Class: Mongo::DB

Inherits:
Object show all
Defined in:
lib/mongo/db.rb

Overview

A MongoDB database.

Constant Summary collapse

SYSTEM_NAMESPACE_COLLECTION = 
"system.namespaces"
SYSTEM_INDEX_COLLECTION = 
"system.indexes"
SYSTEM_PROFILE_COLLECTION = 
"system.profile"
SYSTEM_USER_COLLECTION = 
"system.users"
SYSTEM_JS_COLLECTION = 
"system.js"
SYSTEM_COMMAND_COLLECTION = 
"$cmd"
@@current_request_id =

Counter for generating unique request ids.

0

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name, connection, opts = {}) ⇒ DB

Instances of DB are normally obtained by calling Mongo#db.

Parameters:

  • name (String) —

    the database name.

  • connection (Mongo::Connection) —

    a connection object pointing to MongoDB. Note that databases are usually instantiated via the Connection class. See the examples below.

  • opts (Hash) (defaults to: {}) —

    a customizable set of options

Options Hash (opts):

  • :strict (Boolean) — default: False —

    If true, collections must exist to be accessed and must not exist to be created. See DB#collection and DB#create_collection.

  • :pk (Object, #create_pk(doc)) — default: Mongo::ObjectId —

    A primary key factory object, which should take a hash and return a hash which merges the original hash with any primary key fields the factory wishes to inject. (NOTE: if the object already has a primary key, the factory should not inject a new key).

  • :safe (Boolean, Hash) — default: false —

    Set the default safe-mode options propogated to Collection objects instantiated off of this DB. If no value is provided, the default value set on this instance’s Connection object will be used. This default can be overridden upon instantiation of any collection by explicity setting a :safe value on initialization

  • :cache_time (Integer) — default: 300 —

    Set the time that all ensure_index calls should cache the command.



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# File 'lib/mongo/db.rb', line 79

def initialize(name, connection, opts={})
  @name       = Mongo::Support.validate_db_name(name)
  @connection = connection
  @strict     = opts[:strict]
  @pk_factory = opts[:pk]
  @safe       = opts.fetch(:safe, @connection.safe)
  @cache_time = opts[:cache_time] || 300 #5 minutes.
end

Instance Attribute Details

#cache_time ⇒ Object

The length of time that Collection.ensure_index should cache index calls



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# File 'lib/mongo/db.rb', line 55

def cache_time
  @cache_time
end

#connection ⇒ Object (readonly)

The Mongo::Connection instance connecting to the MongoDB server.



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# File 'lib/mongo/db.rb', line 52

def connection
  @connection
end

#name ⇒ Object (readonly)

The name of the database and the local safe option.



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# File 'lib/mongo/db.rb', line 49

def name
  @name
end

#safe ⇒ Object (readonly)

The name of the database and the local safe option.



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# File 'lib/mongo/db.rb', line 49

def safe
  @safe
end

#strict=(value) ⇒ Object (writeonly)

Strict mode enforces collection existence checks. When true, asking for a collection that does not exist, or trying to create a collection that already exists, raises an error.

Strict mode is disabled by default, but enabled (true) at any time.



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# File 'lib/mongo/db.rb', line 43

def strict=(value)
  @strict = value
end

Instance Method Details

#add_stored_function(function_name, code) ⇒ String

Adds a stored Javascript function to the database which can executed

server-side in map_reduce, db.eval and $where clauses.

Parameters:

Returns:

  • (String) —

    the function name saved to the database



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# File 'lib/mongo/db.rb', line 141

def add_stored_function(function_name, code)
  self[SYSTEM_JS_COLLECTION].save(
    {
      "_id" => function_name, 
      :value => BSON::Code.new(code)
    }
  )
end

#add_user(username, password) ⇒ Hash

Adds a user to this database for use with authentication. If the user already exists in the system, the password will be updated.

Parameters:

Returns:

  • (Hash) —

    an object representing the user.



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# File 'lib/mongo/db.rb', line 171

def add_user(username, password)
  users = self[SYSTEM_USER_COLLECTION]
  user  = users.find_one({:user => username}) || {:user => username}
  user['pwd'] = Mongo::Support.hash_password(username, password)
  users.save(user)
  return user
end

#authenticate(username, password, save_auth = true) ⇒ Boolean

Authenticate with the given username and password. Note that mongod must be started with the –auth option for authentication to be enabled.

