In order to work with JSON, AGS provides a wrapper @autoit-gui-skeleton/ags-wrapper-json of the library JSON.au3, created by Ward. This library allows us to decode/encode JSON with the minimalistic JSON parser jsmn.

How to install AGS-wrapper-json ?

We assume that you have already install Node.js and Yarn, for example with Chocolatey, and to install this package AGS-wrapper-json, you can use the dependencies manager for AutoIt provides in AGS. So just type in the root folder of your project where the package.json is stored:

yarn add @autoit-gui-skeleton/ags-wrapper-json --modules-folder vendor

All project dependencies, as well as daughter dependencies of parent dependencies, are installed in the ./vendor/@autoit-gui-skeleton/ directory. To use it in your AutoIt program, you need to include this library with this instruction:

#include 'vendor/@autoit-gui-skeleton/ags-wrapper-json/JSON.au3'

All AGS packages hosted in this npmjs repository belong to the organization @autoit-gui-skeleton organization. Indeed in order to simplify the management of the dependencies of an AutoIt project built with AGS framework, we have diverted form its initial use the dependency manager npm, and its evolution Yarn. This allows us to manage the dependencies of an AGS project with other AutoIt libraries, and to share these AutoIt packages from the npmjs.org repository.

How to decode a JSON ?

Decode a JSON file from local

For example, create this json file in your ./assets/DROIDS.json folder of your AGS project.

{
  "project": "Listing droids",
  "version": "1.0",
  "author": {
    "name": "Luke",
    "mail": "luke@2080.org"
  },
  "droids": [
    {
      "name": "R2D2",
      "type": "Astromecano",
      "size": "0,96m"
    },
    {
      "name": "BB8",
      "type": "Astromecano",
      "size": "0,67m"
    },
    {
      "name": "C-3PO",
      "type": "Social",
      "size": "1,67m"
    }
  ]
}

To decode this local file, we use this bellow function json_decode_from_file.

#include 'vendor/@autoit-gui-skeleton/ags-wrapper-json/JSON.au3'

;====================================================================================
; Decode JSON from a given local file
;
; @param $jsonfilePath (string)
; @return $object (object), instance return by json_decode
;====================================================================================
Func json_decode_from_file($filePath)
	Local $fileOpen, $fileContent, $object

	$fileOpen = FileOpen($filePath, $FO_READ)
	If $fileOpen = -1 Then
		Return SetError(1, 0, "An error occurred when reading the file " & $filePath)
	EndIf
	$fileContent = FileRead($fileOpen)
	FileClose($fileOpen)
	$object = Json_Decode($fileContent)

	Return $object
EndFunc

According to Ward’s documentation.

The most JSON data type will be decoded into corresponding AutoIt variable, including 1D array, string, number, true, false, and null. JSON object will be decoded into “Windows Scripting Dictionary Object” retuned from ObjCreate("Scripting.Dictionary"). AutoIt build-in functions like IsArray, IsBool, etc. can be used to check the returned data type. But for Object and Null, Json_IsObject() and Json_IsNull() should be used.

If the input JSON string is invalid, @Error will be set to $JSMN_ERROR_INVAL. And if the input JSON string is not finish, @Error will be set to $JSMN_ERROR_PART.

Get values from a json object

To work with $jsonObject, the return of json_decode_from_file, you can use Json_Get function. To select a JSON variable, both dot notation and square bracket notation can be supported.

Local $file = @ScriptDir & "\assets\DROIDS.json"
Local $jsonObject = json_decode_from_file($file)

; With dot notation
Local $project = Json_Get($jsonObject, '.project')     ; Listing droids
Local $name = Json_Get($jsonObject, '.author.name')    ; Luke
Local $mail = Json_Get($jsonObject, '.author.mail')    ; luke@2080.org
local $test = Json_Get($jsonObject, '.droids[1].name') ; BB8

; With array notation
Local $project2 = Json_Get($jsonObject, '["project"]')
Local $name2 = Json_Get($jsonObject, '["author"]["name"]')
Local $mail2 = Json_Get($jsonObject, '["author"]["mail"]')
local $test2 = Json_Get($jsonObject, '["droids"][1]["name"]')

You also can use object help functions. These functions are just warps of Scripting.Dictionary COM object.

