Bloggitation

Outside access to the GAE-powered XMPP bots

2009-09-10T05:52:16Z

Origin: Enabling chat outside Google Apps

To use XMPP bots, deployed on Google AppEngine (thanks to the new AppEngine SDK 1.2.5) from non-Google XMPP accounts (jabber.org etc.), in the DNS records for your domain (example.com) add:

_xmpp-server._tcp.example.com. IN SRV 5 0 5269 xmpp-server.l.google.com.
_xmpp-server._tcp.example.com. IN SRV 20 0 5269 xmpp-server1.l.google.com.
_jabber._tcp.example.com. IN SRV 5 0 5269 xmpp-server.l.google.com.
_jabber._tcp.example.com. IN SRV 20 0 5269 xmpp-server1.l.google.com.

Atom Entries Generator

2009-08-20T03:27:12Z

Recently there are a lot of tools to test the receiving part of your webhooks. I’m personally using http://www.postbin.org/ for my tests. I couldn’t find however a good way to “feed” my webhooks with a constant stream of fresh entries. There is a Superfeedr Simpulator, but it’s to much bound to their service. I needed a more general solution, so I created AtomGen - Infinite Atom Entries Generator.

The application providing two feeds. First one generating Atom entries every minute and the second one - every 5 minutes. The one minute feed is protected by a secret token in the end of the URL.
If your application is installed for example on URL http://example.com/ , the two feeds will be:

http://example.com/feed/1/YouSecretHere    (1min feed)
http://example.com/feed/5                  (5min feed)

The application is currently deployed on Google AppEngine. You can use the 5 minutes feed for your tests - go to
http://pubsubhubbub.appspot.com/subscribe and subscribe for the http://atomgen.appspot.com/feed/5 topic. This will send to your subscribers a new valid Atom entry every 5 minutes.

There is also a FriendFeed group, which is already subscribed to the 5 minutes feed. You can use it to gen notifications via IM etc.

The feeds have atom:link[@rel="hub"] element and the 5 minutes feed is pinging the hub on feed generation. By default the Google’s reference implementation is used.

I tried to make the atom generator a good Internet cityzen by setting up the proper HTTP headers (‘Last-Modified’, ‘ETag’ etc.). ‘Etag’ header contains the ID of the last entry, cryptography signed, like suggested in
http://code.google.com/p/pubsubhubbub/wiki/PublisherEfficiency

The current implementation does not use Google Datastore. Feeds are kept only in the memcached object caching system.

Google Wave Federation Protocol with Prosody XMPP server

2009-07-30T02:42:25Z

To be “on the wave” I’ve done some experiments with Google Wave Federation Protocol. Other people already made it working with OpenFire (and another OpenFire install) and ejabberd, so I decided to try with Prosody - very easy to install Lua-based XMPP server, I’m enjoing recently. From version 0.4.0 Prosody have support for external components. My experiments was with the current (0.5.0) version.

Like always in the beginning RTFM - “Components in Prosody”. For the Wave protocol - no differences from the other manuals - create fedone war, generate certificates, corect the run-server.sh script etc.

For the Prosody XMPP server (/etc/prosody/prosody.cfg.lua):

Host "*"
    ...
    -- External components
    component_ports = { 5275 }
    component_interface = "0.0.0.0"
    ...

-- Google Wave experiments
Component "wave.example.com"
    component_secret = "some_secret"

Restart the Prosody server and execute the run-server.sh (be sure the secret in the Prosody config file and in the run script are the same).

Done. Enjoy.

WebHooks on AppJet

2009-02-23T03:01:54Z

Hi everybody,
I created a small lib-webhook library and a small companion hooks application for easy working with webhooks on AppJet. Like maybe you know, webhooks are one of the current hot topics. They are a very easy way to implement a real-time communications between remote applications.

What you can use it for:

Notify your AppJet based application about changes (commits etc.) in your GitHub repository - have for example ChangeLog + user notifications to some ML:
Just go to GitHub Admin|Hooks page and if the already defined hooks are not enough put http://youhooks.appjet.net/github/SomeSecret/ there.
Post to your AppJet based application by Jabber (XMPP) or from an iPhone:
go to https://ping.fm/custom/ and enter http://youhooks.appjet/pingfm/SomeSecret/ . ping.fm have a XMPP bot and an iPhone application which you can use.
Post to your AppJet application by email:
http://www.smtp2web.com/ , define some email address and point the URL to http://youhooks.appjet.net/something/SomeSecret/. In fact I’m first pointing it to one small application on GAE itself, because parsing multipart/rfc-822 coded message parameter will be difficult on AppJet. So I’m parsing it with message.get_payload() and repacking it in JSON payload. After this it can be send to AppJet.
Posting to XMPP from AppJet - it still missing on AppJet, so I have a small Heroku-hosted Sinatra application to implement this feature. So http://youhooks.appjet.net/xmpp/SomeSecret/ will in turn call that Sinatra application. If you do not trust me with your XMPP information, just create your own application somewhere, where XMPP is possible and call it with a webhooks API (your_url, JSON(payload),JSON(data)).

