Class: Mongo::Database::View

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain: self, Forwardable
Instance Chain: self, `::Mongo::Retryable`, Enumerable
Inherits:	Object
Defined in:	lib/mongo/database/view.rb

Overview

A class representing a view of a database.

Since:

2.0.0

Class Method Summary

.new(database) ⇒ View constructor

Create the new database view.

Instance Attribute Summary

#batch_size ⇒ Integer readonly
#collection ⇒ Collection readonly
#database readonly Internal use only Internal use only
#limit ⇒ Integer readonly

Instance Method Summary

#aggregate(pipeline, options = {}) ⇒ Collection::View::Aggregation Internal use only Internal use only

Execute an aggregation on the database view.
#collection_names(options = {}) ⇒ Array<String>

Get all the names of the non-system collections in the database.
#list_collections(options = {}) ⇒ Array<Hash>

Get info on all the collections in the database.
#collections_info(session, server_selector, options = {}, &block) private
#collections_info_spec(session, options = {}) private
#initial_query_op(session, options = {}) private
#send_initial_query(server, session, options = {}) ⇒ Operation::Result private

Sends command that obtains information about the database.

`::Mongo::Retryable` - Included

#read_worker	Returns the read worker for handling retryable reads.
#select_server	This is a separate method to make it possible for the test suite to assert that server selection is performed during retry attempts.
#write_worker	Returns the write worker for handling retryable writes.

Constructor Details

.new(database) ⇒ `View`

Create the new database view.

Examples:

Create the new database view.

View::Index.new(database)

Parameters:

database (Database) —

The database.

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database/view.rb', line 127


def initialize(database)
  @database = database
  @batch_size =  nil
  @limit = nil
  @collection = @database[Database::COMMAND]
end

Instance Attribute Details

#batch_size ⇒ `Integer` (readonly)

Returns:

(Integer) —

batch_size The size of the batch of results when sending the listCollections command.

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database/view.rb', line 36


attr_reader :batch_size

#collection ⇒ Collection (readonly)

Returns:

(Collection) —

collection The command collection.

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database/view.rb', line 42


attr_reader :collection

#database (readonly)

This method is for internal use only.

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database/view.rb', line 135


attr_reader :database

#limit ⇒ `Integer` (readonly)

Returns:

(Integer) —

limit The limit when sending a command.

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database/view.rb', line 39


attr_reader :limit

Instance Method Details

#aggregate(pipeline, options = {}) ⇒ Collection::View::Aggregation

This method is for internal use only.

Execute an aggregation on the database view.

Examples:

Aggregate documents.

view.aggregate([
  { "$listLocalSessions" => {} }
])

Parameters:

pipeline (Array<Hash>) —

The aggregation pipeline.
options (Hash) (defaults to: {}) —

The aggregation options.

Returns:

(Collection::View::Aggregation) —

The aggregation object.

Since:

2.10.0

[ GitHub ]

# File 'lib/mongo/database/view.rb', line 151


def aggregate(pipeline, options = {})
  Collection::View::Aggregation.new(self, pipeline, options)
end

#collection_names(options = {}) ⇒ `Array`<`String`>

Note:

The set of returned collection names depends on the version of MongoDB server that fulfills the request.

Get all the names of the non-system collections in the database.

Parameters:

options (Hash) (defaults to: {}) —

::Mongo::Options for the listCollections command.

Options Hash (options):

:batch_size (Integer) —

The batch size for results returned from the listCollections command.
:filter (Hash) —

A filter on the collections returned.
:authorized_collections (true, false) —

A flag, when set to true, that allows a user without the required privilege to run the command when access control is enforced.
:comment (Object) —

A user-provided comment to attach to this command.

See mongodb.com/docs/manual/reference/command/listCollections/ for more information and usage.
:session (Session) —

The session to use.

Returns:

(Array<String>) —

The names of all non-system collections.

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database/view.rb', line 67


def collection_names(options = {})
  @batch_size = options[:batch_size]
  session = client.send(:get_session, options)
  cursor = read_with_retry_cursor(session, ServerSelector.primary, self) do |server|
    send_initial_query(server, session, options.merge(name_only: true))
  end
  cursor.map do |info|
    if cursor.initial_result.connection_description.features.list_collections_enabled?
      info['name']
    else
      (info['name'] &&
        info['name'].sub("#{@database.name}.", ''))
    end
  end.reject do |name|
    name.start_with?('system.') || name.include?('$')
  end
end

#collections_info(session, server_selector, options = {}, &block) (private)

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database/view.rb', line 157


def collections_info(session, server_selector, options = {}, &block)
  description = nil
  cursor = read_with_retry_cursor(session, server_selector, self) do |server|
    # TODO take description from the connection used to send the query
    # once https://jira.mongodb.org/browse/RUBY-1601 is fixed.
    description = server.description
    send_initial_query(server, session, options)
  end
  # On 3.0+ servers, we get just the collection names.
  # On 2.6 server, we get collection names prefixed with the database
  # name. We need to filter system collections out here because
  # in the caller we don't know which server version executed the
  # command and thus what the proper filtering logic should be
  # (it is valid for collection names to have dots, thus filtering out
  # collections named system.* here for 2.6 servers would actually
  # filter out collections in the system database).
  if description.server_version_gte?('3.0')
    cursor.reject do |doc|
      doc['name'].start_with?('system.') || doc['name'].include?('$')
    end
  else
    cursor.reject do |doc|
      doc['name'].start_with?("#{database.name}.system") || doc['name'].include?('$')
    end
  end
end

