(Go) Validate JWS Using HMAC SHA-256

Validates a JSON Web Signature (JWS) using HMAC SHA-256.

Note: This example requires Chilkat v9.5.0.66 or greater.

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

    // Note: This example requires Chilkat v9.5.0.66 or greater.

    // This example takes a JSON signature in compact serialization format,
    // and uses a MAC key to validate and recover the protected header and payload.

    jws := chilkat.NewJws()

    // Set the HMAC key:
    hmacKey := "AyM1SysPpbyDfgZld3umj1qzKObwVMkoqQ-EstJQLr_T-1qS0gZH75aKtMN3Yj0iPS4hcgUuTwjAzZr1Z9CAow"
    signatureIndex := 0
    jws.SetMacKey(signatureIndex,hmacKey,"base64url")

    // Load the JWS.
    jwsCompact := "eyJ0eXAiOiJKV1QiLA0KICJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlfQ.dBjftJeZ4CVP-mB92K27uhbUJU1p1r_wW1gFWFOEjXk"
    success := jws.LoadJws(jwsCompact)

    // Validate the 1st (and only) signature at index 0..
    v := jws.Validate(signatureIndex)
    if v < 0 {
        // Perhaps Chilkat was not unlocked or the trial expired..
        fmt.Println("Method call failed for some other reason.")
        fmt.Println(jws.LastErrorText())
        jws.DisposeJws()
        return
    }

    if v == 0 {
        fmt.Println("Invalid signature.  The MAC key was incorrect, the JWS was invalid, or both.")
        jws.DisposeJws()
        return
    }

    // If we get here, the signature was validated..
    fmt.Println("Signature validated.")

    // Recover the original content:
    fmt.Println("Recovered content:")
    fmt.Println(*jws.GetPayload("utf-8"))

    // Examine the protected header:
    joseHeader := jws.GetProtectedHeader(signatureIndex)
    if jws.LastMethodSuccess() != true {
        fmt.Println("No protected header found at the given index.")
        jws.DisposeJws()
        return
    }

    joseHeader.SetEmitCompact(false)

    fmt.Println("Protected (JOSE) header:")
    fmt.Println(*joseHeader.Emit())
    joseHeader.DisposeJsonObject()

    // Output:

    // 	Signature validated.
    // 	Recovered content:
    // 	{"iss":"joe",
    // 	 "exp":1300819380,
    // 	 "http://example.com/is_root":true}
    // 	Protected (JOSE) header:
    // 	{ 
    // 	  "typ": "JWT",
    // 	  "alg": "HS256"
    // 	}

    jws.DisposeJws()