class AWS::S3::Tree

A utility class that supports exploring an S3 {Bucket} like a tree.

Frequently objects stored in S3 have keys that look like a filesystem directory structure.

Given you have 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

You might like to explore the contents of this bucket as a tree:

tree = bucket.as_tree

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

files = tree.children.select(&:leaf?).collect(&:key)
#=> ['README.txt']

If you want to start further down, pass a prefix to {AWS::S3::Bucket#as_tree}:

tree = bucket.as_tree(:prefix => 'photos/2011')

directories = tree.children.select(&:branch?).collect(&:prefix)
#=> ['photos/20011/fall', 'photos/20011/summer']

files = tree.children.select(&:leaf?).collect(&:key)
#=> []

All non-leaf nodes ({Tree} and {Tree::BranchNode} instances) have a {AWS::S3::Tree::Parent#children} method that provides access to the next level of the tree, and all nodes ({Tree}, {Tree::BranchNode}, and {Tree::LeafNode}) have a {parent} method that returns the parent node. In our examples above, the non-leaf nodes are common prefixes to multiple keys (directories) and leaf nodes are object keys.

You can continue crawling the tree using the children collection on each branch node, which will contain the branch nodes and leaf nodes below it.

You can construct a Tree object using the as_tree method of any of the following classes:

The methods to explore the tree are the same for each kind of leaf node, but {AWS::S3::Tree::LeafNode#member} will return a different type of object depending on which kind of collection the tree is using.

Public Class Methods

new(collection, options = {}) click to toggle source

@param [ObjectCollection, BucketVersionCollection,

MultipartUploadCollection] collection The collection whose
members will be explored using the tree.

@param [Hash] options Additional options for constructing the

tree.

@option options [String] :prefix (nil) Set prefix to choose

where the top of the tree will be.  A value of +nil+ means
that the tree will include all objects in the collection.

@option options [String] :delimiter (‘/’) The string that

separates each level of the tree.  This is usually a
directory separator.

@option options [Boolean] :append (true) If true, the delimiter is

appended to the prefix when the prefix does not already end
with the delimiter.
# File lib/aws/s3/tree.rb, line 108
def initialize collection, options = {}
  super
end

Public Instance Methods

each(*args, &block) click to toggle source 
# File spec/aws/s3/tree/child_collection_spec.rb, line 25
def each(*args, &block)
  super(&block)
end
parent() click to toggle source

@return The parent node in the tree. In the case of a Tree,

the parent is always nil.
# File lib/aws/s3/tree.rb, line 114
def parent; nil; end