Represents the condition block of a policy. In JSON, condition blocks look like this:
{ "StringLike": { "s3:prefix": ["photos/*", "photos.html"] } }
ConditionBlock lets you specify conditions like the above example using the add method, for example:
conditions.add(:like, :s3_prefix, "photos/*", "photos.html")
See the add method documentation for more details about how to specify keys and operators.
This class also provides a convenient way to query a condition block to see what operators, keys, and values it has. For example, consider the following condition block (in JSON):
{ "StringEquals": { "s3:prefix": "photos/index.html" }, "DateEquals": { "aws:CurrentTime": ["2010-10-12", "2011-01-02"] }, "NumericEquals": { "s3:max-keys": 10 } }
You can get access to the condition data using #[], keys, operators, and values -- for example:
conditions["DateEquals"]["aws:CurrentTime"].values # => ["2010-10-12", "2011-01-02"]
You can also perform more sophisticated queries, like this one:
conditions[:is].each do |equality_conditions| equality_conditions.keys.each do |key| puts("#{key} may be any of: " + equality_conditions[key].values.join(" ") end end
This would print the following lines:
s3:prefix may be any of: photos/index.html aws:CurrentTime may be any of: 2010-10-12 2011-01-02 s3:max-keys may be any of: 10
@private
@private
# File lib/aws/core/policy.rb, line 299 def initialize(conditions = {}) # filter makes a copy @conditions = filter_conditions(conditions) end
Filters the conditions described in the block, returning a new ConditionBlock that contains only the matching conditions. Each argument is matched against either the keys or the operators in the block, and you can specify the key or operator in any way that's valid for the add method. Some examples:
# all conditions using the StringLike operator conditions["StringLike"] # all conditions using StringEquals, DateEquals, NumericEquals, or Bool conditions[:is] # all conditions on the s3:prefix key conditions["s3:prefix"] # all conditions on the aws:CurrentTime key conditions[:current_time]
Multiple conditions are ANDed together, so the following are equivalent:
conditions[:s3_prefix][:is] conditions[:is][:s3_prefix] conditions[:s3_prefix, :is]
@see add @return [ConditionBlock] A new set of conditions filtered by the
given conditions.
# File lib/aws/core/policy.rb, line 412 def [](*args) filtered = @conditions args.each do |filter| type = valid_operator?(filter) ? nil : :key filtered = filter_conditions(filtered) do |op, key, value| (match, type) = match_triple(filter, type, op, key, value) match end end self.class.new(filtered) end
Adds a condition to the block. This method defines a convenient set of abbreviations for operators based on the type of value passed in. For example:
conditions.add(:is, :secure_transport, true)
Maps to:
{ "Bool": { "aws:SecureTransport": true } }
While:
conditions.add(:is, :s3_prefix, "photos/")
Maps to:
{ "StringEquals": { "s3:prefix": "photos/" } }
The following list shows which operators are accepted as symbols and how they are represented in the JSON policy:
:is
(StringEquals, NumericEquals, DateEquals, or Bool)
:like
(StringLike)
:not_like
(StringNotLike)
:not
(StringNotEquals, NumericNotEquals, or DateNotEquals)
:greater_than
, :gt
(NumericGreaterThan or
DateGreaterThan)
:greater_than_equals
, :gte
(NumericGreaterThanEquals or DateGreaterThanEquals)
:less_than
, :lt
(NumericLessThan or DateLessThan)
:less_than_equals
, :lte
(NumericLessThanEquals or
DateLessThanEquals)
:is_ip_address
(IpAddress)
:not_ip_address
(NotIpAddress)
:is_arn
(ArnEquals)
:not_arn
(ArnNotEquals)
:is_arn_like
(ArnLike)
:not_arn_like
(ArnNotLike)
@param [Symbol or String] operator The operator used to
compare the key with the value. See above for valid values and their interpretations.
@param [Symbol or String] key The key to compare. Symbol
keys are inflected to match AWS conventions. By default, the key is assumed to be in the "aws" namespace, but if you prefix the symbol name with "s3_" it will be sent in the "s3" namespace. For example, +:s3_prefix+ is sent as "s3:prefix" while +:secure_transport+ is sent as "aws:SecureTransport". See http://docs.amazonwebservices.com/AmazonS3/latest/dev/UsingResOpsConditions.html for a list of the available keys for each action in S3.
@param [Mixed] values The value to compare against.
This can be: * a String * a number * a Date, DateTime, or Time * a boolean value This method does not attempt to validate that the values are valid for the operators or keys they are used with.
# File lib/aws/core/policy.rb, line 366 def add(operator, key, *values) if operator.kind_of?(Symbol) converted_values = values.map { |v| convert_value(v) } else converted_values = values end operator = translate_operator(operator, values.first) op = (@conditions[operator] ||= {}) raise "duplicate #{operator} conditions for #{key}" if op[key] op[translate_key(key)] = converted_values end
@return [Array] Returns an array of unique keys used in the block.
# File lib/aws/core/policy.rb, line 430 def keys @conditions.values.map do |keys| keys.keys if keys end.compact.flatten.uniq end
@return [Array] Returns an array of operators used in this block.