#collections_info_spec(session, options = {}) (private)

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database/view.rb', line 184


def collections_info_spec(session, options = {})
  { selector: {
      listCollections: 1,
      cursor: batch_size ? { batchSize: batch_size } : {} },
    db_name: @database.name,
    session: session
  }.tap do |spec|
    spec[:selector][:nameOnly] = true if options[:name_only]
    spec[:selector][:filter] = options[:filter] if options[:filter]
    spec[:selector][:authorizedCollections] = true if options[:authorized_collections]
    spec[:comment] = options[:comment] if options[:comment]
  end
end

#initial_query_op(session, options = {}) (private)

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database/view.rb', line 198


def initial_query_op(session, options = {})
  Operation::CollectionsInfo.new(collections_info_spec(session, options))
end

#list_collections(options = {}) ⇒ `Array`<`Hash`>

Note:

The set of collections returned, and the schema of the information hash per collection, depends on the MongoDB server version that fulfills the request.

Get info on all the collections in the database.

Examples:

Get info on each collection.

database.list_collections

Parameters:

options (Hash) (defaults to: {})

Options Hash (options):

:filter (Hash) —

A filter on the collections returned.
:name_only (true, false) —

Indicates whether command should return just collection/view names and type or return both the name and other information
:authorized_collections (true, false) —

A flag, when set to true and used with nameOnly: true, that allows a user without the required privilege to run the command when access control is enforced

See mongodb.com/docs/manual/reference/command/listCollections/ for more information and usage.
:session (Session) —

The session to use.
:deserialize_as_bson (Boolean) —

Whether to deserialize this message using BSON types instead of native Ruby types wherever possible.

Returns:

(Array<Hash>) —

Info for each collection in the database.

Since:

2.0.5

[ GitHub ]

# File 'lib/mongo/database/view.rb', line 114


def list_collections(options = {})
  session = client.send(:get_session, options)
  collections_info(session, ServerSelector.primary, options)
end

#send_initial_query(server, session, options = {}) ⇒ Operation::Result (private)

Sends command that obtains information about the database.

This command returns a cursor, so there could be additional commands, therefore this method is called send initial command.

Parameters:

server (Server) —

::Mongo::Server to send the query to.
session (Session) —

::Mongo::Session that should be used to send the query.
options (Hash) (defaults to: {})

Options Hash (options):

:filter (Hash | nil) —

A query expression to filter the list of collections.
:name_only (true | false | nil) —

A flag to indicate whether the command should return just the collection/view names and type or return both the name and other information.
:authorized_collections (true | false | nil) —

A flag, when set to true and used with name_only: true, that allows a user without the required privilege (i.e. listCollections action on the database) to run the command when access control is enforced.
:comment (Object | nil) —

A user-provided comment to attach to this command.
:deserialize_as_bson (true | false | nil) —

Whether the query results should be deserialized to BSON types, or to Ruby types (where possible).

Returns:

(Operation::Result) —

Result of the query.

Since:

2.0.0

[ GitHub ]

# File 'lib/mongo/database/view.rb', line 227


def send_initial_query(server, session, options = {})
  opts = options.dup
  execution_opts = {}
  if opts.key?(:deserialize_as_bson)
    execution_opts[:deserialize_as_bson] = opts.delete(:deserialize_as_bson)
  end
  initial_query_op(session, opts).execute(
    server,
    context: Operation::Context.new(client: client, session: session),
    options: execution_opts
  )
end

Class: Mongo::Database::View

Overview

Class Method Summary

Instance Attribute Summary

Instance Method Summary

::Mongo::Retryable - Included

Constructor Details

.new(database) ⇒ View

Instance Attribute Details

#batch_size ⇒ Integer (readonly)

#collection ⇒ Collection (readonly)

#database (readonly)

#limit ⇒ Integer (readonly)

Instance Method Details

#aggregate(pipeline, options = {}) ⇒ Collection::View::Aggregation

#collection_names(options = {}) ⇒ Array<String>

#collections_info(session, server_selector, options = {}, &block) (private)

#collections_info_spec(session, options = {}) (private)

#initial_query_op(session, options = {}) (private)

#list_collections(options = {}) ⇒ Array<Hash>

#send_initial_query(server, session, options = {}) ⇒ Operation::Result (private)

`::Mongo::Retryable` - Included

.new(database) ⇒ `View`

#batch_size ⇒ `Integer` (readonly)

#limit ⇒ `Integer` (readonly)

#collection_names(options = {}) ⇒ `Array`<`String`>

#list_collections(options = {}) ⇒ `Array`<`Hash`>