Chilkat • HOME • Android™ • AutoIt • C • C# • C++ • Chilkat2-Python • CkPython • Classic ASP • DataFlex • Delphi DLL • Go • Java • Node.js • Objective-C • PHP Extension • Perl • PowerBuilder • PowerShell • PureBasic • Ruby • SQL Server • Swift • Tcl • Unicode C • Unicode C++ • VB.NET • VBScript • Visual Basic 6.0 • Visual FoxPro • Xojo Plugin
(Lianja) S3 Resume DownloadSuppose an S3 download of a very large file failed for some reason and you have a partial file on disk. Rather than restart the entire download, you wish to download the remaining portion. This example demonstrates how to finish a previously failed download. Note: This example requires Chilkat v9.5.0.83 or above.
// This example requires the Chilkat API to have been previously unlocked. // See Global Unlock Sample for sample code. loRest = createobject("CkRest") // Connect to the Amazon AWS REST server. llBTls = .T. lnPort = 443 llBAutoReconnect = .T. llSuccess = loRest.Connect("s3.amazonaws.com",lnPort,llBTls,llBAutoReconnect) // --------------------------------------------------------------------------- // 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. loAuthAws = createobject("CkAuthAws") loAuthAws.AccessKey = "AWS_ACCESS_KEY" loAuthAws.SecretKey = "AWS_SECRET_KEY" loAuthAws.ServiceName = "s3" llSuccess = loRest.SetAuthAws(loAuthAws) // Set the bucket name via the HOST header. // In this case, the bucket name is "chilkat100". loRest.Host = "chilkat100.s3.amazonaws.com" // We want to continue downloading a file. // The relative local filepath of our previously partially downoaded file is: qa_output/hamlet.xml // Let's find out how many bytes are already downloaded. loFac = createobject("CkFileAccess") lcLocalFilepath = "qa_output/hamlet.xml" // Note: The FileSize method returns a signed 32-bit integer. If the file is potentially larger than 2GB, call FileSizeStr instead to return // the size of the file as a string, then convert to an integer value. lnSz = loFac.FileSize(lcLocalFilepath) if (lnSz > 0) then ? "sz = " + str(lnSz) // If the sz equals 42375 bytes, then we want to add a Range header that looks like this: // Range: bytes=42375- loSbRange = createobject("CkStringBuilder") loSbRange.Append("bytes=") loSbRange.AppendInt(lnSz) loSbRange.Append("-") loRest.AddHeader("Range",loSbRange.GetAsString()) ? "Added Range: " + loSbRange.GetAsString() endif // Send the request to download the remainder of the file. llSuccess = loRest.SendReqNoBody("GET","/hamlet.xml") if (llSuccess <> .T.) then ? loRest.LastErrorText release loRest release loAuthAws release loFac release loSbRange return endif // Read the response header. lnResponseStatusCode = loRest.ReadResponseHeader() if (lnResponseStatusCode < 0) then ? loRest.LastErrorText release loRest release loAuthAws release loFac release loSbRange return endif ? "Response status code = " + str(lnResponseStatusCode) // We expect a 200 or 206 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 ((lnResponseStatusCode = 200) or (lnResponseStatusCode = 206)) then loBodyStream = createobject("CkStream") // The stream's sink will be a file. // We will append to the file.. loBodyStream.SinkFile = lcLocalFilepath // Indicate that we wish to append to the output file. // The SinkFileAppend property was added in Chilkat v9.50.83 loBodyStream.SinkFileAppend = .T. // 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. llSuccess = loRest.ReadRespBodyStream(loBodyStream,.T.) if (llSuccess <> .T.) then ? loRest.LastErrorText release loRest release loAuthAws release loFac release loSbRange release loBodyStream return endif ? "Successfully downloaded the file." else lcErrResponse = loRest.ReadRespBodyString() if (loRest.LastMethodSuccess <> .T.) then ? loRest.LastErrorText else ? lcErrResponse endif endif release loRest release loAuthAws release loFac release loSbRange release loBodyStream |
© 2000-2025 Chilkat Software, Inc. All Rights Reserved.