class Mongo::Collection

A named collection of documents in a database.

Attributes

db[R]
hint[R]
name[R]
pk_factory[R]
safe[R]

Public Class Methods

new(name, db, opts={}) click to toggle source

Initialize a collection object.

@param [String, Symbol] name the name of the collection. @param [DB] db a MongoDB database instance.

@option opts [:create_pk] :pk (BSON::ObjectId) A primary key factory to use

other than the default BSON::ObjectId.

@option opts [Boolean, Hash] :safe (false) Set the default safe-mode options

for insert, update, and remove method called on this Collection instance. If no
value is provided, the default value set on this instance's DB will be used. This
default can be overridden for any invocation of insert, update, or remove.

@option options [:primary, :secondary] :read The default read preference for queries

initiates from this connection object. If +:secondary+ is chosen, reads will be sent
to one of the closest available secondary nodes. If a secondary node cannot be located, the
read will be sent to the primary. If this option is left unspecified, the value of the read
preference for this collection's associated Mongo::DB object will be used.

@raise [InvalidNSName]

if collection name is empty, contains '$', or starts or ends with '.'

@raise [TypeError]

if collection name is not a string or symbol

@return [Collection]

@core collections constructor_details

# File lib/mongo/collection.rb, line 52
def initialize(name, db, opts={})
  if db.is_a?(String) && name.is_a?(Mongo::DB)
    warn "Warning: the order of parameters to initialize a collection have changed. " +
         "Please specify the collection name first, followed by the db. This will be made permanent" +
         "in v2.0."
    db, name = name, db
  end

  case name
  when Symbol, String
  else
    raise TypeError, "new_name must be a string or symbol"
  end

  name = name.to_s

  if name.empty? or name.include? ".."
    raise Mongo::InvalidNSName, "collection names cannot be empty"
  end
  if name.include? "$"
    raise Mongo::InvalidNSName, "collection names must not contain '$'" unless name =~ /((^\$cmd)|(oplog\.\$main))/
  end
  if name.match(/^\./) or name.match(/\.$/)
    raise Mongo::InvalidNSName, "collection names must not start or end with '.'"
  end

  if opts.respond_to?(:create_pk) || !opts.is_a?(Hash)
    warn "The method for specifying a primary key factory on a Collection has changed.\n" +
      "Please specify it as an option (e.g., :pk => PkFactory)."
    pk_factory = opts
  else
    pk_factory = nil
  end

  @db, @name  = db, name
  @connection = @db.connection
  @logger     = @connection.logger
  @cache_time = @db.cache_time
  @cache = Hash.new(0)
  unless pk_factory
    @safe = opts.fetch(:safe, @db.safe)
    if value = opts[:read]
      Mongo::Support.validate_read_preference(value)
    else
      value = @db.read_preference
    end
    @read_preference = value.is_a?(Hash) ? value.dup : value
  end
  @pk_factory = pk_factory || opts[:pk] || BSON::ObjectId
  @hint = nil
end

Public Instance Methods

<<(doc_or_docs, opts={})
Alias for: insert
[](name) click to toggle source

Return a sub-collection of this collection by name. If 'users' is a collection, then 'users.comments' is a sub-collection of users.

@param [String, Symbol] name

the collection to return

@raise [Mongo::InvalidNSName]

if passed an invalid collection name

@return [Collection]

the specified sub-collection
# File lib/mongo/collection.rb, line 125
def [](name)
  name = "#{self.name}.#{name}"
  return Collection.new(name, db) if !db.strict? ||
    db.collection_names.include?(name.to_s)
  raise "Collection #{name} doesn't exist. Currently in strict mode."
end
capped?() click to toggle source

Indicate whether this is a capped collection.

@raise [Mongo::OperationFailure]

if the collection doesn't exist.

@return [Boolean]

# File lib/mongo/collection.rb, line 110
def capped?
  @db.command({:collstats => @name})['capped'] == 1
end
count(opts={}) click to toggle source

Get the number of documents in this collection.

@option opts [Hash] :query ({}) A query selector for filtering the documents counted. @option opts [Integer] :skip (nil) The number of documents to skip. @option opts [Integer] :limit (nil) The number of documents to limit.

@return [Integer]

# File lib/mongo/collection.rb, line 864
def count(opts={})
  find(opts[:query],
       :skip => opts[:skip],
       :limit => opts[:limit]).count(true)
end
Also aliased as: size
create_index(spec, opts={}) click to toggle source

Create a new index.

@param [String, Array] spec

should be either a single field name or an array of
[field name, direction] pairs. Directions should be specified
as Mongo::ASCENDING, Mongo::DESCENDING, or Mongo::GEO2D.

