Zig

Refresh a Dynamics CRM OAuth2 Access Token

See more OAuth2 Examples

Demonstrates how to refresh an expiring Dynamics CRM access token using the refresh token. endpoint.

(If a REST API call fails with a 401 unauthorized error, an application can auto-recover by refreshing the access token, and then re-send the request using the new token.)

Zig

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

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

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

    // We previously obtained an access token and saved the JSON to a file using this example:
    // Get Dynamics CRM OAuth2 Access Token

    // This example will examine the JSON and expiration date, and if near expiration will
    // refresh the access token.

    const json = try chilkat.JsonObject.init();
    defer json.deinit();
    json.loadFile("qa_data/tokens/dynamicsCrm.json") catch {
        return;
    };

    // The contents of the JSON look like this:
    // {
    //   "token_type": "Bearer",
    //   "scope": "user_impersonation",
    //   "expires_in": "3599",
    //   "ext_expires_in": "0",
    //   "expires_on": "1524783438",
    //   "not_before": "1524779538",
    //   "resource": "https://mydomain.api.crm.dynamics.com",
    //   "access_token": "...",
    //   "refresh_token": "...",
    //   "id_token": "..."
    // }

    // The "expires_on" value is a Unix time.
    const dt_expire = try chilkat.DateTime.init();
    defer dt_expire.deinit();
    dt_expire.setFromUnixTime(false, @as(u32, @intCast(json.intOf("expires_on")))) catch {};

    // If this date/time expires within 10 minutes of the current system time, refresh the token.

    // OK, we need to refresh the access token by sending a POST...
    //

    const req = try chilkat.HttpRequest.init();
    defer req.deinit();
    req.addParam("grant_type", "refresh_token");
    req.addParam("redirect_uri", "http://localhost:3017/");
    req.addParam("client_id", "DYNAMICS-CRM-CLIENT-ID");
    req.addParam("client_secret", "DYNAMICS-CRM-SECRET-KEY");
    req.addParam("refresh_token", try json.stringOf(alloc, "refresh_token"));
    req.addParam("resource", "https://mydynamicsdomain.api.crm.dynamics.com");

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

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

    const resp = try chilkat.HttpResponse.init();
    defer resp.deinit();
    http.httpReq("https://login.microsoftonline.com/DYNAMICS-ENDPOINT-GUID/oauth2/token", req, resp) catch {
        std.debug.print("{s}\n", .{try http.getLastErrorText(alloc)});
        return;
    };

    // Load the JSON response.
    json.load(try resp.getBodyStr(alloc)) catch {};
    json.setEmitCompact(false);

    // Show the JSON response.
    std.debug.print("{s}\n", .{try json.emit(alloc)});

    std.debug.print("Response status code: {d}\n", .{resp.getStatusCode()});

    // If the response status code is not 200, then it's an error.
    if (resp.getStatusCode() != 200) {
        return;
    }

    // If an "expires_on" member does not exist, then add the JSON member by
    // getting the current system date/time and adding the "expires_in" seconds.
    // This way we'll know when the token expires.
    if (!json.hasMember("expires_on")) {
        dt_expire.setFromCurrentSystemTime() catch {};
        dt_expire.addSeconds(json.intOf("expires_in")) catch {};
        json.appendString("expires_on", try dt_expire.getAsUnixTimeStr(alloc, false)) catch {};
    }

    // Save the refreshed access token JSON to a file for future requests.
    const fac = try chilkat.FileAccess.init();
    defer fac.deinit();
    fac.writeEntireTextFile("qa_data/tokens/dynamicsCrm.json", try json.emit(alloc), "utf-8", false) catch {};
}