Rogue

Rogue is a type-safe internal Scala DSL for constructing and executing find and modify commands against MongoDB in the Lift web framework. It is fully expressive with respect to the basic options provided by MongoDB's native query language, but in a type-safe manner, building on the record types specified in your Lift models. An example:

Venue where (_.mayor eqs 1234) and (_.categories contains "Thai") fetch(10)

The type system enforces the following constraints:

• the fields must actually belong to the record (e.g., mayor is a field on the Venue record)
• the field type must match the operand type (e.g., mayor is an IntField)
• the operator must make sense for the field type (e.g., categories is a MongoListField[String])

In addition, the type system ensures that certain builder methods are only used in certain circumstances. For example, take this more complex query:

Venue where (_.closed eqs false) orderAsc(_.popularity) limit(10) modify (_.closed setTo true) updateMulti

This query purportedly finds the 10 least popular open venues and closes them. However, MongoDB does not (currently) allow you to specify limits on modify queries, so Rogue won't let you either. The above will generate a compiler error.

Constructions like this:

def myMayorships = Venue where (_.mayor eqs 1234) limit(5)
...
myMayorships.fetch(10)

will also not compile, here because a limit is being specified twice. Other similar constraints are in place to prevent you from accidentally doing things you don't want to do anyway.

Installation

Because Rogue is designed to work with several versions of lift-mongodb-record (2.2, 2.3, 2.4), you'll want to declare your dependency on Rogue as intransitive and declare an explicit dependency on the version of Lift you want to target. In sbt, that would look like the following:

val rogue           = "com.foursquare" %% "rogue"               % "1.0.27" intransitive()
val liftMongoRecord = "net.liftweb"    %% "lift-mongodb-record" % "2.4-M2"

You can substitute "2.4-M2" for whatever version of Lift you are using. Rogue has been used in production against Lift 2.2 and 2.4-M2. If you encounter problems using Rogue with other versions of Lift, please let us know.

Join the rogue-users google group for help, bug reports, feature requests, and general discussion on Rogue.

More Examples

QueryTest.scala contains sample Records and examples of every kind of query supported by Rogue. It also indicates what each query translates to in MongoDB's JSON query language. It's a good place to look when getting started using Rogue.

NB: The examples in QueryTest only construct query objects; none are actually executed. Once you have a query object, the following operations are supported (listed here because they are not demonstrated in QueryTest):

For "find" query objects

val query = Venue where (_.venuename eqs "Starbucks")
query.count()
query.countDistinct(_.mayor)
query.fetch()
query.fetch(n)
query.get() // equivalent to query.fetch(1).headOption
query.foreach{v: Venue => ... }
query.paginate(pageSize)
query.fetchBatch(pageSize){vs: List[Venue] => ...}
query.bulkDelete_!!
query.blockingBulkDelete_!!
query.findAndDeleteOne()

For "modify" query objects

val modify = query modify (_.popularity inc 1)
modify.updateMulti()
modify.updateOne()
modify.upsertOne()

for "findAndModify" query objects

val modify = query where (_.legacyid eqs 222) findAndModify (_.zip setTo "10003")
modify.updateOne(returnNew = ...)
modify.upsertOne(returnNew = ...)

Releases

The latest release is 1.0.27. See the changelog for more details.

New in 1.0.27:

• Mongo index checking (see here for documentation)

Lots of new features since 1.0.18!:

• $rename support
• ability to supply a WriteConcern to updateOne, updateMulti and upsertOne
• select and selectCase can handle 7 and 8 parameters
• $bit support
• improved support for subfield queries on BsonRecordField
• added "matches" operator (for regexes) on StringFields with explicit index behavior expectations
• sbt 0.10.0
• raw access do BasicDBObjectBuilder in the query builder
• whereOpt support: Venue.whereOpt(uidOpt)(_.userid eqs _)
• findAndModify support
• $or query support
• efficient .exists query method (thanks Jorge!)
• support for BsonRecordField and BsonRecordListField (thanks Marc!)
• type-safe foreign key condtions, e.g., Tip.where(_.venueid eqs venueObj) (thanks dtaylor!)

Please see QueryTest.scala for examples of these new features.

Other recent notable changes:

• .toString produces runnable javascript commands for mongodb console
• added tests for constructions that should not compile
• selectCase() builder method for select()ing via case class
• added blockingBulkDelete_!! method which takes a WriteConcern
• index hinting support
• support for selecting subfields
• support for $maxScan and $comment addSpecial parameters on find() queries
• explain() method on BaseQuery (thanks tjulien!)
• query signatures: string version of a query with all values blanked out
• support for indicating when a query clause is intended to hit an index (for runtime index checking, if you wish to implement it)

Dependencies

lift-mongodb-record (2.2, 2.3, 2.4), mongodb, joda-time, junit. These dependencies are managed by the build system.

Maintainers

Rogue was initially developed by Foursquare Labs for internal use -- nearly all of the MongoDB queries in foursquare's code base go through this library. The current maintainers are:

• Jason Liszka [email protected]
• Jorge Ortiz [email protected]

Contributions welcome!