cgi-spa: Common Gateway Interface for Single Page Applications

CGI-SPA provides a number of globals, helper methods, and monkey patches which simplify the development of single page applications in the form of CGI scripts.

Globals provided

  • $cgi - Common Gateway Interface

  • $param - Access to parameters (read-only OpenStruct like interface)

  • $env - Access to environment variables (read-only OpenStruct like interface)

  • $x - XmlBuilder instance

  • $USER - Host user id

  • $HOME - Home directory

  • $SERVER- Server name

  • SELF - Request URI

  • SELF? - Request URI with '?' appended (avoids spoiling the cache)

  • $USER - user

  • $HOME - user's home directory

  • $HOST - server host

  • $HTTP_GET - request is an HTTP GET

  • $HTTP_POST - request is an HTTP POST

  • $XHR_JSON - request is XmlHttpRequest for JSON

  • $XHTML - user agent accepts XHTML responses

HTML methods

  • style! - argument is indented text/data
  • system! - run command and capture output
  • script! - argument is indented text/data
  • body? - capture exceptions, and produce a stack traceback

CGI methods

  • json - produce JSON output using the block specified
  • json! - produce JSON output using the block specified and exit
  • html - produce HTML output using the block specified
  • html! - produce HTML output using the block specified and exit
  • post - execute block only if method is POST
  • post! - if POST, produce HTML output using the block specified and exit

Helper methods

  • submit: runs command (or block) as a deamon process

OpenStruct methods (for $params and $env)

  • untaint_if_match: untaints value if it matches a regular expression

Builder extensions

  • indented_text: matches text indentation to markup
  • indented_data: useful for script and styles in HTML syntax
  • traceback!: formats an exception traceback
  • method_missing: patched to ensure open tags are closed

Command line options

When run from the command line, CGI name=value pairs can be specified. Additionally, the following options are supported:

  • --html: HTML (HTTP GET) output is expected
  • --post: HTML (HTTP POST) output is expected
  • --json: JSON (XML HTTP Request) output is expected
  • --xhtml: XHTML output is expected
  • --prompt: prompt for key/value pairs using stdin
  • --install=path: produce an suexec-callable wrapper script