Xbase++

(using AWS Signature Version 2) Streaming Download to File

See more Amazon S3 (new) Examples

The main purpose of this example is to demonstrate how to use the older Signature Version 2 authentication w/ S3. It uses V2 authentication to download a file. Xbase++

LOCAL nSuccess
LOCAL oRest
LOCAL nBTls
LOCAL nPort
LOCAL nBAutoReconnect
LOCAL oAuthAws
LOCAL nResponseStatusCode
LOCAL oBodyStream
LOCAL cErrResponse

nSuccess := 0

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

oRest := CreateObject("Chilkat.Rest")

//  Connect to the Amazon AWS REST server.
nBTls := 1
nPort := 443
nBAutoReconnect := 1
//  The file is located in the bucket named "chilkat100", which becomes part of the domain:
nSuccess := oRest:Connect("chilkat100.s3.amazonaws.com", nPort, nBTls, nBAutoReconnect)

//  Provide AWS credentials for the REST call.
oAuthAws := CreateObject("Chilkat.AuthAws")
oAuthAws:AccessKey := "AWS_ACCESS_KEY"
oAuthAws:SecretKey := "AWS_SECRET_KEY"
oAuthAws:ServiceName := "s3"

//  For AWS Signature Version 2, the following two properties need to be set:
oAuthAws:SignatureVersion := 2
//  See http://docs.aws.amazon.com/AmazonS3/latest/dev/RESTAuthentication.html#ConstructingTheCanonicalizedResourceElement
oAuthAws:CanonicalizedResourceV2 := "/chilkat100/starfish.jpg"

nSuccess := oRest:SetAuthAws(oAuthAws)

//  Send the request to download the JPG.
nSuccess := oRest:SendReqNoBody("GET", "/starfish.jpg")
IF (nSuccess != 1)
    ? oRest:LastErrorText
    oRest:destroy()
    oAuthAws:destroy()
    RETURN
ENDIF

//  Read the response header.
nResponseStatusCode := oRest:ReadResponseHeader()
IF (nResponseStatusCode < 0)
    ? oRest:LastErrorText
    oRest:destroy()
    oAuthAws:destroy()
    RETURN
ENDIF

? "Response status code = " + Str(nResponseStatusCode)

//  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 (nResponseStatusCode == 200)

    oBodyStream := CreateObject("Chilkat.Stream")

    //  The stream's sink will be a file.
    oBodyStream:SinkFile := "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.
    nSuccess := oRest:ReadRespBodyStream(oBodyStream, 1)
    IF (nSuccess != 1)
        ? oRest:LastErrorText
        oRest:destroy()
        oAuthAws:destroy()
        oBodyStream:destroy()
        RETURN
    ENDIF

    ? "Successfully received the JPG file."

ELSE
    cErrResponse := oRest:ReadRespBodyString()
    IF (oRest:LastMethodSuccess != 1)
        ? oRest:LastErrorText
    ELSE
        ? cErrResponse
    ENDIF

ENDIF

oRest:destroy()
oAuthAws:destroy()
oBodyStream:destroy()