Lianja

REST Asynchronous Streaming Upload File

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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. Lianja

llSuccess = .F.

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

loRest = createobject("CkRest")

// Connect to the Azure Storage Blob Service
llBTls = .T.
lnPort = 443
llBAutoReconnect = .T.
// In this example, the storage account name is "chilkat".
llSuccess = loRest.Connect("chilkat.blob.core.windows.net",lnPort,llBTls,llBAutoReconnect)
if (llSuccess <> .T.) then
    ? loRest.LastErrorText
    release loRest
    return
endif

// Provide Azure Cloud credentials for the REST call.
loAzAuth = createobject("CkAuthAzureStorage")
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"
llSuccess = loRest.SetAuthAzureStorage(loAzAuth)

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

// 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. 
llSuccess = 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 <> .T.
    loTask.SleepMs(100)
enddo

// Check to see if the call to FullRequestStream in the background thread pool succeeded.
if (loTask.TaskSuccess <> .T.) then
    // Show what would've been the LastErrorText had FullRequestStream been called synchronously
    ? loTask.ResultErrorText
    release loTask
    release loRest
    release loAzAuth
    release loSendStream
    return
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