImg := image.NewRGBA(image.Rect(0, 0, int(maxWidth), int(newH)))
+
+		// Resize
+		draw.BiLinear.Scale(
+			newImg, newImg.Bounds(), img, img.Bounds(), draw.Over, nil,
+		)
+
+		img = newImg
+	}
+
+	switch format {
+	case "jpeg":
+		return jpeg.Encode(out, img, nil)
+	case "png":
+		return png.Encode(out, img)
+	default:
+		return fmt.Errorf("unknown image format %q", format)
+	}
+}
+
+func (a *api) renderPostAssetsIndexHandler() http.Handler {
+
+	tpl := a.mustParseBasedTpl("assets.html")
+
+	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+
+		ids, err := a.params.PostAssetStore.List()
+
+		if err != nil {
+			apiutil.InternalServerError(
+				rw, r, fmt.Errorf("getting list of asset ids: %w", err),
+			)
+			return
+		}
+
+		tplPayload := struct {
+			IDs []string
+		}{
+			IDs: ids,
+		}
+
+		executeTemplate(rw, r, tpl, tplPayload)
+	})
+}
+
+func (a *api) getPostAssetHandler() http.Handler {
+
+	renderIndexHandler := a.renderPostAssetsIndexHandler()
+
+	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+
+		id := filepath.Base(r.URL.Path)
+
+		if id == "/" {
+			renderIndexHandler.ServeHTTP(rw, r)
+			return
+		}
+
+		maxWidth, err := apiutil.StrToInt(r.FormValue("w"), 0)
+		if err != nil {
+			apiutil.BadRequest(rw, r, fmt.Errorf("invalid w parameter: %w", err))
+			return
+		}
+
+		buf := new(bytes.Buffer)
+
+		err = a.params.PostAssetStore.Get(id, buf)
+
+		if errors.Is(err, post.ErrAssetNotFound) {
+			http.Error(rw, "Asset not found", 404)
+			return
+		} else if err != nil {
+			apiutil.InternalServerError(
+				rw, r, fmt.Errorf("fetching asset with id %q: %w", id, err),
+			)
+			return
+		}
+
+		if maxWidth == 0 {
+
+			if _, err := io.Copy(rw, buf); err != nil {
+				apiutil.InternalServerError(
+					rw, r,
+					fmt.Errorf(
+						"copying asset with id %q to response writer: %w",
+						id, err,
+					),
+				)
+			}
+
+			return
+		}
+
+		if !isImgResizable(id) {
+			apiutil.BadRequest(rw, r, fmt.Errorf("cannot resize file %q", id))
+			return
+		}
+
+		if err := resizeImage(rw, buf, float64(maxWidth)); err != nil {
+			apiutil.InternalServerError(
+				rw, r,
+				fmt.Errorf(
+					"resizing image with id %q to size %d: %w",
+					id, maxWidth, err,
+				),
+			)
+		}
+
+	})
+}
+
+func (a *api) postPostAssetHandler() http.Handler {
+
+	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+
+		id := r.PostFormValue("id")
+		if id == "/" {
+			apiutil.BadRequest(rw, r, errors.New("id is required"))
+			return
+		}
+
+		file, _, err := r.FormFile("file")
+		if err != nil {
+			apiutil.BadRequest(rw, r, fmt.Errorf("reading multipart file: %w", err))
+			return
+		}
+		defer file.Close()
+
+		if err := a.params.PostAssetStore.Set(id, file); err != nil {
+			apiutil.InternalServerError(rw, r, fmt.Errorf("storing file: %w", err))
+			return
+		}
+
+		a.executeRedirectTpl(rw, r, a.assetsURL(false))
+	})
+}
+
+func (a *api) deletePostAssetHandler() http.Handler {
+
+	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+
+		id := filepath.Base(r.URL.Path)
+
+		if id == "/" {
+			apiutil.BadRequest(rw, r, errors.New("id is required"))
+			return
+		}
+
+		err := a.params.PostAssetStore.Delete(id)
+
+		if errors.Is(err, post.ErrAssetNotFound) {
+			http.Error(rw, "Asset not found", 404)
+			return
+		} else if err != nil {
+			apiutil.InternalServerError(
+				rw, r, fmt.Errorf("deleting asset with id %q: %w", id, err),
+			)
+			return
+		}
+
+		a.executeRedirectTpl(rw, r, a.assetsURL(false))
+	})
+}