Go

Streaming Download Large File to the Local Filesystem

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Downloads a large file in a streaming fashion to the local filesystem. Go

    success := false

    // Azure File Service Example: Downloads a large file to the local filesystem using a Chilkat stream.
    // See:  https://docs.microsoft.com/en-us/rest/api/storageservices/get-file

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

    rest := chilkat.NewRest()

    // Connect to the Azure Storage Blob Service
    bTls := true
    port := 443
    bAutoReconnect := true
    // In this example, the storage account name is "chilkat".
    success = rest.Connect("chilkat.file.core.windows.net",port,bTls,bAutoReconnect)
    if success != true {
        fmt.Println(rest.LastErrorText())
        rest.DisposeRest()
        return
    }

    // Provide Azure Cloud credentials for the REST calls.
    azAuth := chilkat.NewAuthAzureStorage()
    azAuth.SetAccessKey("AZURE_ACCESS_KEY")
    // The account name used here should match the 1st part of the domain passed in the call to Connect (above).
    azAuth.SetAccount("chilkat")
    azAuth.SetScheme("SharedKey")
    azAuth.SetService("File")
    // This causes the "x-ms-version: 2021-08-06" header to be automatically added.
    azAuth.SetXMsVersion("2021-08-06")
    success = rest.SetAuthAzureStorage(azAuth)

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

    // When streaming a download to the local filesystem or directed elsewhere,
    // the complete HTTP GET operation must be broken into parts.
    // For example, an HTTP GET consists of sending the request, followed by reading the response header,
    // and then finally the response body.  We'll want to read the response header, and then based
    // on the information received (such as success or failure), either read the response body
    // as an error message, or as the file data.

    // Send the HTTP GET request to download the file.
    // The share is named "pip".
    success = rest.SendReqNoBody("GET","/pip/somethingBig.zip")
    if success != true {
        fmt.Println(rest.LastErrorText())
        rest.DisposeRest()
        azAuth.DisposeAuthAzureStorage()
        return
    }

    // Read the response header.
    responseStatusCode := rest.ReadResponseHeader()
    if responseStatusCode < 0 {
        fmt.Println(rest.LastErrorText())
        rest.DisposeRest()
        azAuth.DisposeAuthAzureStorage()
        return
    }

    fmt.Println("Response status code = ", responseStatusCode)

    // We expect a 200 response status if the file data is coming.
    // Otherwise, we'll get a string response body with an error message(or no response body).
    if responseStatusCode == 200 {

        bodyStream := chilkat.NewStream()

        // The stream's sink will be a file.
        bodyStream.SetSinkFile("qa_output/somethingBig.zip")

        // Read the response body to the stream.  Given that we've
        // set the stream's sink to a file, it will stream directly
        // to the file.
        success = rest.ReadRespBodyStream(bodyStream,true)
        if success != true {
            fmt.Println(rest.LastErrorText())
            rest.DisposeRest()
            azAuth.DisposeAuthAzureStorage()
            bodyStream.DisposeStream()
            return
        }

        fmt.Println("Successfully received the large file.")

    } else {
        errResponse := rest.ReadRespBodyString()
        if rest.LastMethodSuccess() != true {
            fmt.Println(rest.LastErrorText())
        } else {
            fmt.Println(*errResponse)
        }

    }


    rest.DisposeRest()
    azAuth.DisposeAuthAzureStorage()
    bodyStream.DisposeStream()