authentication to github private repositories with httr

Question

I am trying to access a private repository on Github using httr. I am able to do so with no problem if I add my github token (stored as an environment variable in GITHUB_TOKEN):

httr::GET("https://api.github.com/repos/aammd/miniature-meme/releases/assets/2859674",
                 httr::write_disk("test.rds", overwrite = TRUE),
                 httr::progress("down"),
                 httr::add_headers(Authorization = paste("token", Sys.getenv("GITHUB_TOKEN"))))

However, if I try to specify another header, I get an error. In this case, I want to download the binary file associated with a release (the "asset", in github terminology):

httr::GET("https://api.github.com/repos/aammd/miniature-meme/releases/assets/2859674",
                 httr::write_disk("test.rds", overwrite = TRUE),
                 httr::progress("down"),
                 httr::add_headers(Authorization = paste("token", Sys.getenv("GITHUB_TOKEN"))),
                 httr::add_headers(Accept = "application/octet-stream"))


?xml version="1.0" encoding="UTF-8"?>
<Error><Code>InvalidArgument</Code><Message>Only one auth mechanism allowed; only the X-Amz-Algorithm query parameter, Signature query string parameter or the Authorization header should be specified</Message>

That's only part of the message (the rest includes my token).

Apparently my authorization is being sent twice! How can I prevent this? Is it related to httr::handle_pool()

EDIT -- connection info

It appears that the original request receives a reply, which contains a signature. This signature, along with my token is then sent back, causing an error. A similar thing happened to these people

-> GET /repos/aammd/miniature-meme/releases/assets/2859674 HTTP/1.1
-> Host: api.github.com
-> User-Agent: libcurl/7.43.0 r-curl/2.3 httr/1.2.1.9000
-> Accept-Encoding: gzip, deflate
-> Authorization: token tttttttt
-> Accept: application/octet-stream
-> 
<- HTTP/1.1 302 Found
<- Server: GitHub.com
<- Date: Tue, 17 Jan 2017 13:28:12 GMT
<- Content-Type: text/html;charset=utf-8
<- Content-Length: 0
<- Status: 302 Found
<- X-RateLimit-Limit: 5000
<- X-RateLimit-Remaining: 4984
<- X-RateLimit-Reset: 1484662101
<- location: https://github-cloud.s3.amazonaws.com/releases/76993567/aee5d0d6-c70a-11e6-9078-b5bee39f9fbc.RDS?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAISTNZFOVBIJMK3TQ%2F20170117%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20170117T132812Z&X-Amz-Expires=300&X-Amz-Signature=ssssssssss&X-Amz-SignedHeaders=host&actor_id=1198242&response-content-disposition=attachment%3B%20filename%3Dff.RDS&response-content-type=application%2Foctet-stream
<- Access-Control-Expose-Headers: ETag, Link, X-GitHub-OTP, X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Reset, X-OAuth-Scopes, X-Accepted-OAuth-Scopes, X-Poll-Interval
<- Access-Control-Allow-Origin: *
<- Content-Security-Policy: default-src 'none'
<- Strict-Transport-Security: max-age=31536000; includeSubdomains; preload
<- X-Content-Type-Options: nosniff
<- X-Frame-Options: deny
<- X-XSS-Protection: 1; mode=block
<- Vary: Accept-Encoding
<- X-Served-By: 3e3b9690823fb031da84658eb58aa83b
<- X-GitHub-Request-Id: 82782802:6E1B:E9F0BE:587E1BEC
<- 
-> GET /releases/76993567/aee5d0d6-c70a-11e6-9078-b5bee39f9fbc.RDS?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAISTNZFOVBIJMK3TQ%2F20170117%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20170117T132812Z&X-Amz-Expires=300&X-Amz-Signature=sssssssssssssss&X-Amz-SignedHeaders=host&actor_id=1198242&response-content-disposition=attachment%3B%20filename%3Dff.RDS&response-content-type=application%2Foctet-stream HTTP/1.1
-> Host: github-cloud.s3.amazonaws.com
-> User-Agent: libcurl/7.43.0 r-curl/2.3 httr/1.2.1.9000
-> Accept-Encoding: gzip, deflate
-> Authorization: token ttttttttttttt
-> Accept: application/octet-stream
-> 
<- HTTP/1.1 400 Bad Request
<- x-amz-request-id: FA56B3D23B468704
<- x-amz-id-2: 49X1mT5j5BrZ4HApeR/+wb7iVOWA8yn1obrgMoeOy44RH414bo/Ov8AAWSx2baEXO0H/WHX5jK0=
<- Content-Type: application/xml
<- Transfer-Encoding: chunked
<- Date: Tue, 17 Jan 2017 13:28:12 GMT
<- Connection: close
<- Server: AmazonS3
<- 

gh doesn't work either

I created a public repo to test this idea out. the JSON can be returned from the API, but not the binary file:

