Zig
Amazon Pay - Complete Checkout Session

Complete Checkout Session after the buyer returns to checkoutResultReturnUrl to finalize the paymentIntent.
Chilkat Zig Downloads

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.

    const http = try chilkat.Http.init();
    defer http.deinit();

    // Implements the following CURL command:

    // curl "https://pay-api.amazon.com/:version/checkoutSessions/:checkoutSessionId/complete" \
    // -X POST
    // -H "authorization:Px2e5oHhQZ88vVhc0DO%2FsShHj8MDDg%3DEXAMPLESIGNATURE"
    // -H "x-amz-pay-date:20201012T235046Z"
    // -H "x-amz-pay-idempotency-key:AVLo5tI10BHgEk2jEXAMPLEKEY"
    // -d '{
    //     "chargeAmount": {
    //         "amount": "14.00",
    //         "currencyCode": "USD"
    //     }
    // }'

    // Use the following online tool to generate HTTP code from a CURL command
    // Convert a cURL Command to HTTP Source Code

    // Use this online tool to generate code from sample JSON:
    // Generate Code to Create JSON

    // The following JSON is sent in the request body.

    // {
    //   "chargeAmount": {
    //     "amount": "14.00",
    //     "currencyCode": "USD"
    //   }
    // }

    const json = try chilkat.JsonObject.init();
    defer json.deinit();
    json.updateString("chargeAmount.amount", "14.00") catch {};
    json.updateString("chargeAmount.currencyCode", "USD") catch {};

    // Load your Amazon Pay private key.
    // There are many other ways to load private keys into the Chilkat private key object, such as from different formats,
    // or from in-memory strings or bytes.
    const priv_key = try chilkat.PrivateKey.init();
    defer priv_key.deinit();
    priv_key.loadPemFile("C:/someDir/myAmazonPayPrivateKey.pem") catch {
        std.debug.print("{s}\n", .{try priv_key.getLastErrorText(alloc)});
        return;
    };

    // Provide your Amazon Pay private key and Public Key ID
    // Use your public key ID here.  It must be the one associated with the private key.
    // Note: The SetAuthPrivateKey method was added in Chilkat v9.5.0.89
    const public_key_id = "SANDBOX-AHEGSJCM3L2S637RBGABLAFW";
    http.setAuthPrivateKey(public_key_id, priv_key) catch {
        std.debug.print("{s}\n", .{try http.getLastErrorText(alloc)});
        return;
    };

    // Note: When the private key is provided as shown above, Chilkat will automatically add the required x-amz-pay-* headers to the HTTP request,
    // and will also sign the request.  Nothing more is needed.
    // Chilkat automatically generates and adds the following headers:
    //
    // x-amz-pay-date
    // x-amz-pay-host
    // x-amz-pay-region
    // x-amz-pay-idempotency-key
    // Authorization

    http.setAccept("application/json");

    // To use the live system, replace "sandbox" with "live" in the URL passed to HttpJson.
    // Also, make sure to use the correct region: pay-api.amazon.com, pay-api.amazon.eu, or pay-api.amazon.jp
    try http.setUrlVar("sessionId", "62b7d028-6c7c-4a43-b077-3897dff27c5b");
    const resp = try chilkat.HttpResponse.init();
    defer resp.deinit();
    http.httpJson("POST", "https://pay-api.amazon.eu/sandbox/v2/checkoutSessions/{$sessionId}/complete", json, "application/json", resp) catch {
        std.debug.print("{s}\n", .{try http.getLastErrorText(alloc)});
        return;
    };

    const sb_response_body = try chilkat.StringBuilder.init();
    defer sb_response_body.deinit();
    resp.getBodySb(sb_response_body) catch {};
    const j_resp = try chilkat.JsonObject.init();
    defer j_resp.deinit();
    j_resp.loadSb(sb_response_body) catch {};
    j_resp.setEmitCompact(false);

    // If the status code is not equal to 200, this will display error information.
    std.debug.print("Response Body:\n", .{});
    std.debug.print("{s}\n", .{try j_resp.emit(alloc)});

    const resp_status_code = resp.getStatusCode();
    std.debug.print("Response Status Code = {d}\n", .{resp_status_code});
    if (resp_status_code != 200) {
        // A sample response body for the case where the session ID does not exist:
        //     {
        //       "reasonCode": "ResourceNotFound",
        //       "message": "Resource you are trying to access is not available. Requested path '/sandbox/v2/checkoutSessions/bd504926-f659-4ad7-a1a9-9a747aaf5275'"
        //     }

