(.NET Core C#) 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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// 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.

Chilkat.Xml xmlInit = new Chilkat.Xml();
bool success = xmlInit.LoadXmlFile("s3_multipart_uploads/initiate.xml");
if (success != true) {
    Debug.WriteLine("Did not find the initiate.xml XML file.");
    return;
}

string uploadId = xmlInit.GetChildContent("UploadId");
Debug.WriteLine("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
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.
int 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.
Chilkat.FileAccess fac = new Chilkat.FileAccess();
fac.OpenForRead(fileToUploadPath);

// How many parts will there be if each part is 5242880 bytes?
int numParts = fac.GetNumBlocks(partSize);
Debug.WriteLine("numParts = " + Convert.ToString(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..
string partsListFile = "s3_multipart_uploads/partsList.xml";
Chilkat.Xml partsListXml = new Chilkat.Xml();
if (fac.FileExists(partsListFile) == true) {
    partsListXml.LoadXmlFile(partsListFile);
}

// 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.
Chilkat.Rest rest = new Chilkat.Rest();

// Connect to the Amazon AWS REST server.
bool bTls = true;
int port = 443;
bool 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.
Chilkat.AuthAws authAws = new Chilkat.AuthAws();
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";
// --------------------------------------

int partNumber = 1;
Chilkat.StringBuilder sbPartNumber = new Chilkat.StringBuilder();

while ((partNumber <= numParts)) {
    Debug.WriteLine("---- " + Convert.ToString(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);

    bool bPartAlreadyUploaded = false;

    // If there are no children, then the XML is empty and no parts have yet been uploaded.
    int 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.
        Chilkat.Xml xRec0 = partsListXml.GetChild(0);
        Chilkat.Xml foundRec = xRec0.FindNextRecord("PartNumber",sbPartNumber.GetAsString());
        if (xRec0.LastMethodSuccess == true) {
            bPartAlreadyUploaded = true;
            Debug.WriteLine("Part " + Convert.ToString(partNumber) + " was previously uploaded.");
            Debug.WriteLine(foundRec.GetXml());

        }

    }

    // 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) {
        Debug.WriteLine("Uploading part " + Convert.ToString(partNumber) + " ...");

        // Setup the stream source for the large file to be uploaded..
        Chilkat.Stream fileStream = new Chilkat.Stream();
        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.
        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.SourceFilePart = partNumber - 1;

        // Because the SourceFilePart and SourceFilePartSize properties are set, the stream will 
        // will provide just that part of the file.  
        string responseStr = rest.FullRequestStream("PUT","/somethingBig.zip",fileStream);
        if (rest.LastMethodSuccess != true) {
            Debug.WriteLine(rest.LastErrorText);
            return;
        }

        if (rest.ResponseStatusCode != 200) {
            // Examine the request/response to see what happened.
            Debug.WriteLine("response status code = " + Convert.ToString(rest.ResponseStatusCode));
            Debug.WriteLine("response status text = " + rest.ResponseStatusText);
            Debug.WriteLine("response header: " + rest.ResponseHeader);
            Debug.WriteLine("response body: " + responseStr);
            Debug.WriteLine("---");
            Debug.WriteLine("LastRequestStartLine: " + rest.LastRequestStartLine);
            Debug.WriteLine("LastRequestHeader: " + rest.LastRequestHeader);
            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.
        string etag = rest.ResponseHdrByName("ETag");
        // It should be present, but just in case there was no ETag header...
        if (rest.LastMethodSuccess != true) {
            Debug.WriteLine("No ETag response header found!");
            Debug.WriteLine("response header: " + rest.ResponseHeader);
            return;
        }

        // 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>
        Chilkat.Xml xPart = partsListXml.NewChild("Part","");
        xPart.NewChildInt2("PartNumber",partNumber);
        xPart.NewChild2("ETag",etag);

        success = partsListXml.SaveXml(partsListFile);
        if (success != true) {
            Debug.WriteLine(partsListXml.LastErrorText);
            return;
        }

        Debug.WriteLine("-- Part " + Convert.ToString(partNumber) + " uploaded. ---------------------");
    }

    partNumber = partNumber + 1;
}

Debug.WriteLine("Finished.  All parts uploaded.");