Question

I am using third party server which return me following things.
1)url
2)acl
3)policy
4)awsAccesskeyID
5)Signature
6)key
I can upload file using following code

final File localFile = new File(localFilePath);

final Part[] parts = { new StringPart("acl", acl),
    new StringPart("policy", policy),
    new StringPart("AWSAccessKeyId", awsAccessKeyId),
    new StringPart("signature", signature),
    new StringPart("key", key, HTTP.UTF_8), 
    new FilePart("file", localFile) };

    final MultipartRequestEntity mpRequestEntity = new MultipartRequestEntity(parts, filePost.getParams());

    filePost.setRequestEntity(mpRequestEntity);
    final HttpClient client = new HttpClient();
    try
    {

       status = client.executeMethod(filePost);
    }

But now I want to use AmazonS3Client using following code but its throwing exception that

10-31 16:21:36.070: INFO/com.amazonaws.request(13882): Received error
response: Status Code: 403, AWS Request ID: 51F7CB27E58F88FD, AWS
Error Code: SignatureDoesNotMatch, AWS Error Message: The request
signature we calculated does not match the signature you provided.
Check your key and signing method., S3 Extended Request ID:
YwNNsWOXg71vXY1VS0apHnHpHp4YVWRJ63xm8C7w36SYg1MNuIykw75YhQco5Lk7

        final AmazonS3Client s3Client = new AmazonS3Client(new BasicAWSCredentials(awsAccessKeyId, key));


        // Create a list of UploadPartResponse objects. You get one of these
        // for each part upload.
        final List<PartETag> partETags = new ArrayList<PartETag>();

        // Step 1: Initialize.
        final InitiateMultipartUploadRequest initRequest = new InitiateMultipartUploadRequest(targetURL, key);
        final InitiateMultipartUploadResult initResponse = s3Client.initiateMultipartUpload(initRequest);

        final File file = new File(localFilePath);
        final long contentLength = file.length();
        long partSize = 5242880; // Set part size to 5 MB.

        try
        {
            // Step 2: Upload parts.
            long filePosition = 0;
            for ( int i = 1; filePosition < contentLength; i++ )
            {
                // Last part can be less than 5 MB. Adjust part size.
                partSize = Math.min(partSize, (contentLength - filePosition));

                // Create request to upload a part.
                final UploadPartRequest uploadRequest = new UploadPartRequest().withBucketName(targetURL).withKey(key)
                        .withUploadId(initResponse.getUploadId()).withPartNumber(i).withFileOffset(filePosition)
                        .withFile(file).withPartSize(partSize);

                // Upload part and add response to our list.
                partETags.add(s3Client.uploadPart(uploadRequest).getPartETag());

                filePosition += partSize;
            }

            // Step 3: complete.
            final CompleteMultipartUploadRequest compRequest = new CompleteMultipartUploadRequest(targetURL, key,
                    initResponse.getUploadId(), partETags);

            s3Client.completeMultipartUpload(compRequest);
        }
        catch ( final Exception e )
        {
            s3Client.abortMultipartUpload(new AbortMultipartUploadRequest(targetURL, key, initResponse.getUploadId()));
            return false;
        }
        return true;

am I missing something here?

Answer 1

I found that server sending signature to upload file in one shot. In case of multipart upload multiple signature needed and that will needed at various steps..
There is no way to upload file in multiple part until server shares the key :(.

http://dextercoder.blogspot.in/2012/02/multipart-upload-to-amazon-s3-in-three.html