Lianja Requires Chilkat v11.0.0+

Verify a JWT Created by the Amazon Cognito Service

See more JSON Web Token (JWT) Examples

Demonstrates how to verify a JWT created by the Amazon Cognito Service. Lianja

llSuccess = .F.

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

//  The public keys for this example are at https://cognito-idp.us-east-2.amazonaws.com/us-east-2_******/.well-known/jwks.json
//  Let's get them:

loHttp = createobject("CkHttp")
loSbJsonKeys = createobject("CkStringBuilder")
llSuccess = loHttp.QuickGetSb("https://cognito-idp.us-east-2.amazonaws.com/us-east-2_******/.well-known/jwks.json",loSbJsonKeys)
if (llSuccess = .F.) then
    ? loHttp.LastErrorText
    release loHttp
    release loSbJsonKeys
    return
endif

loJsonKeys = createobject("CkJsonObject")
loJsonKeys.LoadSb(loSbJsonKeys)
loJsonKeys.EmitCompact = .F.
? loJsonKeys.Emit()

//  Here are the keys:

//  {
//    "keys": [
//      {
//        "alg": "RS256",
//        "e": "AQAB",
//        "kid": "1A/L5Fsb2EsEwxy5E0cmCMS1BnMe6Jl6NXiMig4iNwU=",
//        "kty": "RSA",
//        "n": "y0w7BJrIJYi ... jKG27z2P3OKw",
//        "use": "sig"
//      },
//      {
//        "alg": "RS256",
//        "e": "AQAB",
//        "kid": "mos6VTJnvDwurY3ghJg6IAPUq+dMwl6CL/iThzJOkzg=",
//        "kty": "RSA",
//        "n": "qbIEH-7tg6yrT ... 3Fj94ooTd0w",
//        "use": "sig"
//      }
//    ]
//  }

//  Try the 1st key.
loJsonKey1 = createobject("CkJsonObject")
loJsonKeys.ObjectOf2("keys[0]",loJsonKey1)

loPubKey1 = createobject("CkPublicKey")
llSuccess = loPubKey1.LoadFromString(loJsonKey1.Emit())
if (llSuccess = .F.) then
    ? loPubKey1.LastErrorText
    release loHttp
    release loSbJsonKeys
    release loJsonKeys
    release loJsonKey1
    release loPubKey1
    return
endif

? "Success"

loJwt = createobject("CkJwt")

//  I did not include the an actual AWS Cognito token here because our test sample used customer-provided data..
lcToken = "eyJ..asXg"

//  First verify the signature.
llSigVerified = loJwt.VerifyJwtPk(lcToken,loPubKey1)
? "verified: " + str(llSigVerified)

//  Let's see if the time constraints, if any, are valid.
//  The above JWT was created on the afternoon of 16-May-2016, with an expiration of 1 hour.
//  If the current system time is before the "nbf" time, or after the "exp" time,
//  then IsTimeValid will return false/0.
//  Also, we'll allow a leeway of 60 seconds to account for any clock skew.
//  Note: If the token has no "nbf" or "exp" claim fields, then IsTimeValid is always true.
lnLeeway = 60
llBTimeValid = loJwt.IsTimeValid(lcToken,lnLeeway)
? "time constraints valid: " + str(llBTimeValid)

//  Now let's recover the original claims JSON (the payload).
lcPayload = loJwt.GetPayload(lcToken)
//  The payload will likely be in compact form:
? lcPayload

//  We can format for human viewing by loading it into Chilkat's JSON object
//  and emit.
loJson = createobject("CkJsonObject")
llSuccess = loJson.Load(lcPayload)
loJson.EmitCompact = .F.
? loJson.Emit()

//  We can recover the original JOSE header in the same way:
lcJoseHeader = loJwt.GetHeader(lcToken)
//  The payload will likely be in compact form:
? lcJoseHeader

//  We can format for human viewing by loading it into Chilkat's JSON object
//  and emit.
llSuccess = loJson.Load(lcJoseHeader)
loJson.EmitCompact = .F.
? loJson.Emit()


release loHttp
release loSbJsonKeys
release loJsonKeys
release loJsonKey1
release loPubKey1
release loJwt
release loJson