module Mongo::Collection::View::Readable

Defines read related behaviour for collection view.

@since 2.0.0

Constants

MODIFIERS

The modifiers option constant.

@since 2.2.0

QUERY

The query modifier constant.

@since 2.2.0

Public Instance Methods

aggregate(pipeline, options = {}) click to toggle source

Execute an aggregation on the collection view.

@example Aggregate documents.

view.aggregate([
  { "$group" => { "_id" => "$city", "tpop" => { "$sum" => "$pop" }}}
])

@param [ Array<Hash> ] pipeline The aggregation pipeline. @param [ Hash ] options The aggregation options.

@return [ Aggregation ] The aggregation object.

@since 2.0.0

# File lib/mongo/collection/view/readable.rb, line 47
def aggregate(pipeline, options = {})
  Aggregation.new(self, pipeline, options)
end
allow_partial_results() click to toggle source

Allows the query to get partial results if some shards are down.

@example Allow partial results.

view.allow_partial_results

@return [ View ] The new view.

@since 2.0.0

# File lib/mongo/collection/view/readable.rb, line 59
def allow_partial_results
  configure(:allow_partial_results, true)
end
await_data() click to toggle source

Tell the query's cursor to stay open and wait for data.

@example Await data on the cursor.

view.await_data

@return [ View ] The new view.

@since 2.0.0

# File lib/mongo/collection/view/readable.rb, line 71
def await_data
  configure(:await_data, true)
end
batch_size(batch_size = nil) click to toggle source

The number of documents returned in each batch of results from MongoDB.

@example Set the batch size.

view.batch_size(5)

@note Specifying 1 or a negative number is analogous to setting a limit.

@param [ Integer ] #batch_size The size of each batch of results.

@return [ Integer, View ] Either the #batch_size value or a new View.

@since 2.0.0

# File lib/mongo/collection/view/readable.rb, line 88
def batch_size(batch_size = nil)
  configure(:batch_size, batch_size)
end
comment(comment = nil) click to toggle source

Associate a comment with the query.

@example Add a comment.

view.comment('slow query')

@note Set profilingLevel to 2 and the comment will be logged in the profile

collection along with the query.

@param [ String ] comment The comment to be associated with the query.

@return [ String, View ] Either the comment or a

new +View+.

@since 2.0.0

# File lib/mongo/collection/view/readable.rb, line 106
def comment(comment = nil)
  configure(:comment, comment)
end
count(options = {}) click to toggle source

Get a count of matching documents in the collection.

@example Get the number of documents in the collection.

collection_view.count

@param [ Hash ] options Options for the count command.

@option options :skip [ Integer ] The number of documents to skip. @option options :hint [ Hash ] Override default index selection and force

MongoDB to use a specific index for the query.

@option options :limit [ Integer ] Max number of docs to return. @option options :max_time_ms [ Integer ] The maximum amount of time to allow the

command to run.

@option options [ Hash ] :read The read preference options. @option options [ Hash ] :collation The collation to use.

@return [ Integer ] The document count.

@since 2.0.0

# File lib/mongo/collection/view/readable.rb, line 129
def count(options = {})
  cmd = { :count => collection.name, :query => filter }
  cmd[:skip] = options[:skip] if options[:skip]
  cmd[:hint] = options[:hint] if options[:hint]
  cmd[:limit] = options[:limit] if options[:limit]
  cmd[:maxTimeMS] = options[:max_time_ms] if options[:max_time_ms]
  cmd[:readConcern] = collection.read_concern if collection.read_concern
  preference = ServerSelector.get(options[:read] || read_preference)
  server = preference.select_server(cluster)
  validate_collation!(server, options)
  cmd[:collation] = options[:collation] if options[:collation]
  read_with_retry do
    Operation::Commands::Command.new({
                                       :selector => cmd,
                                       :db_name => database.name,
                                       :options => { :limit => -1 },
                                       :read => preference,
                                     }).execute(server).n.to_i

  end
end
cursor_type(type = nil) click to toggle source

The type of cursor to use. Can be :tailable or :tailable_await.

@example Set the cursor type.

view.cursor_type(:tailable)

@param [ :tailable, :tailable_await ] type The cursor type.

@return [ :tailable, :tailable_await, View ] Either the cursor type setting or a new View.

@since 2.3.0

# File lib/mongo/collection/view/readable.rb, line 452
def cursor_type(type = nil)
  configure(:cursor_type, type)
end
distinct(field_name, options={}) click to toggle source

Get a list of distinct values for a specific field.

@example Get the distinct values.

collection_view.distinct('name')

@param [ String, Symbol ] field_name The name of the field. @param [ Hash ] options Options for the distinct command.

@option options :max_time_ms [ Integer ] The maximum amount of time to allow the

command to run.

@option options [ Hash ] :read The read preference options. @option options [ Hash ] :collation The collation to use.

