2026-05-23 06:01 @216.73.217.24 CrawledBy Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)
NAME MongoDB::Upgrading::v1 - Deprecations and behavior changes from v0 to v1 VERSION version v2.2.2 DESCRIPTION The v1 driver represents a substantial step forward in functionality and consistency. There are many areas where the old API has been deprecated or changed in a backward breaking way. This document is intended to help developers update their code to take into account API changes from the v0 driver to the v1 driver. RATIONALE Changes to the driver were deemed necessary to achieve certain goals: * consistency (intra-driver) – many parts of the v0 API were inconsistent, behaving differently from method to method; the v1 API minimizes developer surprises by improving consistency in return types and exception mechanisms. * consistency (inter-driver) — "next-generation" MongoDB drivers across all languages are converging on common APIs and common behaviors; this simplifies developer education and support, as cross-language examples will be similar. * encapsulation – too many low-level, internal operations were exposed as part of the API, which complicates maintenance work; the v1 API aims to minimize the "public surface" available to developers, allowing faster future development keeping up with MongoDB server enhancements with less risk of breakage. * abstraction – many v0 methods returned raw server documents for end-user code to inspect, which is brittle in the face of changes in server responses over time; the v1 API uses result classes to abstract the details behind standardized accessors. * server compatibility – some new features and behavior changes in the MongoDB server no longer fit the old driver design; the v1 driver transparently supports both old and new servers. * portability – the v0 driver had a large dependency tree and substantial non-portable C code; the v1 driver removes some dependencies and uses widely-used, well-tested CPAN modules in place of custom C code where possible; it lays the groundwork for a future "pure-Perl optional" driver. * round-trippable data – the v0 BSON implementation could easily change data types when round-tripping documents; the v1 driver is designed to round-trip data correctly whenever possible (within the limits of Perl's dynamic typing). INSTALLATION AND DEPENDENCY CHANGES Moo instead of Moose The v1 driver uses Moo instead of Moose. This change results in a slightly faster driver and a significantly reduced deep dependency tree. SSL and SASL The v0 driver required a compiler and OpenSSL and libgsasl for SSL and SASL support, respectively. The v1 driver instead relies on CPAN modules "IO::Socket::SSL" and "Authen::SASL" for SSL and SASL support, respectively. SSL configuration is now possible via the ssl attribute. Authentication configuration is described in "AUTHENTICATION" in MongoDB::MongoClient. BEHAVIOR CHANGES MongoClient configuration New configuration options Several configuration options have been added, with particular emphasis on adding more granular control of timings and timeout behaviors. * "auth_mechanism" * "auth_mechanism_properties" * "bson_codec" * "connect_timeout_ms" * "heartbeat_frequency_ms" * "local_threshold_ms" * "max_time_ms" * "replica_set_name" * "read_pref_mode" * "read_pref_tag_sets" * "server_selection_timeout_ms" * "socket_check_interval_ms" * "socket_timeout_ms" Replica set configuration Connecting to a replica set now requires a replica set name, given either with the "replica_set_name" option for MongoDB::MongoClient or with the "replicaSet" option in a connection string. For example: $client = MongoDB::MongoClient->new( host => "mongodb://rs1.example.com,rs2.example.com/", replica_set_name => 'the_set', ); $client = MongoDB::MongoClient->new( host => "mongodb://rs1.example.com,rs2.example.com/?replicaSet=the_set" ); Configuration options changed to read-only Configuration options are changing to be immutable to prevent surprising action-at-a-distance. (E.g. changing an attribute value in some part of the code changes it for other parts of the code that didn't expect it.) Going forward, options may be set at MongoDB::MongoClient construction time only. The following options have changed to be read-only: * "db_name" * "j" * "password" * "ssl" * "username" * "w" * "wtimeout" Write concern may be overridden at the MongoDB::Database and MongoDB::Collection level during construction of those objects. For more details, see the later section on write concern changes. Mapping between connection string and configuration options Many configuration options may be set via a connection string URI in the "host" option. In the v0 driver, the precedence