VBMAN.Json - JSON Operation Object

Overview

VBMAN.Json provides JSON data parsing and generation functionality, supporting nested objects, arrays, and is the preferred solution for handling JSON data in VB6.

Core Features

• Bidirectional Conversion: Supports JSON string parsing and object encoding
• Nested Support: Unlimited level nested objects and arrays
• Type Safety: Automatic data type conversion handling
• Formatted Output: Supports indentation beautification output
• Chain Building: Fluent JSON building API

Properties

Property	Type	Description
Root	cJson	Root node object
Item(key)	Variant	Access value of specified key (default member)

Methods

Encode

Encode object to JSON string

Public Function Encode(Optional obj As Object, Optional Indent As Integer = 0, Optional UseDoubleQuotes As Boolean = True) As String

Parameters:

• obj - Object to encode (default uses Root)
• Indent - Indentation spaces (0=no line breaks)
• UseDoubleQuotes - Use double quotes (default True)

Example:

' Simple encoding
Dim json As New cJson
json("name") = "Zhang San"
json("age") = 25

Dim jsonStr As String
jsonStr = json.Encode()
' Result: {"name":"Zhang San","age":25}

' Formatted output
Dim prettyJson As String
prettyJson = json.Encode(, 2, True)
' Result:
' {
'   "name": "Zhang San",
'   "age": 25
' }

Decode

Parse JSON string

Public Function Decode(jsonString As String) As cJson

Example:

' Parse JSON
Dim jsonStr As String
jsonStr = "{""name"":""Zhang San"",""age"":25}"

Dim json As cJson
Set json = VBMAN.Json.Decode(jsonStr)

Debug.Print json("name")   ' Zhang San
Debug.Print json("age")    ' 25

Item

Access or set value

' Read
Dim value As Variant
value = json("key")

' Write
json("key") = "value"
json("number") = 123
json("bool") = True

NewItem / NewItems

Create nested object/array

Public Function NewItem() As cJson
Public Function NewItems(key As String) As cJson

Example:

' Create nested object
Dim user As New cJson
user("id") = 1
user("name") = "Zhang San"

With user.NewItem("address")
    .Item("city") = "Beijing"
    .Item("zip") = "100000"
End With

' Create array
Dim users As New cJson

With users.NewItems("data")
    With .NewItem()
        .Item("name") = "Zhang San"
        .Item("age") = 25
    End With
    With .NewItem()
        .Item("name") = "Li Si"
        .Item("age") = 30
    End With
End With

Debug.Print users.Encode(, 2)
' Result:
' {
'   "data": [
'     {"name":"Zhang San","age":25},
'     {"name":"Li Si","age":30}
'   ]
' }

Exists

Check if key exists

Public Function Exists(key As String) As Boolean

Example:

If json.Exists("email") Then
    Debug.Print json("email")
Else
    Debug.Print "email does not exist"
End If

Remove

Delete key

Public Sub Remove(key As String)

Comprehensive Examples

Example 1: Build Complex JSON

Private Sub BuildComplexJson()
    Dim root As New cJson
    
    ' Basic info
    root("status") = "success"
    root("message") = "Operation successful"
    root("timestamp") = Format(Now, "yyyy-MM-ddThh:mm:ss")
    
    ' User data array
    With root.NewItems("users")
        ' First user
        With .NewItem()
            .Item("id") = 1
            .Item("name") = "Zhang San"
            .Item("email") = "zhangsan@example.com"
            
            ' Nested address
            With .NewItem("address")
                .Item("province") = "Beijing"
                .Item("city") = "Beijing City"
                .Item("detail") = "Chaoyang District xxx Street"
            End With
            
            ' Nested orders array
            With .NewItems("orders")
                With .NewItem()
                    .Item("order_id") = "ORD001"
                    .Item("amount") = 199.99
                End With
                With .NewItem()
                    .Item("order_id") = "ORD002"
                    .Item("amount") = 299.99
                End With
            End With
        End With
        
