Zig

ITIDA Canonicalize JSON and Compute SHA256 Hash

See more Egypt ITIDA Examples

Demonstrates creating the canonical (ITIDA) version of a JSON document, and then computes the SHA256 hash of the canonicalized JSON. Zig

const std = @import("std");
const chilkat = @import("chilkat");

pub fn main(init: std.process.Init) !void {
    const alloc = init.arena.allocator();

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

    // Load the JSON containing the document to be signed.

    // The JSON file should look like this:
    // NOTE: The JSON should NOT begin with "{ "documents" : [ ..."

    //       {
    //          "issuer":{
    //             "address":{
    //                "branchID":"0",
    //                "country":"EG",
    //                "regionCity":"Cairo",
    //                "postalCode":"",
    //                "buildingNumber":"0",
    //                "street":"123rd Street",
    //                "governate":"GOVERNATE"
    //             },
    //             "type":"B",
    //             "id":"209999899",
    //             "name":"Xyz SAE"
    //          },
    // ...
    // ...

    const sb = try chilkat.StringBuilder.init();
    defer sb.deinit();
    sb.loadFile("my_invoice.json", "utf-8") catch {
        std.debug.print("Failed to load input file.\n", .{});
        return;
    };

    // Convert the contents of sb to the ITIDA canonical form.
    // Always pass utf-8 for the 2nd arg.
    sb.encode("itida", "utf-8") catch {};

    // Examine the canonicalized JSON
    std.debug.print("{s}\n", .{try sb.getAsString(alloc)});

    // Compute the SHA256 hash and show the SHA256 in hex format
    std.debug.print("SHA256 hash: {s}\n", .{try sb.getHash(alloc, "sha256", "hex", "utf-8")});
}