between the connection string and constructor options was completely inconsistent. In the v1 driver, options set via a connection string URI will take precedence over options passed to the constructor. This is consistent with with other MongoDB drivers (as well as how DBI treats Data Source Names). The list of servers and ports as well as the optional "username", "password" and "db_name" options come directly from URI structure. Other options are parsed as key-value parameters at the end of the connection string. The following table shows how connection string keys map to configuration options in the MongoDB::MongoClient: Connection String Key MongoClient option --------------------------- ----------------------------- authMechanism auth_mechanism authMechanismProperties auth_mechanism_properties connectTimeoutMS connect_timeout_ms heartbeatFrequencyMS heartbeat_frequency_ms journal j localThresholdMS local_threshold_ms maxTimeMS max_time_ms readPreference read_pref_mode readPreferenceTags read_pref_tag_sets replicaSet replica_set_name serverSelectionTimeoutMS server_selection_timeout_ms socketCheckIntervalMS socket_check_interval_ms socketTimeoutMS socket_timeout_ms ssl ssl w w wTimeoutMS wtimeout The "readPreferenceTags" and "authMechanismProperties" keys take colon-delimited, comma-separated pairs: readPreferenceTags=dc:nyeast,rack:1 authMechanismProperties=SERVICE_NAME:mongodb The "readPreferenceTags" option may be repeated to build up a list of tag set documents: readPreferenceTags=dc:nyc,rack:1&readPreferenceTags=dc:nyc Deprecated configuration options Several options have been superseded, replaced or renamed for clarity and are thus deprecated and undocumented. They are kept for a limited degree of backwards compatibility. They will be generally be used as fallbacks for other options. If any were read-write, they have also been changed to read-only. * "dt_type" — see "BSON encoding changes" for details. * "query_timeout" — replaced by "socket_timeout_ms"; if set, this will be used as a fallback default for "socket_timeout_ms". * "sasl" — superseded by "auth_mechanism"; if set, this will be used along with "sasl_mechanism" as a fallback default for "auth_mechanism". * "sasl_mechanism" — superseded by "auth_mechanism"; if set, this will be used as a fallback default for "auth_mechanism". * "timeout" — replaced by "connect_timeout_ms"; if set, this will be used as a fallback default for "connect_timeout_ms". These will be removed in a future major release. Configuration options removed Some configuration options have been removed entirely, as they no longer serve any purpose given changes to server discovery, server selection and connection handling: * "auto_connect" * "auto_reconnect" * "find_master" * "max_bson_size" As described further below in the "BSON encoding changes" section, these BSON encoding configuration options have been removed as well: * "inflate_dbrefs" * "inflate_regexps" Removed configuration options will be ignored if passed to the MongoDB::MongoClient constructor. Lazy connections and reconnections on demand The improved approach to server monitoring and selection allows all connections to be lazy. When the client is constructed, no connections are made until the first network operation is needed. At that time, the client will scan all servers in the seed list and begin regular monitoring. Connections that drop will be re-established when needed. IMPORTANT: Code that used to rely on a fatal exception from "MongoDB::MongoClient->new" when no mongod is available will break. Instead, users are advised to just conduct their operations and be prepared to handle errors. For testing, users may wish to run a simple command to check that a mongod is ready: use Test::More; # OLD WAY: BROKEN plan skip_all => 'no mongod' unless eval { MongoDB::MongoClient->new }; # NEW WAY 1: with MongoDB::MongoClient plan skip_all => 'no mongod' unless eval { MongoDB::MongoClient->new->db('admin')->run_command( [ ismaster => 1 ] ) }; # NEW WAY 2: with MongoDB and connect plan skip_all => 'no mongod' unless eval { MongoDB->connect->db('admin')->run_command([ ismaster => 1 ]) }; See SERVER SELECTION and SERVER MONITORING AND FAILOVER in MongoDB::MongoClient for details. Exceptions are the preferred error handling approach In the v0 driver, errors could be indicated in various ways: * boolean return value * string return value is an error; hash ref is success * document that might contain an 'err', 'errmsg' or '$err' field * thrown string exception Regardless of the documented error handling, every method that involved a network operation would throw an exception on various network errors. In the v1 driver, exceptions objects