Note that geospatial indexing only works with versions of MongoDB >= 1.3.3+. Keep in mind, too,
that in order to geo-index a given field, that field must reference either an array or a sub-object
where the first two values represent x- and y-coordinates. Examples can be seen below.

Also note that it is permissible to create compound indexes that include a geospatial index as
long as the geospatial index comes first.

If your code calls create_index frequently, you can use Collection#ensure_index to cache these calls
and thereby prevent excessive round trips to the database.

@option opts [Boolean] :unique (false) if true, this index will enforce a uniqueness constraint. @option opts [Boolean] :background (false) indicate that the index should be built in the background. This

feature is only available in MongoDB >= 1.3.2.

@option opts [Boolean] :drop_dups (nil) If creating a unique index on a collection with pre-existing records,

this option will keep the first document the database indexes and drop all subsequent with duplicate values.

@option opts [Integer] :min (nil) specify the minimum longitude and latitude for a geo index. @option opts [Integer] :max (nil) specify the maximum longitude and latitude for a geo index.

@example Creating a compound index:

@posts.create_index([['subject', Mongo::ASCENDING], ['created_at', Mongo::DESCENDING]])

@example Creating a geospatial index:

@restaurants.create_index([['location', Mongo::GEO2D]])

# Note that this will work only if 'location' represents x,y coordinates:
{'location': [0, 50]}
{'location': {'x' => 0, 'y' => 50}}
{'location': {'latitude' => 0, 'longitude' => 50}}

@example A geospatial index with alternate longitude and latitude:

@restaurants.create_index([['location', Mongo::GEO2D]], :min => 500, :max => 500)

@return [String] the name of the index created.

@core indexes create_index-instance_method

# File lib/mongo/collection.rb, line 489
def create_index(spec, opts={})
  opts[:dropDups] = opts[:drop_dups] if opts[:drop_dups]
  field_spec = parse_index_spec(spec)
  opts = opts.dup
  name = opts.delete(:name) || generate_index_name(field_spec)
  name = name.to_s if name

  generate_indexes(field_spec, name, opts)
  name
end
distinct(key, query=nil) click to toggle source

Return a list of distinct values for key across all documents in the collection. The key may use dot notation to reach into an embedded object.

@param [String, Symbol, OrderedHash] key or hash to group by. @param [Hash] query a selector for limiting the result set over which to group.

@example Saving zip codes and ages and returning distinct results.

@collection.save({:zip => 10010, :name => {:age => 27}})
@collection.save({:zip => 94108, :name => {:age => 24}})
@collection.save({:zip => 10010, :name => {:age => 27}})
@collection.save({:zip => 99701, :name => {:age => 24}})
@collection.save({:zip => 94108, :name => {:age => 27}})

@collection.distinct(:zip)
  [10010, 94108, 99701]
@collection.distinct("name.age")
  [27, 24]

# You may also pass a document selector as the second parameter
# to limit the documents over which distinct is run:
@collection.distinct("name.age", {"name.age" => {"$gt" => 24}})
  [27]

@return [Array] an array of distinct values.

# File lib/mongo/collection.rb, line 790
def distinct(key, query=nil)
  raise MongoArgumentError unless [String, Symbol].include?(key.class)
  command = BSON::OrderedHash.new
  command[:distinct] = @name
  command[:key]      = key.to_s
  command[:query]    = query

  @db.command(command)["values"]
end
drop() click to toggle source

Drop the entire collection. USE WITH CAUTION.

# File lib/mongo/collection.rb, line 557
def drop
  @db.drop_collection(@name)
end
drop_index(name) click to toggle source

Drop a specified index.

@param [String] name

@core indexes

# File lib/mongo/collection.rb, line 538
def drop_index(name)
  if name.is_a?(Array)
    return drop_index(index_name(name))
  end
  @cache[name.to_s] = nil
  @db.drop_index(@name, name)
end
drop_indexes() click to toggle source

Drop all indexes.

@core indexes

# File lib/mongo/collection.rb, line 549
def drop_indexes
  @cache = {}

  # Note: calling drop_indexes with no args will drop them all.
  @db.drop_index(@name, '*')
end
ensure_index(spec, opts={}) click to toggle source

Calls #create_index and sets a flag to not do so again for another X minutes. this time can be specified as an option when initializing a Mongo::DB object as options Any changes to an index will be propogated through regardless of cache time (e.g., a change of index direction)

The parameters and options for this methods are the same as those for #create_index.

