Fixing "error while loading shared libraries: libnspr4.so" for Playwright with no root access

In a locked-down sandbox environment, where no sudo or passwordless root access is permitted, setting up browser automation using Playwright proved to be a challenging task. The command npx playwright install --with-deps chromium failed immediately, and even running the browser directly resulted in an error message: "error while loading shared libraries: libnspr4.so: cannot open shared object file: No such file or directory."

This issue is a recurring problem in restricted environments such as containers, CI runners, and platforms like Render, Replit, and Streamlit Cloud, where users do not have control over the base image and cannot install anything using apt.

The root cause of this problem lies in the fact that both playwright install --with-deps and playwright install-deps rely on apt-get install, which requires root access. However, in a sandbox environment where no root access is available, neither apt-get install nor apt-get download can be used to install or fetch the necessary libraries.

The solution to this problem is to utilize apt-get download, which does not require root access, and then use dpkg-deb -x to unpack the .deb file into a directory that the user has control over.

To automate this process, a small script was developed that dynamically discovers the package list required by Playwright, downloads each package using apt-get download, and unpacks the contents of the .deb files into a local prefix directory using dpkg-deb -x. This local prefix directory can then be pointed to by the browser using the LD_LIBRARY_PATH environment variable.

By doing so, no changes are made to the /usr directory, no sudo access is required, and the process can be easily undone by simply deleting the local prefix directory.

This rootless approach to setting up Playwright has been packaged into a script (https://github.com/LooseChangeLabs/rootless-playwright) that can be easily installed with the command ./install.sh chromium. The script is MIT-licensed and freely available for anyone facing the same error. By using this script, users can avoid the time-consuming trial-and-error process of manually running the steps required to resolve the issue.