refactor of topic handling and image serving

conference.go

@@ -478,14 +478,7 @@ func ReadPosts(ctxt ui.AmContext) (string, any, error) {
 	comm := ctxt.CurrentCommunity()
 	conf := ctxt.GetScratch("currentConference").(*database.Conference)
 	myLevel := ctxt.GetScratch("levelInConference").(uint16)
-	var topic *database.Topic = nil
+	topic := ctxt.GetScratch("currentTopic").(*database.Topic)
-	if rawTopic, err := strconv.ParseInt(ctxt.URLParam("topic"), 10, 16); err == nil {
-		topic, err = database.AmGetTopicByNumber(ctxt.Ctx(), conf, int16(rawTopic))
-	}
-	if topic == nil {
-		ctxt.SetRC(http.StatusNotFound)
-		return ui.ErrorPage(ctxt, fmt.Errorf("topic not found: %s", ctxt.URLParam("topic")))
-	}
 
 	// Determine the range of posts to display.  The "pin" is the post number after which we display the horizontal line separating old and new posts.
 	lastRead, err := topic.GetLastRead(ctxt.Ctx(), ctxt.CurrentUser())
@@ -642,17 +635,9 @@ func PostInTopic(ctxt ui.AmContext) (string, any, error) {
 	comm := ctxt.CurrentCommunity()
 	conf := ctxt.GetScratch("currentConference").(*database.Conference)
 	level := ctxt.GetScratch("levelInConference").(uint16)
+	topic := ctxt.GetScratch("currentTopic").(*database.Topic)
 
-	var topic *database.Topic = nil
+	urlStem := fmt.Sprintf("/comm/%s/conf/%s/r/%d", comm.Alias, ctxt.GetScratch("currentAlias"), topic.Number)
-	if rawTopic, err := strconv.ParseInt(ctxt.URLParam("topic"), 10, 16); err == nil {
-		topic, err = database.AmGetTopicByNumber(ctxt.Ctx(), conf, int16(rawTopic))
-	}
-	if topic == nil {
-		ctxt.SetRC(http.StatusNotFound)
-		return ui.ErrorPage(ctxt, fmt.Errorf("topic not found: %s", ctxt.URLParam("topic")))
-	}
-
-	urlStem := fmt.Sprintf("/comm/%s/conf/%s/r/%d", comm.Alias, ctxt.URLParam("confid"), topic.Number)
 	if ctxt.FormFieldIsSet("cancel") {
 		return "redirect", urlStem, nil
 	}

main.go

@@ -49,7 +49,7 @@ func setupEcho() *echo.Echo {
 	fn := ui.AmWrap(NotImplPage)
 	e.GET("/TODO/*", fn)
 	e.POST("/TODO/*", fn)
-	e.GET("/img/*", ui.AmWrap(ui.AmServeImage))
+	e.GET("/img/*", ui.AmServeImage)
 	e.GET("/static/*", ui.AmStaticFileHandler())
 	e.GET("/go/:postlink", fn)
 
@@ -98,8 +98,8 @@ func setupEcho() *echo.Echo {
 	confGroup.GET("", ui.AmWrap(Topics))
 	confGroup.GET("/new_topic", ui.AmWrap(NewTopicForm))
 	confGroup.POST("/new_topic", ui.AmWrap(NewTopic))
-	confGroup.GET("/r/:topic", ui.AmWrap(ReadPosts))
+	confGroup.GET("/r/:topic", ui.AmWrap(ReadPosts), ui.SetTopic)
-	confGroup.POST("/r/:topic", ui.AmWrap(PostInTopic))
+	confGroup.POST("/r/:topic", ui.AmWrap(PostInTopic), ui.SetTopic)
 
 	return e
 }

ui/images.go

@@ -28,6 +28,7 @@ import (
 
 	"git.erbosoft.com/amy/amsterdam/database"
 	"github.com/disintegration/imaging"
+	"github.com/labstack/echo/v4"
 )
 