@example Call sequence:

Time t: @posts.ensure_index([['subject', Mongo::ASCENDING])  -- calls create_index and
  sets the 5 minute cache
Time t+2min : @posts.ensure_index([['subject', Mongo::ASCENDING])  -- doesn't do anything
Time t+3min : @posts.ensure_index([['something_else', Mongo::ASCENDING])  -- calls create_index
  and sets 5 minute cache
Time t+10min : @posts.ensure_index([['subject', Mongo::ASCENDING])  -- calls create_index and
  resets the 5 minute counter

@return [String] the name of the index.

# File lib/mongo/collection.rb, line 516
def ensure_index(spec, opts={})
  now = Time.now.utc.to_i
  opts[:dropDups] = opts[:drop_dups] if opts[:drop_dups]
  field_spec = parse_index_spec(spec)

  name = opts[:name] || generate_index_name(field_spec)
  name = name.to_s if name

  if !@cache[name] || @cache[name] <= now
    generate_indexes(field_spec, name, opts)
  end

  # Reset the cache here in case there are any errors inserting. Best to be safe.
  @cache[name] = now + @cache_time
  name
end
find(selector={}, opts={}) { |cursor| ... } click to toggle source

Query the database.

The selector argument is a prototype document that all results must match. For example:

collection.find({"hello" => "world"})

only matches documents that have a key “hello” with value “world”. Matches can have other keys *in addition* to “hello”.

If given an optional block find will yield a Cursor to that block, close the cursor, and then return nil. This guarantees that partially evaluated cursors will be closed. If given no block find returns a cursor.

@param [Hash] selector

a document specifying elements which must be present for a
document to be included in the result set. Note that in rare cases,
(e.g., with $near queries), the order of keys will matter. To preserve
key order on a selector, use an instance of BSON::OrderedHash (only applies
to Ruby 1.8).

@option opts [Array, Hash] :fields field names that should be returned in the result

set ("_id" will be included unless explicity excluded). By limiting results to a certain subset of fields,
you can cut down on network traffic and decoding time. If using a Hash, keys should be field
names and values should be either 1 or 0, depending on whether you want to include or exclude
the given field.

@option opts [:primary, :secondary] :read The default read preference for queries

initiates from this connection object. If +:secondary+ is chosen, reads will be sent
to one of the closest available secondary nodes. If a secondary node cannot be located, the
read will be sent to the primary. If this option is left unspecified, the value of the read
preference for this Collection object will be used.

@option opts [Integer] :skip number of documents to skip from the beginning of the result set @option opts [Integer] :limit maximum number of documents to return @option opts [Array] :sort an array of [key, direction] pairs to sort by. Direction should

be specified as Mongo::ASCENDING (or :ascending / :asc) or Mongo::DESCENDING (or :descending / :desc)

@option opts [String, Array, OrderedHash] :hint hint for query optimizer, usually not necessary if

using MongoDB > 1.1

@option opts [Boolean] :snapshot (false) if true, snapshot mode will be used for this query.

Snapshot mode assures no duplicates are returned, or objects missed, which were preset at both the start and
end of the query's execution.
For details see http://www.mongodb.org/display/DOCS/How+to+do+Snapshotting+in+the+Mongo+Database

@option opts [Boolean] :batch_size (100) the number of documents to returned by the database per

GETMORE operation. A value of 0 will let the database server decide how many results to return.
This option can be ignored for most use cases.

@option opts [Boolean] :timeout (true) when true, the returned cursor will be subject to

the normal cursor timeout behavior of the mongod process. When +false+, the returned cursor will
never timeout. Note that disabling timeout will only work when #find is invoked with a block.
This is to prevent any inadvertant failure to close the cursor, as the cursor is explicitly
closed when block code finishes.

@option opts [Integer] :max_scan (nil) Limit the number of items to scan on both collection scans and indexed queries.. @option opts [Boolean] :show_disk_loc (false) Return the disk location of each query result (for debugging). @option opts [Boolean] :return_key (false) Return the index key used to obtain the result (for debugging). @option opts [Block] :transformer (nil) a block for tranforming returned documents.

This is normally used by object mappers to convert each returned document to an instance of a class.

@raise [ArgumentError]

if timeout is set to false and find is not invoked in a block

@raise [RuntimeError]

if given unknown options

@core find find-instance_method

# File lib/mongo/collection.rb, line 206
def find(selector={}, opts={})
  opts   = opts.dup
  fields = opts.delete(:fields)
  fields = ["_id"] if fields && fields.empty?
  skip   = opts.delete(:skip) || skip || 0
  limit  = opts.delete(:limit) || 0
  sort   = opts.delete(:sort)
  hint   = opts.delete(:hint)
  snapshot   = opts.delete(:snapshot)
  batch_size = opts.delete(:batch_size)
  timeout    = (opts.delete(:timeout) == false) ? false : true
  max_scan   = opts.delete(:max_scan)
  return_key = opts.delete(:return_key)
  transformer = opts.delete(:transformer)
  show_disk_loc = opts.delete(:show_disk_loc)
  read          = opts.delete(:read) || @read_preference

  if timeout == false && !block_given?
    raise ArgumentError, "Collection#find must be invoked with a block when timeout is disabled."
  end

  if hint
    hint = normalize_hint_fields(hint)
  else
    hint = @hint        # assumed to be normalized already
  end

  raise RuntimeError, "Unknown options [#{opts.inspect}]" unless opts.empty?

