Translating CURL to R

Question

Mostly for my own understanding, how would you translate the following toy CURL example to R, using RCurl or httr:

  curl -v -X POST \
    https://someurl/endpoint \
-H "Content-Type: application/json" \
-H 'X-Api-Key: abc123' \
-d '{"parameters": [ 1, "foo", "bar" ]}'

I'm finding both packages a bit awkward for anything beyond simple GET requests.

I've tried:

library(httr)
 POST("https://someurl/endpoint", authenticate("user", "passwrd"), 
body = '{"parameters": [ 1, "foo", "bar" ]}', content_type_json())

Get a 400 status. My Curl version works perfectly.

Also tried:

POST("https://someurl/endpoint", add_headers('X-Api-Key: abc123'), 
body = '{"parameters": [ 1, "foo", "bar" ]}', content_type_json())

Also get 400 status.

I'm pretty sure the issue is with setting the headers.

Does this question help? http://stackoverflow.com/questions/5797688/post-request-using-rcurl — Scott C Wilson, Jan 20 '15 at 21:40
well, for one thing, I can't use dashes in the name value pairs for the headers. — Ben Rollert, Jan 20 '15 at 21:57
Did you try just passing the body as an R list `body = list(parameters = list(1, "foo", "bar" ))` — sckott, Jan 20 '15 at 22:11
yes, I tried that and no success. I think the issue is in setting the headers. How would you set the headers using add_headers, for example? — Ben Rollert, Jan 20 '15 at 22:15
can you share the actual url, and parameters? be easier to debug. Also if you're passing a key in the header, i imagine you don't want to pass basic auth via `authenticate()` — sckott, Jan 20 '15 at 22:45

score 3 · Answer 1 · answered Jan 03 '20 at 15:01

In this web page you can convert curl to many languajes: https://curl.trillworks.com/#r

In this case, in R is:

require(httr)

headers = c(
  'Content-Type' = 'application/json',
  'X-Api-Key' = 'abc123'
)

data = '{"parameters": [ 1, "foo", "bar" ]}'

res <- httr::POST(url = 'https://someurl/endpoint', httr::add_headers(.headers=headers), body = data)

hrbrmstr · Accepted Answer · 2015-01-22T15:27:37.453

2

You can use httpbin.org for testing. Try:

curl -v -X POST \
    https://httpbin.org/post \
-H "Content-Type: application/json" \
-H 'X-Api-Key: abc123' \
-d '{"parameters": [ 1, "foo", "bar" ]}'

and save the result, then see how it compares with:

library(httr)

result <- POST("http://httpbin.org/post",
               verbose(),
               encode="json",
               add_headers(`X-Api-Key`="abc123"),
               body=list(parameters=c(1, "foo", "bar")))

content(result)

It's a pretty straightforward mapping.

edited Jan 22 '15 at 15:27

answered Jan 20 '15 at 22:57

hrbrmstr

77,368
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1

You can remove `content_type_json()` if you use `encode = "json"` – hadley Jan 22 '15 at 14:45

score 0 · Answer 3 · answered Jan 21 '15 at 15:30

0

The key is to escape the header names, in case anyone is curious. The direct translation is as follows:

POST("http://httpbin.org/post",
add_headers(`X-Api-Key`="abc123", `Content-Type` = "application/json"),
body='{"parameters": [ 1, "foo", "bar" ]}')

answered Jan 21 '15 at 15:30

Ben Rollert

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Translating CURL to R

3 Answers3