Archive for Ruby
Juli 8, 2010 at 12:27 pm · Filed under AWS, Ruby
Building on this article here is a simple ruby script, that copies files between two buckets of the same S3 account, omitting files already present (by name).
This variant adds a list of path prefixes, so you can selectively copy only certain directories of your buckets.
Furthermore it copies the original buckets ACLs for each key.
require 'rubygems'
require 'right_aws'
aws_access_key_id = 'YOUR AMAZON ACCESS KEY'
aws_secret_access_key = 'YOUR AMAZON SECRET ACCESS KEY'
source_bucket = 'SOURCE BUCKET NAME'
target_bucket = 'TARGET BUCKET NAME'
prefixes = [PATH_PREFIX1, PATH_PREFIX2, ...]
s3 = RightAws::S3Interface.new(aws_access_key_id, aws_secret_access_key)
copied_keys = Array.new
(prefixes || ['']).each do |prefix|
s3.incrementally_list_bucket(target_bucket, {:prefix => prefix}) do |key_set|
copied_keys << key_set[:contents].map{|k| k[:key]}.flatten
end
end
copied_keys.flatten!
(prefixes || ['']).each do |prefix|
s3.incrementally_list_bucket(source_bucket, {:prefix => prefix}) do |key_set|
key_set[:contents].each do |key|
key = key[:key]
if copied_keys.include?(key)
puts "#{target_bucket} #{key} already exists. Skipping..."
else
puts "Copying #{source_bucket} #{key}, setting acl"
retries=0
begin
s3.copy(source_bucket, key, target_bucket)
acl = s3.get_acl(source_bucket, key)
s3.put_acl(target_bucket, key, acl[:object])
rescue Exception => e
puts "cannot copy key, #{e.inspect}\nretrying #{retries} out of 10 times..."
retries += 1
retry if retries <= 10
end
end
end
end
end
Oktober 18, 2009 at 5:46 pm · Filed under Allgemein, MacOSX, Note to self, Ruby
Suche nach Wort unter dem Cursor in vim: #.
jssh ist eine JavaScript Shell, die den Firefox per Port 9997 fernsteuerbar macht.
Download z.B. hier.
y erzeugt einen YAML dump auf der Rails console, mehr dazu hier.
=3D ist ein escaptes “=” in quoted_printable.
sudo /usr/libexec/locate.updatedb aktualisiert unter MacOSX sofort die locate Datenbank.
rake db:migrate:redo führt unter rails die letzte Migration rückwärts und sofort wieder vorwärts aus, so dass sich die Vorwärts-Action korrigieren läßt
ack -Q bringt ack dazu, literal, also ohne RegExp zu suchen.
Mai 15, 2009 at 7:25 pm · Filed under PHP, Ruby
Laut PHP-Doku ist das Verhalten der Pseudo-Variablen $this wie folgt:
$this is a reference to the calling object (usually the object to which the method belongs, but can be another object, if the method is called statically from the context of a secondary object).
Schauen wir uns folgendes Beispiel an:
class A{
function __construct(){
$this->name = 'A';
}
function echoThisName(){
echo "My Name is {$this->name}.\n";
}
}
Jetzt rufen wir die Methode mal als Instanzmethode und mal statisch auf:
$a = new A();
$a->echoThisName();
A::echoThisName();
My Name is A.
PHP Fatal error: Using $this when not in object context in
/Users/aljoscha/test.php on line 9
Fatal error: Using $this when not in object context in
/Users/aljoscha/test.php on line 9
Das ist vernünftig. (ausser: Warum muss sich PHP eigentlich immer wiederholen? Ist eine Fehlermeldung zu subtil?)
Jetzt rufen wird diese Methoden aus einer anderen Klasse
B heraus auf:
class B{
function __construct(){
$this->name = 'B';
}
function echoAsName(){
$a = new A();
$a->echoThisName();
A::echoThisName();
}
}
$b = new B();
$b->echoAsName();
Und das gibt:
My Name is A.
My Name is B.
Wir haben die Methode
echoThisName der Klasse
A statisch aufgerufen, aber
$this ist darin trotzdem gesetzt, und zwar als wären wir in der Instanz
$b der Klasse
B.
$b hat sich die statische Methode gekapert.
Was sagt Ruby dazu?
class A
def initialize
@name = 'A';
end
def echoThisName
puts "My Name is #{@name}.\n";
end
end
$a = A.new;
$a.echoThisName;
A::echoThisName;
ergibt:
My Name is A.
test.rb:13: undefined method `echoThisName' for A:Class (NoMethodError)
Rufen wir
A::echoThisName aus einer Instanz von
B auf:
class B
def initialize
@name = 'B';
end
def echoAsName
$a = A.new;
$a.echoThisName;
A::echoThisName;
end
end
$b = B.new;
$b.echoAsName;
Ist das Ergebnis entsprechend:
My Name is A.
test.rb:23:in `echoAsName': undefined method `echoThisName'
for A:Class (NoMethodError) from test.rb:28
Besser.
Dank an Stephan für den Hinweis auf die Dokumentation des Verhaltens in PHP.
Oktober 14, 2006 at 1:42 pm · Filed under Javascript, Prototype, Ruby
The following article describes ticket #3592 in the RoR Trac and explains a proposed solution.
Prototypes Enumerable mixin class does not properly respect the mixees internal format. For example the reject and findAll methods, operating on Hashes, return Arrays instead of Hashes.
var a = $H({a:1, b:2, c:1, d:3});
document.writeln(a.inspect().escapeHTML());
=>#<Hash:{'a': 1, 'b': 2, 'c': 1, 'd': 3}>
var b = a.reject(function(val){ return (val[1]==1) });
document.writeln(b.inspect().escapeHTML());
=> [['b', 2], ['d', 3]] // !!! should be hash
var c = b.findAll(function(val){ return (val[0]=='d') });
document.writeln(c.inspect().escapeHTML());
=> [['b', 2], ['d', 3]] // !!! should be hash
In Ruby (from which the inspiration for the Enumerable Mixin stems), the reject method does return a hash, not an array, when operating on an hash:
irb(main):001:0> a={:a => 1, :b => 2, :c => 1, :d => 3}
=> {:b=>2, :c=>1, :a=>1, :d=>3}
irb(main):002:0> b=a.reject{|k,v| v==1}
=> {:b=>2, :d=>3}
The patch requires all classes that want to mixin Enumerable to define two more methods similar to
_each:
_new, which returns an empty object of that class and
_add, that adds an element. Enumerable mixin thus needs to make no more assumptions about the internal structure of its mixee class.
After the fix the methods return correctly:
=> #<Hash:{'b': 2, 'd': 3}>
