How do I get Shiny-server to working with Azure Active Directory

Question

I am using Azure Webapps for Containers to host an R Shiny-Server. I want to use Azure Active Directory to authenticate and authorize the user logging into the app.

I am using the rocker/shiny image from dockerhub and the image builds and run easily. However, when I am turning on Active Directory the app does not work anymore. Any hints and clues on what might be wrong would be of great help.

Answer 1

I got the same problem of an "empty" page, because loading of static files by the browser returned HTTP 400 when activating AD authentication. I have a Shiny app in a docker container on Azure App Services on the latest version of Shiny server (v1.5.12.933) and Shiny (1.4.0).

This means the problem described here https://community.rstudio.com/t/shiny-v1-3-known-regressions-and-serious-issues/28180/4 which I suspected first is not the reason.

w/o AD authentication the page is displayed correctly. The Azure proxy responsible for AD authentication injects some HTTP headers and cookies. I inspected the full HTTP request on server side via tcpflow -p -c -i eth0 port 3838 and had a look at the underlying R library httpuv which is responsible for the HTTP connection to the Shiny server.

When searching where in this library HTTP 400 codes are returned I found https://github.com/rstudio/httpuv/blob/master/src/webapplication.cpp and the following code snippet

// Make sure that there's no message body.
  if (pRequest->hasHeader("Content-Length") || pRequest->hasHeader("Transfer-Encoding")) {
    return error_response(pRequest, 400);
  }

while the request arriving at the server had the header Content-Length: 0 which is not present if AD authentication is turned off.

I created a fix and PR for httpuv, see issue https://github.com/rstudio/httpuv/issues/247.

You can use it as long as it is not merged into their repo.

Just run

R -e 'library(devtools); install_github("LHaferkamp/httpuv")'

in your Dockerfile