(Go) REST Stream Response to File (Streaming Download) (Amazon S3)

Demonstrates how to stream the response body directly to a file. (The example shows how to stream a JPG from the Amazon S3 service.)

Chilkat Go Downloads Go Package for Windows, MacOS, Linux, Alpine Linux, Solaris

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

    rest := chilkat.NewRest()

    // Connect to the Amazon AWS REST server.
    bTls := true
    port := 443
    bAutoReconnect := true
    success := rest.Connect("s3.amazonaws.com",port,bTls,bAutoReconnect)

    // ----------------------------------------------------------------------------
    // Important: For buckets created in regions outside us-east-1,
    // there are three important changes that need to be made.
    // See Working with S3 Buckets in Non-us-east-1 Regions for the details.
    // ----------------------------------------------------------------------------

    // Provide AWS credentials for the REST call.
    authAws := chilkat.NewAuthAws()
    authAws.SetAccessKey("AWS_ACCESS_KEY")
    authAws.SetSecretKey("AWS_SECRET_KEY")
    authAws.SetServiceName("s3")
    success = rest.SetAuthAws(authAws)

    // Set the bucket name via the HOST header.
    // In this case, the bucket name is "chilkat100".
    rest.SetHost("chilkat100.s3.amazonaws.com")

    // Send the request to download the JPG.
    success = rest.SendReqNoBody("GET","/starfish.jpg")
    if success != true {
        fmt.Println(rest.LastErrorText())
        rest.DisposeRest()
        authAws.DisposeAuthAws()
        return
    }

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

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

    // We expect a 200 response status if the JPG 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/starfish.jpg")

        // 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()
            authAws.DisposeAuthAws()
            bodyStream.DisposeStream()
            return
        }

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

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

    }


    rest.DisposeRest()
    authAws.DisposeAuthAws()
    bodyStream.DisposeStream()