How to Convert MongoDBObject to JsonString - mongodb

Question

My mongoDb collection looks like this:
> db.FakeCollection.find().pretty()
{
"_id" : ObjectId("52b2d71c5c197846fd3a2737"),
"categories" : [
{
"categoryname" : "entertainment",
"categoryId" : "d3ffca550ae44904aedf77cdcbd31d7a",
"displayname" : "Entertainment",
"subcategories" : [
{
"subcategoryname" : "games",
"subcategoryId" : "ff3d0cbeb0eb4960b11b47d7fc64991b",
"displayname" : "Games"
}
]
}
]
}
I want to write a test case for the below collection using Specs2 JsonMatchers in scala with MongodbCasbah.
How do I convert DBObjects to Strings?

Answer 1

I believe your approach is slightly wrong here. Your collection should look like:
class Category extends BsonRecord[Category] {
def meta = Category
object categoryname extends StringField(this, 200)
object categoryId extends StringField(this, 64)
object displayname extends StringField(this, 100)
object subcategories extends BsonRecordListField(this, Category)
}
object Category extends Category with BsonMetaRecord[Category] {
}
class FakeCollection extends MongoRecord[FakeCollection] with ObjectIdPk[FakeCollection] {
def meta = FakeCollection
object categories extends BsonRecordListField(this, Category)
}
object FakeCollection extends FakeCollection with MongoMetaRecord[FakeCollection] {
override def collectionName = "fakecollection"
def getEntryByName: List[Category] = {
FakeCollection.find
}
}
With that method you can do:
import net.liftweb.json.JsonAST.JValue;
import net.liftweb.http.js.JsExp;
import net.liftweb.http.js.JsExp._;
import net.liftweb.json.JsonDSL.seq2jvalue
val json: JsExp = seq2JValue(FakeColleciton.find.map(_.asJValue))
val stringContent = json.toJsCmd; // now it's here, you can match.
Have a look HERE, see how you can add Foursquare Rogue to make your life easier.

Answer 2

Short answer:
val doc: com.mongodb.DBObject = ???
pretty(render(net.liftweb.mongodb.JObjectParser.serialize(doc)))
Long answer that explains what's going on. I included full type names for clarity:
import net.liftweb.mongodb.JObjectParser
import net.liftweb.json.DefaultFormats
// default JSON formats for `parse` and `serialize` below
implicit val formats = DefaultFormats
// Convert DBObject to JValue:
val doc: com.mongodb.DBObject = ??? // get it somehow
val jsonDoc: net.liftweb.json.JValue = JObjectParser.serialize(doc)
// Convert JValue to DBObject:
val doc2: net.liftweb.json.JObject = ???
val dbObj: com.mongodb.DBObject = JObjectParser.parse(doc2)
// Render JSON as String:
import net.liftweb.json._
pretty(render(jsonDoc))
// or use compactRender, compact(render(jsonDoc)), etc
To compare JSON docs there is Diff: val Diff(changed, added, deleted) = json1 diff json2.
More info here: https://github.com/lift/lift/tree/master/framework/lift-base/lift-json/.
You can test with specs2 and Lift Diff this way for example:
json1 diff json2 mustEqual Diff(changedJson, addedJson, JNothing)