hewiak
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vjrabauke asked: Wie geht's dir da drüben?

Es geht so. Mußte wieder irgend-so einen Job nehmen. Tschüs, Freizeit…

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I haven’t laughed this hard in a long time…excerpt from chapter 1 of Glenn Beck’s new novel “Agenda 21”

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Please proceed, Governor.

Please proceed, Governor.

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Hey, Sepp! This is a cool poster–maybe too cool; is the show going to be just crap?

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kimpoyfeliciano:

GET INVOLVED. STOP AT NOTHING. THE WORLD MUST KNOW.

I dare you to stop scrolling through your dashboard. Stop checking your Facebook newsfeed that you’ve already checked two seconds ago. Stop updating your Twitter and seeing what your favorite celebrities are saying. Stop watching funny and nonsense videos on Youtube. Take time to educate yourself to MAKE A DIFFERENCE in this world. This is your chance! WATCH THIS VIDEO.

Let’s make JOSEPH KONY Famous!!

Who is JOSEPH KONY?

He is THE WORST LIVING CRIMINAL. He abducts children and makes them use guns to kill their own parents. He takes girls and forces them to be sex slaves. He calls his abducted children the Lord’s Resistance Army, AKA the LRA. He has abducted over 30,000 children and forced them to be child soldiers in Central Africa. He remains at large because he is INVISIBLE to the world. FEW know his name, even FEWER know his crimes. WE ARE MAKING HIM FAMOUS! Because when he is, the world will unite against him and demand his arrest.

We can help make a change. We can make a difference.

I feel so inspired. I feel the need to help and make a difference. This has to happen in 2012. We can’t let him go around and keep doing this to children in Central Africa. Let’s make his name known so he can be stopped. HE CAN NO LONGER BE INVISIBLE!

REBLOG IF YOU CARE.

This will not make your blog ugly, please take a moment to reblog and get the word out. SHARE THIS TO EVERYONE! Be a part of something BIG and when they catch this man, you would be able to say.. “I HELPED.”

LET’S START HERE ON TUMBLR.

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Sorrow - Street Warfare

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The Diaspora Core Team Developer Blog

How Diaspora* Connects Users
How Diaspora* Connects Users avatar

by Sarah Mei on January 22, 2012

Note: this is the first of a series of technical posts about the Diaspora* software architecture. It was originally published in September 2011 on the Diaspora* Foundation blog, but the series will be continuing here. If you have topics you’d like to see in future installments, please comment.

A single installation of the Diaspora* software is called a pod. The Diaspora* distributed network is made up of hundreds of these pods, each with a set of users – sometimes just one on an individual pod, sometimes tens of thousands on a community pod. Each pod is run by a different person or organization. But no matter what pod you sign up on, you can connect with users on any other pod.

When you have friends on different pods, your stream seamlessly mixes updates from remote friends with updates from friends on your pod. In this way Diaspora* is a distributed social network that resembles, from the user’s perspective, a centralized social network.

Users from different pods interact seamlessly in posts and comments in the main stream

But how do these users find each other? In a centralized system, all servers access the same database, so when you search for a friend, there’s only one place to look. But in the Diaspora* ecosystem, each pod has its own database, inaccessible to the other pods. So how does pod A figure out who’s on pod B, or for that matter, pod C that’s never been heard from before?

It all starts with searching. Let’s say you’re setting up your own pod. Once you’ve downloaded the Diaspora* source and gotten it running on a server accessible to the internet, you open it up, log in…and are faced with the vast emptiness of splendid isolation.

Let’s get you some friends

There is no central server that keeps a list of existing pods or existing users. Instead, Diaspora* depends on an emerging-standard protocol called webfinger to discover users on remote pods. This all kicks off when you search for someone’s Diaspora* ID in your pod’s search box.

Aside: A Diaspora* ID is made up of a username, followed by an @ sign, followed by the pod url. It looks a lot like an email address. But just like with Jabber IDs which also look like email addresses, you can’t send email to it. It’s just a unique identifier within the Diaspora* ecosystem.

So you’ve talked to a friend who’s on a (fictional) pod called otherpod.com, and you’ve gotten her Diaspora* ID – sarah@otherpod.com. You want to connect, so you put sarah@otherpod.com into the search box on your pod and hit go. A few seconds later, you see her information on the search page with a nice “Add to Aspect” button alongside.

Magic!

I’d love to claim that, but sadly ponycorns are in short supply around here. Here’s how it goes down behind the scenes. A detailed explanation follows the diagram.

User discovery flowchart

When it gets a search request for a Diaspora* ID, the first thing your pod does is look in its local database to see if it already knows about this person. This is the grey diamond in the diagram. If it can skip all this drama and just show you the information, it does so. But because you’re on a brand new pod, the only user it knows about is you. So it prepares to retrieve the information you requested from the remote pod.

