media,web: add support for fallback avatars

cmd/gomuks/media.go

@@ -113,6 +113,46 @@ func (new *noErrorWriter) Write(p []byte) (n int, err error) {
 	return
 }
 
+// note: this should stay in sync with makeAvatarFallback in web/src/api/media.ts
+const fallbackAvatarTemplate = `<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1000 1000">
+  <circle cx="500" cy="500" r="500" fill="%s"/>
+  <text x="500" y="750" text-anchor="middle" fill="#fff" font-weight="bold" font-size="666"
+    font-family="-apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif"
+  >%s</text>
+</svg>`
+
+type avatarResponseWriter struct {
+	http.ResponseWriter
+	bgColor   string
+	character string
+	data      []byte
+	errored   bool
+}
+
+func (w *avatarResponseWriter) WriteHeader(statusCode int) {
+	if statusCode != http.StatusOK {
+		w.data = []byte(fmt.Sprintf(fallbackAvatarTemplate, w.bgColor, w.character))
+		w.Header().Set("Content-Type", "image/svg+xml")
+		w.Header().Set("Content-Length", strconv.Itoa(len(w.data)))
+		w.Header().Del("Content-Disposition")
+		w.errored = true
+		statusCode = http.StatusOK
+	}
+	w.ResponseWriter.WriteHeader(statusCode)
+}
+
+func (w *avatarResponseWriter) Write(p []byte) (n int, err error) {
+	if w.errored {
+		if w.data != nil {
+			_, err = w.ResponseWriter.Write(w.data)
+			w.data = nil
+		}
+		n = len(p)
+		return
+	}
+	return w.ResponseWriter.Write(p)
+}
+
 func (gmx *Gomuks) DownloadMedia(w http.ResponseWriter, r *http.Request) {
 	mxc := id.ContentURI{
 		Homeserver: r.PathValue("server"),
@@ -123,6 +163,18 @@ func (gmx *Gomuks) DownloadMedia(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	query := r.URL.Query()
+	fallback := query.Get("fallback")
+	if fallback != "" {
+		fallbackParts := strings.Split(fallback, ":")
+		if len(fallbackParts) == 2 {
+			w = &avatarResponseWriter{
+				ResponseWriter: w,
+				bgColor:        fallbackParts[0],
+				character:      fallbackParts[1],
+			}
+		}
+	}
+
 	encrypted, _ := strconv.ParseBool(query.Get("encrypted"))
 
 	logVal := zerolog.Ctx(r.Context()).With().

web/src/api/media.ts

@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU Affero General Public License
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 import { parseMXC } from "@/util/validation.ts"
-import { UserID } from "./types"
+import { MemberEventContent, UserID } from "./types"
 
 export const getMediaURL = (mxc?: string, encrypted: boolean = false): string | undefined => {
 	const [server, mediaID] = parseMXC(mxc)
@@ -28,12 +28,31 @@ export const getEncryptedMediaURL = (mxc?: string): string | undefined => {
 	return getMediaURL(mxc, true)
 }
 
-export const getAvatarURL = (_userID: UserID, mxc?: string): string | undefined => {
+const fallbackColors = [
-	const [server, mediaID] = parseMXC(mxc)
+	"#a4041d", "#9b2200", "#803f00", "#005f00",
+	"#005c45", "#00548c", "#064ab1", "#5d26cd",
+	"#822198", "#9f0850",
+]
+
+// note: this should stay in sync with fallbackAvatarTemplate in cmd/gomuks.media.go
+function makeFallbackAvatar(backgroundColor: string, fallbackCharacter: string): string {
+	return "data:image/svg+xml," + encodeURIComponent(`<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1000 1000">
+  <circle cx="500" cy="500" r="500" fill="${backgroundColor}"/>
+  <text x="500" y="750" text-anchor="middle" fill="#fff" font-weight="bold" font-size="666"
+    font-family="-apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif"
+  >${fallbackCharacter}</text>
+</svg>`)
+
+}
+
+export const getAvatarURL = (userID: UserID, content?: Partial<MemberEventContent>): string | undefined => {
+	const fallbackCharacter = (content?.displayname?.[0]?.toUpperCase() ?? userID[1].toUpperCase()).toWellFormed()
+	const charCodeSum = userID.split("").reduce((acc, char) => acc + char.charCodeAt(0), 0)
+	const backgroundColor = fallbackColors[charCodeSum % fallbackColors.length]
+	const [server, mediaID] = parseMXC(content?.avatar_url)
 	if (!mediaID) {
-		return undefined
+		return makeFallbackAvatar(backgroundColor, fallbackCharacter)
-		// return `_gomuks/avatar/${encodeURIComponent(userID)}`
 	}
-	return `_gomuks/media/${server}/${mediaID}`
+	const fallback = `${backgroundColor}:${fallbackCharacter}`
-	// return `_gomuks/avatar/${encodeURIComponent(userID)}/${server}/${mediaID}`
+	return `_gomuks/media/${server}/${mediaID}?encrypted=false&fallback=${encodeURIComponent(fallback)}`
 }