  cursor = Cursor.new(self, {
    :selector    => selector,
    :fields      => fields,
    :skip        => skip,
    :limit       => limit,
    :order       => sort,
    :hint        => hint,
    :snapshot    => snapshot,
    :timeout     => timeout,
    :batch_size  => batch_size,
    :transformer => transformer,
    :max_scan    => max_scan,
    :show_disk_loc => show_disk_loc,
    :return_key    => return_key,
    :read          => read
  })

  if block_given?
    yield cursor
    cursor.close
    nil
  else
    cursor
  end
end
find_and_modify(opts={}) click to toggle source

Atomically update and return a document using MongoDB's findAndModify command. (MongoDB > 1.3.0)

@option opts [Hash] :query ({}) a query selector document for matching the desired document. @option opts [Hash] :update (nil) the update operation to perform on the matched document. @option opts [Array, String, OrderedHash] :sort ({}) specify a sort option for the query using any

of the sort options available for Cursor#sort. Sort order is important if the query will be matching
multiple documents since only the first matching document will be updated and returned.

@option opts [Boolean] :remove (false) If true, removes the the returned document from the collection. @option opts [Boolean] :new (false) If true, returns the updated document; otherwise, returns the document

prior to update.

@return [Hash] the matched document.

@core findandmodify find_and_modify-instance_method

# File lib/mongo/collection.rb, line 575
def find_and_modify(opts={})
  cmd = BSON::OrderedHash.new
  cmd[:findandmodify] = @name
  cmd.merge!(opts)
  cmd[:sort] = Mongo::Support.format_order_clause(opts[:sort]) if opts[:sort]

  @db.command(cmd)['value']
end
find_one(spec_or_object_id=nil, opts={}) click to toggle source

Return a single object from the database.

@return [OrderedHash, Nil]

a single document or nil if no result is found.

@param [Hash, ObjectId, Nil] spec_or_object_id a hash specifying elements

which must be present for a document to be included in the result set or an
instance of ObjectId to be used as the value for an _id query.
If nil, an empty selector, {}, will be used.

@option opts [Hash]

any valid options that can be send to Collection#find

@raise [TypeError]

if the argument is of an improper type.
# File lib/mongo/collection.rb, line 276
def find_one(spec_or_object_id=nil, opts={})
  spec = case spec_or_object_id
         when nil
           {}
         when BSON::ObjectId
           {:_id => spec_or_object_id}
         when Hash
           spec_or_object_id
         else
           raise TypeError, "spec_or_object_id must be an instance of ObjectId or Hash, or nil"
         end
  find(spec, opts.merge(:limit => -1)).next_document
end
group(opts, condition={}, initial={}, reduce=nil, finalize=nil) click to toggle source

Perform a group aggregation.

@param [Hash] opts the options for this group operation. The minimum required are :initial

and :reduce.

@option opts [Array, String, Symbol] :key (nil) Either the name of a field or a list of fields to group by (optional). @option opts [String, BSON::Code] :keyf (nil) A JavaScript function to be used to generate the grouping keys (optional). @option opts [String, BSON::Code] :cond ({}) A document specifying a query for filtering the documents over

which the aggregation is run (optional).

@option opts [Hash] :initial the initial value of the aggregation counter object (required). @option opts [String, BSON::Code] :reduce (nil) a JavaScript aggregation function (required). @option opts [String, BSON::Code] :finalize (nil) a JavaScript function that receives and modifies

each of the resultant grouped objects. Available only when group is run with command
set to true.

@return [Array] the command response consisting of grouped items.

