Go
Go
S3 Upload the Parts for a Multipart Upload
See more Amazon S3 (new) Examples
This example uploads a large file in parts. The multipart upload needs to have been first initiated prior to uploading the parts.See http://docs.aws.amazon.com/AmazonS3/latest/API/mpUploadUploadPart.html for more information about uploading parts.
Chilkat Go Downloads
success := false
// In the 1st step for uploading a large file, the multipart upload was initiated
// as shown here: Initiate Multipart Upload
// Other S3 Multipart Upload Examples:
// Complete Multipart Upload
// Abort Multipart Upload
// List Parts
// When we initiated the multipart upload, we saved the XML response to a file. This
// XML response contains the UploadId. We'll begin by loading that XML and getting
// the Upload ID.
xmlInit := chilkat.NewXml()
success = xmlInit.LoadXmlFile("s3_multipart_uploads/initiate.xml")
if success != true {
fmt.Println("Did not find the initiate.xml XML file.")
xmlInit.DisposeXml()
return
}
uploadId := xmlInit.GetChildContent("UploadId")
fmt.Println("UploadId = ", *uploadId)
// When uploading parts, we need to keep an XML record of each part number
// and its corresponding ETag, which is received in the response for each part.
// There can be up to 10000 parts, numbered 1 to 10000.
// After all parts have been uploaded, the final step will be to complete
// the multipart upload (see Complete Multipart Upload)
// In this example, the large file we want to upload is somethingBig.zip
fileToUploadPath := "s3_multipart_uploads/somethingBig.zip"
// The minimum allowed part size is 5MB (5242880 bytes). The last part can be smaller because
// it will contain the remainder of the file. (This minimum is enforced by the AWS service.)
// We'll use the minimum allowed part size for this example.
partSize := 5242880
// Let's use Chilkat's FileAccess API to examine the file to be uploaded. We'll get the size
// of the file and find out how many parts will be needed, including the final "partial" part.
fac := chilkat.NewFileAccess()
fac.OpenForRead(fileToUploadPath)
// How many parts will there be if each part is 5242880 bytes?
numParts := fac.GetNumBlocks(partSize)
fmt.Println("numParts = ", numParts)
fac.FileClose()
// Imagine that we may be running this for the 1st time, or maybe we already
// attempted to upload parts, and something failed. Maybe there was a network problem
// the resulted in not all parts getting uploaded. We'll write this code so that if run again,
// it will upload whatever parts haven't yet been uploaded.
// We'll keep a partsList.xml file to record the parts that have already been successfully
// uploaded. If this file does not yet exist, we'll create it..
partsListFile := "s3_multipart_uploads/partsList.xml"
partsListXml := chilkat.NewXml()
if fac.FileExists(partsListFile) == true {
partsListXml.LoadXmlFile(partsListFile)
}
// Make sure the top-level tag is "CompleteMultipartUpload"
partsListXml.SetTag("CompleteMultipartUpload")
// --------------------------------------
// Before entering the loop to upload parts,
// setup the REST object with AWS authentication,
// and make the initial connection.
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")
// --------------------------------------
partNumber := 1
sbPartNumber := chilkat.NewStringBuilder()
for (partNumber <= numParts) {
fmt.Println("---- ", partNumber, " ----")
// This cumbersome way of converting an integer to a string is because
// Chilkat examples are written in a script that is converted to many programming languages.
// At this time, the translator does not have integer-to-string code generation capability..
sbPartNumber.Clear()
sbPartNumber.AppendInt(partNumber)
bPartAlreadyUploaded := false
// If there are no children, then the XML is empty and no parts have yet been uploaded.
numUploadedParts := partsListXml.NumChildren()
if numUploadedParts > 0 {
// If some parts have been uploaded, check to see if this particular part was already upload.
// If so, then it can be skipped.
// Position ourselves at the 1st record.
xRec0 := partsListXml.GetChild(0)
foundRec := xRec0.FindNextRecord("PartNumber",*sbPartNumber.GetAsString())
if xRec0.LastMethodSuccess() == true {
bPartAlreadyUploaded = true
fmt.Println("Part ", partNumber, " was previously uploaded.")
fmt.Println(*foundRec.GetXml())
foundRec.DisposeXml()
}
xRec0.DisposeXml()
}
// If this part was not already uploaded, we need to upload.