are the standard way of indicating errors. The exception hierarchy is described in MongoDB::Error. Cursors and query responses In v0, MongoDB::Cursor objects were used for ordinary queries as well as the query-like commands aggregation and parallel scan. However, only cursor iteration commands worked for aggregation and parallel scan "cursors"; the rest of the MongoDB::Cursor API didn't apply and was fatal. In v1, all result iteration is done via the new MongoDB::QueryResult class. MongoDB::Cursor is now just a thin wrapper that holds query parameters, instantiates a MongoDB::QueryResult on demand, and passes iteration methods through to the query result object. This significantly simplifies the code base and should have little end-user visibility unless users are specifically checking the return type of queries and query-like methods. The "explain" cursor method no longer resets the cursor. The "slave_okay" cursor method now sets the "read_preference" to 'secondaryPreferred' or clears it to 'primary'. The "snapshot" cursor method now requires a boolean argument, allowing it to be turned on or off before executing the query. Calling it without an argument (as it was in v0) is a fatal exception. Parallel scan "cursors" are now QueryResult objects, with the same iteration methods as in v0. The $MongoDB::Cursor::slave_okay global variable has been removed as part of the revision to read preference handling. See the read preferences section below for more details. The $MongoDB::Cursor::timeout global variable has also been removed. Timeouts are set during MongoDB::MongoClient configuration and are immutable. See the section on configuration changes for more. Aggregation API On MongoDB 2.6 or later, "aggregate" always uses a cursor to execute the query. The "batchSize" option has been added (but has no effect prior to 2.6). The "cursor" option is deprecated. The return types for the "aggregate" method are now always QueryResult objects, regardless of whether the aggregation uses a cursor internally or is an 'explain'. NOTE: To help users with a 2.6 mongos and mixed version shards with versions before 2.6, passing the deprecated 'cursor' option with a false value will disable the use of a cursor. This workaround is provided for convenience and will be removed when 2.4 is no longer supported. Read preference objects and the read_preference method A new MongoDB::ReadPreference class is used to encapsulate read preference attributes. In the v1 driver, it is constructed from the "read_pref_mode" and "read_pref_tag_sets" attributes on MongoDB::MongoClient: MongoDB::MongoClient->new( read_pref_mode => 'primaryPreferred', read_pref_tag_sets => [ { dc => 'useast' }, {} ], ); The old "read_preference" method to change the read preference has been removed and trying to set a read preference after the client has been created is a fatal error. The old mode constants PRIMARY, SECONDARY, etc. have been removed. The "read_preference" method now returns the MongoDB::ReadPreference object generated from "read_pref_mode" and "read_pref_tag_sets". It is inherited by MongoDB::Database, MongoDB::Collection, and MongoDB::GridFS objects unless provided as an option to the relevant factory methods: my $coll = $db->get_collection( "foo", { read_preference => 'secondary' } ); Such "read_preference" arguments may be a MongoDB::ReadPreference object, a hash reference of arguments to construct one, or a string that represents the read preference mode. MongoDB::Database and MongoDB::Collection also have "clone" methods that allow easy alteration of a read preference for a limited scope. my $coll2 = $coll->clone( read_preference => 'secondaryPreferred' ); For MongoDB::Cursor, the "read_preference" method sets a hidden read preference attribute that is used for the query in place of the MongoDB::MongoClient default "read_preference" attribute. This means that calling "read_preference" on a cursor object no longer changes the read preference globally on the client – the read preference change is scoped to the cursor object only. Write concern objects and removing the safe argument A new MongoDB::WriteConcern class is used to encapsulate write concern attributes. In the v1 driver, it is constructed from the "w", "wtimeout" and "j" attributes on MongoDB::MongoClient: MongoDB::MongoClient->new( w => 'majority', wtimeout => 1000 ); The "write_concern" method now returns the MongoDB::WriteConcern object generated from "w", "wtimeout" and "j". It is inherited by MongoDB::Database, MongoDB::Collection, and MongoDB::GridFS objects unless provided as an option to the relevant factory methods: $db = $client->get_database( "test", { write_concern => { w => 'majority' } } ); Such "write_concern" arguments may be a MongoDB::WriteConcern object, a hash reference of arguments to construct one, or a string that represents the "w" mode. MongoDB::Database and MongoDB::Collection also have "clone" methods that allow easy alteration of a write concern for a limited scope. my $coll2 = $coll->clone( write_concern => { w => 1 } ); The "safe" argument is no longer used in the new CRUD API. Authentication based only on configuration options Authentication now happens automatically on connection during the "handshake" with any given server based on the auth_mechanism attribute. The old "authenticate" method in MongoDB::MongoClient has been removed. Bulk API Bulk method names changed to match CRUD API Method names match the new CRUD API, e.g. "insert_one" instead of "insert" and so one. The legacy names are deprecated. Bulk insertion Insertion via the bulk API will NOT insert an "_id" into the original document if one does not exist. Previous documentation was not specific whether this was the case or if the "_id" was added to the document sent to the server. Bulk write results The bulk write results class has been renamed to MongoDB::BulkWriteResult. It keeps "MongoDB::WriteResult" as an empty superclass for some backwards compatibility so that "$result->isa("MongoDB::WriteResult")" will continue to work as expected. The attributes have been renamed to be consistent with the new CRUD API. The legacy names are deprecated, but are available as aliases. GridFS The MongoDB::GridFS class now has explicit read preference and write concern attributes inherited from MongoDB::MongoClient or MongoDB::Database, just like MongoDB::Collection. This means that GridFS operations now default to an acknowledged write concern, just like collection operations have been doing since v0.502.0 in 2012. The use of "safe" is deprecated. Support for ancient, undocumented positional parameters circa 2010 has been removed. Low-level functions removed Low-level driver functions have been removed from the public API. MongoDB::Connection removed The "MongoDB::Connection" module was deprecated in v0.502.0 and has been removed. BSON encoding changes In the v1 driver, BSON encoding and decoding have been encapsulated into a MongoDB::BSON codec object. This can be provided at any level, from MongoDB::MongoClient to MongoDB::Collection. If not provided, a default will be created that behaves similarly to the v0 encoding/decoding functions, except for the following changes. $MongoDB::BSON::use_binary removed Historically, this defaulted to false, which corrupts binary data when round tripping. Retrieving a binary data element and re-inserting it would have resulted in a field with UTF-8 encoded string of binary data. Going forward, binary data will be returned as a MongoDB::BSON::Binary object. A future driver may add the ability to control decoding to allow alternative representations. $MongoDB::BSON::use_boolean removed This global variable never worked. BSON booleans were always deserialized as boolean objects. A future driver may add the ability to control boolean representation. $MongoDB::BSON::utf8_flag_on removed In order to ensure round-tripping of string data, this variable is removed. BSON strings will always be decoded to Perl character strings. Anything else risks double-encoding a round-trip. $MongoDB::BSON::looks_like_number and $MongoDB::BSON::char deprecated and re-scoped In order to allow a future driver to provide more flexible user-customized encoding and decoding, these global variables are deprecated. If set, they will be examined during "MongoDB::MongoClient->new()" to set the configuration of a default MongoDB::BSON codec (if one is not provided). Changing them later will NOT change the behavior of the codec object. "MongoDB::MongoClient" option "inflate_regexps" removed Previously, BSON regular expressions decoded to "qr{}" references by default and the "MongoDB::MongoClient" "inflate_regexps" option was available to decode instead to MongoDB::BSON::Regexps. Going forward in the v1.0.0 driver, for safety and consistency with other drivers, BSON regular expressions always decode to MongoDB::BSON::Regexp objects. "MongoDB::MongoClient" option "inflate_dbrefs" removed The "inflate_dbrefs" configuration option has been removed and replaced with a "dbref_callback" option in MongoDB::BSON. By default, the "MongoDB::MongoClient" will create a MongoDB::BSON codec that will construct MongoDB::DBRef objects. This ensures that DBRefs properly round-trip. "MongoDB::MongoClient" option "dt_type" deprecated and changed to read-only The "dt_type" option is now only takes effect if "MongoDB::MongoClient" constructs a MongoDB::BSON