# File lib/mongo/collection.rb, line 665
def group(opts, condition={}, initial={}, reduce=nil, finalize=nil)
  if opts.is_a?(Hash)
    return new_group(opts)
  else
    warn "Collection#group no longer take a list of parameters. This usage is deprecated and will be remove in v2.0." +
         "Check out the new API at http://api.mongodb.org/ruby/current/Mongo/Collection.html#group-instance_method"
  end

  reduce = BSON::Code.new(reduce) unless reduce.is_a?(BSON::Code)

  group_command = {
    "group" => {
      "ns"      => @name,
      "$reduce" => reduce,
      "cond"    => condition,
      "initial" => initial
    }
  }

  if opts.is_a?(Symbol)
    raise MongoArgumentError, "Group takes either an array of fields to group by or a JavaScript function" +
      "in the form of a String or BSON::Code."
  end

  unless opts.nil?
    if opts.is_a? Array
      key_type = "key"
      key_value = {}
      opts.each { |k| key_value[k] = 1 }
    else
      key_type  = "$keyf"
      key_value = opts.is_a?(BSON::Code) ? opts : BSON::Code.new(opts)
    end

    group_command["group"][key_type] = key_value
  end

  finalize = BSON::Code.new(finalize) if finalize.is_a?(String)
  if finalize.is_a?(BSON::Code)
    group_command['group']['finalize'] = finalize
  end

  result = @db.command(group_command)

  if Mongo::Support.ok?(result)
    result["retval"]
  else
    raise OperationFailure, "group command failed: #{result['errmsg']}"
  end
end
hint=(hint=nil) click to toggle source

Set a hint field for query optimizer. Hint may be a single field name, array of field names, or a hash (preferably an [OrderedHash]). If using MongoDB > 1.1, you probably don't ever need to set a hint.

@param [String, Array, OrderedHash] hint a single field, an array of

fields, or a hash specifying fields
# File lib/mongo/collection.rb, line 138
def hint=(hint=nil)
  @hint = normalize_hint_fields(hint)
  self
end
index_information() click to toggle source

Get information on the indexes for this collection.

@return [Hash] a hash where the keys are index names.

@core indexes

# File lib/mongo/collection.rb, line 838
def index_information
  @db.index_information(@name)
end
insert(doc_or_docs, opts={}) click to toggle source

Insert one or more documents into the collection.

@param [Hash, Array] doc_or_docs

a document (as a hash) or array of documents to be inserted.

@return [ObjectId, Array]

The _id of the inserted document or a list of _ids of all inserted documents.

@return [[ObjectId, Array], [Hash, Array]]

1st, the _id of the inserted document or a list of _ids of all inserted documents.
2nd, a list of invalid documents.
Return this result format only when :collect_on_error is true.

@option opts [Boolean, Hash] :safe (false)

run the operation in safe mode, which run a getlasterror command on the
database to report any assertion. In addition, a hash can be provided to
run an fsync and/or wait for replication of the insert (>= 1.5.1). Safe
options provided here will override any safe options set on this collection,
its database object, or the current connection. See the options on
for DB#get_last_error.

@option opts [Boolean] :continue_on_error (false) If true, then

continue a bulk insert even if one of the documents inserted
triggers a database assertion (as in a duplicate insert, for instance).
If not using safe mode, the list of ids returned will
include the object ids of all documents attempted on insert, even
if some are rejected on error. When safe mode is
enabled, any error will raise an OperationFailure exception.
MongoDB v2.0+.

@option opts [Boolean] :collect_on_error (false) if true, then

collects invalid documents as an array. Note that this option changes the result format.

@core insert insert-instance_method

# File lib/mongo/collection.rb, line 348
def insert(doc_or_docs, opts={})
  doc_or_docs = [doc_or_docs] unless doc_or_docs.is_a?(Array)
  doc_or_docs.collect! { |doc| @pk_factory.create_pk(doc) }
  safe = opts.fetch(:safe, @safe)
  result = insert_documents(doc_or_docs, @name, true, safe, opts)
  result.size > 1 ? result : result.first
end
Also aliased as: <<
map_reduce(map, reduce, opts={}) click to toggle source

Perform a map-reduce operation on the current collection.

@param [String, BSON::Code] map a map function, written in JavaScript. @param [String, BSON::Code] reduce a reduce function, written in JavaScript.

@option opts [Hash] :query ({}) a query selector document, like what's passed to find, to limit

the operation to a subset of the collection.

@option opts [Array] :sort ([]) an array of [key, direction] pairs to sort by. Direction should

be specified as Mongo::ASCENDING (or :ascending / :asc) or Mongo::DESCENDING (or :descending / :desc)

@option opts [Integer] :limit (nil) if passing a query, number of objects to return from the collection. @option opts [String, BSON::Code] :finalize (nil) a javascript function to apply to the result set after the

map/reduce operation has finished.

@option opts [String] :out (nil) a valid output type. In versions of MongoDB prior to v1.7.6,

this option takes the name of a collection for the output results. In versions 1.7.6 and later,
this option specifies the output type. See the core docs for available output types.

@option opts [Boolean] :keeptemp (false) if true, the generated collection will be persisted. The defualt

is false. Note that this option has no effect is versions of MongoDB > v1.7.6.