Parameters:

  • username (String)
  • password (String)
  • save_auth (Boolean) (defaults to: true) —

    Save this authentication to the connection object using Connection#add_auth. This will ensure that the authentication will be applied on database reconnect. Note that this value must be true when using connection pooling.

Returns:

  • (Boolean)

Raises:



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# File 'lib/mongo/db.rb', line 103

def authenticate(username, password, save_auth=true)
  if @connection.pool_size > 1
    if !save_auth
      raise MongoArgumentError, "If using connection pooling, :save_auth must be set to true."
    end
    @connection.authenticate_pools
  end

  issue_authentication(username, password, save_auth)
end

#collection(name, opts = {}) ⇒ Mongo::Collection Also known as: []

Get a collection by name.

Parameters:

  • name (String) —

    the collection name.

  • opts (Hash) (defaults to: {}) —

    any valid options that can me passed to Collection#new.

Returns:

Raises:

  • (MongoDBError) —

    if collection does not already exist and we’re in strict mode.



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# File 'lib/mongo/db.rb', line 295

def collection(name, opts={})
  if strict? && !collection_names.include?(name)
    raise Mongo::MongoDBError, "Collection #{name} doesn't exist. Currently in strict mode."
  else
    opts[:safe] = opts.fetch(:safe, @safe)
    opts.merge!(:pk => @pk_factory) unless opts[:pk]
    Collection.new(name, self, opts)
  end
end

#collection_names ⇒ Array

Get an array of collection names in this database.

Returns:

  • (Array) 


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# File 'lib/mongo/db.rb', line 221

def collection_names
  names = collections_info.collect { |doc| doc['name'] || '' }
  names = names.delete_if {|name| name.index(@name).nil? || name.index('$')}
  names.map {|name| name.sub(@name + '.', '')}
end

#collections ⇒ Array<Mongo::Collection>

Get an array of Collection instances, one for each collection in this database.

Returns:



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# File 'lib/mongo/db.rb', line 230

def collections
  collection_names.map do |name|
    Collection.new(name, self)
  end
end

#collections_info(coll_name = nil) ⇒ Mongo::Cursor

Get info on system namespaces (collections). This method returns a cursor which can be iterated over. For each collection, a hash will be yielded containing a ‘name’ string and, optionally, an ‘options’ hash.

Parameters:

  • coll_name (String) (defaults to: nil) —

    return info for the specifed collection only.

Returns:



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# File 'lib/mongo/db.rb', line 243

def collections_info(coll_name=nil)
  selector = {}
  selector[:name] = full_collection_name(coll_name) if coll_name
  Cursor.new(Collection.new(SYSTEM_NAMESPACE_COLLECTION, self), :selector => selector)
end

#command(selector, opts = {}) ⇒ Hash

Send a command to the database.

Note: DB commands must start with the “command” key. For this reason, any selector containing more than one key must be an OrderedHash.

Note also that a command in MongoDB is just a kind of query that occurs on the system command collection ($cmd). Examine this method’s implementation to see how it works.

key, specifying the command to be performed. In Ruby 1.9, OrderedHash isn’t necessary since hashes are ordered by default.

command fails.

Parameters:

  • selector (OrderedHash, Hash) —

    an OrderedHash, or a standard Hash with just one

  • opts (Hash) (defaults to: {}) —

    a customizable set of options

Options Hash (opts):

  • :check_response (Boolean) — default: true —

    If true, raises an exception if the

  • :socket (Socket) —

    a socket to use for sending the command. This is mainly for internal use.

Returns:

Raises:



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# File 'lib/mongo/db.rb', line 483

def command(selector, opts={})
  check_response = opts.fetch(:check_response, true)
  socket         = opts[:socket]
  raise MongoArgumentError, "command must be given a selector" unless selector.is_a?(Hash) && !selector.empty?
  if selector.keys.length > 1 && RUBY_VERSION < '1.9' && selector.class != BSON::OrderedHash
    raise MongoArgumentError, "DB#command requires an OrderedHash when hash contains multiple keys"
  end

  begin
    result = Cursor.new(system_command_collection,
      :limit => -1, :selector => selector, :socket => socket).next_document
  rescue OperationFailure => ex
    raise OperationFailure, "Database command '#{selector.keys.first}' failed: #{ex.message}"
  end

  if result.nil?
    raise OperationFailure, "Database command '#{selector.keys.first}' failed: returned null."
  elsif (check_response && !ok?(result))
    raise OperationFailure, "Database command '#{selector.keys.first}' failed: #{result.inspect}"
  else
    result
  end
end

#create_collection(name, opts = {}) ⇒ Mongo::Collection

Create a collection.

new collection. If strict is true, will raise an error if collection name already exists.

