nfJson

Project developer: Marco Plaza GitHub/nfoxdev

Issues? - Discussions/Ideas

A set of fast performance, reliable and easy to use Json functions using pure VFP.

Functions & Usage

( Each function is a single prg - No additional dependencies / Requires VFP9 )

• oJson = nfJsonRead(cJsonString , lReviveCollections)
  Example :
  jsonstr = '{"name":"John", "age":30, "family":{"wife":"Susana","son":"Tom"}, "location":"texas"}'
  vfpobj = nfJsonRead(jsonstr)
  ? vfpobj.age && 30
  ? vfpobj.family.son && Tom

  • lReviveCollections: nfJsoncreate stringify key/keyless kcollections as arrays; set this flag if you are parsing json created with nfjsoncreate that you know have a vfp collection; this will perform a extra step to get your collections back from the array representation ( revive it ) or set it to false to view your collections as arrays for debugging purposes -check collectiontest.prg in test folder.

• cJsonString = nfJsonCreate(oVfp, lFormattedOutput, lNoNullArrayItems,cRootName,aMembersFlag, tlNoCollectionName, taProperties)

  • tlNoCollectionName: .F. or not passed means collections are given a name like propertyname_kv_collection. .T. means collections are not assign new names. See the CollectionTest2.prg test program.
  • taProperties: an optional array that specifies how to handle certain properties. See the PropertyNameCase.prg, IncludeNativeNames.prg, and HandlEmptyValues.prg test programs.

• nfJsonToCursor(cJson, cCursorName , lForceImportFromArray) ( creates cursor back from Json created using nfCursorToJson4vfp, for any other case see nfOpenJson and notes below: )

• cJsonString = nfCursorToJson4vfp() && converts current open table/cursor to Json suitable for later use of nfJsonToCursor()

• cJsonString = nfCursorToJson(lReturnArray, lArrayofValues, lIncludestruct, lFormattedOutput) converts current open table/cursor to Json

• oJson = nfCursorToObject(lCopyToArray, lIncludeStruct)

• cJsonString = jsonFormat( cJsonStr )* Format json string w/o validate or change element positions

• nfOpenJson(** cJsonString , [ cArrayPath ], [cCursorStructure & object mappings ] )

  Similar to SqlServer 2016 openJson function

To convert json to cursor:

For simple 1:1 conversion I recommend to simply use nfJsonRead and a existing destination cursor like this:

TEXT to mssample2 noshow
[
{ "CorpCode": "KAKK01",
"MobNo": "9447820950",
"KitID": "2320007005",
"EwireTxnNo": "2"
},
{ "CorpCode": "KAKK01",
"MobNo": "9544727140",
"KitID": "2320007006",
"EwireTxnNo": "2"
}
]
ENDTEXT

ox = nfJsonRead(m.mssample2)
Create Cursor temp ( corpcode v(10), mobno v(20),kitid v(10), ewireTxnNo v(10) )

For Each Row In ox.Array
	Insert Into temp From Name Row
Endfor

BROWSE TITLE 'using nfJsonRead'

** Use nfOpenJson to flatten objects with ease ( check a discussion here https://www.tek-tips.com/viewthread.cfm?qid=1796615 )

*** using nfOpenJson:

TEXT to mssample3 noshow
[
{ "CorpCode": "KAKK01",
"MobNo": "9447820950",
"KitID": "2320007005",
"EwireTxnNo": "2",
"person":{"name":"Curt","age":54,"phone":["12345","5645466"]}
},
{ "CorpCode": "KAKK01",
"MobNo": "9544727140",
"KitID": "2320007006",
"EwireTxnNo": "2",
"person":{"name":"David","age":55,"phone":["142145","4665465"]}
}
]
ENDTEXT

TEXT TO curstruc NOSHOW TEXTMERGE PRETEXT 8
- corpcode v(10) $.corpCode
- mobno v(20) $.mobNo
- kitid v(10) $.kitid
- ewireTxnNo v(10) $.ewireTxnNo
- name v(10) $.person.Name
- age i $.person.age
- phone1 v(10) $.person.phone[1]
- phone2 v(10) $.person.phone[2]
ENDTEXT

nfOpenJson( m.mssample3,'array',m.curstruc)

BROWSE TITLE 'Using nfOpenJson'

Tests & Sample files

• nfOpenJsonTest: samples taken from https://docs.microsoft.com/en-us/sql/t-sql/functions/openjson-transact-sql

• nfJsonPerfTest.prg: just run it and choose one of the embedded json samples from the list to check performance on your pc. ( Allows you to parse Json from clipboard too. )

• examples.prg will parse the next Json files included in JsonSamples folder. just run from test folder and see sample code and output.

