Lighttpd

-- redirect-map.lua

--

-- Summary: redirect-map based on url-path

--

--

-- Copyright (c) 2021, Glenn Strauss (gstrauss () gluelogic.com)

-- All rights reserved.

--

-- License: 3-clause BSD

--

--

-- prep:

-- * replace all "/path/to" in instructions and script with actual path to files

-- * build mcdb

--     https://github.com/gstrauss/mcdb/blob/master/README

--     https://github.com/gstrauss/mcdb/blob/master/INSTALL

-- * install mcdb or use qualified path to mcdbctl when creating database

-- * build lua-mcdb and copy mcdb.so to /path/to/

--     https://github.com/gstrauss/mcdb/blob/master/contrib/lua-mcdb/README

-- * create url-path mapping database (orig-url-path -> new-url-path or URI)

--     (see mcdb documentation)

-- * modify script below to send one of 301, 302, 303, 307, 308, as desired

-- * note: database performs exact matches.  If case-insensitive is required,

--     then lowercase input when database is created (lc($_)) and modify code

--     below to lowercase request item before querying database

--

-- lighttpd.conf

--   server.modules += ("mod_magnet")

--   magnet.attract-raw-url-to = ( "/path/to/redirect-map.lua" )

-- get database file handle (cached in global)

-- note: when database changes, 'touch' file containing this script in order to

-- trigger lighttpd mod_magnet_cache to reload this script and re-open the mcdb

-- (lighttpd etags must be enabled (default) for modified script to be noticed)

-- (alternative: skip caching open mcdb in _G to have mcdb opened each request)

local redirmap = _G.redirmapdb

if (not redirmap) then

  -- open database file

  local db = "/path/to/redirect-map.mcdb"

  local mcdb = package.loaded["mcdb"]

  if (not mcdb) then

    -- update search path with path to mcdb.so

    -- (todo: should skip if already present)

    --package.cpath = '/path/to/?.so'

    package.cpath = package.cpath .. ';/path/to/?.so'

    mcdb = require("mcdb")

  end

  local redirmapdb, errstr = mcdb.init(db)

  if redirmapdb == nil then

    io.stderr:write('mcdb.init("' .. db .. '"): ' .. errstr .. '\n')

    return 0   -- fail open (not closed); allow request to proceed

  end

  _G.redirmapdb = redirmapdb

  redirmap = redirmapdb

end

-- check map for (url-decoded) url-path ("uri.path" in mod_magnet)

local redirect = redirmap(lighty.env["uri.path"])  -- exact match

if (redirect ~= nil) then

  lighty.header["Location"] = redirect

  return 301  -- HTTP 301 Moved Permanently

end

-- allow request to proceed

return 0