Do not try to (repeatedly) fetch profile pictures when not available

The server has a capability to indicate that profile pictures (avatars)
are not available. Previously, the client would try to fetch them no
matter what, and even retry when the server responded with a 404. Now
we take the server capability into account, and do not try to fetch
those when not available.

Fixes: #8758

src/gui/connectionvalidator.cpp

@@ -286,14 +286,24 @@ void ConnectionValidator::slotUserFetched(const QJsonDocument &json)
     if (!displayName.isEmpty()) {
         _account->setDavDisplayName(displayName);
     }
+
+    auto capabilities = _account->capabilities();
+    // We should have received the capabilities by now. Check that assumption in a debug build. If
+    // it's not the case, the code below will assume that they are not available.
+    Q_ASSERT(capabilities.isValid());
+
 #ifndef TOKEN_AUTH_ONLY
-    AvatarJob *job = new AvatarJob(_account, _account->davUser(), 128, this);
-    job->setTimeout(20 * 1000);
-    QObject::connect(job, &AvatarJob::avatarPixmap, this, &ConnectionValidator::slotAvatarImage);
-    job->start();
-#else
-    reportResult(Connected);
+    if (capabilities.isValid() && capabilities.avatarsAvailable()) {
+        AvatarJob *job = new AvatarJob(_account, _account->davUser(), 128, this);
+        job->setTimeout(20 * 1000);
+        QObject::connect(job, &AvatarJob::avatarPixmap, this, &ConnectionValidator::slotAvatarImage);
+        job->start();
+        // reportResult will be called when the avatar has been received by `slotAvatarImage`
+    } else
 #endif
+    {
+        reportResult(Connected);
+    }
 }
 
 #ifndef TOKEN_AUTH_ONLY

src/gui/shareusergroupwidget.cpp

@@ -465,9 +465,13 @@ void ShareUserLine::loadAvatar()
      * Currently only regular users can have avatars.
      */
     if (_share->getShareWith()->type() == Sharee::User) {
-        AvatarJob *job = new AvatarJob(_share->account(), _share->getShareWith()->shareWith(), avatarSize, this);
-        connect(job, &AvatarJob::avatarPixmap, this, &ShareUserLine::slotAvatarLoaded);
-        job->start();
+        auto account = _share->account();
+        auto capabilities = account->capabilities();
+        if (capabilities.isValid() && capabilities.avatarsAvailable()) {
+            AvatarJob *job = new AvatarJob(account, _share->getShareWith()->shareWith(), avatarSize, this);
+            connect(job, &AvatarJob::avatarPixmap, this, &ShareUserLine::slotAvatarLoaded);
+            job->start();
+        }
     }
 }
 

src/libsync/capabilities.cpp

@@ -222,6 +222,13 @@ bool Capabilities::versioningEnabled() const
     return _capabilities.value(QStringLiteral("files")).toMap().value(QStringLiteral("versioning")).toBool();
 }
 
+bool Capabilities::avatarsAvailable() const
+{
+    auto userCaps = _fileSharingCapabilities.value(QStringLiteral("user")).toMap();
+    // true by default for older servers, because turning off profile pictures was introduced in later versions
+    return userCaps.value(QStringLiteral("profile_picture"), true).toBool();
+}
+
 QStringList Capabilities::blacklistedFiles() const
 {
     return _capabilities.value(QStringLiteral("files")).toMap().value(QStringLiteral("blacklisted_files")).toStringList();
@@ -243,4 +250,5 @@ bool TusSupport::isValid() const
 {
     return !version.isNull();
 }
-}
+
+} // namespace OCC

src/libsync/capabilities.h

@@ -180,6 +180,9 @@ class OWNCLOUDSYNC_EXPORT Capabilities
     /** Is versioning available? */
     bool versioningEnabled() const;
 
+    /** Are avatars (profile pictures) available? */
+    bool avatarsAvailable() const;
+
 private:
     QVariantMap _capabilities;
     QVariantMap _fileSharingCapabilities;