Refactor feed subscription to use IQ stanzas and allow following any contact

src/main/java/eu/siacs/conversations/generator/IqGenerator.java

@@ -954,4 +954,24 @@ public class IqGenerator extends AbstractGenerator {
         retract.addChild("item").setAttribute("id", id);
         return packet;
     }
+
+    public Iq generateSubscriptionIq(final Jid to, final String node, final Jid from) {
+        final Iq iq = new Iq(Iq.Type.SET);
+        iq.setTo(to);
+        final Element pubsub = iq.addChild("pubsub", Namespace.PUBSUB);
+        final Element subscribe = pubsub.addChild("subscribe");
+        subscribe.setAttribute("node", node);
+        subscribe.setAttribute("jid", from.asBareJid().toString());
+        return iq;
+    }
+
+    public Iq generateUnsubscriptionIq(final Jid to, final String node, final Jid from) {
+        final Iq iq = new Iq(Iq.Type.SET);
+        iq.setTo(to);
+        final Element pubsub = iq.addChild("pubsub", Namespace.PUBSUB);
+        final Element unsubscribe = pubsub.addChild("unsubscribe");
+        unsubscribe.setAttribute("node", node);
+        unsubscribe.setAttribute("jid", from.asBareJid().toString());
+        return iq;
+    }
 }

src/main/java/eu/siacs/conversations/services/XmppConnectionService.java

@@ -8330,4 +8330,14 @@ public class XmppConnectionService extends Service {
             listener.onPostRetracted(postId);
         }
     }
+
+    public void subscribeTo(final Account account, final Jid to, final String node, final Consumer<Iq> callback) {
+        final Iq iq = getIqGenerator().generateSubscriptionIq(to, node, account.getJid());
+        sendIqPacket(account, iq, callback);
+    }
+
+    public void unsubscribeFrom(final Account account, final Jid to, final String node, final Consumer<Iq> callback) {
+        final Iq iq = getIqGenerator().generateUnsubscriptionIq(to, node, account.getJid());
+        sendIqPacket(account, iq, callback);
+    }
 }

src/main/java/eu/siacs/conversations/ui/ContactDetailsActivity.java

@@ -100,6 +100,8 @@ import eu.siacs.conversations.xmpp.Jid;
 import eu.siacs.conversations.xmpp.OnKeyStatusUpdated;
 import eu.siacs.conversations.xmpp.OnUpdateBlocklist;
 import eu.siacs.conversations.xmpp.XmppConnection;
+import im.conversations.android.xmpp.model.stanza.Iq;
+
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
@@ -185,8 +187,31 @@ public class ContactDetailsActivity extends OmemoActivity
     private final OnCheckedChangeListener mOnFollowFeedCheckedChange =
             (buttonView, isChecked) -> {
                 if (contact != null) {
-                    contact.setFollowed(isChecked);
-                    xmppConnectionService.updateContact(contact);
+                    if (isChecked) {
+                        xmppConnectionService.subscribeTo(contact.getAccount(), contact.getJid(), "urn:xmpp:microblog:0", packet -> {
+                            runOnUiThread(() -> {
+                                if (packet.getType() == Iq.Type.RESULT) {
+                                    contact.setFollowed(true);
+                                    xmppConnectionService.updateContact(contact);
+                                } else {
+                                    mFollowFeedSwitch.setChecked(false);
+                                    Toast.makeText(ContactDetailsActivity.this, R.string.error_subscribing_to_feed, Toast.LENGTH_SHORT).show();
+                                }
+                            });
+                        });
+                    } else {
+                        xmppConnectionService.unsubscribeFrom(contact.getAccount(), contact.getJid(), "urn:xmpp:microblog:0", packet -> {
+                            runOnUiThread(() -> {
+                                if (packet.getType() == Iq.Type.RESULT) {
+                                    contact.setFollowed(false);
+                                    xmppConnectionService.updateContact(contact);
+                                } else {
+                                    mFollowFeedSwitch.setChecked(true);
+                                    Toast.makeText(ContactDetailsActivity.this, R.string.error_unsubscribing_from_feed, Toast.LENGTH_SHORT).show();
+                                }
+                            });
+                        });
+                    }
                 }
             };
 

