(PureBasic) 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.

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IncludeFile "CkAuthAws.pb"
IncludeFile "CkFileAccess.pb"
IncludeFile "CkXml.pb"
IncludeFile "CkStream.pb"
IncludeFile "CkStringBuilder.pb"
IncludeFile "CkRest.pb"

Procedure ChilkatExample()

    ; 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.i = CkXml::ckCreate()
    If xmlInit.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success.i = CkXml::ckLoadXmlFile(xmlInit,"s3_multipart_uploads/initiate.xml")
    If success <> 1
        Debug "Did not find the initiate.xml XML file."
        CkXml::ckDispose(xmlInit)
        ProcedureReturn
    EndIf

    uploadId.s = CkXml::ckGetChildContent(xmlInit,"UploadId")
    Debug "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.s = "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.i = 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.i = CkFileAccess::ckCreate()
    If fac.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkFileAccess::ckOpenForRead(fac,fileToUploadPath)

    ; How many parts will there be if each part is 5242880 bytes?
    numParts.i = CkFileAccess::ckGetNumBlocks(fac,partSize)
    Debug "numParts = " + Str(numParts)
    CkFileAccess::ckFileClose(fac)

    ; 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.s = "s3_multipart_uploads/partsList.xml"
    partsListXml.i = CkXml::ckCreate()
    If partsListXml.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    If CkFileAccess::ckFileExists(fac,partsListFile) = 1
        CkXml::ckLoadXmlFile(partsListXml,partsListFile)
    EndIf

    ; Make sure the top-level tag is "CompleteMultipartUpload"
    CkXml::setCkTag(partsListXml, "CompleteMultipartUpload")

    ; --------------------------------------
    ; Before entering the loop to upload parts,
    ; setup the REST object with AWS authentication,
    ; and make the initial connection.
    rest.i = CkRest::ckCreate()
    If rest.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; Connect to the Amazon AWS REST server.
    bTls.i = 1
    port.i = 443
    bAutoReconnect.i = 1
    success = CkRest::ckConnect(rest,"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.i = CkAuthAws::ckCreate()
    If authAws.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkAuthAws::setCkAccessKey(authAws, "AWS_ACCESS_KEY")
    CkAuthAws::setCkSecretKey(authAws, "AWS_SECRET_KEY")
    CkAuthAws::setCkServiceName(authAws, "s3")
    success = CkRest::ckSetAuthAws(rest,authAws)

    ; Set the bucket name via the HOST header.
    ; In this case, the bucket name is "chilkat100".
    CkRest::setCkHost(rest, "chilkat100.s3.amazonaws.com")
    ; --------------------------------------

    partNumber.i = 1
    sbPartNumber.i = CkStringBuilder::ckCreate()
    If sbPartNumber.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    While (partNumber <= numParts)
        Debug "---- " + Str(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..
        CkStringBuilder::ckClear(sbPartNumber)
        CkStringBuilder::ckAppendInt(sbPartNumber,partNumber)

        bPartAlreadyUploaded.i = 0

        ; If there are no children, then the XML is empty and no parts have yet been uploaded.
        numUploadedParts.i = CkXml::ckNumChildren(partsListXml)
        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.i = CkXml::ckGetChild(partsListXml,0)
            foundRec.i = CkXml::ckFindNextRecord(xRec0,"PartNumber",CkStringBuilder::ckGetAsString(sbPartNumber))
            If CkXml::ckLastMethodSuccess(xRec0) = 1
                bPartAlreadyUploaded = 1
                Debug "Part " + Str(partNumber) + " was previously uploaded."
                Debug CkXml::ckGetXml(foundRec)
                CkXml::ckDispose(foundRec)

            EndIf

            CkXml::ckDispose(xRec0)

        EndIf

        ; 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
            Debug "Uploading part " + Str(partNumber) + " ..."

