S3_PING.java

    /**
     * Use this helper method to generate pre-signed S3 urls for use with S3_PING.
     * You'll need to generate urls for both the put and delete http methods.
     * Example:
     * Your AWS Access Key is "abcd".
     * Your AWS Secret Access Key is "efgh".
     * You want this node to write its information to "/S3_PING/DemoCluster/node1".
     * So, your bucket is "S3_PING" and your key is "DemoCluster/node1".
     * You want this to expire one year from now, or
     *   (System.currentTimeMillis / 1000) + (60 * 60 * 24 * 365)
     *   Let's assume that this equals 1316286684
     * 
     * Here's how to generate the value for the pre_signed_put_url property:
     * String putUrl = S3_PING.generatePreSignedUrl("abcd", "efgh", "put",
     *                                              "S3_Ping", "DemoCluster/node1",
     *                                              1316286684);
     *                                              
     * Here's how to generate the value for the pre_signed_delete_url property:
     * String deleteUrl = S3_PING.generatePreSignedUrl("abcd", "efgh", "delete",
     *                                                 "S3_Ping", "DemoCluster/node1",
     *                                                 1316286684);
     * 
     * @param awsAccessKey Your AWS Access Key
     * @param awsSecretAccessKey Your AWS Secret Access Key
     * @param method The HTTP method - use "put" or "delete" for use with S3_PING
     * @param bucket The S3 bucket you want to write to
     * @param key The key within the bucket to write to
     * @param expirationDate The date this pre-signed url should expire, in seconds since epoch
     * @return The pre-signed url to be used in pre_signed_put_url or pre_signed_delete_url properties
     */
    public static String generatePreSignedUrl(String awsAccessKey, String awsSecretAccessKey, String method,
                                              String bucket, String key, long expirationDate);