I'm trying to write a function that handles some of the authentication for Spotify's API. I can get it to work with a fairly simple curl command, but when I try to use httr or RCurl, I get 415 Unsupported Media Type responses. I'm somewhat at a loss at this point. I've gotten POST(), and GET() to work with this API already, but this endpoint is not working.
Using httr:
response <- POST('https://accounts.spotify.com/api/token',
accept_json(),
add_headers('Authorization'=paste('Basic',base64(paste(client_id,':',client_secret)),sep=' ')),
body=list(grant_type='client_credentials'),
encode='json')
I get a 415 status_code(response)
Using RCurl:
httpheader <- c('Authorization'=paste('Basic ',base64(paste(client_id,':',client_secret,sep='')),sep=''))
jsonbody <- toJSON(list(grant_type='client_credentials'))
postForm('https://accounts.spotify.com/api/token/',
postfields=jsonbody,
# grant_type='client_credentials',
.opts = list(httpheader=httpheader,
verbose=TRUE))
postForm output:
* Hostname was NOT found in DNS cache
* Trying 194.132.198.228...
* Connected to accounts.spotify.com (194.132.198.228) port 443 (#9)
* found 173 certificates in /etc/ssl/certs/ca-certificates.crt
* server certificate verification OK
* common name: *.spotify.com (matched)
* server certificate expiration date OK
* server certificate activation date OK
* certificate public key: RSA
* certificate version: #3
* subject: C=SE,ST=Stockholm,L=Stockholm,O=Spotify AB,CN=*.spotify.com
* start date: Tue, 15 Apr 2014 00:00:00 GMT
* expire date: Wed, 21 Jun 2017 12:00:00 GMT
* issuer: C=US,O=DigiCert Inc,CN=DigiCert SHA2 Secure Server CA
* compression: NULL
* cipher: AES-256-CBC
* MAC: SHA256
> POST /api/token/ HTTP/1.1
Host: accounts.spotify.com
Accept: */*
Authorization: Basic ZWE...zE=
Content-Length: 182
Expect: 100-continue
Content-Type: multipart/form-data; boundary=------------------------95ce917e6abd21b1
< HTTP/1.1 100 Continue
< HTTP/1.1 415 Unsupported Media Type
* Server nginx is not blacklisted
< Server: nginx
< Date: Wed, 21 Oct 2015 01:38:39 GMT
< Content-Length: 990
< Connection: keep-alive
< Keep-Alive: timeout=10
* HTTP error before end of send, stop sending
<
* Closing connection 9
Error: Unsupported Media Type
using curl through a system call (or from command line) actually works:
system(
paste('curl https://accounts.spotify.com/api/token -H "Authorization: Basic ',
base64(paste(client_id,':',client_secret,sep='')),
'" -d grant_type=client_credentials ',
sep=''),
intern=TRUE)
Not sure if this is useful at this point.
> devtools::session_info()
Session info -------------------------------------------------------------------------------------------------------
setting value
version R version 3.2.2 (2015-08-14)
system x86_64, linux-gnu
ui RStudio (0.99.441)
language en_US
collate en_US.UTF-8
tz <NA>
date 2015-10-20
Packages -----------------------------------------------------------------------------------------------------------
package * version date source
bitops 1.0-6 2013-08-17 CRAN (R 3.2.1)
caTools 1.17.1 2014-09-10 CRAN (R 3.2.1)
colorspace 1.2-6 2015-03-11 CRAN (R 3.2.1)
curl 0.9.3 2015-08-25 CRAN (R 3.2.2)
DBI 0.3.1 2014-09-24 CRAN (R 3.2.1)
devtools * 1.9.1.9000 2015-10-21 Github (hadley/devtools@0295d20)
digest 0.6.8 2014-12-31 CRAN (R 3.2.1)
git2r 0.11.0 2015-08-12 CRAN (R 3.2.2)
httr * 1.0.0.9000 2015-10-21 Github (hadley/httr@f7593b7)
jsonlite * 0.9.17 2015-09-06 CRAN (R 3.2.2)
knitr 1.11 2015-08-14 CRAN (R 3.2.2)
magrittr 1.5 2014-11-22 CRAN (R 3.2.1)
memoise 0.2.1 2014-04-22 CRAN (R 3.2.1)
R6 2.1.1 2015-08-19 CRAN (R 3.2.2)
Rcpp 0.12.1 2015-09-10 CRAN (R 3.2.2)
RCurl * 1.96-0 2015-07-27 local
RJSONIO * 1.3-0 2014-07-28 CRAN (R 3.2.2)
roxygen2 4.1.1 2015-04-15 CRAN (R 3.2.1)
RSelenium * 1.3.5 2014-10-26 CRAN (R 3.2.2)
rstudioapi 0.3.1 2015-04-07 CRAN (R 3.2.1)
stringi 0.5-5 2015-06-29 CRAN (R 3.2.2)
stringr * 1.0.0 2015-04-30 CRAN (R 3.2.2)
XML * 3.98-1.3 2015-06-30 CRAN (R 3.2.2)
That particular Spotify endpoint is looking for Content-Type: application/x-www-form-urlencoded vs JSON as you have it. This should work (it did for me):
library(httr)
response <- POST('https://accounts.spotify.com/api/token',
accept_json(),
authenticate(Sys.getenv("SPOTIFY_CLIENT_ID"), Sys.getenv("SPOTIFY_CLIENT_SECRET")),
body=list(grant_type='client_credentials'),
encode='form',
verbose())
(You can remove the verbose() in production)
Note the encode='form' but also note that you can use authenticate() vs build your own basic auth header (I store all keys in env variables, hence the use of Sys.getenv().
A HTTP 415 response code usually indicates you are specifying a Content-Type header that the server doesn't support, or maybe you aren't specifying one at all.
415 Unsupported Media Type: The server is refusing to service the request because the entity of the request is in a format not supported by the requested resource for the requested method.
The postForm example you have above is specifying Content-Type: multipart/form-data;. I can reproduce the HTTP 415 response with the following curl:
curl -v -X POST 'https://accounts.spotify.com/api/token' -H 'Content-Type: multipart/form-data'
If you change the content type to application/x-www-form-urlencoded it should work.
curl -v -X POST 'https://accounts.spotify.com/api/token' -H 'Content-Type: application/x-www-form-urlencoded'
来源：https://stackoverflow.com/questions/33249660/415-code-using-httr-and-rcurl-but-not-just-curl