@option opts [Boolean ] :verbose (false) if true, provides statistics on job execution time. @option opts [Boolean] :raw (false) if true, return the raw result object from the #map_reduce command, and not

the instantiated collection that's returned by default. Note if a collection name isn't returned in the
map-reduce output (as, for example, when using :out => { :inline => 1 }), then you must specify this option
or an ArgumentError will be raised.

@return [Collection, Hash] a Mongo::Collection object or a Hash with the map-reduce command's results.

@raise ArgumentError if you specify { :out => { :inline => true }} but don't specify :raw => true.

@see www.mongodb.org/display/DOCS/MapReduce Offical MongoDB map/reduce documentation.

@core mapreduce map_reduce-instance_method

# File lib/mongo/collection.rb, line 614
def map_reduce(map, reduce, opts={})
  map    = BSON::Code.new(map) unless map.is_a?(BSON::Code)
  reduce = BSON::Code.new(reduce) unless reduce.is_a?(BSON::Code)
  raw    = opts.delete(:raw)

  hash = BSON::OrderedHash.new
  hash['mapreduce'] = self.name
  hash['map'] = map
  hash['reduce'] = reduce
  hash.merge! opts
  if hash[:sort]
    hash[:sort] = Mongo::Support.format_order_clause(hash[:sort])
  end

  result = @db.command(hash)
  unless Mongo::Support.ok?(result)
    raise Mongo::OperationFailure, "map-reduce failed: #{result['errmsg']}"
  end

  if raw
    result
  elsif result["result"]
    if result['result'].is_a? BSON::OrderedHash and result['result'].has_key? 'db' and result['result'].has_key? 'collection'
      otherdb = @db.connection[result['result']['db']]
      otherdb[result['result']['collection']]
    else
      @db[result["result"]]
    end
  else
    raise ArgumentError, "Could not instantiate collection from result. If you specified " +
      "{:out => {:inline => true}}, then you must also specify :raw => true to get the results."
  end
end
Also aliased as: mapreduce
mapreduce(map, reduce, opts={})
Alias for: map_reduce
options() click to toggle source

Return a hash containing options that apply to this collection. For all possible keys and values, see Mongo::DB#create_collection.

@return [Hash] options that apply to this collection.

# File lib/mongo/collection.rb, line 846
def options
  @db.collections_info(@name).next_document['options']
end
read_preference() click to toggle source

The value of the read preference. This will be either :primary, :secondary, or an object representing the tags to be read from.

# File lib/mongo/collection.rb, line 719
def read_preference
  @read_preference
end
remove(selector={}, opts={}) click to toggle source

Remove all documents from this collection.

@param [Hash] selector

If specified, only matching documents will be removed.

@option opts [Boolean, Hash] :safe (false)

run the operation in safe mode, which will run a getlasterror command on the
database to report any assertion. In addition, a hash can be provided to
run an fsync and/or wait for replication of the remove (>= 1.5.1). Safe
options provided here will override any safe options set on this collection,
its database, or the current connection. See the options for DB#get_last_error for more details.

@example remove all documents from the 'users' collection:

users.remove
users.remove({})

@example remove only documents that have expired:

users.remove({:expire => {"$lte" => Time.now}})

@return [Hash, true] Returns a Hash containing the last error object if running in safe mode.

Otherwise, returns true.

@raise [Mongo::OperationFailure] an exception will be raised iff safe mode is enabled

and the operation fails.

@core remove remove-instance_method

# File lib/mongo/collection.rb, line 383
def remove(selector={}, opts={})
  # Initial byte is 0.
  safe = opts.fetch(:safe, @safe)
  message = BSON::ByteBuffer.new("\00\\00\\00\\00"")
  BSON::BSON_RUBY.serialize_cstr(message, "#{@db.name}.#{@name}")
  message.put_int(0)
  message.put_binary(BSON::BSON_CODER.serialize(selector, false, true, @connection.max_bson_size).to_s)

  instrument(:remove, :database => @db.name, :collection => @name, :selector => selector) do
    if safe
      @connection.send_message_with_safe_check(Mongo::Constants::OP_DELETE, message, @db.name, nil, safe)
    else
      @connection.send_message(Mongo::Constants::OP_DELETE, message)
      true
    end
  end
end
rename(new_name) click to toggle source

Rename this collection.

Note: If operating in auth mode, the client must be authorized as an admin to perform this operation.

@param [String] new_name the new name for this collection

@return [String] the name of the new collection.

@raise [Mongo::InvalidNSName] if new_name is an invalid collection name.

