The Web server and website written in C

Document markup

A troff-like syntax is used to describe a Web page. Commands are drawn from the mom macro set. Currently only http:191.252.220.165/movies.html is being generated, which is defined in movies.txt. A state machine specified in parse2.rl reads the markup and builds a linked list of elements. This specification employs Ragel. Moreover, the state machine allows mixing LF and CRLF for line endings.

This linked list is defined in movie.h, and is consumed by an ad-hoc state machine implemented in parse.c, which finally generates HTML. There is currently no HTML escaping or sanitization, so the user must write stuff like & manually.

The output device is generic, and its interface is found in parse.h. Thus, the simple debug batch implementation batch.c writes directly to stdout, but the actual Web server code performs two passes: one device counts bytes, and the second writes to a buffer, because HTML generation is deterministic and reproducible. main.c handles all of this across several callbacks.

Commands and elements

Commands start obligatorily at the beginning of a line. Free text is currently only understood after .PP command. All mentions to digits refers to decimal Arabic numerals.

All commands span a single line, and there is no mechanism such as escaping the end of line sequence with \ to continue a command or element in the next line.

This syntax is very far away from being compatible with troff. Actually, it is already incompatible.

• .\"

  This a "comment command", anything that follows is ignored. They can appear anywhere.

• .TITLE quoted_text

  quoted_text is suffixed with - aqueduct1 and placed inside <title>..</title>. It must start and end with a " character. Embedded "s must not be escaped.

• .HEADING level quoted_text

  level is a number from 1 to 6, which is translated to <hlevel>..</hlevel>. As in .TITLE, quoted_text allows embedded "s and these must not be escaped, but it is copied inside the section heading tags as it is, without any suffix.

• .PP

  Starts a paragraph. The lines that follow until any command appears are added between <p>..</p>. No argument is expected for this command.

• .MOV symbol [imdb_code year title]

  A sequence of .MOV commands creates an unordered list <ul>..</ul> of movies, where each item <li>..</li> is in the form text (year), and text is a hyperlink <a href=..</a> pointing to the movie's entry in IMDb. Any other command after .MOV will end the list.

  To define a movie, the second form of the command, with all optional arguments present, must be used.

  • symbol is a sequence of character uppercase or number or underline, but the first one must not be a number.
  • imdb_code is tt followed by at least 7 digits.¹
  • year is exactly four digits.
  • title is the remainder of the line until its end, and must not be quoted anyhow.

  Once a movie defined, and only once, it is also output to HTML as described before. Further, a movie definition can be reused before or after the initial definition using the first form of the command, simply through its symbol.

Footnotes

1. https://developer.imdb.com/documentation/key-concepts#imdb-ids ↩