hw-json

hw-json is a succinct JSON parsing library.

It uses succinct data-structures to allow traversal of large JSON strings with minimal memory overhead.

For an example, see app/Main.hs

Prerequisites

• cabal version 2.2 or later
• Depending on your use case you may need additional package dependencies. These can be found in the library dependencies of the examples library component in the cabal file.

Memory benchmark

If you need a repl to run any of the Haskell examples in this README, please run the command:

cabal v2-repl lib:examples

For rexamples these examples are also found in Haskell modules under the examples directory.

Parsing large Json files in Scala with Argonaut

      S0U       EU           OU       MU     CCSU CMD
--------- --------- ----------- -------- -------- ---------------------------------------------------------------
      0.0  80,526.3    76,163.6 72,338.6 13,058.6 sbt console
      0.0 536,660.4    76,163.6 72,338.6 13,058.6 import java.io._, argonaut._, Argonaut._
      0.0 552,389.1    76,163.6 72,338.6 13,058.6 val file = new File("/Users/jky/Downloads/78mbs.json"
      0.0 634,066.5    76,163.6 72,338.6 13,058.6 val array = new Array[Byte](file.length.asInstanceOf[Int])
      0.0 644,552.3    76,163.6 72,338.6 13,058.6 val is = new FileInputStream("/Users/jky/Downloads/78mbs.json")
      0.0 655,038.1    76,163.6 72,338.6 13,058.6 is.read(array)
294,976.0 160,159.7 1,100,365.0 79,310.8 13,748.1 val json = new String(array)
285,182.9 146,392.6 1,956,264.5 82,679.8 14,099.6 val data = Parse.parse(json)
                    ***********

Parsing large Json files in Haskell with Aeson

-- CMD                                                     -- Mem (MB)
---------------------------------------------------------- -- --------
import Control.DeepSeq                                     --      345
import Data.Aeson                                          --      371
import qualified Data.ByteString.Lazy as LBS               --      376
!bs <- LBS.readFile "corpus/bench/hospitalisation.json"    --      380
let !y = decode bs :: Maybe Value                          --      928

Parsing large Json files in Haskell with hw-json

-- CMD                                                                -- Mem (MB)
--------------------------------------------------------------------- -- --------
import qualified HaskellWorks.Data.ByteString                as BS    --      351
import qualified HaskellWorks.Data.Json.Standard.Cursor.Fast as JCF   --      353

!jsonBs <- BS.mmap "corpus/bench/hospitalisation.json"                --      355
let !ibip = JCF.simdToIbBp jsonBs                                     --      358
let !c    = JCF.fromBsIbBp jsonBs ibip                                --      495

Examples

Navigation example

import Control.Monad

import qualified Data.ByteString                             as BS
import qualified HaskellWorks.Data.Json.Standard.Cursor.Fast as JCF
import qualified HaskellWorks.Data.TreeCursor                as TC

let fc = TC.firstChild
let ns = TC.nextSibling
let pn = TC.parent
let ss = TC.subtreeSize
let jsonBs  = "[null, {\"field\": 1}]" :: BS.ByteString
let ibip    = JCF.simdToIbBp jsonBs
let cursor  = JCF.fromBsIbBp jsonBs ibip
fc cursor
(fc >=> ns) cursor

Querying example

import Control.Monad
import Data.Function
import Data.List
import HaskellWorks.Data.Json.PartialValue
import HaskellWorks.Data.Json.Standard.Cursor.Load.Cursor
import HaskellWorks.Data.Json.Standard.Load.Partial
import HaskellWorks.Data.MQuery
import HaskellWorks.Data.MQuery.Micro

import qualified Data.DList as DL

!cursor <- loadPartial "corpus/bench/78mb.json"
!cursor <- loadCursorWithIndex "corpus/bench/78mb.json"
!cursor <- loadCursor "corpus/bench/78mb.json"
!cursor <- loadCursorWithCsPoppyIndex "corpus/bench/78mb.json"
let !json = jsonPartialJsonValueAt cursor
let q = MQuery (DL.singleton json)

putPretty $ q >>= item & limit 10
putPretty $ q >>= item & page 10 1
putPretty $ q >>= item >>= hasKV "founded_year" (JsonPartialNumber 2005) & limit 10
putPretty $ q >>= item >>= entry
putPretty $ q >>= item >>= entry >>= named "name" & limit 10
putPretty $ q >>= (item >=> entry >=> named "acquisition" >=> entry >=> named "price_currency_code")
putPretty $ q >>= (item >=> entry >=> named "acquisition" >=> entry >=> named "price_currency_code") & onList (uniq . sort)
putPretty $ q >>= (item >=> entry >=> named "acquisition" >=> entry >=> named "price_currency_code" >=> asString >=> valueOf "USD") & limit 10
putPretty $ q >>= (item >=> entry >=> named "acquisition" >=> having (entry >=> named "price_currency_code" >=> asString >=> valueOf "USD") >=> entry >=> named "price_amount") & limit 10
putPretty $ q >>= (item >=> entry >=> named "acquisition" >=> having (entry >=> named "price_currency_code" >=> asString >=> valueOf "USD") >=> entry >=> named "price_amount" >=> castAsInteger ) & limit 10
putPretty $ q >>= (item >=> entry >=> named "acquisition" >=> having (entry >=> named "price_currency_code" >=> asString >=> valueOf "USD") >=> entry >=> named "price_amount" >=> castAsInteger ) & aggregate sum

putPretty $ q >>= item & limit 10
putPretty $ q >>= item & page 10 1
putPretty $ q >>= item >>= entry
putPretty $ q >>= item >>= entry >>= named "name" & limit 10
putPretty $ q >>= (item >=> entry >=> named "acquisition" >=> entry >=> named "price_currency_code" >=> asString)
putPretty $ q >>= (item >=> entry >=> named "acquisition" >=> entry >=> named "price_currency_code" >=> asString) & onList (uniq . sort)
putPretty $ q >>= (item >=> entry >=> named "acquisition" >=> entry >=> named "price_currency_code" >=> asString >=> valueOf "USD") & limit 10
putPretty $ q >>= (item >=> entry >=> named "acquisition" >=> having (entry >=> named "price_currency_code" >=> asString >=> valueOf "USD") >=> entry >=> named "price_amount") & limit 10
putPretty $ q >>= (item >=> entry >=> named "acquisition" >=> having (entry >=> named "price_currency_code" >=> asString >=> valueOf "USD") >=> entry >=> named "price_amount" >=> castAsInteger ) & limit 10
putPretty $ q >>= (item >=> entry >=> named "acquisition" >=> having (entry >=> named "price_currency_code" >=> asString >=> valueOf "USD") >=> entry >=> named "price_amount" >=> castAsInteger ) & aggregate sum

References

• Semi-Indexing Semi-Structured Data in Tiny Space
• Succinct Data Structures talk by Edward Kmett
• Typed Tagless Final Interpreters

Special mentions

• Sydney Paper Club