▼Web Server: Racket HTTP Server
►6 Troubleshooting and Tips
On this page:
6.1 How do I use Apache with the Racket Web Server?
6.2 Can the server create a PID file?
6.3 How do I set up the server to use HTTPS?
6.4 How do I limit the number of requests serviced at once by the Web Server?
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6 Troubleshooting and Tips

6.1 How do I use Apache with the Racket Web Server?

You may want to put Apache in front of your Racket Web Server application. Apache can rewrite and proxy requests for a private (or public) Racket Web Server:

RewriteEngine on

RewriteRule ^(.*)$ http://localhost:8080/$1 [P,NE]

The first argument to RewriteRule is a match pattern. The second is how to rewrite the URL. The bracketed part contains flags that specify the type of rewrite, in this case the P flag instructs Apache to proxy the request. (If you do not include this, Apache will return an HTTP Redirect response and the client will make a second request to localhost:8080 which will not work on a different machine.) In addition, the NE flag is needed to avoid escaping parts of the URL — without it, a ; is escaped as %3B which will break the proxied request.

See Apache’s documentation for more details on RewriteRule.

6.2 Can the server create a PID file?

The server has no option for this, but you can add it very easily. There’s two techniques.

First, if you use a UNIX platform, in your shell startup script you can use

echo $$ > PID

exec run-web-server

Using exec will reuse the same process, and therefore, the PID file will be accurate.

Second, if you want to make your own Racket start-up script, you can write:

  (require mzlib/os)
  (with-output-to-file your-pid-file (lambda () (write (getpid))))
  (start-server)

6.3 How do I set up the server to use HTTPS?

This requires an SSL certificate and private key. This is very platform specific, but we will provide the details for using OpenSSL on UNIX:

  openssl genrsa -des3 -out private-key.pem 1024

This will generate a new private key, but it will have a passphrase on it. You can remove this via:

  openssl rsa -in private-key.pem -out private-key.pem
  chmod 400 private-key.pem

Now, we generate a self-signed certificate:

  openssl req -new -x509 -nodes -sha1 -days 365 -key private-key.pem > server-cert.pem

(Each certificate authority has different instructions for generating certificate signing requests.)

We can now start the server with:

  plt-web-server --ssl

The Web Server will start on port 443 (which can be overridden with the -p option) using the "private-key.pem" and "server-cert.pem" we’ve created.

6.4 How do I limit the number of requests serviced at once by the Web Server?

Refer to Limiting Requests.

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