Profile pictures not loading for most WebID users after commit 2ae197c #29

Description

After commit 2ae197c ("Add inline avatar support for JSON-LD messages"), profile pictures stopped working for most WebID users in regular Solid chats.

User Report

From testpro in Solid Chat Global:

"I am logged in as testpro.solidweb.org, it shows 4 chats at the left including saved messages, I have scanned through all 4 chats, and the only 3 profile pics that show are yours, espenmartine and ewingson/solidcommunity"

"and angelo, all other just single letters"

"to be even more precise: either question mark, or single letter, or capitalized two letters one prename, one surname"

Expected Behavior

All users with foaf:img in their WebID profile should display their avatar.

Actual Behavior

• Only ~4 out of many users have working avatars
• All others show fallback: ?, single letter initials, or two-letter initials
• Affects solid-chat.com with regular Solid chats

Root Cause Analysis

The commit 2ae197c changed the avatar loading logic:

BEFORE:

async function fetchAvatar(webId, store, $rdf) {
  try {
    const doc = profile.doc()
    await store.fetcher.load(doc, ...)  // ALWAYS fetches
    let avatar = store.any(profile, FOAF('img'))?.value
    // ...
  } catch (e) { ... }
}

AFTER:

async function fetchAvatar(webId, store, $rdf) {
  // First check store
  let avatar = store.any(profile, FOAF('img'))?.value
  
  // Only fetch if not found AND http URI
  if (!avatar && webId.startsWith('http')) {
    await store.fetcher.load(doc, ...)
    avatar = store.any(profile, FOAF('img'))?.value
  }
}

Potential Issues

1. rdflib fetcher caching: When store.fetcher.load() is called for a document that was previously loaded (by login flow, solid-ui, or another pane), the fetcher may skip re-fetching. The previous load might not have included avatar data.

2. In-memory cache persistence: The avatarCache Map persists across SPA navigation. If a profile fetch fails once, the null is cached permanently.

3. Race condition: If something else partially loads a profile before fetchAvatar runs, the fetcher might think it's already loaded.

Possible Fixes

1. Add { force: true } option to store.fetcher.load() to bypass fetcher cache
2. Clear avatar cache on chat load
3. Revert to always calling store.fetcher.load() for http WebIDs, while still checking store first for non-http URIs (Matrix)

Environment

• solid-chat.com
• Users on various pod providers (solidweb.org, solidcommunity.net, etc.)

Related

• Commit: 2ae197c ("Add inline avatar support for JSON-LD messages")
• The change was intended to support Matrix-bridged messages with matrix: URIs