PureBasic

Azure Storage: Download Blob to File

See more Azure Cloud Storage Examples

Sample code to download an Azure blob to a file. PureBasic

IncludeFile "CkRest.pb"
IncludeFile "CkAuthAzureStorage.pb"
IncludeFile "CkStream.pb"

Procedure ChilkatExample()

    success.i = 0

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

    rest.i = CkRest::ckCreate()
    If rest.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; Connect to the Azure Storage Blob Service
    bTls.i = 1
    port.i = 443
    bAutoReconnect.i = 1
    ; In this example, the storage account name is "chilkat".
    success = CkRest::ckConnect(rest,"chilkat.blob.core.windows.net",port,bTls,bAutoReconnect)
    If success <> 1
        Debug CkRest::ckLastErrorText(rest)
        CkRest::ckDispose(rest)
        ProcedureReturn
    EndIf

    ; Provide Azure Cloud credentials for the REST call.
    azAuth.i = CkAuthAzureStorage::ckCreate()
    If azAuth.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkAuthAzureStorage::setCkAccessKey(azAuth, "AZURE_ACCESS_KEY")
    ; The account name used here should match the 1st part of the domain passed in the call to Connect (above).
    CkAuthAzureStorage::setCkAccount(azAuth, "chilkat")
    CkAuthAzureStorage::setCkScheme(azAuth, "SharedKey")
    CkAuthAzureStorage::setCkService(azAuth, "Blob")
    ; This causes the "x-ms-version: 2021-08-06" header to be automatically added.
    CkAuthAzureStorage::setCkXMsVersion(azAuth, "2021-08-06")
    success = CkRest::ckSetAuthAzureStorage(rest,azAuth)

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

    ; Setup a file stream for the download
    fileStream.i = CkStream::ckCreate()
    If fileStream.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkStream::setCkSinkFile(fileStream, "C:/temp/qa_output/starfish.jpg")

    ; Indicate that the call to FullRequestNoBody should send the response body
    ; to fileStream if the response status code is 200.
    ; If a non-success response status code is received, then nothing
    ; is streamed to the output file and the error response is returned by FullRequestNoBody.
    expectedStatus.i = 200
    CkRest::ckSetResponseBodyStream(rest,expectedStatus,1,fileStream)

    ; The Azure blob container is "test", the file is "starfish.jpg"
    responseStr.s = CkRest::ckFullRequestNoBody(rest,"GET","/test/starfish.jpg")
    If CkRest::ckLastMethodSuccess(rest) <> 1

        ; Examine the request/response to see what happened.
        Debug "response status code = " + Str(CkRest::ckResponseStatusCode(rest))
        Debug "response status text = " + CkRest::ckResponseStatusText(rest)
        Debug "response header: " + CkRest::ckResponseHeader(rest)
        Debug "response body (if any): " + responseStr
        Debug "---"
        Debug "LastRequestStartLine: " + CkRest::ckLastRequestStartLine(rest)
        Debug "LastRequestHeader: " + CkRest::ckLastRequestHeader(rest)
        CkRest::ckDispose(rest)
        CkAuthAzureStorage::ckDispose(azAuth)
        CkStream::ckDispose(fileStream)
        ProcedureReturn
    EndIf

    Debug "Success."


    CkRest::ckDispose(rest)
    CkAuthAzureStorage::ckDispose(azAuth)
    CkStream::ckDispose(fileStream)


    ProcedureReturn
EndProcedure