feat: get image blob in backend (#495)

* feat: get image blob in backend

* chore: update

server/http_getter.go

@@ -0,0 +1,70 @@
+package server
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+
+	"github.com/labstack/echo/v4"
+	getter "github.com/usememos/memos/plugin/http_getter"
+	metric "github.com/usememos/memos/plugin/metrics"
+)
+
+func (s *Server) registerCrawlerPublicRoutes(g *echo.Group) {
+	g.GET("/get/httpmeta", func(c echo.Context) error {
+		ctx := c.Request().Context()
+		urlStr := c.QueryParam("url")
+		if urlStr == "" {
+			return echo.NewHTTPError(http.StatusBadRequest, "Missing website url")
+		}
+		if _, err := url.Parse(urlStr); err != nil {
+			return echo.NewHTTPError(http.StatusBadRequest, "Wrong url").SetInternal(err)
+		}
+
+		htmlMeta, err := getter.GetHTMLMeta(urlStr)
+		if err != nil {
+			return echo.NewHTTPError(http.StatusNotAcceptable, fmt.Sprintf("Failed to get website meta with url: %s", urlStr)).SetInternal(err)
+		}
+		s.Collector.Collect(ctx, &metric.Metric{
+			Name: "getter used",
+			Labels: map[string]string{
+				"type": "httpmeta",
+			},
+		})
+
+		c.Response().Header().Set(echo.HeaderContentType, echo.MIMEApplicationJSONCharsetUTF8)
+		if err := json.NewEncoder(c.Response().Writer).Encode(composeResponse(htmlMeta)); err != nil {
+			return echo.NewHTTPError(http.StatusInternalServerError, "Failed to encode website HTML meta").SetInternal(err)
+		}
+		return nil
+	})
+	g.GET("/get/image", func(c echo.Context) error {
+		ctx := c.Request().Context()
+		urlStr := c.QueryParam("url")
+		if urlStr == "" {
+			return echo.NewHTTPError(http.StatusBadRequest, "Missing image url")
+		}
+		if _, err := url.Parse(urlStr); err != nil {
+			return echo.NewHTTPError(http.StatusBadRequest, "Wrong url").SetInternal(err)
+		}
+
+		image, err := getter.GetImage(urlStr)
+		if err != nil {
+			return echo.NewHTTPError(http.StatusNotAcceptable, fmt.Sprintf("Failed to get image url: %s", urlStr)).SetInternal(err)
+		}
+		s.Collector.Collect(ctx, &metric.Metric{
+			Name: "getter used",
+			Labels: map[string]string{
+				"type": "image",
+			},
+		})
+
+		c.Response().Writer.WriteHeader(http.StatusOK)
+		c.Response().Writer.Header().Set("Content-Type", image.Mediatype)
+		if _, err := c.Response().Writer.Write(image.Blob); err != nil {
+			return echo.NewHTTPError(http.StatusInternalServerError, "Failed to write image blob").SetInternal(err)
+		}
+		return nil
+	})
+}