nginx case insensitive file search with lua

local start=os.clock()
local string=string


local lfs=require"lfs"
function isdir(fn)

    return (lfs.attributes(fn, "mode") == 'directory')
end
function exists(fn)
    return lfs.attributes(fn, "mode")
end

local function findcorrect(path,what)
    local ok,a,b,c,d=pcall(lfs.dir,path)
    if not ok then return false,a end

    what=what:lower()

    local found=false
    for file in a,b,c,d do
        if file ~= "." and file ~= ".." then
            if file:lower()==what then
                found=file
                break
            end
        end
    end

    return found
end


ngx.status=ngx.HTTP_NOT_FOUND
status = ngx.status
local root=ngx.var.document_root
local url=ngx.var.uri


-- find it the easy way
local reqpath,delim,reqfile=url:match("(.*)([/\\])(.+)")
local path=ngx.var.document_root..reqpath--lfs.currentdir()
local correct=findcorrect(path,reqfile)
if correct then
    ngx.status=ngx.HTTP_MOVED_PERMANENTLY
    status = ngx.status
    local f = reqpath..delim..correct
    return ngx.redirect(f, ngx.HTTP_MOVED_PERMANENTLY)
end

-- nope, let's find it the hard way. ADD CACHING D:
local nowpath=""
for str in url:gmatch"[^/]+" do
    local dir=exists(root..nowpath..str)
    local setstr

    if not dir then
        setstr=findcorrect(root..nowpath,str)
    else
        setstr=str
    end
    if not setstr then nowpath=false  break end
    nowpath=nowpath..'/'..setstr

end
if nowpath then
    ngx.status=ngx.HTTP_MOVED_PERMANENTLY
    status = ngx.status
    return ngx.redirect(nowpath, ngx.HTTP_MOVED_PERMANENTLY)
end

ngx.status=ngx.HTTP_NOT_FOUND
status = ngx.status
ngx.say(string.format("Sorry, couldn't find that file. I looked it for: %.2f\n", os.clock() - start))
return ngx.exit(ngx.HTTP_NOT_FOUND)