# this works fine
gh::gh("https://api.github.com/repos/aammd/test_idea/releases/assets/2998763")

# this does not
gh::gh("https://api.github.com/repos/aammd/test_idea/releases/assets/2998763", .send_headers = c("Accept" = "application/octet-stream"))

wget might work, however

I've found a gist that shows how to do this with wget. The key component seems to be:

wget -q --auth-no-challenge --header='Accept:application/octet-stream' \
  https://$TOKEN:@api.github.com/repos/$REPO/releases/assets/$asset_id \
-O $2

However if I try to replicate that in httr::GET I am not successful:

auth_url <- sprintf("https://%s:@api.github.com/repos/aammd/miniature-meme/releases/assets/2859674", Sys.getenv("GITHUB_TOKEN"))
httr::GET(auth_url,
          httr::write_disk("test.rds", overwrite = TRUE),
          httr::progress("down"),
          httr::add_headers(Accept = "application/octet-stream"))

Calling wget from R DOES work, but this solution is not totally satisfying because I can't guarantee that all my users have wget installed (unless there is a way to do that?).

system(sprintf("wget --auth-no-challenge --header='Accept:application/octet-stream' %s -O testwget.rds", auth_url))

output of wget (note the absence of -q above) included here (again, tokens and signatures redacted, hopefully):

--2017-01-18 13:21:55--  https://ttttt:*password*@api.github.com/repos/aammd/miniature-meme/releases/assets/2859674
Resolving api.github.com... 192.30.253.117, 192.30.253.116
Connecting to api.github.com|192.30.253.117|:443... connected.
HTTP request sent, awaiting response... 302 Found
Location: https://github-cloud.s3.amazonaws.com/releases/76993567/aee5d0d6-c70a-11e6-9078-b5bee39f9fbc.RDS?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAISTNZFOVBIJMK3TQ%2F20170118%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20170118T122156Z&X-Amz-Expires=300&X-Amz-Signature=SSSSSSSS-Amz-SignedHeaders=host&actor_id=1198242&response-content-disposition=attachment%3B%20filename%3Dff.RDS&response-content-type=application%2Foctet-stream [following]
--2017-01-18 13:21:55--  https://github-cloud.s3.amazonaws.com/releases/76993567/aee5d0d6-c70a-11e6-9078-b5bee39f9fbc.RDS?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAISTNZFOVBIJMK3TQ%2F20170118%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20170118T122156Z&X-Amz-Expires=300&X-Amz-Signature=SSSSSSSSSSSS-Amz-SignedHeaders=host&actor_id=1198242&response-content-disposition=attachment%3B%20filename%3Dff.RDS&response-content-type=application%2Foctet-stream
Resolving github-cloud.s3.amazonaws.com... 52.216.226.120
Connecting to github-cloud.s3.amazonaws.com|52.216.226.120|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 682 [application/octet-stream]
Saving to: ‘testwget.rds’

     0K                                                       100% 15.5M=0s

2017-01-18 13:21:56 (15.5 MB/s) - ‘testwget.rds’ saved [682/682]

Answer 1

Try sending the auth token as a query param instead of an auth header. That way when GitHub's Oauth redirects you it'll strip the original token & the X-Amz-Algorithm param will be left to do it's job.

httr::GET(paste("https://api.github.com/repos/aammd/miniature-meme/releases/assets/2859674?access_token=", Sys.getenv("GITHUB_TOKEN")),
             httr::write_disk("test.rds", overwrite = TRUE),
             httr::progress("down"))

Answer 2

It turns out that there are two possible solutions to this problem!

solution the first: token as parameter

As suggested by @user7433058, we can indeed pass the token through as a parameter! note however that we have to use paste0. This is the approach suggested by Github themselves on their API documentation

## pass oauth in the url
httr::GET(paste0("https://api.github.com/repos/aammd/miniature-meme/releases/assets/2859674?access_token=", Sys.getenv("GITHUB_TOKEN")),
          httr::write_disk("test.rds", overwrite = TRUE),
          httr::progress("down"),
          httr::add_headers(Accept = "application/octet-stream"))

tt <- readRDS("test.rds")

Solution the second: ask again

Another solution is to make the request the first time, then extract the URL and use it to make a second request. Since the problem is caused by sending Authorization information twice -- once in the URL, once in the header -- we can avoid the problem by only using the URL.

## alternatively, get the query url (containing signature) from the (failed) html request made the first time
firsttry <- httr::GET("https://api.github.com/repos/aammd/miniature-meme/releases/assets/2859674",
                      httr::add_headers(Authorization = paste("token", Sys.getenv("GITHUB_TOKEN")),
                                        Accept = "application/octet-stream"))

httr::GET(firsttry$url, httr::write_disk("test.rds", overwrite = TRUE),
          httr::write_disk("test2.rds", overwrite = TRUE),
          httr::progress("down"),
          httr::add_headers(Accept = "application/octet-stream"))

tt2 <- readRDS("test2.rds")

This is, I suppose, a bit less efficient (making 3 requests total instead of 2). However, since only the first request is to the actual github API, it only counts for 1 towards your rate-limiting step.

a small refinement: no redirect from httr

We can make only 2, not 3, http requests if you tell httr not to follow redirects. To do this use httr::config(followlocation = FALSE) in the first of the two requests (i.e. to get firsttry)