/usr/lib/ruby/vendor_ruby/sequel/plugins/json_serializer.rb is in ruby-sequel 4.15.0-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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module Sequel
module Plugins
# The json_serializer plugin handles serializing entire Sequel::Model
# objects to JSON, as well as support for deserializing JSON directly
# into Sequel::Model objects. It requires the json library, and can
# work with either the pure ruby version or the C extension.
#
# Basic Example:
#
# album = Album[1]
# album.to_json
# # => '{"json_class"=>"Album","id"=>1,"name"=>"RF","artist_id"=>2}'
#
# In addition, you can provide options to control the JSON output:
#
# album.to_json(:only=>:name)
# album.to_json(:except=>[:id, :artist_id])
# # => '{"json_class"="Album","name"=>"RF"}'
#
# album.to_json(:include=>:artist)
# # => '{"json_class":"Album","id":1,"name":"RF","artist_id":2,
# # "artist":{"json_class":"Artist","id":2,"name":"YJM"}}'
#
# You can use a hash value with <tt>:include</tt> to pass options
# to associations:
#
# album.to_json(:include=>{:artist=>{:only=>:name}})
# # => '{"json_class":"Album","id":1,"name":"RF","artist_id":2,
# # "artist":{"json_class":"Artist","name":"YJM"}}'
#
# You can specify the <tt>:root</tt> option to nest the JSON under the
# name of the model:
#
# album.to_json(:root => true)
# # => '{"album":{"id":1,"name":"RF","artist_id":2}}'
#
# Additionally, +to_json+ also exists as a class and dataset method, both
# of which return all objects in the dataset:
#
# Album.to_json
# Album.filter(:artist_id=>1).to_json(:include=>:tags)
#
# If you have an existing array of model instances you want to convert to
# JSON, you can call the class to_json method with the :array option:
#
# Album.to_json(:array=>[Album[1], Album[2]])
#
# In addition to creating JSON, this plugin also enables Sequel::Model
# classes to create instances directly from JSON using the from_json class
# method:
#
# json = album.to_json
# album = Album.from_json(json)
#
# The array_from_json class method exists to parse arrays of model instances
# from json:
#
# json = Album.filter(:artist_id=>1).to_json
# albums = Album.array_from_json(json)
#
# These does not necessarily round trip, since doing so would let users
# create model objects with arbitrary values. By default, from_json will
# call set with the values in the hash. If you want to specify the allowed
# fields, you can use the :fields option, which will call set_fields with
# the given fields:
#
# Album.from_json(album.to_json, :fields=>%w'id name')
#
# If you want to update an existing instance, you can use the from_json
# instance method:
#
# album.from_json(json)
#
# Both of these allow creation of cached associated objects, if you provide
# the :associations option:
#
# album.from_json(json, :associations=>:artist)
#
# You can even provide options when setting up the associated objects:
#
# album.from_json(json, :associations=>{:artist=>{:fields=>%w'id name', :associations=>:tags}})
#
# Note that active_support/json makes incompatible changes to the to_json API,
# and breaks some aspects of the json_serializer plugin. You can undo the damage
# done by active_support/json by doing:
#
# class Array
# def to_json(options = {})
# JSON.generate(self)
# end
# end
#
# class Hash
# def to_json(options = {})
# JSON.generate(self)
# end
# end
#
# Note that this will probably cause active_support/json to no longer work
# correctly in some cases.
#
# Usage:
#
# # Add JSON output capability to all model subclass instances (called before loading subclasses)
# Sequel::Model.plugin :json_serializer
#
# # Add JSON output capability to Album class instances
# Album.plugin :json_serializer
module JsonSerializer
# Set up the column readers to do deserialization and the column writers
# to save the value in deserialized_values.
def self.configure(model, opts={})
model.instance_eval do
@json_serializer_opts = (@json_serializer_opts || {}).merge(opts)
end
end
# Helper class used for making sure that cascading options
# for model associations works correctly. Cascaded options
# work by creating instances of this class, which take a
# literal JSON string and have +to_json+ return it.
class Literal
# Store the literal JSON to use
def initialize(json)
@json = json
end
# Return the literal JSON to use
def to_json(*a)
@json
end
end
module ClassMethods
# The default opts to use when serializing model objects to JSON.
attr_reader :json_serializer_opts
# Attempt to parse a single instance from the given JSON string,
# with options passed to InstanceMethods#from_json_node.
def from_json(json, opts=OPTS)
v = Sequel.parse_json(json)
case v
when self
v
when Hash
new.from_json_node(v, opts)
else
raise Error, "parsed json doesn't return a hash or instance of #{self}"
end
end
# Attempt to parse an array of instances from the given JSON string,
# with options passed to InstanceMethods#from_json_node.
def array_from_json(json, opts=OPTS)
v = Sequel.parse_json(json)
if v.is_a?(Array)
raise(Error, 'parsed json returned an array containing non-hashes') unless v.all?{|ve| ve.is_a?(Hash) || ve.is_a?(self)}
v.map{|ve| ve.is_a?(self) ? ve : new.from_json_node(ve, opts)}
else
raise(Error, 'parsed json did not return an array')
end
end
Plugins.inherited_instance_variables(self, :@json_serializer_opts=>lambda do |json_serializer_opts|
opts = {}
json_serializer_opts.each{|k, v| opts[k] = (v.is_a?(Array) || v.is_a?(Hash)) ? v.dup : v}
opts
end)
Plugins.def_dataset_methods(self, :to_json)
end
module InstanceMethods
# Parse the provided JSON, which should return a hash,
# and process the hash with from_json_node.
def from_json(json, opts=OPTS)
from_json_node(Sequel.parse_json(json), opts)
