phoenix-framework - Elixir HTTPoison 没有 case 子句匹配：错误错误

Question

我目前正在尝试在 Elixir 中构建一个简单的 HTTP 服务，该服务HTTPoison通过代理查询 Web 服务 (SOAP) API。这就是我的代码的样子：

defp body do
  """
  <?xml version="1.0" encoding="UTF-8"?>
  <soap:Envelope xmlns:xsi="http://wwww.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://wwww.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
    <soap:Body>
      <ExecuteDatasetStoredProcedure>
        <securityPassword>ApiKey1234</securityPassword>
        <name>pa_sp_GetContactInfo</name>
        <parameters></parameters>
      </ExecuteDatasetStoredProcedure>
    </soap:Body>
  </soap:Envelope>
  """
end

defp headers do
  [{"Content-Type", "text/xml"},
   {"Host", "example-api.example.com"},
   {"SOAPAction", "https://example-api.example.com/Execute/Stored/Procedure"}]
end

defp options do
  [{:proxy, "http://username:password@eu-west-static-01.quotaguard.com:9293"}, 
   {:proxy_auth, {"username", "password"}}, 
   {:ssl, [{:versions, [:'tlsv1.2']}]}]
end

def show(conn, %{"email" => email}) do
  case HTTPoison.post(api_url, body, headers, options) do
    {:ok, %HTTPoison.Response{body: body}} ->
      conn |> json(%{reason: body})
    {:error, %HTTPoison.Error{reason: reason}} ->
      conn |> json(%{error: reason})
  end
end

但是，当我运行此代码时，它会返回：

no case clause matching: false

当我检查控制台时，我看到：

[error] proxy error: "HTTP/1.1 400 Bad Request\r\nContent-Type: text/plain\r\nConnection: close\r\n\r\n400 Bad Request: missing required Host header"

我已经验证没有任何标题或选项是错误的。由于某种原因，它无法识别Host标题存在。