(Swift 3,4,5...) Create JWS using the Flattened JSON Serialization Format

Creates a JSON Web Signature (JWS) containing 1 signature and output using the flattened JSON serialization format.

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

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func chilkatTest() {
    // 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.

    // The JWS to be created will contain one signature using an ECDSA key.

    let sbEccJwk = CkoStringBuilder()!
    sbEccJwk.append("{\"kty\":\"EC\",")
    sbEccJwk.append("\"crv\":\"P-256\",")
    sbEccJwk.append("\"x\":\"f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU\",")
    sbEccJwk.append("\"y\":\"x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0\",")
    sbEccJwk.append("\"d\":\"jpsQnnGQmL-YBIffH1136cspYG6-0iY7X1fCE9-E9LI\"")
    sbEccJwk.append("}")

    let eccKey = CkoPrivateKey()!
    // Note: This example loads the ECDSA key from JWK format.  Any format can be loaded
    // into the private key object. (See the online reference documentation..)
    var success: Bool = eccKey.loadJwk(sbEccJwk.getAsString())
    if success != true {
        print("\(eccKey.lastErrorText!)")
        return
    }

    // ---------------------------------------------------
    // Prepare both a protected and unprotected header.

    let jwsProtHdr = CkoJsonObject()!
    jwsProtHdr.append("alg", value: "ES256")

    let jwsUnprotHdr = CkoJsonObject()!
    jwsUnprotHdr.append("kid", value: "myEcKey")

    // ---------------------------------------------------
    let jws = CkoJws()!

    jws.setProtectedHeader(0, json: jwsProtHdr)
    jws.setUnprotectedHeader(0, json: jwsUnprotHdr)

    jws.setPrivateKey(0, privKey: eccKey)

    var bIncludeBom: Bool = false
    var payloadStr: String? = "In our village, folks say God crumbles up the old moon into stars."
    jws.setPayload(payloadStr, charset: "utf-8", includeBom: bIncludeBom)

    // ---------------------------------------------------
    // Create the JWS.
    // Indicate we prefer the non-compact, flattened serialization.
    jws.preferCompact = false
    jws.preferFlattened = true

    var jwsStr: String? = jws.createJws()
    if jws.lastMethodSuccess != true {
        print("\(jws.lastErrorText!)")
        return
    }

    // The jwsStr is contains the flattened JSON in the smallest possible size, which is a single line.
    // To get in human-readable format, load into a Chilkat JSON object and emit..
    let json = CkoJsonObject()!
    json.load(jwsStr)
    json.emitCompact = false
    print("\(json.emit()!)")

    // Sample output:

    // { 
    //   "payload": "SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu",
    //   "protected": "eyJhbGciOiJFUzI1NiJ9",
    //   "header": { 
    //     "kid": "myEcKey"
    //   },
    //   "signature": "b7V2UpDPytr-kMnM_YjiQ3E0J2ucOI9LYA7mt57vccrK1rb84j9areqgQcJwOA00aWGoz4hf6sMTBfobdcJEGg"
    // }

}