Objective-C 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. Objective-C

#import <CkoFormats.h>
#import <CkoJsonObject.h>

BOOL success = NO;

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

CkoFormats *fmt = [[CkoFormats alloc] init];
CkoJsonObject *json = [[CkoJsonObject alloc] init];
CkoJsonObject *jsonOut = [[CkoJsonObject alloc] init];

//  1. A misspelled option: "moduleSise" for "moduleSize".
[json UpdateString: @"payload.text" value: @"https://www.chilkatsoft.com/"];
[json UpdateInt: @"render.moduleSise" value: [NSNumber numberWithInt: 8]];
success = [fmt QrCode: @"generate" jsonIn: json jsonOut: jsonOut];
if (success == NO) {
    NSLog(@"%@%@",@"code: ",[jsonOut StringOf: @"errors[0].code"]);
    NSLog(@"%@%@",@"path: ",[jsonOut StringOf: @"errors[0].path"]);
    NSLog(@"%@%@",@"message: ",[jsonOut StringOf: @"errors[0].message"]);
}

//  2. A value out of range: QR versions are 1 to 40.
[json Clear];
[json UpdateString: @"payload.text" value: @"https://www.chilkatsoft.com/"];
[json UpdateInt: @"encoding.qr.version" value: [NSNumber numberWithInt: 41]];
success = [fmt QrCode: @"generate" jsonIn: json jsonOut: jsonOut];
if (success == NO) {
    NSLog(@"%@%@",@"code: ",[jsonOut StringOf: @"errors[0].code"]);
    NSLog(@"%@%@",@"path: ",[jsonOut StringOf: @"errors[0].path"]);
    NSLog(@"%@%@",@"message: ",[jsonOut StringOf: @"errors[0].message"]);
}

//  3. Too much data: this text does not fit a version 1 symbol.
[json Clear];
[json UpdateString: @"payload.text" value: @"https://www.chilkatsoft.com/barcode_overview.asp"];
[json UpdateInt: @"encoding.qr.version" value: [NSNumber numberWithInt: 1]];
success = [fmt QrCode: @"generate" jsonIn: json jsonOut: jsonOut];
if (success == NO) {
    NSLog(@"%@%@",@"code: ",[jsonOut StringOf: @"errors[0].code"]);
    NSLog(@"%@%@",@"path: ",[jsonOut StringOf: @"errors[0].path"]);
    NSLog(@"%@%@",@"message: ",[jsonOut StringOf: @"errors[0].message"]);
}

//  A program can act on the code.
if ([jsonOut StringOf: @"errors[0].code"] == @"capacityExceeded") {
    NSLog(@"%@",@"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.