CODEWITHSUNDEEP
rrestapitimestampauthorization
Andreas Meinke
Andreas Meinke

Reputation: 5

Retrieving Data from Marvel's API in R (Error: is.response(x) is not TRUE)

I am trying to retrieve Data from Marvel's API with R. Yet my code looks like this:

library(jsonlite)
library(httr)
library(digest)

pb.txt <- Sys.time()
pb.date <- as.POSIXct(pb.txt, tz = Sys.timezone)
time.stamp = strtrim(format(pb.date, tz = "GMT", usetz = FALSE, "%Y-%m-%dT%H:%M:%SZ"), 24)

public.key <- "***********************"

private.key <- "**********************************"

hash <- digest(paste0(time.stamp, private.key, public.key), algo = "md5")

url <- GET(paste("http://gateway.marvel.com/v1/public/characters?ts=", time.stamp, "&apikey=", public.key, "&hash=", hash, sep = ""))

The Error I get here is after:

> content(url) 

$code
[1] "InvalidCredentials"

$message
[1] "That hash, timestamp and key combination is invalid."

Beforehand the main problem was the timestamp, and I am still not sure if I calculate it the right way. Here is the Documentation for the API.

I hope anybody with more experiences with APIs could help me.

Upvotes: 0

Views: 4414

Answers (1)

hrbrmstr
hrbrmstr

Reputation: 78832

You can use this to bootstrap the parameters to the API requests (storing your keys in the fairly obviously named environment variables, best set in ~/.Renviron):

marvel_hash_params <- function() {

  ts <- round(as.numeric(Sys.time())*1000) # can totally be just Sys.time(), too
  to_hash <- sprintf("%s%s%s",
                     ts,
                     Sys.getenv("MARVEL_API_PRIVATE_KEY"),
                     Sys.getenv("MARVEL_API_PUBLIC_KEY"))

  list(
    ts=ts,
    hash=digest::digest(to_hash, "md5", FALSE),
    apikey=Sys.getenv("MARVEL_API_PUBLIC_KEY")
  )

}

Then initialize them right away in your helper functions:

get_characters <- function(name) {

  params <- marvel_hash_params()
  params$name <- name

  res <- httr::GET("https://gateway.marvel.com:443/v1/public/characters",
                   query=params)

  httr::stop_for_status(res)

  httr::content(res, as="parsed")

}

get_characters("spider-man")

Even if you're not writing a full-on package, I'd suggest reading Hadley's recommendations

Upvotes: 2

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