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(Visual Basic 6.0) S3 Upload the Parts for a Multipart Upload
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.
' 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. Dim xmlInit As New ChilkatXml Dim success As Long success = xmlInit.LoadXmlFile("s3_multipart_uploads/initiate.xml") If (success <> 1) Then Debug.Print "Did not find the initiate.xml XML file." Exit Sub End If Dim uploadId As String uploadId = xmlInit.GetChildContent("UploadId") Debug.Print "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 Dim fileToUploadPath As String 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. Dim partSize As Long 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. Dim fac As New CkFileAccess success = fac.OpenForRead(fileToUploadPath) ' How many parts will there be if each part is 5242880 bytes? Dim numParts As Long numParts = fac.GetNumBlocks(partSize) Debug.Print "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.. Dim partsListFile As String partsListFile = "s3_multipart_uploads/partsList.xml" Dim partsListXml As New ChilkatXml If (fac.FileExists(partsListFile) = 1) Then success = partsListXml.LoadXmlFile(partsListFile) End If ' Make sure the top-level tag is "CompleteMultipartUpload" partsListXml.Tag = "CompleteMultipartUpload" ' -------------------------------------- ' Before entering the loop to upload parts, ' setup the REST object with AWS authentication, ' and make the initial connection. Dim rest As New ChilkatRest ' Connect to the Amazon AWS REST server. Dim bTls As Long bTls = 1 Dim port As Long port = 443 Dim bAutoReconnect As Long bAutoReconnect = 1 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. Dim authAws As New ChilkatAuthAws authAws.AccessKey = "AWS_ACCESS_KEY" authAws.SecretKey = "AWS_SECRET_KEY" authAws.ServiceName = "s3" success = rest.SetAuthAws(authAws) ' Set the bucket name via the HOST header. ' In this case, the bucket name is "chilkat100". rest.Host = "chilkat100.s3.amazonaws.com" ' -------------------------------------- Dim partNumber As Long partNumber = 1 Dim sbPartNumber As New ChilkatStringBuilder Do While (partNumber <= numParts) Debug.Print "---- " & 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 success = sbPartNumber.AppendInt(partNumber) Dim bPartAlreadyUploaded As Long bPartAlreadyUploaded = 0 ' If there are no children, then the XML is empty and no parts have yet been uploaded. Dim numUploadedParts As Long numUploadedParts = partsListXml.NumChildren If (numUploadedParts > 0) Then ' 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. Dim xRec0 As ChilkatXml Set xRec0 = partsListXml.GetChild(0) Dim foundRec As ChilkatXml Set foundRec = xRec0.FindNextRecord("PartNumber",sbPartNumber.GetAsString()) If (xRec0.LastMethodSuccess = 1) Then bPartAlreadyUploaded = 1 Debug.Print "Part " & partNumber & " was previously uploaded." Debug.Print foundRec.GetXml() End If End If ' 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 = 0) Then Debug.Print "Uploading part " & partNumber & " ..." ' Setup the stream source for the large file to be uploaded.. Dim fileStream As New ChilkatStream fileStream.SourceFile = 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.SourceFilePartSize = 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. success = rest.ClearAllQueryParams() success = rest.AddQueryParam("partNumber",sbPartNumber.GetAsString()) success = 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.SourceFilePart = partNumber - 1 ' Because the SourceFilePart and SourceFilePartSize properties are set, the stream will ' will provide just that part of the file. Dim responseStr As String responseStr = rest.FullRequestStream("PUT","/somethingBig.zip",fileStream) If (rest.LastMethodSuccess <> 1) Then Debug.Print rest.LastErrorText Exit Sub End If If (rest.ResponseStatusCode <> 200) Then ' Examine the request/response to see what happened. Debug.Print "response status code = " & rest.ResponseStatusCode Debug.Print "response status text = " & rest.ResponseStatusText Debug.Print "response header: " & rest.ResponseHeader Debug.Print "response body: " & responseStr Debug.Print "---" Debug.Print "LastRequestStartLine: " & rest.LastRequestStartLine Debug.Print "LastRequestHeader: " & rest.LastRequestHeader Exit Sub End If ' OK, this part was uploaded.. ' The response will have a 0-length body. The only information we need is the ' ETag response header field. Dim etag As String etag = rest.ResponseHdrByName("ETag") ' It should be present, but just in case there was no ETag header... If (rest.LastMethodSuccess <> 1) Then Debug.Print "No ETag response header found!" Debug.Print "response header: " & rest.ResponseHeader Exit Sub End If ' We need to add record to the partsListXml. ' The record will look like this: ' <Part> ' <PartNumber>PartNumber</PartNumber> ' <ETag>ETag</ETag> ' </Part> Dim xPart As ChilkatXml Set xPart = partsListXml.NewChild("Part","") xPart.NewChildInt2 "PartNumber",partNumber xPart.NewChild2 "ETag",etag success = partsListXml.SaveXml(partsListFile) If (success <> 1) Then Debug.Print partsListXml.LastErrorText Exit Sub End If Debug.Print "-- Part " & partNumber & " uploaded. ---------------------" End If partNumber = partNumber + 1 Loop Debug.Print "Finished. All parts uploaded."
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