Visual FoxPro

REST Asynchronous Streaming Upload File

See more REST Examples

Demonstrates how to asynchronous streaming upload a file to cloud storage. This particular example demonstrates an upload to the Azure Cloud Storage service. The same concepts apply to S3, Google Cloud, and Google Drive. Visual FoxPro

LOCAL lnSuccess
LOCAL loRest
LOCAL lnBTls
LOCAL lnPort
LOCAL lnBAutoReconnect
LOCAL loAzAuth
LOCAL loSendStream
LOCAL loTask
LOCAL lnCurPctDone
LOCAL lnResponseStatusCode
LOCAL lcResponseBodyStr

lnSuccess = 0

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

loRest = CreateObject('Chilkat.Rest')

* Connect to the Azure Storage Blob Service
lnBTls = 1
lnPort = 443
lnBAutoReconnect = 1
* In this example, the storage account name is "chilkat".
lnSuccess = loRest.Connect("chilkat.blob.core.windows.net",lnPort,lnBTls,lnBAutoReconnect)
IF (lnSuccess <> 1) THEN
    ? loRest.LastErrorText
    RELEASE loRest
    CANCEL
ENDIF

* Provide Azure Cloud credentials for the REST call.
loAzAuth = CreateObject('Chilkat.AuthAzureStorage')
loAzAuth.AccessKey = "AZURE_ACCESS_KEY"
* The account name used here should match the 1st part of the domain passed in the call to Connect (above).
loAzAuth.Account = "chilkat"
loAzAuth.Scheme = "SharedKey"
loAzAuth.Service = "Blob"
* This causes the "x-ms-version: 2021-08-06" header to be automatically added.
loAzAuth.XMsVersion = "2021-08-06"
lnSuccess = loRest.SetAuthAzureStorage(loAzAuth)

* Set some request headers.
lnSuccess = loRest.AddHeader("x-ms-blob-content-disposition",'attachment; filename="thisIsATest.txt"')
lnSuccess = loRest.AddHeader("x-ms-blob-type","BlockBlob")
lnSuccess = loRest.AddHeader("x-ms-meta-m1","v1")
lnSuccess = loRest.AddHeader("x-ms-meta-m2","v2")

* Note: The application does not need to explicitly set the following
* headers: x-ms-date, Authorization, and Content-Length.  These headers
* are automatically set by Chilkat.

loSendStream = CreateObject('Chilkat.Stream')

* Define the source data for the stream to be a file.
loSendStream.SourceFile = "qa_data/hamlet.xml"

* Create a background thread task to upload from the stream
* The name of the Azure storage container is "test".
loTask = loRest.FullRequestStreamAsync("PUT","/test/thisIsATest.txt",loSendStream)

* Start the task. 
lnSuccess = loTask.Run()

* In this example, we'll simply sleep and periodically
* check to see if the REST upload if finished.
lnCurPctDone = 0
DO WHILE loTask.Finished <> 1
    loTask.SleepMs(100)
ENDDO

* Check to see if the call to FullRequestStream in the background thread pool succeeded.
IF (loTask.TaskSuccess <> 1) THEN
    * Show what would've been the LastErrorText had FullRequestStream been called synchronously
    ? loTask.ResultErrorText
    RELEASE loTask
    RELEASE loRest
    RELEASE loAzAuth
    RELEASE loSendStream
    CANCEL
ENDIF

lnResponseStatusCode = loRest.ResponseStatusCode

* When successful, the Azure Storage service will respond with a 201 response code,
* with an empty body.  Therefore, in the success condition, the responseStr is empty.
IF (lnResponseStatusCode = 201) THEN
    ? "File uploaded."
ELSE
    * It failed, so examine the response body, if one was returned:
    * Given that FullRequestStream returns a string, the return value is obtained via GetResultString.
    lcResponseBodyStr = loTask.GetResultString()
    ? "response body (if any): " + lcResponseBodyStr

    * Examine the request/response to see what happened.
    ? "response status code = " + STR(loRest.ResponseStatusCode)
    ? "response status text = " + loRest.ResponseStatusText
    ? "response header: " + loRest.ResponseHeader
    ? "---"
    ? "LastRequestStartLine: " + loRest.LastRequestStartLine
    ? "LastRequestHeader: " + loRest.LastRequestHeader
ENDIF

RELEASE loTask

RELEASE loRest
RELEASE loAzAuth
RELEASE loSendStream