Add helper method for automatic paging
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@ -28,6 +28,43 @@ require 'hurley/addressable'
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module Google
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module Apis
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module Core
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# Helper class for enumerating over a result set requiring multiple fetches
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class PagedResults
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include Enumerable
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attr_reader :last_result
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# @param [BaseService] service
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# Current service instance
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# @param [Fixnum] max
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# Maximum number of items to iterate over. Nil if no limit
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# @param [Symbol] items
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# Name of the field in the result containing the items. Defaults to :items
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def initialize(service, max: nil, items: :items, &block)
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@service = service
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@block = block
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@max = max
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@items_field = items
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end
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# Iterates over result set, fetching additional pages as needed
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def each
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page_token = nil
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item_count = 0
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loop do
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@last_result = @block.call(page_token, @service)
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for item in @last_result.send(@items_field)
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item_count = item_count + 1
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break if @max && item_count > @max
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yield item
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end
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break if @max && item_count >= @max
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break if @last_result.next_page_token.nil? || @last_result.next_page_token == page_token
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page_token = @last_result.next_page_token
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end
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end
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end
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# Base service for all APIs. Not to be used directly.
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#
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class BaseService
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@ -90,12 +127,12 @@ module Google
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# request to the server.
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#
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# @example
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# service.batch do |service|
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# service.get_item(id1) do |res, err|
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# service.batch do |s|
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# s.get_item(id1) do |res, err|
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# # process response for 1st call
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# end
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# # ...
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# service.get_item(idN) do |res, err|
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# s.get_item(idN) do |res, err|
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# # process response for Nth call
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# end
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# end
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@ -122,12 +159,12 @@ module Google
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# files, use single requests which use a resumable upload protocol.
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#
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# @example
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# service.batch do |service|
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# service.insert_item(upload_source: 'file1.txt') do |res, err|
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# service.batch do |s|
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# s.insert_item(upload_source: 'file1.txt') do |res, err|
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# # process response for 1st call
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# end
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# # ...
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# service.insert_item(upload_source: 'fileN.txt') do |res, err|
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# s.insert_item(upload_source: 'fileN.txt') do |res, err|
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# # process response for Nth call
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# end
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# end
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@ -191,6 +228,34 @@ module Google
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execute_or_queue_command(command, &block)
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end
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# Executes a given query with paging, automatically retrieving
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# additional pages as necessary. Requires a block that returns the
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# result set of a page. The current page token is supplied as an argument
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# to the block.
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#
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# Note: The returned enumerable also contains a `last_result` field
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# containing the full result of the last query executed.
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#
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# @param [Fixnum] max
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# Maximum number of items to iterate over. Defaults to nil -- no upper bound.
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# @param [Symbol] items
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# Name of the field in the result containing the items. Defaults to :items
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# @return [Enumerble]
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# @yield [token, service]
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# Current page token & service instance
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# @yieldparam [String] token
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# Current page token to be used in the query
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# @yieldparm [service]
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# Current service instance
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#
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# @example Retrieve files,
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# file_list = service.fetch_all { |token, s| s.list_files(page_token: token) }
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# file_list.each { |f| ... }
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def fetch_all(max: nil, items: :items, &block)
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fail "fetch_all may no be used inside a batch" if batch?
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return PagedResults.new(self, max: max, items: items, &block)
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end
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protected
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# Create a new upload command.
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@ -17,6 +17,7 @@ require 'google/apis/options'
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require 'google/apis/core/base_service'
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require 'google/apis/core/json_representation'
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require 'hurley/test'
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require 'ostruct'
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RSpec.describe Google::Apis::Core::BaseService do
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include TestHelpers
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@ -243,5 +244,43 @@ EOF
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end
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end.to raise_error(Google::Apis::ClientError)
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end
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context 'with fetch_all' do
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let(:responses) do
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data = {}
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data[nil] = OpenStruct.new(next_page_token: 'p1', items: ['a', 'b', 'c'], alt_items: [1, 2 , 3])
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data['p1'] = OpenStruct.new(next_page_token: 'p2', items: ['d', 'e', 'f'], alt_items: [4, 5, 6])
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data['p2'] = OpenStruct.new(next_page_token: nil, items: ['g', 'h', 'i'], alt_items: [7,8, 9])
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data
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end
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let(:items) { service.fetch_all { |token| responses[token] } }
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it 'should fetch pages until next page token is nil' do
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expect(items).to contain_exactly('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i')
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end
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it 'should stop on repeated page token' do
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responses['p2'].next_page_token = 'p2'
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expect(items).to contain_exactly('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i')
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end
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it 'should allow selecting another field for items' do
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expect(service.fetch_all(items: :alt_items) { |token| responses[token] } ).to contain_exactly(1, 2, 3, 4, 5, 6, 7, 8, 9)
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end
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it 'should allow limiting the number of items to fetch' do
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expect(service.fetch_all(max: 5) { |token| responses[token] } ).to contain_exactly('a', 'b', 'c', 'd', 'e')
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end
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it 'should yield the next token' do
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expect do |b|
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service.fetch_all do |token|
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b.to_proc.call(token)
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responses[token]
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end.count
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end.to yield_successive_args(nil, 'p1', 'p2')
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end
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end
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end
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end
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