end
# Using the provided hash, update the instance with data contained in the hash. By default, just
# calls set with the hash values.
#
# Options:
# :associations :: Indicates that the associations cache should be updated by creating
# a new associated object using data from the hash. Should be a Symbol
# for a single association, an array of symbols for multiple associations,
# or a hash with symbol keys and dependent association option hash values.
# :fields :: Changes the behavior to call set_fields using the provided fields, instead of calling set.
def from_json_node(hash, opts=OPTS)
unless hash.is_a?(Hash)
raise Error, "parsed json doesn't return a hash"
end
populate_associations = {}
if assocs = opts[:associations]
assocs = case assocs
when Symbol
{assocs=>{}}
when Array
assocs_tmp = {}
assocs.each{|v| assocs_tmp[v] = {}}
assocs_tmp
when Hash
assocs
else
raise Error, ":associations should be Symbol, Array, or Hash if present"
end
assocs.each do |assoc, assoc_opts|
if assoc_values = hash.delete(assoc.to_s)
unless r = model.association_reflection(assoc)
raise Error, "Association #{assoc} is not defined for #{model}"
end
populate_associations[assoc] = if r.returns_array?
raise Error, "Attempt to populate array association with a non-array" unless assoc_values.is_a?(Array)
assoc_values.map{|v| v.is_a?(r.associated_class) ? v : r.associated_class.new.from_json_node(v, assoc_opts)}
else
raise Error, "Attempt to populate non-array association with an array" if assoc_values.is_a?(Array)
assoc_values.is_a?(r.associated_class) ? assoc_values : r.associated_class.new.from_json_node(assoc_values, assoc_opts)
end
end
end
end
if fields = opts[:fields]
set_fields(hash, fields, opts)
else
set(hash)
end
populate_associations.each do |assoc, values|
associations[assoc] = values
end
self
end
# Return a string in JSON format. Accepts the following
# options:
#
# :except :: Symbol or Array of Symbols of columns not
# to include in the JSON output.
# :include :: Symbol, Array of Symbols, or a Hash with
# Symbol keys and Hash values specifying
# associations or other non-column attributes
# to include in the JSON output. Using a nested
# hash, you can pass options to associations
# to affect the JSON used for associated objects.
# :only :: Symbol or Array of Symbols of columns to only
# include in the JSON output, ignoring all other
# columns.
# :root :: Qualify the JSON with the name of the object.
def to_json(*a)
if opts = a.first.is_a?(Hash)
opts = model.json_serializer_opts.merge(a.first)
a = []
else
opts = model.json_serializer_opts
end
vals = values
cols = if only = opts[:only]
Array(only)
else
vals.keys - Array(opts[:except])
end
h = {}
cols.each{|c| h[c.to_s] = send(c)}
if inc = opts[:include]
if inc.is_a?(Hash)
inc.each do |k, v|
v = v.empty? ? [] : [v]
h[k.to_s] = case objs = send(k)
when Array
objs.map{|obj| Literal.new(Sequel.object_to_json(obj, *v))}
else
Literal.new(Sequel.object_to_json(objs, *v))
end
end
else
Array(inc).each{|c| h[c.to_s] = send(c)}
end
end
h = {model.send(:underscore, model.to_s) => h} if opts[:root]
Sequel.object_to_json(h, *a)
end
end
module DatasetMethods
# Return a JSON string representing an array of all objects in
# this dataset. Takes the same options as the instance
# method, and passes them to every instance. Additionally,
# respects the following options:
#
# :array :: An array of instances. If this is not provided,
# calls #all on the receiver to get the array.
# :root :: If set to :collection, only wraps the collection
# in a root object. If set to :instance, only wraps
# the instances in a root object. If set to :both,
# wraps both the collection and instances in a root
# object. Unfortunately, for backwards compatibility,
# if this option is true and doesn't match one of those
# symbols, it defaults to both. That may change in a
# future version, so for forwards compatibility, you
# should pick a specific symbol for your desired
# behavior.
def to_json(*a)
if opts = a.first.is_a?(Hash)
opts = model.json_serializer_opts.merge(a.first)
a = []
else
opts = model.json_serializer_opts
end
collection_root = case opts[:root]
when nil, false, :instance
false
when :both
true
else
opts = opts.dup
opts.delete(:root)
true
end
res = if row_proc
array = if opts[:array]
opts = opts.dup
opts.delete(:array)
else
all
end
array.map{|obj| Literal.new(Sequel.object_to_json(obj, opts))}
else
all
end
if collection_root
Sequel.object_to_json({model.send(:pluralize, model.send(:underscore, model.to_s)) => res}, *a)
else
Sequel.object_to_json(res, *a)
end
end
end
end
end
end
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