 //go:embed static_images/*
@@ -55,14 +56,12 @@ func mimeTypeFromFilename(filename string) string {
 
 /* AmServeImage serves an image from internal storage.
  * Parameters:
- *     ctxt - The AmContext for the request.
+ *     c - The Echo context for this request.
  * Returns:
- *     Type of content to be rendered
+ *     Standard Go error return.
- *     Content to be rendered
- *     Standard Go error return
  */
-func AmServeImage(ctxt AmContext) (string, any, error) {
+func AmServeImage(c echo.Context) error {
-	components := strings.SplitAfter(ctxt.URLPath(), "/")
+	components := strings.SplitAfter(c.Request().URL.Path, "/")
 	var err error = nil
 	if len(components) == 4 {
 		switch components[2] {
@@ -70,27 +69,24 @@ func AmServeImage(ctxt AmContext) (string, any, error) {
 			var b []byte
 			b, err = static_images.ReadFile(filepath.Join("static_images", components[3]))
 			if err == nil {
-				ctxt.SetOutputType(mimeTypeFromFilename(components[3]))
+				return c.Blob(http.StatusOK, mimeTypeFromFilename(components[3]), b)
-				return "bytes", b, nil
 			}
 		case "store/":
 			var id int
 			id, err = strconv.Atoi(components[3])
 			if err == nil {
 				var img *database.ImageStore
-				img, err = database.AmLoadImage(ctxt.Ctx(), int32(id))
+				img, err = database.AmLoadImage(c.Request().Context(), int32(id))
 				if err == nil {
-					ctxt.SetOutputType(img.MimeType)
+					return c.Blob(http.StatusOK, img.MimeType, img.Data)
-					return "bytes", img.Data, nil
 				}
 			}
 		}
 	}
-	ctxt.SetRC(http.StatusNotFound)
 	if err == nil {
-		err = fmt.Errorf("image not found: %s", ctxt.URLPath())
+		err = fmt.Errorf("image not found: %s", c.Request().URL.Path)
 	}
-	return ErrorPage(ctxt, err)
+	return c.String(http.StatusNotFound, err.Error())
 }
 
 /* AmProcessUploadedImage takes an image and resizes it to a specified size, returning its data.

ui/middleware.go

@@ -12,8 +12,10 @@ package ui
 
 import (
 	"errors"
+	"fmt"
 	"net/http"
 	"net/url"
+	"strconv"
 
 	"git.erbosoft.com/amy/amsterdam/config"
 	"git.erbosoft.com/amy/amsterdam/database"
@@ -119,6 +121,7 @@ func ValidateConference(next echo.HandlerFunc) echo.HandlerFunc {
 	}
 }
 
+// SetConference is middleware that sets the conference context based on the URL.
 func SetConference(next echo.HandlerFunc) echo.HandlerFunc {
 	return func(c echo.Context) error {
 		ctxt := AmContextFromEchoContext(c)
@@ -140,3 +143,22 @@ func SetConference(next echo.HandlerFunc) echo.HandlerFunc {
 		return next(c)
 	}
 }
+
+// SetTopic is middleware that sets the topic context based on the URL.
+func SetTopic(next echo.HandlerFunc) echo.HandlerFunc {
+	return func(c echo.Context) error {
+		ctxt := AmContextFromEchoContext(c)
+		conf := ctxt.GetScratch("currentConference").(*database.Conference)
+
+		var topic *database.Topic = nil
+		if rawTopic, err := strconv.ParseInt(ctxt.URLParam("topic"), 10, 16); err == nil {
+			topic, err = database.AmGetTopicByNumber(ctxt.Ctx(), conf, int16(rawTopic))
+		}
+		if topic == nil {
+			ctxt.SetRC(http.StatusNotFound)
+			return middlewareErrorPage(c, ctxt, fmt.Errorf("topic not found: %s", ctxt.URLParam("topic")))
+		}
+		ctxt.SetScratch("currentTopic", topic)
+		return next(c)
+	}
+}