Parameters:

  • name (String) —

    the name of the new collection.

  • opts (Hash) (defaults to: {}) —

    a customizable set of options

Options Hash (opts):

  • :capped (Boolean) — default: False —

    created a capped collection.

  • :size (Integer) — default: Nil —

    If capped is true, specifies the maximum number of bytes for the capped collection. If false, specifies the number of bytes allocated for the initial extent of the collection.

  • :max (Integer) — default: Nil —

    If capped is true, indicates the maximum number of records in a capped collection.

Returns:

Raises:

  • (MongoDBError) —

    raised under two conditions: either we’re in strict mode and the collection already exists or collection creation fails on the server.



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# File 'lib/mongo/db.rb', line 269

def create_collection(name, opts={})
  # Does the collection already exist?
  if collection_names.include?(name)
    if strict?
      raise MongoDBError, "Collection #{name} already exists. Currently in strict mode."
    else
      return Collection.new(name, self)
    end
  end

  # Create a new collection.
  oh = BSON::OrderedHash.new
  oh[:create] = name
  doc = command(oh.merge(opts || {}))
  return Collection.new(name, self, :pk => @pk_factory) if ok?(doc)
  raise MongoDBError, "Error creating collection: #{doc.inspect}"
end

#dereference(dbref) ⇒ Hash

Dereference a DBRef, returning the document it points to.

Parameters:

  • dbref (Mongo::DBRef)

Returns:

  • (Hash) —

    the document indicated by the db reference.

See Also:



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# File 'lib/mongo/db.rb', line 375

def dereference(dbref)
  collection(dbref.namespace).find_one("_id" => dbref.object_id)
end

#drop_collection(name) ⇒ Boolean

Drop a collection by name.

Parameters:

Returns:

  • (Boolean) —

    true on success or false if the collection name doesn’t exist.



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# File 'lib/mongo/db.rb', line 311

def drop_collection(name)
  return true unless collection_names.include?(name)

  ok?(command(:drop => name))
end

#drop_index(collection_name, index_name) ⇒ True

Drop an index from a given collection. Normally called from Collection#drop_index or Collection#drop_indexes.

Parameters:

Returns:

  • (True) —

    returns true on success.

Raises:

  • MongoDBError if there’s an error renaming the collection.



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# File 'lib/mongo/db.rb', line 423

def drop_index(collection_name, index_name)
  oh = BSON::OrderedHash.new
  oh[:deleteIndexes] = collection_name
  oh[:index] = index_name.to_s
  doc = command(oh, :check_response => false)
  ok?(doc) || raise(MongoDBError, "Error with drop_index command: #{doc.inspect}")
end

#error? ⇒ Boolean

Return true if an error was caused by the most recently executed database operation.

Returns:

  • (Boolean) 


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# File 'lib/mongo/db.rb', line 339

def error?
  get_last_error['err'] != nil
end

#eval(code, *args) ⇒ String

Evaluate a JavaScript expression in MongoDB.

Parameters:

  • code (String, Code) —

    a JavaScript expression to evaluate server-side.

  • args (Integer, Hash) —

    any additional argument to be passed to the code expression when it’s run on the server.

Returns:

  • (String) —

    the return value of the function.



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# File 'lib/mongo/db.rb', line 386

def eval(code, *args)
  if not code.is_a? BSON::Code
    code = BSON::Code.new(code)
  end

  oh = BSON::OrderedHash.new
  oh[:$eval] = code
  oh[:args]  = args
  doc = command(oh)
  doc['retval']
end

#full_collection_name(collection_name) ⇒ String

A shortcut returning db plus dot plus collection name.

Parameters:

Returns:



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# File 'lib/mongo/db.rb', line 512

def full_collection_name(collection_name)
  "#{@name}.#{collection_name}"
end

#get_last_error(opts = {}) ⇒ Hash

Run the getlasterror command with the specified replication options.

Parameters:

  • opts (Hash) (defaults to: {}) —

    a customizable set of options

Options Hash (opts):

  • :fsync (Boolean) — default: false
  • :w (Integer) — default: nil
  • :wtimeout (Integer) — default: nil

Returns:

  • (Hash) —

    the entire response to getlasterror.

