cleanup http code & fix session_token arg (closes #9)

R/http.r

@@ -3,10 +3,12 @@
 #' @details This function constructs and signs an SQS API request and returns the results thereof, or relevant debugging information in the case of error.
 #' @param url A character string containing an SQS API endpoint URL.
 #' @param query An optional named list containing query string parameters and their character values.
-#' @param region A character string containing an AWS region. If missing, the default \dQuote{us-east-1} is used.
-#' @param key A character string containing an AWS Access Key ID. See \code{\link[aws.signature]{locate_credentials}}.
-#' @param secret A character string containing an AWS Secret Access Key. See \code{\link[aws.signature]{locate_credentials}}.
-#' @param session_token Optionally, a character string containing an AWS temporary Session Token. See \code{\link[aws.signature]{locate_credentials}}.
+#' @param headers A list of headers to pass to the HTTP request.
+#' @param verbose A logical indicating whether to be verbose. Default is given by \code{options("verbose")}.
+#' @param region A character string specifying an AWS region. See \code{\link[aws.signature]{locate_credentials}}.
+#' @param key A character string specifying an AWS Access Key. See \code{\link[aws.signature]{locate_credentials}}.
+#' @param secret A character string specifying an AWS Secret Key. See \code{\link[aws.signature]{locate_credentials}}.
+#' @param session_token Optionally, a character string specifying an AWS temporary Session Token to use in signing a request. See \code{\link[aws.signature]{locate_credentials}}.
 #' @param ... Additional arguments passed to \code{\link[httr]{GET}}.
 #' @return If successful, a named list. Otherwise, a data structure of class
 #' \dQuote{aws_error} containing any error message(s) from AWS and information
@@ -17,20 +19,33 @@
 #' @importFrom xml2 read_xml as_list
 #' @import httr
 #' @export
-sqsHTTP <- function(url = NULL, 
-                    query = list(), 
-                    region = Sys.getenv("AWS_DEFAULT_REGION", "us-east-1"), 
-                    key = NULL, 
-                    secret = NULL, 
-                    session_token = NULL,
-                    ...) {
+sqsHTTP <- 
+function(
+  url = NULL, 
+  headers = list(),
+  query = list(), 
+  verbose = getOption("verbose", FALSE),
+  region = Sys.getenv("AWS_DEFAULT_REGION", "us-east-1"), 
+  key = NULL, 
+  secret = NULL, 
+  session_token = NULL,
+  ...
+) {
+    # locate and validate credentials
+    credentials <- locate_credentials(key = key, secret = secret, session_token = session_token, region = region, verbose = verbose)
+    key <- credentials[["key"]]
+    secret <- credentials[["secret"]]
+    session_token <- credentials[["session_token"]]
+    region <- credentials[["region"]]
+
+    # generate request signature
     if (is.null(url)) {
         url <- paste0("https://sqs.",region,".amazonaws.com")
     }
     p <- parse_url(url)
     action <- if(p$path == "") "/" else paste0("/", p$path)
     d_timestamp <- format(Sys.time(), "%Y%m%dT%H%M%SZ", tz = "UTC")
-    S <- signature_v4_auth(
+    Sig <- signature_v4_auth(
            datetime = d_timestamp,
            region = region,
            service = "sqs",
@@ -42,15 +57,18 @@ sqsHTTP <- function(url = NULL,
            request_body = "",
            key = key,
            secret = secret,
-           session_token = session_token)
-    headers <- list(`x-amz-date` = d_timestamp, 
-                    `x-amz-content-sha256` = S$BodyHash,
-                    Authorization = S$SignatureHeader)
+           session_token = session_token,
+           verbose = verbose)
+    # setup request headers
+    headers[["x-amz-date"]] <- d_timestamp
+    headers[["x-amz-content-sha256"]] <- Sig$BodyHash
+    headers[["Authorization"]] <- Sig[["SignatureHeader"]]
     if (!is.null(session_token) && session_token != "") {
         headers[["x-amz-security-token"]] <- session_token
     }
     H <- do.call(add_headers, headers)
 
+    # execute request
     if (length(query)) {
         r <- GET(url, H, query = query, ...)
     } else {
@@ -61,16 +79,16 @@ sqsHTTP <- function(url = NULL,
     if (http_error(r)) {
         x <- try(as_list(read_xml(cont)), silent = TRUE)
         if (inherits(x, "try-error")) {
-            x <- try(fromJSON(cont)$Error, silent = TRUE)
+            x <- try(jsonlite::fromJSON(cont)$Error, silent = TRUE)
         }
         warning(paste0(http_status(r)$message, ": ", x$Code, " (", x$Message, ")"))
         h <- headers(r)
         out <- structure(x, headers = h, class = "aws_error")
-        attr(out, "request_canonical") <- S$CanonicalRequest
-        attr(out, "request_string_to_sign") <- S$StringToSign
-        attr(out, "request_signature") <- S$SignatureHeader
+        attr(out, "request_canonical") <- Sig$CanonicalRequest
+        attr(out, "request_string_to_sign") <- Sig$StringToSign
+        attr(out, "request_signature") <- Sig$SignatureHeader
     } else {
-        out <- try(fromJSON(cont), silent = TRUE)
+        out <- try(jsonlite::fromJSON(cont), silent = TRUE)
         if (inherits(out, "try-error")) {
             out2 <- try(as_list(read_xml(cont)), silent = TRUE)
             if (inherits(out2, "try-error")) {