(Swift 3,4,5...) Lower-Level REST API Methods (Google Cloud Storage)

The FullRequest* methods, such as FullRequestBinary, FullRequestMultipart, FullRequestNoBody, FullRequestStream, FullRequestString, etc. are high-level REST API methods that both send the request and receive the response. It is often the case that an application needs make a REST call, but with a finer level of control. The Chilkat REST API provides this feature. An application can break a REST call into the following parts:

1. Send the HTTP request. (via the SendReq* methods)
2. Receive the HTTP response header. (ReadResponseHeader)
3. Receive the HTTP response body. (via the ReadRespBody* methods)

This example demonstrates a REST call using SendReqStringBody, ReadResonseHeader, and ReadRespBodyString.

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func chilkatTest() {
    // This example demonstrates a REST call using SendReqStringBody, ReadResonseHeader, and ReadRespBodyString.
    // It will create a bucket in Google Cloud Storage.
    var success: Bool

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

    let gAuth = CkoAuthGoogle()!
    // Obtain an access token as shown in one of the following examples:
    // See Get Access Token using a Service Account JSON Key
    // See Get Access Token using a P12 File

    let rest = CkoRest()!

    // Connect using TLS.
    var bAutoReconnect: Bool = true
    success = rest.connect("www.googleapis.com", port: 443, tls: true, autoReconnect: bAutoReconnect)

    // Provide the authentication credentials (i.e. the access key)
    success = rest.setAuthGoogle(gAuth)

    // Build the JSON request body for creating a bucket.
    // The only required property is the "name", but we'll add more
    // to make a better example..
    let jsonReqBody = CkoJsonObject()!
    success = jsonReqBody.addString(at: -1, name: "name", value: "chilkat-bucket-c")
    success = jsonReqBody.addString(at: -1, name: "kind", value: "storage#bucket")
    success = jsonReqBody.addString(at: -1, name: "location", value: "US")
    success = jsonReqBody.add(at: -1, name: "versioning")

    var pObjVersioning: CkoJsonObject? = jsonReqBody.object(of: "versioning")
    success = pObjVersioning!.addBool(at: -1, name: "enabled", value: true)
    pObjVersioning = nil

    // Show the HTTP request body we'll be sending.
    print("\(jsonReqBody.emit()!)")

    // Add the required query parameter.
    // See https://cloud.google.com/storage/docs/json_api/v1/buckets/insert
    success = rest.addQueryParam("project", value: "chilkattest-1050")

    // Add the Content-Type HTTP request header.
    success = rest.addHeader("Content-Type", value: "application/json; charset=UTF-8")

    // Send the REST HTTP request.
    success = rest.sendReqStringBody("POST", uriPath: "/storage/v1/b", bodyText: jsonReqBody.emit())
    if success != true {
        print("\(rest.lastErrorText!)")
        return
    }

    // Read the response header.
    var responseStatusCode: Int = rest.readResponseHeader().intValue
    if responseStatusCode < 0 {
        // We were unable to receive the response header.
        print("\(rest.lastErrorText!)")
        return
    }

    if responseStatusCode != 200 {
        // The response was not successful.  We'll still need to receive 
        // the response body, which may contain an error message from the server.
        // If the response has no body, then the method for reading the
        // response body can still be called.  It will simply return with an empty
        // response body.

        // We can examine the response header and status text:
        print("Response status text: \(rest.responseStatusText!)")
        print("Response header: \(rest.responseHeader!)")
    }

    // Read the response body.  In this case we're expecting it to be JSON..
    var responseBodyStr: String? = rest.readRespBodyString()
    if rest.lastMethodSuccess != true {
        // We were unable to receive the response body.
        // Note: If the response did not include a body (such as for cases where
        // the Content-Length header is 0, or if the response status code implicitly
        // indicates no body, then ReadRespBodyString returns cktrue, and the
        // responseBodyString will be an empty string.
        print("\(rest.lastErrorText!)")
        return
    }

    // Show the JSON response.
    print("Json Response: \(responseBodyStr!)")

}