CODEWITHSUNDEEP
jsonvb6
Manoj Patil
Manoj Patil

Reputation: 65

JSON Escape character of double quote prints in the string

I'm generating a JSON file using VB6 and one of my strings has a double quote in between. I have used the double quote escape character but now the escape character is also printing in the string, even though the JSON is successful when I put the file in JSON formatter.

The string is:

"productName":"16X12 / 46/4X46 63" DRILL"

This string have a double quote in it when I use escape character and check it the JSON formatter , the JSON is successful but product name string becomes

"productName":"16X12 / 46/4X46 63\"DRILL"

as u can see the escape character is printing in the string before the double quote, How can I escape the double quote without printing the escape character.

I have tried with \ and \\ but every \ get prints.

Upvotes: 0

Views: 1359

Answers (1)

wqw
wqw

Reputation: 11991

You need a proper JSON string escaping implementation, e.g. try this

Private Function JsonEscape(sText As String) As String
    Const STR_CODES     As String = "\u0000|\u0001|\u0002|\u0003|\u0004|\u0005|\u0006|\u0007|\b|\t|\n|\u000B|\f|\r|\u000E|\u000F|\u0010|\u0011|\u0012|\u0013|\u0014|\u0015|\u0016|\u0017|\u0018|\u0019|\u001A|\u001B|\u001C|\u001D|\u001E|\u001F"
    Static vTranscode   As Variant
    Dim lIdx            As Long
    Dim lAsc            As Long

    If IsEmpty(vTranscode) Then
        vTranscode = Split(STR_CODES, "|")
    End If
    For lIdx = 1 To Len(sText)
        lAsc = AscW(Mid$(sText, lIdx, 1))
        If lAsc = 92 Or lAsc = 34 Then '--- \ and "
            JsonEscape = JsonEscape & "\" & ChrW$(lAsc)
        ElseIf lAsc >= 32 And lAsc < 256 Then
            JsonEscape = JsonEscape & ChrW$(lAsc)
        ElseIf lAsc >= 0 And lAsc < 32 Then
            JsonEscape = JsonEscape & vTranscode(lAsc)
        ElseIf Asc(Mid$(sText, lIdx, 1)) <> 63 Or Mid$(sText, lIdx, 1) = "?" Then '--- ?
            JsonEscape = JsonEscape & ChrW$(AscW(Mid$(sText, lIdx, 1)))
        Else
            JsonEscape = JsonEscape & "\u" & Right$("0000" & Hex$(lAsc), 4)
        End If
    Next
End Function

This takes care of " and \ in strings as well as vbCrLf and other special symbols (charcode < 32). This handles unicode characters too (charcode > 256).

Btw, you'll have to escape all user-supplied strings (either in keys or values) to prevent producing invalid JSON in all cases.

Upvotes: 3

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