(Go) Verify a JWT Created by the Amazon Cognito Service

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

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    // 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:

    http := chilkat.NewHttp()
    sbJsonKeys := chilkat.NewStringBuilder()
    success := http.QuickGetSb("https://cognito-idp.us-east-2.amazonaws.com/us-east-2_******/.well-known/jwks.json",sbJsonKeys)
    if success == false {
        fmt.Println(http.LastErrorText())
        http.DisposeHttp()
        sbJsonKeys.DisposeStringBuilder()
        return
    }

    jsonKeys := chilkat.NewJsonObject()
    jsonKeys.LoadSb(sbJsonKeys)
    jsonKeys.SetEmitCompact(false)
    fmt.Println(*jsonKeys.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.
    jsonKey1 := jsonKeys.ObjectOf("keys[0]")
    if jsonKeys.LastMethodSuccess() == false {
        fmt.Println("Did not get the 1st JSON public key.")
        http.DisposeHttp()
        sbJsonKeys.DisposeStringBuilder()
        jsonKeys.DisposeJsonObject()
        return
    }

    pubKey1 := chilkat.NewPublicKey()
    success = pubKey1.LoadFromString(*jsonKey1.Emit())
    if success == false {
        fmt.Println(pubKey1.LastErrorText())
        http.DisposeHttp()
        sbJsonKeys.DisposeStringBuilder()
        jsonKeys.DisposeJsonObject()
        pubKey1.DisposePublicKey()
        return
    }

    jsonKey1.DisposeJsonObject()

    fmt.Println("Success")

    jwt := chilkat.NewJwt()

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

    // First verify the signature.
    sigVerified := jwt.VerifyJwtPk(token,pubKey1)
    fmt.Println("verified: ", sigVerified)

    // 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.
    leeway := 60
    bTimeValid := jwt.IsTimeValid(token,leeway)
    fmt.Println("time constraints valid: ", bTimeValid)

    // Now let's recover the original claims JSON (the payload).
    payload := jwt.GetPayload(token)
    // The payload will likely be in compact form:
    fmt.Println(*payload)

    // We can format for human viewing by loading it into Chilkat's JSON object
    // and emit.
    json := chilkat.NewJsonObject()
    success = json.Load(*payload)
    json.SetEmitCompact(false)
    fmt.Println(*json.Emit())

    // We can recover the original JOSE header in the same way:
    joseHeader := jwt.GetHeader(token)
    // The payload will likely be in compact form:
    fmt.Println(*joseHeader)

    // We can format for human viewing by loading it into Chilkat's JSON object
    // and emit.
    success = json.Load(*joseHeader)
    json.SetEmitCompact(false)
    fmt.Println(*json.Emit())

    http.DisposeHttp()
    sbJsonKeys.DisposeStringBuilder()
    jsonKeys.DisposeJsonObject()
    pubKey1.DisposePublicKey()
    jwt.DisposeJwt()
    json.DisposeJsonObject()