foundationdb/recipes/ruby-recipes/micro_doc.rb

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2017-05-26 04:48:44 +08:00
#
# micro_doc.rb
#
# This source file is part of the FoundationDB open source project
#
# Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
require 'fdb'
require 'ostruct'
require 'json'
FDB.api_version 300
@db = FDB.open()
@doc_space = FDB::Subspace.new(['D'])
EMPTY_OBJECT = -2
EMPTY_ARRAY = -1
def to_tuples(item)
if item.is_a?(Hash)
return [[EMPTY_OBJECT,nil]] if item.empty?
final = []
item.each do |k,v|
to_tuples(v).each do |sub|
tup = [*k,*sub]
final.push(tup)
end
end
return final
elsif item.is_a?(Array)
return [[EMPTY_ARRAY,nil]] if item.empty?
final = []
item.each_with_index do |k,v|
to_tuples(v).each do |sub|
tup = [*sub,*k]
final.push(tup)
end
end
return final
else
return [[item]]
end
end
def from_tuples(tuples)
return {} if tuples.nil?
first = tuples.first # Determine kind of object from first tuple
return first.first if first.size == 1 # Primitive value
return {} if first == [EMPTY_OBJECT,nil]
return [] if first == [EMPTY_ARRAY,nil]
# For an object or array, we need to group the tuples by their first element
groups = tuples.group_by { |t| t.first }.map { |k,g| g }
if first.first == 0 # array
return groups.map { |g| from_tuples(g.map { |t| t[1..-1] }) }
else # object
obj = {}
groups.each do |g|
obj[g[0][0]] = from_tuples(g.map { |t| t[1..-1] })
end
return obj
end
end
def insert_doc(db,doc)
db.transact do |tr|
if doc.is_a?(String)
doc = json.loads(doc)
end
if !doc.include?('doc_id')
new_id = get_new_id(tr)
doc['doc_id'] = new_id
end
to_tuples(doc).each do |tup|
tr[@doc_space.pack([doc['doc_id']] + tup[0..-2])] = FDB::Tuple.pack([tup[-1]])
end
end
doc['doc_id']
end
def get_new_id(db)
db.transact do |tr|
found = false
while !found
new_id = rand(100000000)+1
found = true
tr.get_range(*@doc_space[new_id].range) do |k|
found = false
break
end
end
new_id
end
end
def get_doc(db,doc_id,prefix=[])
db.transact do |tr|
v = tr[@doc_space.pack([doc_id] + prefix)]
if !v.nil?
# next is safer than return because it lets transact finish
next from_tuples([prefix + FDB::Tuple.unpack(v)])
end
tuples = tr.get_range(*@doc_space.range([doc_id]+prefix)).map do |kv|
@doc_space.unpack(kv.key)[1..-1] + FDB::Tuple.unpack(kv.value)
end
from_tuples tuples
end
end
def clear_subspace(db,subspace)
db.transact do |tr|
tr.clear_range_start_with(subspace.key)
end
end
clear_subspace(@db,@doc_space)
h1 = {'user' => {'jones' => {'friend_of' => 'smith', 'group' => ['sales','service']}, 'smith' => {'friend_of' => 'jones','group'=>['dev','research']}}}
id = insert_doc(@db,h1)
puts get_doc(@db,id,['user','smith','group'])