pserv/src/jwt_demo_hs256.c
Godmar Back 06153db5c1 handout Fall'22
- added Jansson examples to jwt_demo_hs256
- added cookie property tests
2022-11-17 01:10:53 -05:00

103 lines
2.5 KiB
C

/*
* Quick demo of how to use libjwt using a HS256.
*
* @author gback, CS 3214, Spring 2018, updated Spring 2021
* Added Jansson demo Fall'22
*
* I included the necessary free() operations here which
* are needed in a long-running server.
*/
#include <jwt.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <errno.h>
#include <jansson.h>
static const char * NEVER_EMBED_A_SECRET_IN_CODE = "supa secret";
static void
die(const char *msg, int error)
{
fprintf(stderr, "%s: %s\n", msg, strerror(error));
exit(EXIT_FAILURE);
}
int
main()
{
jwt_t *mytoken;
int rc = jwt_new(&mytoken);
if (rc)
die("jwt_new", rc);
rc = jwt_add_grant(mytoken, "sub", "user0");
if (rc)
die("jwt_add_grant sub", rc);
time_t now = time(NULL);
rc = jwt_add_grant_int(mytoken, "iat", now);
if (rc)
die("jwt_add_grant iat", rc);
rc = jwt_add_grant_int(mytoken, "exp", now + 3600 * 24);
if (rc)
die("jwt_add_grant exp", rc);
rc = jwt_set_alg(mytoken, JWT_ALG_HS256,
(unsigned char *)NEVER_EMBED_A_SECRET_IN_CODE,
strlen(NEVER_EMBED_A_SECRET_IN_CODE));
if (rc)
die("jwt_set_alg", rc);
printf("dump:\n");
rc = jwt_dump_fp(mytoken, stdout, 1);
if (rc)
die("jwt_dump_fp", rc);
char *encoded = jwt_encode_str(mytoken);
if (encoded == NULL)
die("jwt_encode_str", ENOMEM);
jwt_free(mytoken);
printf("encoded as %s\nTry entering this at jwt.io\n", encoded);
jwt_t *ymtoken;
rc = jwt_decode(&ymtoken, encoded,
(unsigned char *)NEVER_EMBED_A_SECRET_IN_CODE,
strlen(NEVER_EMBED_A_SECRET_IN_CODE));
if (rc)
die("jwt_decode", rc);
free(encoded);
char *grants = jwt_get_grants_json(ymtoken, NULL); // NULL means all
if (grants == NULL)
die("jwt_get_grants_json", ENOMEM);
jwt_free(ymtoken);
printf("redecoded: %s\n", grants);
// an example of how to use Jansson
json_error_t error;
json_t *jgrants = json_loadb(grants, strlen(grants), 0, &error);
if (jgrants == NULL)
die("json_loadb", EINVAL);
free (grants);
json_int_t exp, iat;
const char *sub;
rc = json_unpack(jgrants, "{s:I, s:I, s:s}",
"exp", &exp, "iat", &iat, "sub", &sub);
if (rc == -1)
die("json_unpack", EINVAL);
printf ("exp: %lld\n", exp);
printf ("iat: %lld\n", iat);
printf ("sub: %s\n", sub);
json_decref(jgrants);
}