Zig

USPS OAuth2 Client Credentials

See more OAuth2 Examples

Get an OAuth2 access token for the United States Postal Service (USPS) REST API. 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 -X POST https://apis.usps.com/oauth2/v3/token \
    //   -H "Content-Type: application/x-www-form-urlencoded" \
    //   -d "grant_type=client_credentials" \
    //   -d "client_id=123456789" \
    //   -d "client_secret=A1B2C3D4E5" \
    //   -d "scope=ResourceA+ResourceB+ResourceC"

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

    const req = try chilkat.HttpRequest.init();
    defer req.deinit();
    req.addParam("grant_type", "client_credentials");
    req.addParam("client_id", "123456789");
    req.addParam("client_secret", "A1B2C3D4E5");
    req.addParam("scope", "ResourceA+ResourceB+ResourceC");

    req.setHttpVerb("POST");
    req.setContentType("application/x-www-form-urlencoded");

    const resp = try chilkat.HttpResponse.init();
    defer resp.deinit();
    http.httpReq("https://apis.usps.com/oauth2/v3/token", req, 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);

    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 >= 400) {
        std.debug.print("Response Header:\n", .{});
        std.debug.print("{s}\n", .{try resp.getHeader(alloc)});
        std.debug.print("Failed.\n", .{});
        return;
    }

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

    // {
    //   "access_token": "eyJraWQiOiIxMDEwMTAiLCJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiJ9.eyJzdWIiOiIiLCJhdWQiOiJhZGRyZXNzZXMgaW50ZXJuYXRpb25hbC1wcmljZXMgc3Vic2NyaXB0aW9ucyBwYXltZW50cyBwaWNrdXAgdHJhY2tpbmcgbGFiZWxzIHNjYW4tZm9ybXMgY29tcGFuaWVzIHNlcnZpY2UtZGVsaXZlcnktc3RhbmRhcmRzIGxvY2F0aW9ucyBpbnRlcm5hdGlvbmFsLWxhYmVscyBwcmljZXMiLCJhenAiOiJoeXI3YjN2Q1J0cFl0QUhNMWE4Y2RVcmt5eUZtTmtiZyIsIm9yZ2FuaXphdGlvbl9pZCI6IjAiLCJpc3MiOiJ1cm46XC9cL2FwaS51c3BzLmNvbSIsImV4cCI6MTY4MDkxNzc4NiwiaWF0IjoxNjgwODg4OTg2LCJqdGkiOiI3YjU5MzJlMS05NjIxLTQzZDAtYTMyNy0xMzIxYWVjNzJjZGYifQ.QzrUxlT2rG4jvYbMDGnk23j8ZYfHJcdXPKR9CbSmcKeVpURaHhEMpPB6K4x5ut3xxeEGSzeE5VRz8vixI4iqyHsD8rSdkLTPHy0iovUHOZQBAJVQ6hii9jpLhxUXmiTtH3jKzSj_f2fuNmZbIGhf-CR2FBeWF-aBPzEDEMV95nkCUMfW_Z2BmkbraSfvQZxkCO-cLrMAwlYcrzUtaJ7vnazeQB4sep5BBHBEvsa4kfq6_tz6BAKgv3R7cI2NkSv-wgy_IGoTjVCMTS8mJHGs_t8cWCO8-z4lxW1tUwIBKOCUDpmEEnGgiG6Sl0C_gGl4bZ5cDSl4IgPpcOVi9jZ7LA",
    //   "token_type": "Bearer",
    //   "issued_at": 1680888985929,
    //   "expires_in": 28799,
    //   "status": "approved",
    //   "scope": "addresses international-prices subscriptions payments pickup tracking labels scan-forms companies service-delivery-standards locations international-labels prices",
    //   "issuer": "api.usps.com",
    //   "client_id": "hyr7b3vCRtpYtAHM1a8cdUrkyyFmNkbg",
    //   "application_name": "Silver Shipper Developer",
    //   "api_products": "[Shipping-Silver]",
    //   "public_key": "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"
    // }

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

    _ = try j_resp.stringOf(alloc, "access_token");
    _ = try j_resp.stringOf(alloc, "token_type");
    _ = j_resp.intOf("issued_at");
    _ = j_resp.intOf("expires_in");
    _ = try j_resp.stringOf(alloc, "status");
    _ = try j_resp.stringOf(alloc, "scope");
    _ = try j_resp.stringOf(alloc, "issuer");
    _ = try j_resp.stringOf(alloc, "client_id");
    _ = try j_resp.stringOf(alloc, "application_name");
    _ = try j_resp.stringOf(alloc, "api_products");
    _ = try j_resp.stringOf(alloc, "public_key");
}