DirectoryDisplay.erl

<erl>

out(Arg) ->

% change directory to the document root of the webserver
  c:cd(Arg#arg.docroot),

% determining YAWS' current working directory
% usually where you were when you typed sudo yaws
% not normally the same as the document root
  CurrentDir = element(2,file:get_cwd()),

% pull up a directory listing
  DirList = element(2,file:list_dir(CurrentDir)),

% define a function for our filter
  IsDir = fun(F) -> filelib:is_dir(F) end,

% filter out all the directories
  AllDirs = lists:filter(IsDir,DirList),

% make directories into links using a mapping function
  ConvertToLink = fun(D) ->
    "<a href=\"" ++ D ++ "\">" ++ D ++ "</a>" end,
  LinkedDirs = lists:map(ConvertToLink,AllDirs),

% define a filter function and use it to
% filter out all the regular files
  IsReg = fun(F) -> filelib:is_regular(F) end,
  AllRegs = lists:filter(IsReg,DirList),

% HTML-ify the two lists ready for output
  DirBlock = string:join(LinkedDirs,"</li>\n<li>"),
  RegBlock = string:join(AllRegs,"</li>\n<li>"),

% send output back to the browser
  {html,
    "<h1>" ++ CurrentDir ++ "</h1>\n" ++
    "<h2>Directories</h2>\n" ++
    "<ul>\n<li>" ++ DirBlock ++ "</li>\n</ul>\n" ++
    "<h2>Regular Files</h2>\n" ++
    "<ul>\n<li>" ++ RegBlock ++ "</li>\n</ul>\n"
  }.

</erl>