3.1 KiB
R7RS Scheme library for Common Gateway Interface
If you dont know what CGI is, in short server runs your Scheme script and displays it's output as a webpage. Also checkout https://git.sr.ht/~retropikzel/scheme-php.
Caveats
- Works only on unix as it reads from /dev/fd/0 and /dev/random.
Buggy on implementations
- Does not work with mit-scheme
- For some reason mit-scheme exits when it reads eof-object from standard input
- STklos
- No output for some reason
How to use
Example using Gauche in Docker.
lighttpd.conf:
server.document-root = "/workdir"
server.port = 3000
server.modules += ("mod_cgi", "mod_dirlisting")
cgi.assign = (".scm" => "/usr/bin/scheme-script")
dir-listing.activate = "enable"
Dockerfile:
FROM schemers/gauche
RUN apt-get update && apt-get install -y --no-install-recommends lighttpd
WORKDIR /workdir
EXPOSE 3000
COPY lighttpd.conf /lighttpd.conf
RUN echo "#!/bin/sh" > /usr/bin/scheme-script
RUN echo "exec gosh -r7 -I ./snow \$@" >> /usr/bin/scheme-script
RUN chmod +x /usr/bin/scheme-script
ENTRYPOINT ["/usr/sbin/lighttpd", "-D", "-f", "/lighttpd.conf"]
hello.scm:
(import (scheme base)
(scheme write)
(retropikzel cgi))
(display "Content-type: text/html")
(display "\r\n")
(display "\r\n")
(display "Hello")
(display "</br>")
(display "Request: ")
(write (get-request))
(display "</br>")
(cgi-exit)
Run:
docker build . --tag=scheme-cgi
docker run -it -v ${PWD}:/workdir -p 3000:3000 scheme-cgi
Then navigate with your browser to http://127.0.0.1:3000
Documentation
Reference
get-request
Returns the whole request as association list.
get-header name
Name can be symbol or a string. Returns the value of given header or #f.
get-headers
Returns association list of all headers.
get-parameter name
Name can be symbol or a string. Returns the value of given parameter or #f.
get-parameters
Returns association list of all parameters.
get-cookie name
Returns the value of given cookie or #f if.
get-cookies
Returns association list of all cookies.
get-file filename
Filename is a symbol or a string. Returns the path of given file from files or #f.
Uploaded files are stored in /tmp, with randomly generated prefix on their name. They are not deleted unless cgi-exit is called. Use move-file to move them into preferred location.
get-files
Returns association list of all files.
move-file from to
Moves a file from from path to to path.
get-body
Returns the request body.
cgi-exit
cgi-exit code
Does necessary cleanup and exits the script. Code is a number, if it is given then that is used as exit code.
Environment variables
SCHEME_CGI_TMP_PATH
Path to where uploaded files are stored. Default is /tmp.