How to use lib-webhook and hooks application:

Clone the hooks application to (for example) http://youhooks.appjet.net/

Set your secret token - it will be added to the end of the URLs:

  // from the shell
  import ("storage", "lib-webhook");
  storage.token = "SomeSecret";

Define users for the hooks, that needed them. I need for example user/password for the XMPP hook and user/key for the http://bit.ly/ URL shortening service. In this way they will be not visible in your application sources.
```
// from the shell
HOOK.addUser("xmpp", {user:"...", password:"..."});
```
In the moment my hooks application just inserting the user’s data with the same name as the hook, if such user exists:
```
data = HOOK.addUserData(data, hook);
```

The library itself provide two main functions:

// universal caller - remote or local hooks:
string callH(url, JSON(payload), JSON(data));
// call local hooks by name
string callLocalH(name, payload, data);

The rest are just some small helpers for user’s data management.

I’ll be very happy to see clones of hooks application with some interesting webhooks (http://pbwiki.com/ for example also supporting webhooks. and by the way PayPal also wink ). And about lib-webhook - will add twitter, identi.ca and maybe some others local hooks ASAP.

Let’s the source be with you.

Ruby Sinatra: uninitialized constant Rack::File::MIME_TYPES

2009-01-27T08:44:59Z

Original: rack newb problem w/ 0.9.0

When tried to run a sinatra based application, I received an error message:

./sinatra/lib/sinatra.rb:1156:in `mime': uninitialized constant Rack::File::MIME_TYPES (NameError)

According to Ryan Tomayko “…MIME_TYPES constant got shuffled around in this release (rack release)…”.
The solution (temporary) is to define Rack::File::MIME_TYPES by yourself before requiring sinatra:

require 'rack/file'
class Rack::File
   MIME_TYPES = Hash.new { |hash, key|
   Rack::Mime::MIME_TYPES[".#{key}"] }
end
require 'sinatra'
...

Subscribe to this blog via XMPP (Jabber)

2009-01-09T09:04:09Z

If you have http://notifixio.us/ account, you can receive notifications, for articles, posted to this blog via email, XMPP etc. I installed Notifixious Plugin (see the sidebar, Notifixio.us section). Need JavaScript enabled.

How to use Archlinux Pacman?

2008-11-07T03:48:25Z

Packages installation:

pacman -Sy package_name - packages installation and local packages db sync
pacman -S package_name - packages installation along with dependencies
pacman -Sl repository_name - display packages list of a given repository
pacman -Sv package_name - information about operation

Removing packages:

pacman -R package_name - removing package without dependencies
pacman -Rs package_name - removing package along with dependencies
pacman -Rn package_name - purging package

System update:

pacman -Su - update all the packages
pacman -Syu - update all the packages and synchronize local packages database

Database queries:

pacman -Ss keyword - search for all packages matching the keyword
                               (where the keyword is a part of the package name)
pacman -Qi package_name - information about package
pacman -Ql package_name - list files that a given package consist of
pacman -Qs package_name - search files installed on hard disk

Other commands:

pacman -Sw package_name - download package without installation
pacman -A /file/path/file.tar - install package
pacman -Sc - clean cache (old files)
pacman -Scc - clean cache (all files)

Original article

GMail backup

2008-10-09T05:49:38Z

After the rumors about locked GMail accounts, decided to backup my important emails. The article How to back up your Gmail on Linux in four easy steps helped me a lot. My setting in ~/.getmail/getmail.gmail are (IMAP, Maildir):
[retriever] type = SimpleIMAPSSLRetriever server = imap.gmail.com username = my_name password = my_secret mailboxes = (”personal”,”important”)


[destination]

type = Maildir

path = ~/gmail-archive/

[options] verbose = 2 message_log = ~/.getmail/gmail.log
The backup itself was done via:
$ getmail -r ~/.getmail/getmail.gmail

github error: failed to push some refs

2008-09-29T02:21:07Z

When trying to push to github received:

$ git push
To git@github.com:zh/laconica.git
 ! [rejected]        master -> master (non-fast forward)
error: failed to push some refs to 'git@github.com:zh/laconica.git'

The solution

$ git pull
....
$ git push

Install merb from git

2008-09-16T03:10:21Z

Trying to install the development version of merb , i’ve got:

no such file to load -- extlib/tasks/release

Seems the extlib gem is too old for merb. Fix:

$ git clone git://github.com/sam/extlib.git
$ cd extlib
$ rake gem
$ sudo gem install pkg/extlib-0.9.4.gem

The rest of installation process:

$ sudo gem install sake erubis mime-types
$ sake -i http://merbivore.com/merb-dev.sake
$ mkdir ~/merb_src && cd ~/merb_src
$ sake merb:clone
$ sake merb:install:all

Your first application:

$ merb-gen app my_app --flat && cd my_app