Visual FoxPro

Lower-Level REST API Methods (Google Cloud Storage)

See more REST Examples

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.

Visual FoxPro

LOCAL lnSuccess
LOCAL loGAuth
LOCAL loRest
LOCAL lnBAutoReconnect
LOCAL loJsonReqBody
LOCAL loObjVersioning
LOCAL lnResponseStatusCode
LOCAL lcResponseBodyStr

lnSuccess = 0

* This example demonstrates a REST call using SendReqStringBody, ReadResonseHeader, and ReadRespBodyString.
* It will create a bucket in Google Cloud Storage.

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

loGAuth = CreateObject('Chilkat.AuthGoogle')
* 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

loRest = CreateObject('Chilkat.Rest')

* Connect using TLS.
lnBAutoReconnect = 1
lnSuccess = loRest.Connect("www.googleapis.com",443,1,lnBAutoReconnect)

* Provide the authentication credentials (i.e. the access key)
lnSuccess = loRest.SetAuthGoogle(loGAuth)

* 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..
loJsonReqBody = CreateObject('Chilkat.JsonObject')
lnSuccess = loJsonReqBody.AddStringAt(-1,"name","chilkat-bucket-c")
lnSuccess = loJsonReqBody.AddStringAt(-1,"kind","storage#bucket")
lnSuccess = loJsonReqBody.AddStringAt(-1,"location","US")

loObjVersioning = CreateObject('Chilkat.JsonObject')
loJsonReqBody.AppendObject2("versioning",loObjVersioning)
lnSuccess = loObjVersioning.AddBoolAt(-1,"enabled",1)

* Show the HTTP request body we'll be sending.
? loJsonReqBody.Emit()

* Add the required query parameter.
* See https://cloud.google.com/storage/docs/json_api/v1/buckets/insert
lnSuccess = loRest.AddQueryParam("project","chilkattest-1050")

* Add the Content-Type HTTP request header.
lnSuccess = loRest.AddHeader("Content-Type","application/json; charset=UTF-8")

* Send the REST HTTP request.
lnSuccess = loRest.SendReqStringBody("POST","/storage/v1/b",loJsonReqBody.Emit())
IF (lnSuccess = 0) THEN
    ? loRest.LastErrorText
    RELEASE loGAuth
    RELEASE loRest
    RELEASE loJsonReqBody
    RELEASE loObjVersioning
    CANCEL
ENDIF

* Read the response header.
lnResponseStatusCode = loRest.ReadResponseHeader()
IF (lnResponseStatusCode < 0) THEN
    * We were unable to receive the response header.
    ? loRest.LastErrorText
    RELEASE loGAuth
    RELEASE loRest
    RELEASE loJsonReqBody
    RELEASE loObjVersioning
    CANCEL
ENDIF

IF (lnResponseStatusCode <> 200) THEN
    * 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:
    ? "Response status text: " + loRest.ResponseStatusText
    ? "Response header: " + loRest.ResponseHeader
ENDIF

* Read the response body.  In this case we're expecting it to be JSON..
lcResponseBodyStr = loRest.ReadRespBodyString()
IF (loRest.LastMethodSuccess <> 1) THEN
    * 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.
    ? loRest.LastErrorText
    RELEASE loGAuth
    RELEASE loRest
    RELEASE loJsonReqBody
    RELEASE loObjVersioning
    CANCEL
ENDIF

* Show the JSON response.
? "Json Response: " + lcResponseBodyStr

RELEASE loGAuth
RELEASE loRest
RELEASE loJsonReqBody
RELEASE loObjVersioning