web/src/api/statestore/main.ts

@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU Affero General Public License
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 import unhomoglyph from "unhomoglyph"
-import { getMediaURL } from "@/api/media.ts"
+import { getAvatarURL } from "@/api/media.ts"
 import { NonNullCachedEventDispatcher } from "@/util/eventdispatcher.ts"
 import { focused } from "@/util/focus.ts"
 import type {
@@ -26,11 +26,13 @@ import type {
 	SendCompleteData,
 	SyncCompleteData,
 	SyncRoom,
+	UserID,
 } from "../types"
 import { RoomStateStore } from "./room.ts"
 
 export interface RoomListEntry {
 	room_id: RoomID
+	dm_user_id?: UserID
 	sorting_timestamp: number
 	preview_event?: MemDBEvent
 	preview_sender?: MemDBEvent
@@ -97,6 +99,8 @@ export class StateStore {
 		const name = entry.meta.name ?? "Unnamed room"
 		return {
 			room_id: entry.meta.room_id,
+			dm_user_id: entry.meta.lazy_load_summary?.heroes?.length === 1
+				? entry.meta.lazy_load_summary.heroes[0] : undefined,
 			sorting_timestamp: entry.meta.sorting_timestamp,
 			preview_event,
 			preview_sender,
@@ -183,7 +187,7 @@ export class StateStore {
 			body = body.slice(0, 350) + " […]"
 		}
 		const memberEvt = room.getStateEvent("m.room.member", evt.sender)
-		const icon = `${getMediaURL(memberEvt?.content.avatar_url)}&image_auth=${this.imageAuthToken}`
+		const icon = `${getAvatarURL(evt.sender, memberEvt?.content)}&image_auth=${this.imageAuthToken}`
 		const roomName = room.meta.current.name ?? "Unnamed room"
 		const senderName = memberEvt?.content.displayname ?? evt.sender
 		const title = senderName === roomName ? senderName : `${senderName} (${roomName})`

web/src/ui/roomlist/Entry.tsx

@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU Affero General Public License
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 import { memo, use, useLayoutEffect, useRef, useState } from "react"
-import { getMediaURL } from "@/api/media.ts"
+import { getAvatarURL } from "@/api/media.ts"
 import type { RoomListEntry } from "@/api/statestore"
 import type { MemDBEvent, MemberEventContent } from "@/api/types"
 import { ClientContext } from "../ClientContext.ts"
@@ -54,7 +54,12 @@ const EntryInner = ({ room }: InnerProps) => {
 	const [previewText, croppedPreviewText] = usePreviewText(room.preview_event, room.preview_sender)
 	return <>
 		<div className="room-entry-left">
-			<img loading="lazy" className="avatar room-avatar" src={getMediaURL(room.avatar)} alt=""/>
+			<img
+				loading="lazy"
+				className="avatar room-avatar"
+				src={getAvatarURL(room.dm_user_id ?? room.room_id, { avatar_url: room.avatar, displayname: room.name })}
+				alt=""
+			/>
 		</div>
 		<div className="room-entry-right">
 			<div className="room-name">{room.name}</div>

web/src/ui/timeline/ReplyBody.tsx

@@ -78,7 +78,7 @@ export const ReplyBody = ({ room, event, onClose, isThread }: ReplyBodyProps) =>
 				<img
 					className="small avatar"
 					loading="lazy"
-					src={getAvatarURL(event.sender, memberEvtContent?.avatar_url)}
+					src={getAvatarURL(event.sender, memberEvtContent)}
 					alt=""
 				/>
 			</div>

web/src/ui/timeline/TimelineEvent.tsx

@@ -98,7 +98,7 @@ const TimelineEvent = ({ room, evt, prevEvt, setReplyToRef }: TimelineEventProps
 			<img
 				className={`${smallAvatar ? "small" : ""} avatar`}
 				loading="lazy"
-				src={getAvatarURL(evt.sender, memberEvtContent?.avatar_url)}
+				src={getAvatarURL(evt.sender, memberEvtContent)}
 				onClick={use(LightboxContext)!}
 				alt=""
 			/>

web/src/ui/timeline/content/MemberBody.tsx

@@ -25,7 +25,7 @@ function useChangeDescription(
 	const targetAvatar = <img
 		className="small avatar"
 		loading="lazy"
-		src={getAvatarURL(target, content?.avatar_url)}
+		src={getAvatarURL(target, content)}
 		onClick={use(LightboxContext)!}
 		alt=""
 	/>
@@ -50,7 +50,7 @@ function useChangeDescription(
 					className="small avatar"
 					loading="lazy"
 					height={16}
-					src={getAvatarURL(target, prevContent?.avatar_url)}
+					src={getAvatarURL(target, prevContent)}
 					onClick={use(LightboxContext)!}
 					alt=""
 				/> to {targetAvatar}

web/tsconfig.json

@@ -1,9 +1,9 @@
 {
 	"compilerOptions": {
-		"target": "ES2023",
+		"target": "ESNext",
 		"useDefineForClassFields": true,
 		"lib": [
-			"ES2023",
+			"ESNext",
 			"DOM",
 			"DOM.Iterable"
 		],