How to get jwt token from Authorization

Question

I'm sending the request with jwt token in Authorization. I need to fetch it somehow and I tried by this way:

@GetMapping
fun getUser(@AuthenticationPrincipal jwt: Jwt<*, *>): ResponseEntity<UserDto?> {
   val allClaimsFromToken: Claims? = getAllClaimsFromToken(jwt.toString());
   val userNameFromJwtToken: Any? = allClaimsFromToken?.get("sub");
   ....
}

Unfortunately I get all the time null as jwt variable. Could you tell me what am I doing wrong?

I guess the first question is how are you receiving the token? Are you using spring security OAuth2? Or is it just a header that gets passed? — ced-b, Oct 04 '20 at 03:55
@ced-b it's just header through Authorization field in postman — papakakaka, Oct 04 '20 at 09:47
Ok, that's simple enough, what library are you using for JWT? — ced-b, Oct 04 '20 at 14:59

score 0 · Accepted Answer · answered Oct 04 '20 at 20:13

Probably the most straight forward way of doing this would be to get the raw header value and then parse it with JJWT.

@GetMapping
fun getUser(@RequestHeader (name="Authorization") tokenEncoded: String): ResponseEntity<UserDto?> {
   Jwt myToken = Jwts.parserBuilder()    
     .setSigningKey(yourKeyHere)
     .build()
     .parseClaimsJws(tokenEncoded.removePrefix("Bearer").trim());

   // do something
}

You could also look into using the Spring library for OAuth2 it automates a bit more. Or you can create a filter that does the parsing so you don't have to repeat this on every web call.

Also see this post for further ideas Accessing JWT Token from a Spring Boot Rest Controller . It's Java, but basically the same applies.

How to get jwt token from Authorization

1 Answers1