            ; Setup the stream source for the large file to be uploaded..
            fileStream.i = CkStream::ckCreate()
            If fileStream.i = 0
                Debug "Failed to create object."
                ProcedureReturn
            EndIf

            CkStream::setCkSourceFile(fileStream, 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.
            CkStream::setCkSourceFilePartSize(fileStream, 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.
            CkRest::ckClearAllQueryParams(rest)
            CkRest::ckAddQueryParam(rest,"partNumber",CkStringBuilder::ckGetAsString(sbPartNumber))
            CkRest::ckAddQueryParam(rest,"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.
            CkStream::setCkSourceFilePart(fileStream, partNumber - 1)

            ; Because the SourceFilePart and SourceFilePartSize properties are set, the stream will 
            ; will provide just that part of the file.  
            responseStr.s = CkRest::ckFullRequestStream(rest,"PUT","/somethingBig.zip",fileStream)
            If CkRest::ckLastMethodSuccess(rest) <> 1
                Debug CkRest::ckLastErrorText(rest)
                CkXml::ckDispose(xmlInit)
                CkFileAccess::ckDispose(fac)
                CkXml::ckDispose(partsListXml)
                CkRest::ckDispose(rest)
                CkAuthAws::ckDispose(authAws)
                CkStringBuilder::ckDispose(sbPartNumber)
                CkStream::ckDispose(fileStream)
                ProcedureReturn
            EndIf

            If CkRest::ckResponseStatusCode(rest) <> 200
                ; Examine the request/response to see what happened.
                Debug "response status code = " + Str(CkRest::ckResponseStatusCode(rest))
                Debug "response status text = " + CkRest::ckResponseStatusText(rest)
                Debug "response header: " + CkRest::ckResponseHeader(rest)
                Debug "response body: " + responseStr
                Debug "---"
                Debug "LastRequestStartLine: " + CkRest::ckLastRequestStartLine(rest)
                Debug "LastRequestHeader: " + CkRest::ckLastRequestHeader(rest)
                CkXml::ckDispose(xmlInit)
                CkFileAccess::ckDispose(fac)
                CkXml::ckDispose(partsListXml)
                CkRest::ckDispose(rest)
                CkAuthAws::ckDispose(authAws)
                CkStringBuilder::ckDispose(sbPartNumber)
                CkStream::ckDispose(fileStream)
                ProcedureReturn
            EndIf

            ; 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.s = CkRest::ckResponseHdrByName(rest,"ETag")
            ; It should be present, but just in case there was no ETag header...
            If CkRest::ckLastMethodSuccess(rest) <> 1
                Debug "No ETag response header found!"
                Debug "response header: " + CkRest::ckResponseHeader(rest)
                CkXml::ckDispose(xmlInit)
                CkFileAccess::ckDispose(fac)
                CkXml::ckDispose(partsListXml)
                CkRest::ckDispose(rest)
                CkAuthAws::ckDispose(authAws)
                CkStringBuilder::ckDispose(sbPartNumber)
                CkStream::ckDispose(fileStream)
                ProcedureReturn
            EndIf

            ; We need to add record to the partsListXml.
            ; The record will look like this:
            ; &lt;Part>
            ;   &lt;PartNumber>PartNumber&lt;/PartNumber>
            ;   &lt;ETag>ETag&lt;/ETag>
            ; &lt;/Part>
            xPart.i = CkXml::ckNewChild(partsListXml,"Part","")
            CkXml::ckNewChildInt2(xPart,"PartNumber",partNumber)
            CkXml::ckNewChild2(xPart,"ETag",etag)
            CkXml::ckDispose(xPart)

            success = CkXml::ckSaveXml(partsListXml,partsListFile)
            If success <> 1
                Debug CkXml::ckLastErrorText(partsListXml)
                CkXml::ckDispose(xmlInit)
                CkFileAccess::ckDispose(fac)
                CkXml::ckDispose(partsListXml)
                CkRest::ckDispose(rest)
                CkAuthAws::ckDispose(authAws)
                CkStringBuilder::ckDispose(sbPartNumber)
                CkStream::ckDispose(fileStream)
                ProcedureReturn
            EndIf

            Debug "-- Part " + Str(partNumber) + " uploaded. ---------------------"
        EndIf

        partNumber = partNumber + 1
    Wend

    Debug "Finished.  All parts uploaded."


    CkXml::ckDispose(xmlInit)
    CkFileAccess::ckDispose(fac)
    CkXml::ckDispose(partsListXml)
    CkRest::ckDispose(rest)
    CkAuthAws::ckDispose(authAws)
    CkStringBuilder::ckDispose(sbPartNumber)
    CkStream::ckDispose(fileStream)


    ProcedureReturn
EndProcedure