Rust 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. Rust

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

let fmt = chilkat::Formats::new();
let json = chilkat::JsonObject::new();
let json_out = chilkat::JsonObject::new();

// 1. A misspelled option: "moduleSise" for "moduleSize".
let _ = json.update_string("payload.text", "https://www.chilkatsoft.com/");
let _ = json.update_int("render.moduleSise", 8);
if fmt.qr_code("generate", &json, &json_out).is_err() {
    println!("code: {}", json_out.string_of("errors[0].code").unwrap_or_default());
    println!("path: {}", json_out.string_of("errors[0].path").unwrap_or_default());
    println!("message: {}", json_out.string_of("errors[0].message").unwrap_or_default());
}

// 2. A value out of range: QR versions are 1 to 40.
json.clear();
let _ = json.update_string("payload.text", "https://www.chilkatsoft.com/");
let _ = json.update_int("encoding.qr.version", 41);
if fmt.qr_code("generate", &json, &json_out).is_err() {
    println!("code: {}", json_out.string_of("errors[0].code").unwrap_or_default());
    println!("path: {}", json_out.string_of("errors[0].path").unwrap_or_default());
    println!("message: {}", json_out.string_of("errors[0].message").unwrap_or_default());
}

// 3. Too much data: this text does not fit a version 1 symbol.
json.clear();
let _ = json.update_string("payload.text", "https://www.chilkatsoft.com/barcode_overview.asp");
let _ = json.update_int("encoding.qr.version", 1);
if fmt.qr_code("generate", &json, &json_out).is_err() {
    println!("code: {}", json_out.string_of("errors[0].code").unwrap_or_default());
    println!("path: {}", json_out.string_of("errors[0].path").unwrap_or_default());
    println!("message: {}", json_out.string_of("errors[0].message").unwrap_or_default());
}

// A program can act on the code.
if json_out.string_of("errors[0].code").unwrap_or_default() == "capacityExceeded" {
    println!("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.