Getstream.io Querying Channels - Without SDK UI dependency - iOS

ChannelQueryLogic.swift

     func getChannelList() {
        // Define demo search keyword for testing
        let searchKeyword = "rand"
            
        // Declare datastore to store list of channels
        var channelsList: [ChatChannel]?
                    
        //  Query list of channels and conversation as per search keyword
        /// NOTE: This query is optimized to search for groups which match only name instead of group member's name [JIRA Issue- CHAT-65]
        let query = ChannelListQuery(filter: .or([.and([.autocomplete(.memberName, text: searchKeyword),
                                                        .containMembers(userIds: [currentUserId]), .nonEmpty, .lessOrEqual(.memberCount, than: 2)]),
            .and([.autocomplete(.name, text: searchKeyword), .containMembers(userIds: [currentUserId]),
                  .nonEmpty])]))

        // ChannelListController is only used for querying Stream Chat backend - NO SDK UI level dependency is required
        let listQueryController = ChatClient.shared?.channelListController(query: query, filter: { channel in
            if let name = channel.name {
                return name.hasPrefix(searchKeyword)
            }
            return channel.name == nil && channel.membership != nil
        })
            
        // trigger the query
        listQueryController?.synchronize { error in
            // handle error if any
            guard error == nil else {
                print(error.debugDescription)
                return
            }
            /// store list of channels in `channelsList` data store
            channelsList = listQueryController?.channels.map { $0 }
                        
            guard channelsList?.count ?? 0 > 0 else {
                print("No channel or conversation exist")
                return
            }
                        
            // print channel names which are  matched by search keyword for demo purpose
            /// NOTE:- In case of channel name is nil / empty it means it's a conversation channel .
            /// So for Conversation channel we have to find the member name from channel object to define channel name
            channelsList?.forEach {
                if let name = $0.name { // i.e Channel
                    print("./" + name)
                } else { // i.e Conversation
                    // find member name with Search keyword to display channel name
                    let members = $0.lastActiveMembers
                    let matchMember = members.first { obj in
                        obj.name?.contains(searchKeyword) ?? false
                    }
                    print("./" + (matchMember?.name ?? "Unknown User"))
                }
                            
                // Show last conversation for demo purpose
                let conversation = $0.latestMessages
                let lastConversation = conversation.last
                let author = lastConversation?.author
                if author?.id == ChatClient.shared?.currentUserId {
                    print("./" + "You: " + (lastConversation?.text ?? ""))
                } else {
                    if let authorName = author?.name {
                        print("./" + authorName + ": " + (lastConversation?.text ?? ""))
                    }
                }
            }
        }
    }