// Also update the partsListXml and save as each part is successfully uploaded.
if bPartAlreadyUploaded == false {
fmt.Println("Uploading part ", partNumber, " ...")
// Setup the stream source for the large file to be uploaded..
fileStream := chilkat.NewStream()
fileStream.SetSourceFile(fileToUploadPath)
// The Chilkat Stream API has features to make uploading a parts
// of a file easy. Indicate the part size by setting the SourceFilePartSize
// property.
fileStream.SetSourceFilePartSize(partSize)
// Our HTTP start line to upload a part will look like this:
// PUT /ObjectName?partNumber=PartNumber&uploadId=UploadId HTTP/1.1
// Set the query params. We'll need partNumber and uploadId.
// Make sure the query params from previous iterations are clear.
rest.ClearAllQueryParams()
rest.AddQueryParam("partNumber",*sbPartNumber.GetAsString())
rest.AddQueryParam("uploadId",*uploadId)
// Upload this particular file part.
// Tell the fileStream which part is being uploaded.
// Our partNumber is 1-based (the 1st part is at index 1), but the fileStream's SourceFilePart
// property is 0-based. Therefore we use partNumber-1.
fileStream.SetSourceFilePart(partNumber - 1)
// Because the SourceFilePart and SourceFilePartSize properties are set, the stream will
// will provide just that part of the file.
responseStr := rest.FullRequestStream("PUT","/somethingBig.zip",fileStream)
if rest.LastMethodSuccess() != true {
fmt.Println(rest.LastErrorText())
xmlInit.DisposeXml()
fac.DisposeFileAccess()
partsListXml.DisposeXml()
rest.DisposeRest()
authAws.DisposeAuthAws()
sbPartNumber.DisposeStringBuilder()
fileStream.DisposeStream()
return
}
if rest.ResponseStatusCode() != 200 {
// Examine the request/response to see what happened.
fmt.Println("response status code = ", rest.ResponseStatusCode())
fmt.Println("response status text = ", rest.ResponseStatusText())
fmt.Println("response header: ", rest.ResponseHeader())
fmt.Println("response body: ", *responseStr)
fmt.Println("---")
fmt.Println("LastRequestStartLine: ", rest.LastRequestStartLine())
fmt.Println("LastRequestHeader: ", rest.LastRequestHeader())
xmlInit.DisposeXml()
fac.DisposeFileAccess()
partsListXml.DisposeXml()
rest.DisposeRest()
authAws.DisposeAuthAws()
sbPartNumber.DisposeStringBuilder()
fileStream.DisposeStream()
return
}
// OK, this part was uploaded..
// The response will have a 0-length body. The only information we need is the
// ETag response header field.
etag := rest.ResponseHdrByName("ETag")
// It should be present, but just in case there was no ETag header...
if rest.LastMethodSuccess() != true {
fmt.Println("No ETag response header found!")
fmt.Println("response header: ", rest.ResponseHeader())
xmlInit.DisposeXml()
fac.DisposeFileAccess()
partsListXml.DisposeXml()
rest.DisposeRest()
authAws.DisposeAuthAws()
sbPartNumber.DisposeStringBuilder()
fileStream.DisposeStream()
return
}
// We need to add record to the partsListXml.
// The record will look like this:
// <Part>
// <PartNumber>PartNumber</PartNumber>
// <ETag>ETag</ETag>
// </Part>
xPart := partsListXml.NewChild("Part","")
xPart.NewChildInt2("PartNumber",partNumber)
xPart.NewChild2("ETag",*etag)
xPart.DisposeXml()
success = partsListXml.SaveXml(partsListFile)
if success != true {
fmt.Println(partsListXml.LastErrorText())
xmlInit.DisposeXml()
fac.DisposeFileAccess()
partsListXml.DisposeXml()
rest.DisposeRest()
authAws.DisposeAuthAws()
sbPartNumber.DisposeStringBuilder()
fileStream.DisposeStream()
return
}
fmt.Println("-- Part ", partNumber, " uploaded. ---------------------")
}
partNumber = partNumber + 1
}
fmt.Println("Finished. All parts uploaded.")
xmlInit.DisposeXml()
fac.DisposeFileAccess()
partsListXml.DisposeXml()
rest.DisposeRest()
authAws.DisposeAuthAws()
sbPartNumber.DisposeStringBuilder()
fileStream.DisposeStream()