User-based Website Directories with Nginx

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Many webservers allow users on the machine to create personal websites, usually with urls starting with /~username, where the web files are contained in a directory like /home/username/public_html/. With Apache and Lighttpd, this is done with the module mod_userdir, but there does not appear to be an equivalent for Nginx. I developed a method for doing so, using only Nginx’s standard configuration directives.

One website recommended using Nginx’s rewrite rules to emulate user-based website directories. This worked fairly well, except for one problem. Nginx has this internal behavior of fixing URL requests for directories so that they have a trailing slash. But when a rewrite rule was applied first, the fixed URL, presented to the web browser, was the rewritten location (with the trailing slash).

The rewrite rule looked like:

/~[username]/[file] => /home/[username]/[file]
Then I would make a request for:
http://www.sbf5.com/~cduan/subdir
and Nginx would rewrite the URL, add the slash, and redirect my browser to:
http://www.sbf5.com/home/cduan/subdir/
which, of course, caused an error.

My solution to this problem was to first parse the URL to determine the username, requested file, and presence or absence of trailing slashes. Then, I manually redirect requests for directories that lack trailing slashes, thus circumventing any attempt by Nginx to (mis)redirect the requests on its own.

I developed one “trick” to get around Nginx’s lack of support for nested conditionals. Whenever I came to a point where I would normally have used a nested conditional, I used a rewrite to add a special prefix to the front of the URL, and then created a special location block, using that special prefix, where execution would continue (and thus where I could put a second conditional). Nginx always puts a slash in front of URLs it creates, so all of my special prefixes contained no leading slash, ensuring that a user could not accidentally stumble on them.

The code is as follows:

# For requests starting with a tilde, break them into three components:
# 1. The username, everything after the tilde up to the first slash
# 2. The file location, everything after the username up to the last slash
# 3. The trailing slash(es)
# Then, rewrite to go to the f~/ branch.
location /~ {
    if ($request_uri ~ ^/~([^/]*)(/.*[^/]|)(/*)$) {
        set $homedir $1;
        set $filedir $2;
        set $trailingslashes $3;
        rewrite ^/~([^/]*)(/|$)(.*)$ f~/$3;
    }
}

Here, the user-directory components have been parsed. Use an alias to set

the file directory prefix. But if the file at the requested URI is a

directory, we jump to the ~/ branch for additional processing.

location f~/ { alias /home/$homedir/public_html/; if (-d /home/$homedir/public_html$filedir) { rewrite ^f~/(.*) ~/$1; } }

Here, the request is for a directory in a user’s home directory. We check

that the request URI contained trailing slashes. If it did not, then we

add the slashes and send a redirect. This circumvents Nginx’s faulty

internal slash-adding mechanism.

location ~/ { autoindex on; alias /home/$homedir/public_html/; if ($trailingslashes = “") { rewrite .* /~$homedir$filedir/ redirect; } }

Improvements and suggestions are greatly appreciated.

UPDATE: If you want PHP support, follow the instructions in this post.