Class: AWS::S3::ObjectCollection

Inherits:
Object
  • Object
show all
Includes:
Core::Model, PrefixAndDelimiterCollection, Enumerable
Defined in:
lib/aws/s3/object_collection.rb

Overview

Represents a collection of S3 objects.

Getting an S3Object by Key

If you know the key of the object you want, you can reference it this way:

# this will not make any requests against S3
object = bucket.objects['foo.jpg']
object.key #=> 'foo.jpg'

Finding objects with a Prefix

Given a bucket with the following keys:

photos/sunset.jpg
photos/sunrise.jpg
photos/winter.jpg
videos/comedy.mpg
videos/dancing.mpg

You can list objects that share a prefix:

bucket.objects.with_prefix('videos').collect(&:key)
#=> ['videos/comedy.mpg', 'videos/dancing.mpg']

Exploring Objects with a Tree Interface

Given a bucket with the following keys:

README.txt
videos/wedding.mpg
videos/family_reunion.mpg
photos/2010/house.jpg
photos/2011/fall/leaves.jpg
photos/2011/summer/vacation.jpg
photos/2011/summer/family.jpg

tree = bucket.objects.with_prefix('photos').as_tree

directories = tree.children.select(&:branch?).collect(&:prefix)
#=> ['photos/2010', 'photos/2011']

Defined Under Namespace

Classes: BatchHelper

Instance Attribute Summary collapse

Attributes included from PrefixedCollection

#prefix

Attributes included from Core::Model

#config

Instance Method Summary collapse

Methods included from PrefixAndDelimiterCollection

#as_tree

Methods included from Core::Collection::Limitable

#each_batch

Methods included from Core::Collection

#each_batch, #enum, #first, #in_groups_of, #page

Methods included from Core::Model

#client, #config_prefix, #inspect

Constructor Details

#initialize(bucket, options = {}) ⇒ ObjectCollection

Returns a new instance of ObjectCollection.

Parameters:

  • bucket (Bucket)

    The S3 bucket this object collection belongs to.

  • options (Hash) (defaults to: {})

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# File 'lib/aws/s3/object_collection.rb', line 67

def initialize(bucket, options = {})
  @bucket = bucket
  super
end

Instance Attribute Details

#bucketBucket (readonly)

Returns The bucket this collection belongs to.

Returns:

  • (Bucket)

    The bucket this collection belongs to.


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# File 'lib/aws/s3/object_collection.rb', line 73

def bucket
  @bucket
end

Instance Method Details

#[](key) ⇒ S3Object

Returns an S3Object given its name. For example:

Examples:


object = bucket.objects['file.txt']
object.class #=> S3Object

Parameters:

  • key (String)

    The object key.

Returns:


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# File 'lib/aws/s3/object_collection.rb', line 97

def [] key
  S3Object.new(bucket, key.to_s)
end

#create(key, *args) ⇒ S3Object

Writes a new object to S3.

The first param is the key you want to write this object to. All other params/options are documented in S3Object#write.

Parameters:

  • key (String)

    Where in S3 to write the object.

Returns:

See Also:


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# File 'lib/aws/s3/object_collection.rb', line 84

def create key, *args
  self[key].write(*args)
end

#delete(*objects) ⇒ nil

Deletes the objects provided in as few requests as possible.

# delete 2 objects (by key) in a single request
bucket.objects.delete('abc', 'xyz')

You can delete objects also by passing their S3Object representation:

to_delete = []
to_delete << buckets.objects['foo']
to_delete << buckets.objects['bar']

bucket.objects.delete(to_delete)

Parameters:

  • objects (Mixed)

    One or more objects to delete. Each object can be one of the following:

Returns:

  • (nil)

Raises:

  • (BatchDeleteError)

    If any of the objects failed to delete, a BatchDeleteError will be raised with a summary of the errors.