Raises:



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# File 'lib/mongo/db.rb', line 326

def get_last_error(opts={})
  cmd = BSON::OrderedHash.new
  cmd[:getlasterror] = 1
  cmd.merge!(opts)
  doc = command(cmd, :check_response => false)
  raise MongoDBError, "error retrieving last error: #{doc.inspect}" unless ok?(doc)
  doc
end

#index_information(collection_name) ⇒ Hash

Get information on the indexes for the given collection. Normally called by Collection#index_information.

Parameters:

Returns:

  • (Hash) —

    keys are index names and the values are lists of [key, direction] pairs defining the index.



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# File 'lib/mongo/db.rb', line 438

def index_information(collection_name)
  sel  = {:ns => full_collection_name(collection_name)}
  info = {}
  Cursor.new(Collection.new(SYSTEM_INDEX_COLLECTION, self), :selector => sel).each do |index|
    info[index['name']] = index
  end
  info
end

#issue_authentication(username, password, save_auth = true, opts = {}) ⇒ Object

Raises:



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# File 'lib/mongo/db.rb', line 114

def issue_authentication(username, password, save_auth=true, opts={})
  doc = command({:getnonce => 1}, :check_response => false, :socket => opts[:socket])
  raise MongoDBError, "Error retrieving nonce: #{doc}" unless ok?(doc)
  nonce = doc['nonce']

  auth = BSON::OrderedHash.new
  auth['authenticate'] = 1
  auth['user'] = username
  auth['nonce'] = nonce
  auth['key'] = Mongo::Support.auth_key(username, password, nonce)
  if ok?(self.command(auth, :check_response => false, :socket => opts[:socket]))
    if save_auth
      @connection.add_auth(@name, username, password)
    end
    true
  else
    raise(Mongo::AuthenticationError, "Failed to authenticate user '#{username}' on db '#{self.name}'")
  end
end

#issue_logout(opts = {}) ⇒ Object 



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# File 'lib/mongo/db.rb', line 208

def issue_logout(opts={})
  doc = command({:logout => 1}, :socket => opts[:socket])
  if ok?(doc)
    @connection.remove_auth(@name)
    true
  else
    raise MongoDBError, "error logging out: #{doc.inspect}"
  end
end

#logout(opts = {}) ⇒ Boolean

Deauthorizes use for this database for this connection. Also removes any saved authentication in the connection class associated with this database.

Returns:

  • (Boolean)

Raises:



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# File 'lib/mongo/db.rb', line 200

def logout(opts={})
  if @connection.pool_size > 1
    @connection.logout_pools(@name)
  end

  issue_logout(opts)
end

#ok?(doc) ⇒ Boolean

Return true if the supplied doc contains an ‘ok’ field with the value 1.

Parameters:

Returns:

  • (Boolean) 


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# File 'lib/mongo/db.rb', line 459

def ok?(doc)
  Mongo::Support.ok?(doc)
end

#pk_factory ⇒ Object, Nil

The primary key factory object (or nil).

Returns:



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# File 'lib/mongo/db.rb', line 519

def pk_factory
  @pk_factory
end

#pk_factory=(pk_factory) ⇒ Object

Specify a primary key factory if not already set.

Raises:



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# File 'lib/mongo/db.rb', line 526

def pk_factory=(pk_factory)
  if @pk_factory
    raise MongoArgumentError, "Cannot change primary key factory once it's been set"
  end

  @pk_factory = pk_factory
end

#previous_error ⇒ String, Nil

Get the most recent error to have occured on this database.

This command only returns errors that have occured since the last call to DB#reset_error_history - returns nil if there is no such error.

Returns:

  • (String, Nil) —

    the text of the error or nil if no error has occurred.



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# File 'lib/mongo/db.rb', line 349

def previous_error
  error = command(:getpreverror => 1)
  if error["err"]
    error
  else
    nil
  end
end

#profiling_info ⇒ Array

Get the current profiling information.

Returns:

  • (Array) —

    a list of documents containing profiling information.



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# File 'lib/mongo/db.rb', line 580

def profiling_info
  Cursor.new(Collection.new(SYSTEM_PROFILE_COLLECTION, self), :selector => {}).to_a
end

#profiling_level ⇒ Symbol

Return the current database profiling level. If profiling is enabled, you can get the results using DB#profiling_info.