From here the process is:

1. Figure out where to search
2. Search
3. Retrieve detailed information
4. Cache data locally
5. Profit!

I suppose the last one is optional.

1. Find out where to search

Your pod extracts the pod URL from the Diaspora* ID (sarah@otherpod.com becomes otherpod.com) and appends a standard location called “the host-meta route” to get this URL:

http://otherpod.com/.well-known/host-meta

This route is part of the webfinger standard. It’s the basic way you ask a server whether or not it supports webfinger.

Your pod then accesses this location and gets back a piece of XML in a format called XRD. Basically, accessing the host-meta route is the same as asking the pod, “How should I send you inquiries about users?” The XRD document that it returns tells your pod how to construct the query for the particular user you’re interested in. Here’s what it looks like:

 <?xml version='1.0' encoding='UTF-8'?>
 <XRD xmlns='http://docs.oasis-open.org/ns/xri/xrd-1.0' xmlns:hm='http://host-meta.net/xrd/1.0'>
   <hm:Host>otherpod.com</hm:Host>
   <Link rel='lrdd' template='https://otherpod.com/webfinger?q={uri}'>
     <Title>Resource Descriptor</Title>
   </Link>
 </XRD>


The “template” on line 4 is the key. It tells your pod to query for the user by substituting their Diaspora* ID for {uri}. So to search for your friend, your pod needs to construct need a URL like this:

https://otherpod.com/webfinger?q=sarah@otherpod.com

Aside: All Diaspora* pods accept user queries at the same location, so this step might seem redundant. But Diaspora* pods also inter-operate with other, non-Diaspora* social systems, and those may have different locations for querying for a user. In other words, when we get a Diaspora* ID, we don’t actually know whether the pod is a Diaspora* pod or something else. So we ask for the search route each time.

2. Search

Having figured out the right way to ask, your pod now queries for the user it wants. It accesses the query URL:

https://otherpod.com/webfinger?q=sarah@otherpod.com

This returns us another piece of XML – another XRD document – that gives us some basic information about the user, but mostly just tells us where to go to find more detailed info. Here’s what it looks like:

  <?xml version="1.0" encoding="UTF-8"?>
  <XRD xmlns="http://docs.oasis-open.org/ns/xri/xrd-1.0">
    <Subject>acct:sarah@otherpod.com</Subject>
    <Alias>"https://otherpod.com/"</Alias>
    <Link rel="http://microformats.org/profile/hcard" type="text/html" href="https://otherpod.com/hcard/users/4cec1e372c174347b90000ad"/>
    <Link rel="http://otherpod.com/seed_location" type = 'text/html' href="https://otherpod.com/"/>
    <Link rel="http://otherpod.com/guid" type = 'text/html' href="4cec1e372c174347b90000ad"/>
    <Link rel='http://webfinger.net/rel/profile-page' type='text/html' href='https://otherpod.com/u/sarah'/>
    <Link rel="http://schemas.google.com/g/2010#updates-from" type="application/atom+xml" href="https://otherpod.com/public/sarah.atom"/>
    <Link rel="diaspora-public-key" type = 'RSA' href="[public key omitted for length]"/>
 </XRD>

Aside: The webfinger XRD document is supposed to be just links to information elsewhere. However, as you can see, Diaspora* embeds some actual information, such as the person’s public key, in the document. We implemented this before we fully understood how XRD was supposed to work. We should at some point move that information to the hcard (see next section).

3. Retrieve profile

To fill out profile details, the pod extracts the “hcard location” from the webfinger XRD document. An hcard is a standard, structured way to represent profile data in HTML. The hcard location is on line 5 of the document above, with URL:

https://otherpod.com/hcard/users/4cec1e372c174347b90000ad

Your pod accesses the hcard location, and gets back a piece of HTML with additional profile details for the remote user, such as name. Here’s an excerpt of that hcard – it’s quite long.

  <div id='content'>
    <h1>Sarah Mei</h1>
    <div id='content_inner'>
      <div class='entity_profile vcard author' id='i'>
        <h2>User profile</h2>
        <dl class='entity_nickname'>
          <dt>Nickname</dt>
          <dd>
            <a class='nickname url uid' href='https://otherpod.com/' rel='me'>Sarah Mei</a>
         </dd>
       </dl>


It goes on, but I think you get the idea.

4. Cache data locally

Finally, having searched for the user and then retrieved her hcard, your pod extracts the profile details and saves them in its local database. sarah@otherpod.com now shows up in searches you do on your pod.

5. Profit!

Once you start following your friend, you’ll get her updates as though she were a user local to your pod. If she also follows you, she’ll get your updates in her stream too. From there…who knows what could happen.

This walkthrough covered just searching and basic user discovery, which is a tiny part of how Diaspora* pods interoperate. Once you get into federation of posts and other content between pods, it’s a whole different ballgame. Stay tuned for that in an upcoming installment.