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# File 'lib/aws/s3/object_collection.rb', line 132

def delete *objects

  objects = objects.flatten.collect do |obj|
    case obj
    when String        then { :key => obj }
    when Hash          then obj
    when S3Object      then { :key => obj.key }
    when ObjectVersion then { :key => obj.key, :version_id => obj.version_id }
    else  
      msg = "objects must be keys (strings or hashes with :key and " +
            ":version_id), S3Objects or ObjectVersions, got " +
            object.class.name
      raise ArgumentError, msg
    end
  end

  batch_helper = BatchHelper.new(1000) do |batch|
    client_opts = {}
    client_opts[:bucket_name] = bucket.name
    client_opts[:quiet] = true
    client_opts[:objects] = batch
    client.delete_objects(client_opts)
  end

  error_counts = {}
  batch_helper.after_batch do |response|
    response.errors.each do |error|
      error_counts[error.code] ||= 0
      error_counts[error.code] += 1
    end
  end

  objects.each do |object|
    batch_helper.add(object)
  end

  batch_helper.complete!

  raise Errors::BatchDeleteError.new(error_counts) unless 
    error_counts.empty?

  nil

end

#delete_allArray

Deletes all objects represented by this collection.

Examples:

Delete all objects from a bucket


bucket.objects.delete_all

Delete objects with a given prefix


bucket.objects.with_prefix('2009/').delete_all

Returns:

  • (Array)

    Returns an array of results

Raises:

  • (BatchDeleteError)

    If any of the objects failed to delete, a BatchDeleteError will be raised with a summary of the errors.


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

def delete_all

  error_counts = {}

  each_batch do |objects|
    begin
      delete(objects)
    rescue Errors::BatchDeleteError => error
      error.error_counts.each_pair do |code,count|
        error_counts[code] ||= 0
        error_counts[code] += count
      end
    end
  end

  raise Errors::BatchDeleteError.new(error_counts) unless 
    error_counts.empty?

  nil

end

#delete_if {|object| ... } ⇒ Object

Deletes each object in the collection that returns a true value from block passed to this method. Deletes are batched for efficiency.

# delete text files in the 2009 "folder"
bucket.objects.with_prefix('2009/').delete_if {|o| o.key =~ /\.txt$/ }

Yield Parameters:

Raises:

  • (BatchDeleteError)

    If any of the objects failed to delete, a BatchDeleteError will be raised with a summary of the errors.


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# File 'lib/aws/s3/object_collection.rb', line 188

def delete_if &block

  error_counts = {}

  batch_helper = BatchHelper.new(1000) do |objects| 
    begin
      delete(objects)
    rescue Errors::BatchDeleteError => error
      error.error_counts.each_pair do |code,count|
        error_counts[code] ||= 0
        error_counts[code] += count
      end
    end
  end

  each do |object|
    batch_helper.add(object) if yield(object)
  end

  batch_helper.complete!

  raise Errors::BatchDeleteError.new(error_counts) unless 
    error_counts.empty?

  nil

end

#each(options = {}, &block) ⇒ nil

Iterates the collection, yielding instances of S3Object.

Use break or raise an exception to terminate the enumeration.

Parameters:

  • options (Hash) (defaults to: {})

Options Hash (options):

  • :limit (Integer) — default: nil

    The maximum number of objects to yield.

  • :batch_size (Integer) — default: 1000

    The number of objects to fetch each request to S3. Maximum is 1000 keys at time.

Returns:

  • (nil)

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# File 'lib/aws/s3/object_collection.rb', line 263

def each options = {}, &block
  super
end

#with_prefix(prefix, mode = :replace) ⇒ Collection

Returns a new collection with a different prefix

Examples:

objects = collection.with_prefix('photos')
objects.prefix #=> 'photos'

Chaining with_prefix replaces previous prefix

objects = collection.with_prefix('photos').with_prefix('videos')
objects.prefix #=> 'videos'

Chaining with_prefix with :append

objects = collection.with_prefix('a/').with_prefix('b/', :append)
objects.prefix #=> 'a/b/'

Chaining with_prefix with :prepend

objects = collection.with_prefix('a/').with_prefix('b/', :prepend)
objects.prefix #=> 'b/a/'

Parameters:

  • prefix (String)

    The prefix condition that limits what objects are returned by this collection.

  • mode (Symbol) (defaults to: :replace)

    (:replace) If you chain calls to #with_prefix the mode affects if the prefix prepends, appends, or replaces. Valid modes are:

    • :replace

    • :append

    • :prepend

Returns:

  • (Collection)

    Returns a new collection with a modified prefix.


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# File 'lib/aws/s3/object_collection.rb', line 102

def with_prefix prefix, mode = :replace
  super(prefix, mode)
end