        // Another sample failure response (status code = 422)
        //     {
        //       "reasonCode": "InvalidCheckoutSessionStatus",
        //       "message": "You tried to call an operation on a Checkout Session that is in a state where that operation is not allowed"
        //     }

        std.debug.print("Failed.\n", .{});
        return;
    }

    // Sample JSON response:
    // (Sample code for parsing the JSON response is shown below)

    // {
    //   "checkoutSessionId": "bd504926-f659-4ad7-a1a9-9a747aaf5275",
    //   "webCheckoutDetails": null,
    //   "chargePermissionType": "OneTime",
    //   "recurringMetadata": null,
    //   "productType": null,
    //   "paymentDetails": null,
    //   "merchantMetadata": null,
    //   "supplementaryData": null,
    //   "buyer": null,
    //   "billingAddress": null,
    //   "paymentPreferences": [
    //     null
    //   ],
    //   "statusDetails": {
    //     "state": "Completed",
    //     "reasonCode": null,
    //     "reasonDescription": null,
    //     "lastUpdatedTimestamp": "20191015T204327Z"
    //   },
    //   "shippingAddress": null,
    //   "platformId": null,
    //   "chargePermissionId": "S01-5105180-3221187",
    //   "chargeId": "S01-5105180-3221187-C056351",
    //   "constraints": [
    //     null
    //   ],
    //   "creationTimestamp": "20191015T204313Z",
    //   "expirationTimestamp": null,
    //   "storeId": null,
    //   "deliverySpecifications": null,
    //   "providerMetadata": null,
    //   "releaseEnvironment": null
    // }

    // Sample code for parsing the JSON response...
    // Use the following online tool to generate parsing code from sample JSON:
    // Generate Parsing Code from JSON

    var null_val: bool = false;

    _ = try j_resp.stringOf(alloc, "checkoutSessionId");
    _ = try j_resp.stringOf(alloc, "webCheckoutDetails");
    _ = try j_resp.stringOf(alloc, "chargePermissionType");
    _ = try j_resp.stringOf(alloc, "recurringMetadata");
    _ = try j_resp.stringOf(alloc, "productType");
    _ = try j_resp.stringOf(alloc, "paymentDetails");
    _ = try j_resp.stringOf(alloc, "merchantMetadata");
    _ = try j_resp.stringOf(alloc, "supplementaryData");
    _ = try j_resp.stringOf(alloc, "buyer");
    _ = try j_resp.stringOf(alloc, "billingAddress");
    _ = try j_resp.stringOf(alloc, "statusDetails.state");
    _ = try j_resp.stringOf(alloc, "statusDetails.reasonCode");
    _ = try j_resp.stringOf(alloc, "statusDetails.reasonDescription");
    _ = try j_resp.stringOf(alloc, "statusDetails.lastUpdatedTimestamp");
    _ = try j_resp.stringOf(alloc, "shippingAddress");
    _ = try j_resp.stringOf(alloc, "platformId");
    _ = try j_resp.stringOf(alloc, "chargePermissionId");
    _ = try j_resp.stringOf(alloc, "chargeId");
    _ = try j_resp.stringOf(alloc, "creationTimestamp");
    _ = try j_resp.stringOf(alloc, "expirationTimestamp");
    _ = try j_resp.stringOf(alloc, "storeId");
    _ = try j_resp.stringOf(alloc, "deliverySpecifications");
    _ = try j_resp.stringOf(alloc, "providerMetadata");
    _ = try j_resp.stringOf(alloc, "releaseEnvironment");
    var i: i32 = 0;
    var count_i: i32 = j_resp.sizeOfArray("paymentPreferences");
    while (i < count_i) {
        j_resp.setI(i);
        null_val = j_resp.isNullOf("paymentPreferences[i]");
        i = i + 1;
    }

    i = 0;
    count_i = j_resp.sizeOfArray("constraints");
    while (i < count_i) {
        j_resp.setI(i);
        null_val = j_resp.isNullOf("constraints[i]");
        i = i + 1;
    }
}