Class: AWS::S3::Base

Inherits:
Object
  • Object
show all
Defined in:
lib/aws/s3/base.rb,
lib/aws/s3/response.rb

Overview

AWS::S3::Base is the abstract super class of all classes who make requests against S3, such as the built in Service, Bucket and S3Object classes. It provides methods for making requests, inferring or setting response classes, processing request options, and accessing attributes from S3’s response data.

Establishing a connection with the Base class is the entry point to using the library:

AWS::S3::Base.establish_connection!(:access_key_id => '...', :secret_access_key => '...')

The :access_key_id and :secret_access_key are the two required connection options. More details can be found in the docs for Connection::Management::ClassMethods.

Extensive examples can be found in the README.

Direct Known Subclasses

Bucket, S3Object, Service

Defined Under Namespace

Classes: RequestOptions, Response

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(attributes = {}) ⇒ Base

:nodoc:



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# File 'lib/aws/s3/base.rb', line 231

def initialize(attributes = {}) #:nodoc:
  @attributes = attributes
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method, *args, &block) ⇒ Object (private) 



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# File 'lib/aws/s3/base.rb', line 258

def method_missing(method, *args, &block)
  case
  when attributes.has_key?(method.to_s) 
    attributes[method.to_s]
  when attributes.has_key?(method)
    attributes[method]
  else 
    super
  end
end

Class Method Details

.current_bucket ⇒ Object 



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# File 'lib/aws/s3/base.rb', line 128

def current_bucket
  connection.subdomain or raise CurrentBucketNotSpecified.new(connection.http.address)
end

.current_host ⇒ Object

Called when a method which requires a bucket name is called without that bucket name specified. It will try to infer the current bucket by looking for it as the subdomain of the current connection’s address. If no subdomain is found, CurrentBucketNotSpecified will be raised.

MusicBucket.establish_connection! :server => 'jukeboxzero.s3.amazonaws.com'
MusicBucket.connection.server
=> 'jukeboxzero.s3.amazonaws.com'
MusicBucket.current_bucket
=> 'jukeboxzero'

Rather than infering the current bucket from the subdomain, the current class’ bucket can be explicitly set with set_current_bucket_to.



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# File 'lib/aws/s3/base.rb', line 120

def current_host
  @@current_host
end

.current_host=(host) ⇒ Object 



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# File 'lib/aws/s3/base.rb', line 124

def current_host=(host)
  @@current_host = host
end

.request(verb, path, options = {}, body = nil, attempts = 0, &block) ⇒ Object

Wraps the current connection’s request method and picks the appropriate response class to wrap the response in. If the response is an error, it will raise that error as an exception. All such exceptions can be caught by rescuing their superclass, the ResponseError exception class.

It is unlikely that you would call this method directly. Subclasses of Base have convenience methods for each http request verb that wrap calls to request.



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# File 'lib/aws/s3/base.rb', line 69

def request(verb, path, options = {}, body = nil, attempts = 0, &block)
  Service.response = nil
  process_options!(options, verb)
  response = response_class.new(connection.request(verb, path, options, body, attempts, current_host, &block))
  Service.response = response

  Error::Response.new(response.response).error.raise if response.error?
  if attempts > 0 && !current_host.match(".#{DEFAULT_HOST}")
    establish_connection!(:server => DEFAULT_HOST)
  end
  response
# Once in a while, a request to S3 returns an internal error. A glitch in the matrix I presume. Since these 
# errors are few and far between the request method will rescue InternalErrors the first three times they encouter them
# and will retry the request again. Most of the time the second attempt will work.
rescue InternalError, RequestTimeout
  if attempts == 3
    raise
  else
    attempts += 1
    retry
  end
rescue
  raise unless response
  if response.redirect?
    new_host = response.parsed['endpoint']
    establish_connection!(:server => new_host)
  end
  attempts == 3 || !response.redirect? ? raise : (attempts += 1; retry)
end

.set_current_bucket_to(name) ⇒ Object Also known as: current_bucket=

If you plan on always using a specific bucket for certain files, you can skip always having to specify the bucket by creating a subclass of Bucket or S3Object and telling it what bucket to use:

class JukeBoxSong < AWS::S3::S3Object
  set_current_bucket_to 'jukebox'
end

For all methods that take a bucket name as an argument, the current bucket will be used if the bucket name argument is omitted.

other_song = 'baby-please-come-home.mp3'
JukeBoxSong.store(other_song, open(other_song))

This time we didn’t have to explicitly pass in the bucket name, as the JukeBoxSong class knows that it will always use the ‘jukebox’ bucket.

“Astute readers”, as they say, may have noticed that we used the third parameter to pass in the content type, rather than the fourth parameter as we had the last time we created an object. If the bucket can be inferred, or is explicitly set, as we’ve done in the JukeBoxSong class, then the third argument can be used to pass in options.

Now all operations that would have required a bucket name no longer do.

other_song = JukeBoxSong.find('baby-please-come-home.mp3')

Raises:

  • (ArgumentError) 


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# File 'lib/aws/s3/base.rb', line 155

def set_current_bucket_to(name)
  raise ArgumentError, "`#{__method__}' must be called on a subclass of #{self.name}" if self == AWS::S3::Base
  instance_eval(<<-EVAL)
    def current_bucket
      '#{name}'
    end
  EVAL
end