# File lib/mongo/collection.rb, line 810
def rename(new_name)
  case new_name
  when Symbol, String
  else
    raise TypeError, "new_name must be a string or symbol"
  end

  new_name = new_name.to_s

  if new_name.empty? or new_name.include? ".."
    raise Mongo::InvalidNSName, "collection names cannot be empty"
  end
  if new_name.include? "$"
    raise Mongo::InvalidNSName, "collection names must not contain '$'"
  end
  if new_name.match(/^\./) or new_name.match(/\.$/)
    raise Mongo::InvalidNSName, "collection names must not start or end with '.'"
  end

  @db.rename_collection(@name, new_name)
  @name = new_name
end
save(doc, opts={}) click to toggle source

Save a document to this collection.

@param [Hash] doc

the document to be saved. If the document already has an '_id' key,
then an update (upsert) operation will be performed, and any existing
document with that _id is overwritten. Otherwise an insert operation is performed.

@return [ObjectId] the _id of the saved document.

@option opts [Boolean, Hash] :safe (false)

run the operation in safe mode, which run a getlasterror command on the
database to report any assertion. In addition, a hash can be provided to
run an fsync and/or wait for replication of the save (>= 1.5.1). See the options
for DB#error.

@raise [OperationFailure] when :safe mode fails.

# File lib/mongo/collection.rb, line 306
def save(doc, opts={})
  if doc.has_key?(:_id) || doc.has_key?('_id')
    id = doc[:_id] || doc['_id']
    update({:_id => id}, doc, :upsert => true, :safe => opts.fetch(:safe, @safe))
    id
  else
    insert(doc, :safe => opts.fetch(:safe, @safe))
  end
end
size(opts={})
Alias for: count
stats() click to toggle source

Return stats on the collection. Uses MongoDB's collstats command.

@return [Hash]

# File lib/mongo/collection.rb, line 853
def stats
  @db.command({:collstats => @name})
end
update(selector, document, opts={}) click to toggle source

Update one or more documents in this collection.

@param [Hash] selector

a hash specifying elements which must be present for a document to be updated. Note:
the update command currently updates only the first document matching the
given selector. If you want all matching documents to be updated, be sure
to specify :multi => true.

@param [Hash] document

a hash specifying the fields to be changed in the selected document,
or (in the case of an upsert) the document to be inserted

@option opts [Boolean] :upsert (false) if true, performs an upsert (update or insert) @option opts [Boolean] :multi (false) update all documents matching the selector, as opposed to

just the first matching document. Note: only works in MongoDB 1.1.3 or later.

@option opts [Boolean] :safe (false)

If true, check that the save succeeded. OperationFailure
will be raised on an error. Note that a safe check requires an extra
round-trip to the database. Safe options provided here will override any safe
options set on this collection, its database object, or the current collection.
See the options for DB#get_last_error for details.

@return [Hash, true] Returns a Hash containing the last error object if running in safe mode.

Otherwise, returns true.

@core update update-instance_method

# File lib/mongo/collection.rb, line 426
def update(selector, document, opts={})
  # Initial byte is 0.
  safe = opts.fetch(:safe, @safe)
  message = BSON::ByteBuffer.new("\00\\00\\00\\00"")
  BSON::BSON_RUBY.serialize_cstr(message, "#{@db.name}.#{@name}")
  update_options  = 0
  update_options += 1 if opts[:upsert]
  update_options += 2 if opts[:multi]
  message.put_int(update_options)
  message.put_binary(BSON::BSON_CODER.serialize(selector, false, true).to_s)
  message.put_binary(BSON::BSON_CODER.serialize(document, false, true, @connection.max_bson_size).to_s)

  instrument(:update, :database => @db.name, :collection => @name, :selector => selector, :document => document) do
    if safe
      @connection.send_message_with_safe_check(Mongo::Constants::OP_UPDATE, message, @db.name, nil, safe)
    else
      @connection.send_message(Mongo::Constants::OP_UPDATE, message)
    end
  end
end

Protected Instance Methods

normalize_hint_fields(hint) click to toggle source
# File lib/mongo/collection.rb, line 874
def normalize_hint_fields(hint)
  case hint
  when String
    {hint => 1}
  when Hash
    hint
  when nil
    nil
  else
    h = BSON::OrderedHash.new
    hint.to_a.each { |k| h[k] = 1 }
    h
  end
end

