Thanks, Joni.
On Wed, Dec 16, 2009 at 4:24 PM, Joni Freeman <freeman.j...@gmail.com>wrote:
> Hi,
>
> Yes, that's a way to convert JSON AST to string and vice versa. All
> functions in lift-json operate on AST instances. This is lets us post-
> and pre-process JSON in many ways before converting it to string. See
> for instance functions map, merge, diff, \, etc. defined in JsonAST
> (scaladocs still missing but will be provided before Lift 2.0 is
> released). Typical conversions might for instance remove some data
> from JSON, convert data types, change structure of resulting JSON and
> so on.
>
> I usually import all needed objects and their members. After that the
> code becomes a bit more concise (the cast is unfortunately needed
> since JSON comes from the wild and can be anything):
>
> def encodeAsJsonString(in: A) = compact(render(encodeAsJson(in)))
> def buildFromJsonString(json: String): A = buildFromJson(parse
> (json).asInstanceOf[JObject])
>
> Cheers Joni
>
>
> On 16 joulu, 09:03, Xuefeng Wu <ben...@gmail.com> wrote:
> > Hi,
> > I add two method to en/decode JObject/String
> >
> > def encodeAsJsonString(in: A): String =
> > Printer.compact(JsonAST.render(encodeAsJson(in)))
> > def buildFromJsonString(json: String): A =
> > buildFromJson(JsonParser.parse(json).asInstanceOf[JsonAST.JObject])
> >
> > Do there have better way?
> >
> > On Thu, Dec 3, 2009 at 5:15 AM, David Pollak
> > <feeder.of.the.be...@gmail.com>wrote:
> >
> >
> >
> > > Folks (HarryH -- this means you),
> >
> > > I've just checked in code on the dpp_issue_213 that does Mapper <->
> JObject
> > > bridging using the awesome lift-json library.
> >
> > > The methods on MetaMapper:
> > > protected def encodeAsJSON_! (toEncode: A): JsonAST.JObject
> > > protected def decodeFromJSON_!(json: JsonAST.JObject): A
> >
> > > Implement the bridge. They are protected and have a _! in their name
> > > because they are *dangerous* in that data can be exposed on the JSON
> object
> > > that you might not want exposed and these methods should be used with
> > > extreme caution.
> >
> > > An example of usage can be found in the MapperSpecs:
> >
> > > object SampleModel extends SampleModel with KeyedMetaMapper[Long,
> > > SampleModel] {
> > > def encodeAsJson(in: SampleModel): JsonAST.JObject =
> encodeAsJSON_!(in)
> > > def buildFromJson(json: JsonAST.JObject): SampleModel =
> > > decodeFromJSON_!(json)
> > > }
> >
> > > class SampleModel extends KeyedMapper[Long, SampleModel] {
> > > def getSingleton = SampleModel // what's the "meta" server
> > > def primaryKeyField = id
> >
> > > object id extends MappedLongIndex(this)
> > > object firstName extends MappedString(this, 32)
> > > object moose extends MappedNullableLong(this)
> > > object notNull extends MappedString(this, 32) {
> > > override def dbNotNull_? = true
> > > }
> >
> > > def encodeAsJson(): JsonAST.JObject = SampleModel.encodeAsJson(this)
> > > }
> >
> > > So, you can use this mechanism to serialize a Mapper object to JSON,
> shovel
> > > the object into memcached and then pull it out, mutate a field and save
> the
> > > object back to the database (although connection identifier is lost, so
> if
> > > you are sharding your database, this will not work).
> >
> > > Please give it a try, give me feedback. I'll put it on review board
> > > tomorrow after any feedback and get it into Lift.
> >
> > > Thanks,
> >
> > > David
> >
> > > --
> > > Lift, the simply functional web frameworkhttp://liftweb.net
> > > Beginning Scalahttp://www.apress.com/book/view/1430219890
> > > Follow me:http://twitter.com/dpp
> > > Surf the harmonics
> >
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