R/v2.R

In zhangxing-love/qingstor.signature: Qingstor Web Services Request Signatures

#' @title Signature Version 2
#' @description Generates AWS Signature Version 2
#' @param datetime A character string containing a date in the form of \dQuote{YYYY-MM-DDTH:M:S}. If missing, it is generated automatically using \code{\link[base]{Sys.time}}.
#' @param verb A character string specify an HTTP verb/method (e.g., \dQuote{GET}).
#' @param service A character string containing the full hostname of an AWS service (e.g., \dQuote{iam.amazonaws.com}, etc.)
#' @param path A character string specify the path to the API endpoint.
#' @param query_args A list containing named query arguments.
#' @param key An AWS Access Key ID. If missing, it is retrieved using \code{Sys.getenv("AWS_ACCESS_KEY_ID")}.
#' @param secret An AWS Secret Access Key. If missing, it is retrieved using \code{Sys.getenv("AWS_SECRET_ACCESS_KEY")}.
#' @details This function generates an AWS Signature Version 2 for authorizing API requests. The function returns both an updated set of query string parameters, containing the required signature-related entries, as well as a \code{Signature} field containing the Signature string itself.
#' @return A list
#' @author Thomas J. Leeper <thosjleeper@gmail.com>
#' @references \href{http://docs.aws.amazon.com/general/latest/gr/signature-version-2.html}{AWS General Reference: Signature Version 2 Signing Process}
#' @examples
#' # examples from:
#' # http://docs.aws.amazon.com/general/latest/gr/signature-version-2.html
#' 
#' true_string <- paste0("GET\n",
#' "elasticmapreduce.amazonaws.com\n",
#' "/\n",
#' "AWSAccessKeyId=AKIAIOSFODNN7EXAMPLE",
#' "&Action=DescribeJobFlows",
#' "&SignatureMethod=HmacSHA256",
#' "&SignatureVersion=2",
#' "&Timestamp=2011-10-03T15\%3A19\%3A30",
#' "&Version=2009-03-31", collapse = "")
#' true_sig <- "i91nKc4PWAt0JJIdXwz9HxZCJDdiy6cf/Mj6vPxyYIs="
#' 
#' q1 <- 
#' list(Action = "DescribeJobFlows",
#'      Version = "2009-03-31",
#'      AWSAccessKeyId = "AKIAIOSFODNN7EXAMPLE",
#'      SignatureVersion = "2",
#'      SignatureMethod = "HmacSHA256",
#'      Timestamp = "2011-10-03T15:19:30")
#' 
#' sig1 <- 
#' signature_v2_auth(datetime = "2011-10-03T15:19:30",
#'                   service = "elasticmapreduce.amazonaws.com",
#'                   verb = "GET",
#'                   path = "/",
#'                   query_args = q1,
#'                   key = q1$AWSAccessKeyId,
#'                   secret = "wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY")
#' identical(true_string, sig1$CanonicalRequest)
#' identical(true_sig, sig1$Signature)
#' 
#' # leaving out some defaults
#' q2 <- 
#' list(Action = "DescribeJobFlows",
#'      Version = "2009-03-31",
#'      Timestamp = "2011-10-03T15:19:30")
#' sig2 <- 
#' signature_v2_auth(datetime = "2011-10-03T15:19:30",
#'                   service = "elasticmapreduce.amazonaws.com",
#'                   verb = "GET",
#'                   path = "/",
#'                   query_args = q2,
#'                   key = "AKIAIOSFODNN7EXAMPLE",
#'                   secret = "wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY")
#' identical(true_string, sig2$CanonicalRequest)
#' identical(true_sig, sig2$Signature)
#' 
#' @seealso \code{\link{signature_v4_auth}}, \code{\link{use_credentials}}
#' @importFrom digest digest hmac
#' @importFrom base64enc base64encode
#' @export
signature_v2_auth <- 
function(datetime = format(Sys.time(),"%Y-%M-%dT%H:%M:%S", tz = "UTC"),
         verb, service, path, query_args = list(),
         key = Sys.getenv("AWS_ACCESS_KEY_ID"),
         secret = Sys.getenv("AWS_SECRET_ACCESS_KEY")) {
    if(is.null(key) || key == ""){
        stop("Missing AWS Access Key ID")
    }
    if(is.null(secret) || secret == ""){
        stop("Missing AWS Secret Access Key")
    }
    
    # set sort locale
    lc <- Sys.getlocale(category = "LC_COLLATE")
    Sys.setlocale(category = "LC_COLLATE", locale = "C")
    on.exit(Sys.setlocale(category = "LC_COLLATE", locale = lc))
    
    # sort query arguments
    if (!"Timestamp" %in% names(query_args)) {
        query_args$Timestamp = datetime
    } else {
        datetime <- query_args$Timestamp
    }
    if (!"SignatureVersion" %in% names(query_args)) {
        query_args$SignatureVersion = "2"
    }
    if (!"SignatureMethod" %in% names(query_args)) {
        query_args$SignatureMethod = "HmacSHA256"
    }
    if (!"AWSAccessKeyId" %in% names(query_args)) {
        query_args$AWSAccessKeyId = key
    }
    query_to_parse <- unlist(query_args[order(names(query_args))])
    a <- paste0(sapply(names(query_to_parse), URLencode, reserved = TRUE), "=", 
                sapply(as.character(query_to_parse), URLencode, reserved = TRUE))
    query_string <- paste(a, sep = "", collapse = "&")
    
    canonical_request <- paste(verb, service, path, query_string, sep = "\n")
    signature <- hmac(key = secret, object = canonical_request, 
                      algo = "sha256", serialize = FALSE, raw = TRUE)
    sig_encoded <- base64encode(signature)
    query_args$Signature <- sig_encoded
    
    # return list
    structure(list(CanonicalRequest = canonical_request,
                   StringToSign = canonical_request,
                   Query = query_args,
                   Signature = sig_encoded), class = "aws_signature_v2")
}