@return [ Array<Object> ] The list of distinct values.

@since 2.0.0

# File lib/mongo/collection/view/readable.rb, line 167
def distinct(field_name, options={})
  cmd = { :distinct => collection.name,
          :key => field_name.to_s,
          :query => filter }
  cmd[:maxTimeMS] = options[:max_time_ms] if options[:max_time_ms]
  cmd[:readConcern] = collection.read_concern if collection.read_concern
  preference = ServerSelector.get(options[:read] || read_preference)
  server = preference.select_server(cluster)
  validate_collation!(server, options)
  cmd[:collation] = options[:collation] if options[:collation]
  read_with_retry do
    Operation::Commands::Command.new({
                                       :selector => cmd,
                                       :db_name => database.name,
                                       :options => { :limit => -1 },
                                       :read => preference
                                     }).execute(server).first['values']

  end
end
hint(hint = nil) click to toggle source

The index that MongoDB will be forced to use for the query.

@example Set the index hint.

view.hint(name: 1)

@param [ Hash ] hint The index to use for the query.

@return [ Hash, View ] Either the hint or a new View.

@since 2.0.0

# File lib/mongo/collection/view/readable.rb, line 198
def hint(hint = nil)
  configure(:hint, hint)
end
limit(limit = nil) click to toggle source

The max number of docs to return from the query.

@example Set the limit.

view.limit(5)

@param [ Integer ] limit The number of docs to return.

@return [ Integer, View ] Either the limit or a new View.

@since 2.0.0

# File lib/mongo/collection/view/readable.rb, line 212
def limit(limit = nil)
  configure(:limit, limit)
end
map_reduce(map, reduce, options = {}) click to toggle source

Execute a map/reduce operation on the collection view.

@example Execute a map/reduce.

view.map_reduce(map, reduce)

@param [ String ] map The map js function. @param [ String ] reduce The reduce js function. @param [ Hash ] options The map/reduce options.

@return [ MapReduce ] The map reduce wrapper.

@since 2.0.0

# File lib/mongo/collection/view/readable.rb, line 228
def map_reduce(map, reduce, options = {})
  MapReduce.new(self, map, reduce, options)
end
max_await_time_ms(max = nil) click to toggle source

A cumulative time limit in milliseconds for processing get more operations on a cursor.

@example Set the max await time ms value.

view.max_await_time_ms(500)

@param [ Integer ] max The max time in milliseconds.

@return [ Integer, View ] Either the max await time ms value or a new View.

@since 2.1.0

# File lib/mongo/collection/view/readable.rb, line 424
def max_await_time_ms(max = nil)
  configure(:max_await_time_ms, max)
end
max_scan(value = nil) click to toggle source

Set the max number of documents to scan.

@example Set the max scan value.

view.max_scan(1000)

@param [ Integer ] value The max number to scan.

@return [ Integer, View ] The value or a new View.

@since 2.0.0

# File lib/mongo/collection/view/readable.rb, line 242
def max_scan(value = nil)
  configure(:max_scan, value)
end
max_time_ms(max = nil) click to toggle source

A cumulative time limit in milliseconds for processing operations on a cursor.

@example Set the max time ms value.

view.max_time_ms(500)

@param [ Integer ] max The max time in milliseconds.

@return [ Integer, View ] Either the max time ms value or a new View.

@since 2.1.0

# File lib/mongo/collection/view/readable.rb, line 438
def max_time_ms(max = nil)
  configure(:max_time_ms, max)
end
max_value(value = nil) click to toggle source

Set the maximum value to search.

@example Set the max value.

view.max_value(_id: 1)

@param [ Hash ] value The max field and value.

@return [ Hash, View ] The value or a new View.

@since 2.1.0

# File lib/mongo/collection/view/readable.rb, line 256
def max_value(value = nil)
  configure(:max_value, value)
end
min_value(value = nil) click to toggle source

Set the minimum value to search.

@example Set the min value.

view.min_value(_id: 1)

@param [ Hash ] value The min field and value.

@return [ Hash, View ] The value or a new View.

@since 2.1.0

# File lib/mongo/collection/view/readable.rb, line 270
def min_value(value = nil)
  configure(:min_value, value)
end
modifiers(doc = nil) click to toggle source

“meta” operators that let you modify the output or behavior of a query.

@example Set the modifiers document.

view.modifiers(:$orderby => Mongo::Index::ASCENDING)

@param [ Hash ] doc The modifiers document.

@return [ Hash, View ] Either the modifiers document or a new View.

@since 2.1.0

# File lib/mongo/collection/view/readable.rb, line 408
def modifiers(doc = nil)
  return Builder::Modifiers.map_server_modifiers(options) if doc.nil?
  new(options.merge(Builder::Modifiers.map_driver_options(doc)))
end
no_cursor_timeout() click to toggle source

The server normally times out idle cursors after an inactivity period (10 minutes) to prevent excess memory use. Set this option to prevent that.