  • Json_ObjCreate()
  • Json_ObjPut(ByRef $Object, $Key, $Value)
  • Json_ObjGet(ByRef $Object, $Key)
  • Json_ObjDelete(ByRef $Object, $Key)
  • Json_ObjExists(ByRef $Object, $Key)
  • Json_ObjGetCount(ByRef $Object)
  • Json_ObjGetKeys(ByRef $Object)
  • Json_ObjClear(ByRef $Object)

Work with an object collection, and iterate its items

To iterate values from an array json

Local $file = @ScriptDir & "\assets\DROIDS.json"
Local $jsonObject = json_decode_from_file($file)

; Check if exists an item droid into the collection `droids`
Local $droids = Json_Get($jsonObject, '.droids')
If UBound($droids) = 0 Then
    Return SetError(3, 0, "Array attribute 'droids' is empty.")
EndIf

; Iterate items collection to store values into an array 
Local $array[UBound($droids)][3]
For $i = 0 To UBound($droids) - 1 Step 1
    $array[$i][0] = Json_Get($jsonObject, '.droids' & '[' & $i & '].name')
    $array[$i][1] = Json_Get($jsonObject, '.droids' & '[' & $i & '].type')
    $array[$i][2] = Json_Get($jsonObject, '.droids' & '[' & $i & '].size')
Next

Add object into a JSON

You can do it with Json_Put:

Local $Obj
Json_Put($Obj, ".foo", "foo")
Json_Put($Obj, ".bar[0]", "bar")
Json_Put($Obj, ".test[1].foo.bar[2].foo.bar", "Test")

Local $Test = Json_Get($Obj, '["test"][1]["foo"]["bar"][2]["foo"]["bar"]') ; "Test"

Decode a JSON file from a remote server

To decode a JSON file hosted on a remote server, or built from a webservice or from a REST API, you can use the component @autoit-gui-skeleton/ags-component-http-request to make HTTP requests to a given URL.

#include 'vendor/@autoit-gui-skeleton/ags-component-http-request/ags-component-http-request.au3'

;====================================================================================
; Decode JSON from a given URL
;
; @param $jsonfileUrl (string)
; @param $proxy (string), by default we load proxy settings form configuration file
; @return $object (object), instance return by json_decode
;====================================================================================
Func json_decode_from_url($jsonfileUrl, $proxy = "")
	Local $response = HttpGET($jsonfileUrl, Default, $proxy)
	If (@error) Then
		Return SetError(@error, $response, _ 
		    "Unable to get json file on server " & $jsonfileUrl & ".")
	EndIf
	Local $data = $response.ResponseText
	Local $object = json_decode($data)

	Return $object
EndFunc

Local $jsonObject = json_decode_from_url(https://api.spacexdata.com/v2/info)

Local $name = Json_Get($jsonObject, '.name')        ; SpaceX
Local $founder = Json_Get($jsonObject, '.founder')  ; Elon Musk
Local $founded = Json_Get($jsonObject, '.founded')  ; 2002

How to encode a JSON ?

According to Ward’s documentation, you can use Json_Encode($Data, $Option = 0, $Indent = "\t", $ArraySep = ",\r\n", $ObjectSep = ",\r\n", $ColonSep = ": ").

  • $Data can be a string, number, bool, keyword : default or null, 1D array, or Scripting.Dictionary COM object.
  • Binary will be converted to string in UTF8 encoding.
  • Ptr will be converted to number
  • Other unsupported types like 2D array, dllstruct or object will be encoded into null.

$Option is bitmask consisting following constant:

  • $JSON_UNESCAPED_ASCII ; Don’t escape ascii charcters between chr(1) ~ chr(0x1f)
  • $JSON_UNESCAPED_UNICODE ; Encode multibyte Unicode characters literally
  • $JSON_UNESCAPED_SLASHES ; Don’t escape /
  • $JSON_HEX_TAG ; All < and > are converted to \u003C and \u003E
  • $JSON_HEX_AMP ; All &amp;amp;amp;s are converted to \u0026
  • $JSON_HEX_APOS ; All ‘ are converted to \u0027
  • $JSON_HEX_QUOT ; All “ are converted to \u0022
  • $JSON_PRETTY_PRINT ; Use whitespace in returned data to format it
  • $JSON_STRICT_PRINT ; Make sure returned JSON string is RFC4627 compliant
  • $JSON_UNQUOTED_STRING ; Output unquoted string if possible (conflicting with $JSMN_STRICT_PRINT)

For example to encode in JSON:

Local $file = @ScriptDir & "\assets\DROIDS.json"
Local $jsonObject = json_decode_from_file($file)
Local $jsonEncoded = Json_Encode($jsonObject, $JSON_PRETTY_PRINT)

ConsoleWrite($jsonEncoded)

Most encoding option have the same means like PHP’s json_encode() function. When $JSON_PRETTY_PRINT is set, output format can be change by other 4 parameters : ($Indent, $ArraySep, $ObjectSep, $ColonSep). Because these 4 output format parameters will be checked inside Jsmn_Encode() function, returned string will be always accepted by Jsmn_Decode(). $JSON_UNQUOTED_STRING can be used to output unquoted string that also accetped by Jsmn_Decode(). $JSON_STRICT_PRINT is used to check output format setting and avoid non-standard JSON output. So this option is conflicting with $JSON_UNQUOTED_STRING.


Continue reading ?

https://www.autoitscript.com/forum/topic/148114-a-non-strict-json-udf-jsmn/

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