# File lib/aws/core/policy.rb, line 425 def operators @conditions.keys end
@private
# File lib/aws/core/policy.rb, line 379 def to_h @conditions end
Returns all values used in the block. Note that the values may not all be from the same condition; for example:
conditions.add(:like, :user_agent, "mozilla", "explorer") conditions.add(:lt, :s3_max_keys, 12) conditions.values # => ["mozilla", "explorer", 12]
@return [Array] Returns an array of values used in this condition block.
# File lib/aws/core/policy.rb, line 444 def values @conditions.values.map do |keys| keys.values end.compact.flatten end
@private
# File lib/aws/core/policy.rb, line 637 def base_translate(example, base_operator, *modifiers) "#{type_notation(example)}#{base_operator}#{modifiers.join}" end
@private
# File lib/aws/core/policy.rb, line 658 def convert_value(value) case value when DateTime, Time Time.parse(value.to_s).iso8601 when Date value.strftime("%Y-%m-%d") else value end end
@private
# File lib/aws/core/policy.rb, line 488 def filter_conditions(conditions = @conditions) conditions.inject({}) do |m, (op, keys)| m[op] = keys.inject({}) do |m2, (key, value)| m2[key] = value if !block_given? or yield(op, key, value) m2 end m.delete(op) if m[op].empty? m end end
@private
# File lib/aws/core/policy.rb, line 482 def match_key(filter, key, value = nil) translate_key(filter) == key end
@private
# File lib/aws/core/policy.rb, line 473 def match_operator(filter, op, value) # dates are the only values that don't come back as native types in JSON # but where we use the type as a cue to the operator translation value = Date.today if op =~ %r^Date/ translate_operator(filter, value) == op end
@private
# File lib/aws/core/policy.rb, line 452 def match_triple(filter, type, op, key, value) value = [value].flatten.first if type target = (type == :operator ? op : key) match = send("match_#{type}", filter, target, value) else if match_operator(filter, op, value) match = true type = :operator elsif match_key(filter, key) match = true type = :key else match = false end end [match, type] end
@private
# File lib/aws/core/policy.rb, line 671 def strip_modifiers(operator) opts = {} MODIFIERS.each do |(regex, mod)| ruby_name = Inflection.ruby_name(mod).to_sym opts[ruby_name] = "" if operator.to_s =~ regex opts[ruby_name] = mod operator = operator.to_s.sub(regex, '').to_sym end end [operator, opts] end
@private
# File lib/aws/core/policy.rb, line 588 def translate_greater_than(example, opts) base_translate(example, "GreaterThan", opts[:equals]) end
@private
# File lib/aws/core/policy.rb, line 595 def translate_gte(example, opts) translate_greater_than(example, { :equals => "Equals" }) end
@private
# File lib/aws/core/policy.rb, line 550 def translate_is(example, opts) return "Bool" if type_notation(example) == "Bool" base_translate(example, "Equals", opts[:ignore_case]) end
@private
# File lib/aws/core/policy.rb, line 613 def translate_is_arn(example, opts) "ArnEquals" end
@private
# File lib/aws/core/policy.rb, line 625 def translate_is_arn_like(example, opts) "ArnLike" end
@private
# File lib/aws/core/policy.rb, line 601 def translate_is_ip_address(example, opts) "IpAddress" end
@private
# File lib/aws/core/policy.rb, line 501 def translate_key(key) if key.kind_of?(Symbol) if key.to_s =~ %r^s3_(.*)$/ s3_name = $1 if s3_name == "version_id" or s3_name == "location_constraint" s3_name = Inflection.class_name(s3_name) else s3_name.tr!('_', '-') end "s3:#{s3_name}" else "aws:#{Inflection.class_name(key.to_s)}" end else key end end
@private
# File lib/aws/core/policy.rb, line 575 def translate_less_than(example, opts) base_translate(example, "LessThan", opts[:equals]) end
@private
# File lib/aws/core/policy.rb, line 563 def translate_like(example, opts) base_translate(example, "Like") end
@private
# File lib/aws/core/policy.rb, line 582 def translate_lte(example, opts) translate_less_than(example, { :equals => "Equals" }) end
@private
# File lib/aws/core/policy.rb, line 557 def translate_not(example, opts) base_translate(example, "NotEquals", opts[:ignore_case]) end
@private
# File lib/aws/core/policy.rb, line 619 def translate_not_arn(example, opts) "ArnNotEquals" end
@private
# File lib/aws/core/policy.rb, line 631 def translate_not_arn_like(example, opts) "ArnNotLike" end
@private
# File lib/aws/core/policy.rb, line 607 def translate_not_ip_address(example, opts) "NotIpAddress" end
@private
# File lib/aws/core/policy.rb, line 569 def translate_not_like(example, opts) base_translate(example, "NotLike") end
@private
# File lib/aws/core/policy.rb, line 537 def translate_operator(operator, example_value) return operator if operator.kind_of?(String) original_operator = operator (operator, opts) = strip_modifiers(operator) raise ArgumentError.new("unrecognized operator #{original_operator}") unless respond_to?("translate_#{operator}", true) send("translate_#{operator}", example_value, opts) end
@private
# File lib/aws/core/policy.rb, line 643 def type_notation(example) case example when String "String" when Numeric "Numeric" when Time, Date "Date" when true, false "Bool" end end
@private
# File lib/aws/core/policy.rb, line 528 def valid_operator?(operator) translate_operator(operator, "") true rescue ArgumentError => e false end