codec object. It has been changed to a read-only attribute so that any code that relied on changing "dt_type" after constructing a "MongoDB::MongoClient" object will fail instead of being silently ignored. Int32 vs Int64 encoding changes On 64-bit Perls, integers that fit in 32-bits will be encoded as BSON Int32 (whereas previously these were always encoded as BSON Int64). Math::BigInt objects will always be encoded as BSON Int64, which allows users to force 64-bit encoding if desired. Added support for Time::Moment Time::Moment is a much faster replacement for the venerable DateTime module. The BSON codec will serialize Time::Moment objects correctly and can use that module as an argument for the "dt_type" codec attribute. Added support for encoding common JSON boolean classes Most JSON libraries on CPAN implement their own boolean classes. The following libraries boolean types will now encode correctly as BSON booleans: * JSON::XS * Cpanel::JSON::XS * JSON::PP * JSON::Tiny * Mojo::JSON DBRef objects The "fetch" method and related attributes "client", "verify_db", and "verify_coll" have been removed from MongoDB::DBRef. Providing a "fetch" method was inconsistent with other MongoDB drivers, which either never provided it, or have dropped it in the next-generation drivers. It requires a "client" attribute, which tightly couples BSON decoding to the client model, causing circular reference issues and triggering Perl memory bugs under threads. Therefore, the v1.0.0 driver no longer support fetching directly from MongoDB::DBRef; users will need to implement their own methods for dereferencing. Additionally, the "db" attribute is now optional, consistent with the specification for DBRefs. Also, all attributes ("ref", "id" and "db") are now read-only, consistent with the move toward immutable objects throughout the driver. To support round-tripping DBRefs with additional fields other than $ref, $id and $db, the DBRef class now has an attribute called "extra". As not all drivers support this feature, using it for new DBRefs is not recommended. DEPRECATED METHODS Deprecated options and methods may be removed in a future release. Their documentation has been removed to discourage ongoing use. Unless otherwise stated, they will continue to behave as they previously did, allowing a degree of backwards compatibility until code is updated to the new MongoDB driver API. MongoDB::Database * eval – MongoDB 3.0 deprecated the '$eval' command, so this helper method is deprecated as well. * last_error — Errors are now indicated via exceptions at the time database commands are executed. MongoDB::Collection * insert, batch_insert, remove, update, save, query and find_and_modify — A new common driver CRUD API replaces these legacy methods. * get_collection — This method implied that collections could be contained inside collection. This doesn't actually happen so it's confusing to have a Collection be a factory for collections. Users who want nested namespaces should be explicit and create them off Database objects instead. * ensure_index, drop_indexes, drop_index, get_index — A new MongoDB::IndexView class is accessible through the "indexes" method, offering greater consistency in behavior across drivers. * validate — The return values have changed over different server versions, so this method is risky to use; it has more use as a one-off tool, which can be accomplished via "run_command". MongoDB::CommandResult * result — has been renamed to 'output' for clarity MongoDB::Cursor * slave_ok — this modifier method is superseded by the 'read_preference' modifier method * count — this is superseded by the "MongoDB::Collection#count" in MongoDB::Collection count method. Previously, this ignored skip/limit unless a true argument was passed, which was a bizarre, non-intuitive and inconsistent API. MongoDB::BulkWrite and MongoDB::BulkWriteView * insert — renamed to 'insert_one' for consistency with CRUD API * update — renamed to 'update_many' for consistency with CRUD API * remove — renamed to 'delete_many' for consistency with CRUD API * remove_one — renamed to 'delete_one' for consistency with CRUD API AUTHORS * David Golden <david AT mongodb.com> * Rassi <rassi AT mongodb.com> * Mike Friedman <friedo AT friedo.com> * Kristina Chodorow <k.chodorow AT gmail.com> * Florian Ragwitz <rafl AT debian.org> COPYRIGHT AND LICENSE This software is Copyright (c) 2020 by MongoDB, Inc. This is free software, licensed under: The Apache License, Version 2.0, January 2004
Generated by phpMan Author: Che Dong On Apache Under GNU General Public License - MarkDown Format
2026-05-23 06:01 @216.73.217.24 CrawledBy Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)