Private Instance Methods

generate_index_name(spec) click to toggle source
# File lib/mongo/collection.rb, line 992
def generate_index_name(spec)
  indexes = []
  spec.each_pair do |field, direction|
    indexes.push("#{field}_#{direction}")
  end
  indexes.join("_")
end
generate_indexes(field_spec, name, opts) click to toggle source
# File lib/mongo/collection.rb, line 919
def generate_indexes(field_spec, name, opts)
  selector = {
    :name   => name,
    :ns     => "#{@db.name}.#{@name}",
    :key    => field_spec
  }
  selector.merge!(opts)

  begin
  insert_documents([selector], Mongo::DB::SYSTEM_INDEX_COLLECTION, false, true)

  rescue Mongo::OperationFailure => e
    if selector[:dropDups] && e.message =~ /^11000/
      # NOP. If the user is intentionally dropping dups, we can ignore duplicate key errors.
    else
      raise Mongo::OperationFailure, "Failed to create index #{selector.inspect} with the following error: " +
       "#{e.message}"
    end
  end

  nil
end
index_name(spec) click to toggle source
# File lib/mongo/collection.rb, line 891
def index_name(spec)
  field_spec = parse_index_spec(spec)
  index_information.each do |index|
    return index[0] if index[1]['key'] == field_spec
  end
  nil
end
insert_documents(documents, collection_name=@name, check_keys=true, safe=false, flags={}) click to toggle source

Sends a Mongo::Constants::OP_INSERT message to the database. Takes an array of documents, an optional collection_name, and a check_keys setting.

# File lib/mongo/collection.rb, line 945
def insert_documents(documents, collection_name=@name, check_keys=true, safe=false, flags={})
  if flags[:continue_on_error]
    message = BSON::ByteBuffer.new
    message.put_int(1)
  else
    message = BSON::ByteBuffer.new("\00\\00\\00\\00"")
  end

  collect_on_error = !!flags[:collect_on_error]
  error_docs = [] if collect_on_error

  BSON::BSON_RUBY.serialize_cstr(message, "#{@db.name}.#{collection_name}")
  documents =
    if collect_on_error
      documents.select do |doc|
        begin
          message.put_binary(BSON::BSON_CODER.serialize(doc, check_keys, true, @connection.max_bson_size).to_s)
          true
        rescue StandardError # StandardError will be replaced with BSONError
          doc.delete(:_id)
          error_docs << doc
          false
        end
      end
    else
      documents.each do |doc|
        message.put_binary(BSON::BSON_CODER.serialize(doc, check_keys, true, @connection.max_bson_size).to_s)
      end
    end
  raise InvalidOperation, "Exceded maximum insert size of 16,000,000 bytes" if message.size > 16_000_000

  instrument(:insert, :database => @db.name, :collection => collection_name, :documents => documents) do
    if safe
      @connection.send_message_with_safe_check(Mongo::Constants::OP_INSERT, message, @db.name, nil, safe)
    else
      @connection.send_message(Mongo::Constants::OP_INSERT, message)
    end
  end

  doc_ids = documents.collect { |o| o[:_id] || o['_id'] }
  if collect_on_error
    return doc_ids, error_docs
  else
    doc_ids
  end
end
new_group(opts={}) click to toggle source
# File lib/mongo/collection.rb, line 725
def new_group(opts={})
  reduce   =  opts[:reduce]
  finalize =  opts[:finalize]
  cond     =  opts.fetch(:cond, {})
  initial  =  opts[:initial]

  if !(reduce && initial)
    raise MongoArgumentError, "Group requires at minimum values for initial and reduce."
  end

  cmd = {
    "group" => {
      "ns"      => @name,
      "$reduce" => reduce.to_bson_code,
      "cond"    => cond,
      "initial" => initial
    }
  }

  if finalize
    cmd['group']['finalize'] = finalize.to_bson_code
  end

  if key = opts[:key]
    if key.is_a?(String) || key.is_a?(Symbol)
      key = [key]
    end
    key_value = {}
    key.each { |k| key_value[k] = 1 }
    cmd["group"]["key"] = key_value
  elsif keyf = opts[:keyf]
    cmd["group"]["$keyf"] = keyf.to_bson_code
  end

  result = @db.command(cmd)
  result["retval"]
end
parse_index_spec(spec) click to toggle source
# File lib/mongo/collection.rb, line 899
def parse_index_spec(spec)
  field_spec = BSON::OrderedHash.new
  if spec.is_a?(String) || spec.is_a?(Symbol)
    field_spec[spec.to_s] = 1
  elsif spec.is_a?(Array) && spec.all? {|field| field.is_a?(Array) }
    spec.each do |f|
      if [Mongo::ASCENDING, Mongo::DESCENDING, Mongo::GEO2D, Mongo::GEOHAYSTACK].include?(f[1])
        field_spec[f[0].to_s] = f[1]
      else
        raise MongoArgumentError, "Invalid index field #{f[1].inspect}; " +
          "should be one of Mongo::ASCENDING (1), Mongo::DESCENDING (-1) or Mongo::GEO2D ('2d')."
      end
    end
  else
    raise MongoArgumentError, "Invalid index specification #{spec.inspect}; " +
      "should be either a string, symbol, or an array of arrays."
  end
  field_spec
end