@example Set the cursor to not timeout.

view.no_cursor_timeout

@return [ View ] The new view.

@since 2.0.0

# File lib/mongo/collection/view/readable.rb, line 283
def no_cursor_timeout
  configure(:no_cursor_timeout, true)
end
projection(document = nil) click to toggle source

The fields to include or exclude from each doc in the result set.

@example Set the fields to include or exclude.

view.projection(name: 1)

@note A value of 0 excludes a field from the doc. A value of 1 includes it.

Values must all be 0 or all be 1, with the exception of the _id value.
The _id field is included by default. It must be excluded explicitly.

@param [ Hash ] document The field and 1 or 0, to include or exclude it.

@return [ Hash, View ] Either the fields or a new View.

@since 2.0.0

# File lib/mongo/collection/view/readable.rb, line 301
def projection(document = nil)
  validate_doc!(document) if document
  configure(:projection, document)
end
read(value = nil) click to toggle source

The read preference to use for the query.

@note If none is specified for the query, the read preference of the

collection will be used.

@param [ Hash ] value The read preference mode to use for the query.

@return [ Symbol, View ] Either the read preference or a

new +View+.

@since 2.0.0

# File lib/mongo/collection/view/readable.rb, line 317
def read(value = nil)
  return default_read if value.nil?
  selector = ServerSelector.get(value)
  configure(:read, selector)
end
return_key(value = nil) click to toggle source

Set whether to return only the indexed field or fields.

@example Set the return key value.

view.return_key(true)

@param [ true, false ] value The return key value.

@return [ true, false, View ] The value or a new View.

@since 2.1.0

# File lib/mongo/collection/view/readable.rb, line 333
def return_key(value = nil)
  configure(:return_key, value)
end
show_disk_loc(value = nil) click to toggle source

Set whether the disk location should be shown for each document.

@example Set show disk location option.

view.show_disk_loc(true)

@param [ true, false ] value The value for the field.

@return [ true, false, View ] Either the value or a new

+View+.

@since 2.0.0

# File lib/mongo/collection/view/readable.rb, line 348
def show_disk_loc(value = nil)
  configure(:show_disk_loc, value)
end
Also aliased as: show_record_id
show_record_id(value = nil)
Alias for: show_disk_loc
skip(number = nil) click to toggle source

The number of docs to skip before returning results.

@example Set the number to skip.

view.skip(10)

@param [ Integer ] number Number of docs to skip.

@return [ Integer, View ] Either the skip value or a

new +View+.

@since 2.0.0

# File lib/mongo/collection/view/readable.rb, line 364
def skip(number = nil)
  configure(:skip, number)
end
snapshot(value = nil) click to toggle source

Set the snapshot value for the view.

@note When set to true, prevents documents from returning more than

once.

@example Set the snapshot value.

view.snapshot(true)

@param [ true, false ] value The snapshot value.

@since 2.0.0

# File lib/mongo/collection/view/readable.rb, line 379
def snapshot(value = nil)
  configure(:snapshot, value)
end
sort(spec = nil) click to toggle source

The key and direction pairs by which the result set will be sorted.

@example Set the sort criteria

view.sort(name: -1)

@param [ Hash ] spec The attributes and directions to sort by.

@return [ Hash, View ] Either the sort setting or a

new +View+.

@since 2.0.0

# File lib/mongo/collection/view/readable.rb, line 394
def sort(spec = nil)
  configure(:sort, spec)
end

Private Instance Methods

default_read() click to toggle source
# File lib/mongo/collection/view/readable.rb, line 458
def default_read
  options[:read] || read_preference
end
parallel_scan(cursor_count, options = {}) click to toggle source
# File lib/mongo/collection/view/readable.rb, line 462
def parallel_scan(cursor_count, options = {})
  server = read.select_server(cluster, false)
  cmd = Operation::Commands::ParallelScan.new({
          :coll_name => collection.name,
          :db_name => database.name,
          :cursor_count => cursor_count,
          :read_concern => collection.read_concern
        }.merge!(options))
  cmd.execute(server).cursor_ids.map do |cursor_id|
    result = if server.features.find_command_enabled?
        Operation::Commands::GetMore.new({
          :selector => { :getMore => cursor_id, :collection => collection.name },
          :db_name  => database.name
        }).execute(server)
      else
        Operation::Read::GetMore.new({
          :to_return => 0,
          :cursor_id => cursor_id,
          :db_name   => database.name,
          :coll_name => collection.name
        }).execute(server)
    end
    Cursor.new(self, result, server)
  end
end
validate_doc!(doc) click to toggle source
# File lib/mongo/collection/view/readable.rb, line 488
def validate_doc!(doc)
  raise Error::InvalidDocument.new unless doc.respond_to?(:keys)
end