        ' Second user
        With .NewItem()
            .Item("id") = 2
            .Item("name") = "Li Si"
            .Item("email") = "lisi@example.com"
        End With
    End With
    
    ' Pagination info
    With root.NewItem("pagination")
        .Item("page") = 1
        .Item("page_size") = 20
        .Item("total") = 100
    End With
    
    ' Output JSON
    Dim jsonStr As String
    jsonStr = root.Encode(, 2, True)
    Debug.Print jsonStr
End Sub

Example 2: Parse API Response

Private Sub ParseApiResponse(response As String)
    Dim json As cJson
    Set json = VBMAN.Json.Decode(response)
    
    ' Check status
    If json("status") = "success" Then
        ' Get user array
        Dim users As cJson
        Set users = json("data")("users")
        
        ' Iterate users
        Dim i As Integer
        For i = 0 To users.Count - 1
            Dim user As cJson
            Set user = users(i)
            
            Debug.Print "ID: " & user("id")
            Debug.Print "Name: " & user("name")
            Debug.Print "Email: " & user("email")
            
            ' Check if address exists
            If user.Exists("address") Then
                Debug.Print "City: " & user("address")("city")
            End If
            
            Debug.Print "---"
        Next i
        
        ' Get pagination info
        Debug.Print "Total: " & json("data")("pagination")("total")
    Else
        Debug.Print "Error: " & json("message")
    End If
End Sub

Example 3: Usage in Real Projects (from demos)

' Build JSON response
Public Sub Json(ctx As cHttpServerContext)
    Dim ID As Long: ID = ctx.Request.QueryString("id")
    
    With New cJson
        .Item("id") = ID
        .Item("face") = ChrW(&H263A)
        .Item("timestamp") = Now
        .Item("status") = "success"
        
        ctx.Response.Json .Root
    End With
End Sub

' Parse request data
Public Sub HandleRequest(ctx As cHttpServerContext)
    Dim requestData As String
    requestData = ctx.Request.Body
    
    Dim json As cJson
    Set json = VBMAN.Json.Decode(requestData)
    
    Dim username As String
    Dim password As String
    
    username = json("username")
    password = json("password")
    
    ' Process login...
End Sub

Example 4: Database Record to JSON

Private Sub RecordsetToJson(rs As ADODB.Recordset)
    Dim root As New cJson
    
    ' Add metadata
    root("count") = rs.RecordCount
    root("timestamp") = Now
    
    ' Add data array
    With root.NewItems("data")
        Do While Not rs.EOF
            With .NewItem()
                Dim i As Integer
                For i = 0 To rs.Fields.Count - 1
                    .Item(rs.Fields(i).Name) = rs.Fields(i).Value
                Next i
            End With
            rs.MoveNext
        Loop
    End With
    
    ' Output
    Debug.Print root.Encode(, 2)
End Sub

Example 5: INI Config to JSON

Private Sub IniToJson()
    VBMAN.Ini.LoadFrom App.Path & "\\config.ini"
    
    Dim json As New cJson
    
    ' Convert all Sections
    Dim sectionKey As Variant
    For Each sectionKey In VBMAN.Ini.Root.Keys
        With json.NewItem(CStr(sectionKey))
            Dim key As Variant
            For Each key In VBMAN.Ini.Root(sectionKey).Keys
                .Item(key) = VBMAN.Ini.Root(sectionKey)(key)
            Next key
        End With
    Next sectionKey
    
    ' Save as JSON file
    VBMAN.FileEx.SetBufferText(json.Encode(, 2), "UTF-8").SaveData App.Path & "\\config.json"
End Sub

Best Practices

1. Use Parameters: When building JSON, try to use NewItem/NewItems
2. Check Existence: Use Exists to check if key exists before reading
3. Error Handling: Add error handling when parsing JSON
4. Type Attention: VB6 is weakly typed, note the difference between numbers and strings
5. Formatted Output: Use indentation formatting for easier reading during debugging