我正在尝试使用httr访问Github上的私有存储库。如果我添加我的github令牌（存储为GITHUB_TOKEN中的环境变量），我可以毫无问题地执行此操作：
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"))))
但是，如果我尝试指定另一个标头，则会出错。在这种情况下，我想下载与发布相关联的二进制文件（＆＃34;资产＆＃34;，在github术语中）：
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>
这只是信息的一部分（其余部分包括我的令牌）。
显然我的授权被发送了两次！我怎么能阻止这个？它与httr::handle_pool()
原始请求似乎收到包含签名的回复。然后将此签名与我的令牌一起发回，从而导致错误。类似的事情发生在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
<-
我创建了一个公开的回购来测试这个想法。可以从API返回JSON，但不能返回二进制文件：
# 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可能有效，但是我找到了shows how to do this with wget的要点。关键部分似乎是：
wget -q --auth-no-challenge --header='Accept:application/octet-stream' \
https://$TOKEN:@api.github.com/repos/$REPO/releases/assets/$asset_id \
-O $2
但是，如果我尝试在httr::GET中复制它，我就不会成功：
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"))
从R DOES 调用wget，但此解决方案并不完全令人满意，因为我无法保证我的所有用户都安装了wget（除非那里）是一种方法吗？）。
system(sprintf("wget --auth-no-challenge --header='Accept:application/octet-stream' %s -O testwget.rds", auth_url))
输出wget（注意上面没有-q）包含在这里（再次，令牌和签名被编辑，希望如此）：
--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]
答案 0 :(得分：3)
事实证明，这个问题有两种可能的解决方案！
根据@ user7433058的建议，我们确实可以将令牌作为参数传递！ 请注意，我们必须使用paste0。这是Github自己提出的方法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")
另一个解决方案是第一次发出请求，然后提取URL并使用它来发出第二个请求。由于问题是由两次发送授权信息引起的 - 一次在URL中，一次在标题中 - 我们可以通过仅使用URL来避免此问题。
## 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")
我想，这是效率低一点（总共3个请求而不是2个）。但是，由于只有第一个请求是针对实际的github API，因此在速率限制步骤中它只计为1。
如果您告诉httr不遵循重定向，我们只能发出2个而不是3个http请求。为此，请在两个请求中的第一个请求中使用httr::config(followlocation = FALSE)（即获取firsttry）
答案 1 :(得分：2)
尝试将身份验证令牌作为查询参数而不是auth标头发送。这样，当GitHub的Oauth重定向您时，它会删除原始令牌＆amp; X-Amz-Algorithm参数将留给它完成它的工作。
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"))