创建gist后无法立即更新gist

Question

我正在尝试使用gist API作为一个特别的diff工具。为此，我想将一些文本上传到gist，然后更新它并查看diff。出于某种原因，我得到了"{\"message\":\"Not Found\",\"documentation_url\":\"https://developer.github.com/v3\"}"的结果。这有点令人困惑，因为当我查看url时，我可以看到GIST很好。

我的代码如下

uri = URI("https://api.github.com/gists")

first_payload = {
    'description' => "My test gist",
    'public' => true,
    'files' => {
        'change.yml' => {
            'content' => "before"
        }
    }
}

req = Net::HTTP::Post.new(uri.path)
req.body = first_payload.to_json
req.basic_auth("username", "password")
res = Net::HTTP.start(uri.hostname, uri.port, :use_ssl => true) do |http|
  http.request(req)
end

second_uri = URI(JSON.parse(res.body)["url"])
second_payload = {
    'description' => "My test gist",
    'public' => true,
    'files' => {
        'change.yml' => {
            'content' => ':after'
        }
    }
}

second_req = Net::HTTP::Put.new(second_uri.path)
second_req.body = second_payload.to_json
second_req.basic_auth("username", "password")
second_res = Net::HTTP.start(second_uri.hostname, second_uri.port, :use_ssl => true) do |http|
  http.request(second_req)
end