Returns:

  • (Symbol) —

    :off, :slow_only, or :all



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# File 'lib/mongo/db.rb', line 540

def profiling_level
  oh = BSON::OrderedHash.new
  oh[:profile] = -1
  doc = command(oh, :check_response => false)
  raise "Error with profile command: #{doc.inspect}" unless ok?(doc) && doc['was'].kind_of?(Numeric)
  case doc['was'].to_i
  when 0
    :off
  when 1
    :slow_only
  when 2
    :all
  else
    raise "Error: illegal profiling level value #{doc['was']}"
  end
end

#profiling_level=(level) ⇒ Object

Set this database’s profiling level. If profiling is enabled, you can get the results using DB#profiling_info.

Parameters:

  • level (Symbol) —

    acceptable options are :off, :slow_only, or :all.



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# File 'lib/mongo/db.rb', line 561

def profiling_level=(level)
  oh = BSON::OrderedHash.new
  oh[:profile] = case level
                 when :off
                   0
                 when :slow_only
                   1
                 when :all
                   2
                 else
                   raise "Error: illegal profiling level value #{level}"
                 end
  doc = command(oh, :check_response => false)
  ok?(doc) || raise(MongoDBError, "Error with profile command: #{doc.inspect}")
end

#remove_stored_function(function_name) ⇒ Boolean

Removes stored Javascript function from the database. Returns false if the function does not exist

Parameters:

Returns:

  • (Boolean) 


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# File 'lib/mongo/db.rb', line 156

def remove_stored_function(function_name)
  if self[SYSTEM_JS_COLLECTION].find_one({"_id" => function_name})
    self[SYSTEM_JS_COLLECTION].remove({"_id" => function_name}, :safe => true)
  else
    return false
  end
end

#remove_user(username) ⇒ Boolean

Remove the given user from this database. Returns false if the user doesn’t exist in the system.

Parameters:

Returns:

  • (Boolean) 


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# File 'lib/mongo/db.rb', line 185

def remove_user(username)
  if self[SYSTEM_USER_COLLECTION].find_one({:user => username})
    self[SYSTEM_USER_COLLECTION].remove({:user => username}, :safe => true)
  else
    return false
  end
end

#rename_collection(from, to) ⇒ True

Rename a collection.

Parameters:

  • from (String) —

    original collection name.

  • to (String) —

    new collection name.

Returns:

  • (True) —

    returns true on success.

Raises:

  • MongoDBError if there’s an error renaming the collection.



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# File 'lib/mongo/db.rb', line 406

def rename_collection(from, to)
  oh = BSON::OrderedHash.new
  oh[:renameCollection] = "#{@name}.#{from}"
  oh[:to] = "#{@name}.#{to}"
  doc = DB.new('admin', @connection).command(oh, :check_response => false)
  ok?(doc) || raise(MongoDBError, "Error renaming collection: #{doc.inspect}")
end

#reset_error_history ⇒ Hash

Reset the error history of this database

Calls to DB#previous_error will only return errors that have occurred since the most recent call to this method.

Returns:



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# File 'lib/mongo/db.rb', line 364

def reset_error_history
  command(:reseterror => 1)
end

#stats ⇒ Hash

Return stats on this database. Uses MongoDB’s dbstats command.

Returns:



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# File 'lib/mongo/db.rb', line 450

def stats
  self.command({:dbstats => 1})
end

#strict? ⇒ Boolean

Returns the value of the strict flag.

Returns:

  • (Boolean) 


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# File 'lib/mongo/db.rb', line 46

def strict?; @strict; end

#validate_collection(name) ⇒ Hash

Validate a named collection.

Parameters:

  • name (String) —

    the collection name.

Returns:

  • (Hash) —

    validation information.

Raises:

  • (MongoDBError) —

    if the command fails or there’s a problem with the validation data, or if the collection is invalid.



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# File 'lib/mongo/db.rb', line 592

def validate_collection(name)
  doc = command({:validate => name}, :check_response => false)
  raise MongoDBError, "Error with validate command: #{doc.inspect}" unless ok?(doc)
  result = doc['result']
  raise MongoDBError, "Error with validation data: #{doc.inspect}" unless result.kind_of?(String)
  raise MongoDBError, "Error: invalid collection #{name}: #{doc.inspect}" if result =~ /\b(exception|corrupt)\b/i
  doc
end