#' A function to call Azure Blob using httr
#' @param url url of the blob
#' @param verb "PUT GET CREATE DELETE"
#' @param key "SAS ket to access the blob"
#' @export
azureBlobCall <- function(url, verb, key, requestBody=NULL, headers=NULL, ifMatch="", md5="",verbose = FALSE) {
urlcomponents <- httr::parse_url(url)
account <- gsub(".blob.core.windows.net", "", urlcomponents$hostname, fixed = TRUE)
container <- urlcomponents$path
# get timestamp in us locale
lct <- Sys.getlocale("LC_TIME");
#Sys.setlocale("LC_TIME", "us")
`x-ms-date` <- format(Sys.time(),"%a, %d %b %Y %H:%M:%S %Z", tz="GMT")
Sys.setlocale("LC_TIME", lct)
# if requestBody exist get content length in bytes and content type
`Content-Length` <- ""; `Content-Type` <- ""
if(!is.null(requestBody)) {
if(class(requestBody) == "form_file") {
`Content-Length` <- (file.info(requestBody$path))$size
`Content-Type` <- requestBody$type
} else {
requestBody <- enc2utf8(as.character(requestBody))
`Content-Length` <- nchar(requestBody, "bytes")
`Content-Type` <- "text/plain; charset=UTF-8"
}
}
# combine timestamp and version headers with any input headers, order and create the CanonicalizedHeaders
headers <- setNames(c(`x-ms-date`, "2015-04-05", unlist(headers)),
c("x-ms-date", "x-ms-version", unclass(names(unlist(headers)))))
headers <- headers[order(names(headers))]
CanonicalizedHeaders <- paste(names(headers), headers, sep=":", collapse = "\n")
# create CanonicalizedResource headers and add any queries to it
if(!is.null(urlcomponents$query)) {
components <- setNames(unlist(urlcomponents$query), unclass(names(unlist(urlcomponents$query))))
componentstring <- paste0("\n", paste(names(components[order(names(components))]),
components[order(names(components))], sep=":", collapse = "\n"))
} else componentstring <- ""
CanonicalizedResource <- paste0("/",account,"/",container, componentstring)
# create the authorizationtoken
signaturestring <- paste0(verb, "\n\n\n", `Content-Length`, "\n", md5, "\n", `Content-Type`, "\n\n\n",
ifMatch, "\n\n\n\n", CanonicalizedHeaders, "\n", CanonicalizedResource)
requestspecificencodedkey <- RCurl::base64(
digest::hmac(key=RCurl::base64Decode(key, mode="raw"),
object=enc2utf8(signaturestring),
algo= "sha256", raw=TRUE)
)
authorizationtoken <- paste0("SharedKey ", account, ":", requestspecificencodedkey)
# make the call
headers_final <- add_headers(Authorization=authorizationtoken, headers, `Content-Type` = `Content-Type`)
if(verbose) {
call <- httr::VERB(verb=verb, url=url, config=headers_final, body=requestBody, verbose())
print("signaturestring");print(signaturestring);
print(headers_final); print(call)
} else {
call <- httr::VERB(verb=verb, url=url, config=headers_final, body=requestBody)
}
return(content(call))
}
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.