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Cinan Rakosnik authored on 25/03/2013 at 00:25:16Showing 1 changed files
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+layout: post |
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+title: "XMPP4R: Get client's complete roster the right way" |
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+date: 2013-03-25 00:28 |
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+comments: true |
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+categories: [] |
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+cover: /images/cover/avatar.png |
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+keywords: |
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+description: |
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+--- |
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+ |
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+Connect to Jabber. With [XMPP4R](http://home.gna.org/xmpp4r/), a library for |
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+Ruby, it is possible, but not as easy as you could think. |
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+ |
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+*One could ask "Why don't you use |
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+[xmpp4r-simple?](http://xmpp4r-simple.rubyforge.org/)". My answer: "I'm not a |
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+pussy!".* |
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+ |
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+There are many little bastards you should know before fetching client's |
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+roster with contacts' vcard (nickname, full name, avatar, ...), status (online, |
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+away, ...) or status message. This is how I do this task. It works flawlessly. |
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+ |
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+This is simplified code I use in my chat application. Reading comments might be |
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+helpful. |
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+ |
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+{% codeblock lang:ruby %}
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+# Enable to see requests and responses between your machine and your jabber |
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+# server (easy to read XML). Recommended. |
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+Jabber::debug = true |
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+ |
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+# first, sign in to your jabber account with your Jabber ID and password |
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+client = Jabber::Client.new("someuser@somejabberserver.tld")
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+client.connect() |
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+client.auth("my password")
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+ |
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+# now we are authenticated, let's fetch roster with all information we want |
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+ |
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+# initialize roster |
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+roster = Jabber::Roster::Helper.new(client) |
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+ |
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+# request roster from jabber server, wait for response |
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+roster.get_roster() |
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+roster.wait_for_roster() |
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+ |
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+# now we know your friends' Jabber Ids |
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+roster.items.each do |jid, contact| |
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+ puts "In roster I have: " + jid |
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+end |
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+ |
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+# we don't know their status and status message, let's do it |
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+ |
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+# First, add presence callback. If anyone in roster change his/her state |
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+# (e.g. come online), you will know it. |
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+roster.add_presence_callback do |roster_item, old_presence, new_presence| |
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+ puts "Somebody changed his/her state to " + new_presence.status.to_s |
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+ # new_presence also offers status message and other stuff |
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+end |
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+ |
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+# To start receiving presence messages from your jabber server, you have to |
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+# send your presence first. It's really important to send your presence |
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+# AFTER roster.add_presence_callback, because the callback will not catch |
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+# every presence message which your jabber server sent to you. |
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+client.send(Jabber::Presence.new.set_type(:available)) |
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+ |
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+# Now you know who is online in your roster. If somebody from your |
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+# roster won't be caught in roster.add_presence_callback block, then |
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+# it just means he/she is offline. |
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+ |
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+# get vcard |
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+ |
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+roster.items.each do |jid, contact| |
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+ # According to documentation, fetching vcard can take longer time. |
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+ # Use threads if you think it is a good idea. |
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+ Thread.new do |
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+ vcard = Jabber::Vcard::Helper.get(client, jid) |
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+ nickname = vcard && vcard["FN"] || '' |
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+ #get avatar or other information here |
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+ end |
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+end |
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+{% endcodeblock %}
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+ |
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+What I've learned from using XMPP4R library in my project -- callbacks are good |
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+thing and use them. |