Tcl Requires Chilkat v11.7.0+

Handle QR Code Errors

See more QR Code Examples

Demonstrates what happens when a request is refused. QrCode returns false and the response holds errors[0] with three members: a code that does not change between versions, the path of the request member at fault (a JSON Pointer such as /encoding/qr/version), and a message. Requests are checked strictly, so a misspelled option is an error rather than being silently ignored. LastErrorText has the same information in more detail. Tcl

load ./chilkat.dll

set success 0

#  This example requires the Chilkat API to have been previously unlocked.
#  See Global Unlock Sample for sample code.

set fmt [new_CkFormats]

set json [new_CkJsonObject]

set jsonOut [new_CkJsonObject]

#  1. A misspelled option: "moduleSise" for "moduleSize".
CkJsonObject_UpdateString $json "payload.text" "https://www.chilkatsoft.com/"
CkJsonObject_UpdateInt $json "render.moduleSise" 8
set success [CkFormats_QrCode $fmt "generate" $json $jsonOut]
if {$success == 0} then {
    puts "code: [CkJsonObject_stringOf $jsonOut {errors[0].code}]"
    puts "path: [CkJsonObject_stringOf $jsonOut {errors[0].path}]"
    puts "message: [CkJsonObject_stringOf $jsonOut {errors[0].message}]"
}

#  2. A value out of range: QR versions are 1 to 40.
CkJsonObject_Clear $json
CkJsonObject_UpdateString $json "payload.text" "https://www.chilkatsoft.com/"
CkJsonObject_UpdateInt $json "encoding.qr.version" 41
set success [CkFormats_QrCode $fmt "generate" $json $jsonOut]
if {$success == 0} then {
    puts "code: [CkJsonObject_stringOf $jsonOut {errors[0].code}]"
    puts "path: [CkJsonObject_stringOf $jsonOut {errors[0].path}]"
    puts "message: [CkJsonObject_stringOf $jsonOut {errors[0].message}]"
}

#  3. Too much data: this text does not fit a version 1 symbol.
CkJsonObject_Clear $json
CkJsonObject_UpdateString $json "payload.text" "https://www.chilkatsoft.com/barcode_overview.asp"
CkJsonObject_UpdateInt $json "encoding.qr.version" 1
set success [CkFormats_QrCode $fmt "generate" $json $jsonOut]
if {$success == 0} then {
    puts "code: [CkJsonObject_stringOf $jsonOut {errors[0].code}]"
    puts "path: [CkJsonObject_stringOf $jsonOut {errors[0].path}]"
    puts "message: [CkJsonObject_stringOf $jsonOut {errors[0].message}]"
}

#  A program can act on the code.
if {[CkJsonObject_stringOf $jsonOut "errors[0].code"] == "capacityExceeded"} then {
    puts "The text is too long for the symbol size allowed."
}

#  Sample output:

#  code: unknownOption
#  path: /render/moduleSise
#  message: unknown option
#  code: outOfRange
#  path: /encoding/qr/version
#  message: the value is out of range
#  code: capacityExceeded
#  path: /payload
#  message: the payload does not fit the requested QR version at the requested error-correction level
#  The text is too long for the symbol size allowed.

delete_CkFormats $fmt
delete_CkJsonObject $json
delete_CkJsonObject $jsonOut