src/main/java/eu/siacs/conversations/ui/PostsActivity.java

@@ -246,7 +246,7 @@ public class PostsActivity extends XmppActivity implements XmppConnectionService
                 for (Contact contact : account.getRoster().getContacts()) {
                     if (contact.isFollowed()) {
                         sourcesToFetch.add(contact.getJid().asBareJid());
-                    } else if (contact.showInRoster() && (contact.resourceWhichSupport(Namespace.PUBSUB_SOCIAL_FEED) != null || contact.resourceWhichSupport("urn:xmpp:microblog:0") != null)) {
+                    } else if (contact.showInRoster()) {
                         mFollowSuggestions.add(contact);
                     }
                 }

src/main/java/eu/siacs/conversations/ui/adapter/FollowSuggestionAdapter.java

@@ -7,6 +7,7 @@ import android.view.ViewGroup;
 import android.widget.Button;
 import android.widget.ImageView;
 import android.widget.TextView;
+import android.widget.Toast;
 
 import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.RecyclerView;
@@ -14,10 +15,12 @@ import androidx.recyclerview.widget.RecyclerView;
 import java.util.List;
 
 import eu.siacs.conversations.R;
+import eu.siacs.conversations.entities.Account;
 import eu.siacs.conversations.entities.Contact;
 import eu.siacs.conversations.services.XmppConnectionService;
 import eu.siacs.conversations.ui.PostsActivity;
 import eu.siacs.conversations.ui.util.AvatarWorkerTask;
+import im.conversations.android.xmpp.model.stanza.Iq;
 
 public class FollowSuggestionAdapter extends RecyclerView.Adapter<FollowSuggestionAdapter.ViewHolder> {
 
@@ -45,11 +48,20 @@ public class FollowSuggestionAdapter extends RecyclerView.Adapter<FollowSuggesti
         AvatarWorkerTask.loadAvatar(contact, holder.mAvatar, R.dimen.feed_suggestions_avatar_size);
         holder.mAvatar.setOnClickListener(v -> mPostsActivity.switchToContactDetails(contact));
         holder.mFollowButton.setOnClickListener(v -> {
-            contact.setFollowed(true);
-            mXmppConnectionService.updateContact(contact);
-            mContacts.remove(contact);
-            notifyDataSetChanged();
-            mPostsActivity.loadPosts(); // Refresh posts to show new content
+            final Account account = contact.getAccount();
+            mXmppConnectionService.subscribeTo(account, contact.getJid(), "urn:xmpp:microblog:0", packet -> {
+                mPostsActivity.runOnUiThread(() -> {
+                    if (packet.getType() == Iq.Type.RESULT) {
+                        contact.setFollowed(true);
+                        mXmppConnectionService.updateContact(contact);
+                        mContacts.remove(contact);
+                        notifyDataSetChanged();
+                        mPostsActivity.loadPosts();
+                    } else {
+                        Toast.makeText(mPostsActivity, R.string.error_subscribing_to_feed, Toast.LENGTH_SHORT).show();
+                    }
+                });
+            });
         });
     }
 

src/main/res/values/strings.xml

@@ -1628,6 +1628,8 @@
     <string name="follow_suggestions">Suggestions</string>
     <string name="toggle_suggestions">Toggle suggestions</string>
     <string name="forward">Forward</string>
+    <string name="error_subscribing_to_feed">Could not subscribe to feed</string>
+    <string name="error_unsubscribing_from_feed">Could not unsubscribe from feed</string>
     <plurals name="publishing_to_x_contacts">
         <item quantity="one">Publishing to %d contact</item>
         <item quantity="other">Publishing to %d contacts</item>