• collectionTest.prg: creates a complex collection , converts it to Json and back to vfp.

• Sample Json files included:

  • youtubesearch.json
  • cycloneForecast.json
  • dropbox.json
  • googleMapsDistance.json
  • iphone photo.json
  • mapquest.json
  • mySimpleArray.json
  • tweeter.json
  • weatherService.json
  • yahooweather.json

Release Notes

2026/02/11 (DougHennig)

• nfJsonRead: handle dates with thousandths of seconds, such as 2017-03-10T17:43:55.123
• nfJsonCreate:
  • Accept an array of properties. The first column is the property name, the case of which is used in the JSON (for example, output as "myProperty" rather than "myproperty"), and the second is .T. to exclude the property or .F. to include it
  • Handle collections better: don't add {"collectionitems": ... }
  • Don't add a extra comma at the start of a property
  • Don't add a second name to the JSON
  • Don't add a duplicate }

2022/07/09 ( PatrickvonDeetzen )

• create json with special characters is now significantly faster (changes made in function "escapeandencode")
• updated performance test & added new test sample
• bug fix: missing m. in nfcursortoobject.prg

2019/06/14

• JsonFormat function by Carlos Alloati

2017/08/05

• no matter wich strictdate setting you have set, a JsonDateTime "0000-00-00T00:00:00" will return an empty date.
• valid JsonDates with time "T00:00:00" will return a date value ( ie: {"testDate":"2017-12-01T00:00:00"} )
• invalid dates ( ie 2017/50/50 ) properly formatted as Json Date ( ie: 2017-50-50T00:00:00 ) will throw error; ( previous behavior was to return .null. )

2017/03/10

• fixed: proper support for 19 character strings with ISO basic date format & different strictdate settings.

2017/02/05

• fixed: nfJsonRead bug fix: incorrect parsing for strings terminated with escaped double quotes; minor changes & code refactoring.

2017/01/11

• fixed: nfJsonRead: incorrect unescaped output with "set exact = on"
• escapetest.prg - removed "leftover" lines.

2017/01/11

• fixed issue escaping values terminated with "
• nfJsonRead: removed parameter "isFile" now you can just pass a file name or string
• added test: escapeTest.prg

2016/09/28

• minor bug fix: zero item collections created as 1 empty item collection
• proper indent for raw/formatted collection objects

2016/08/16

• nfJsonPerfTest: added compiled exe, samples file ships as a separate file for you to edit
• fixed bug on test prgs: clean installs would fail due to missing temp folder on distribution zip w/o tests\temp folder
• fixed bug on collectionTest

2016/07/22

• nfJsonRead: Improved error management
• CollectionTest: added new test

2016/07/20

• Fixed bug: missing closing curly brace on collections as object member
• Updated collections program test

2016/07/09

• Automatic cast for datetime properties ( ISO-8601 basic format & vfp compilant as described on https://en.wikipedia.org/wiki/ISO_8601#Times. )
• nfJsonToCursor Bug Fix: "Date/datetime evaluated to an invalid value" while running under "strictdate = 1" converting empty dates back from Json

2016/07/04

• Added support for control characters encoding ( chr( 0) ~ chr(31) )

2016/05/05

• invalid Json error shows calling program information

2016/04/02

• complex nested objects/arrays validation
• missing object/array closures validation

2016/03/28

• nfJsonRead performs JSON validation: invalid Json throws error indicating reason.
• nfJsonPerfTest: proper error management enabled for invalid Json input from clipboard
• nfJsonToCursor: use of strict date format