SSOwat/access.lua

--
-- Load configuration
--
cache = ngx.shared.cache
srvkey = cache:get("srvkey")
if not srvkey then
    math.randomseed(os.time())
    srvkey = tostring(math.random(1111111, 9999999))
    cache:add("srvkey", srvkey)
end
cookies = {}
lang = ngx.req.get_headers()["Accept-Language"]
if lang then
    lang = string.sub(lang, 1, 2)
end

-- Load conf file
local conf_file = assert(io.open(conf_path, "r"), "Configuration file is missing")
local conf = json.decode(conf_file:read("*all"))

-- Load additional rules
local persistent_conf_file = io.open(conf_path..".persistent", "r")
if persistent_conf_file ~= nil then
    for k, v in pairs(json.decode(persistent_conf_file:read("*all"))) do
       -- If key already exists and is a table, merge it
       if conf[k] and type(v) == "table" then
           for subk, subv in pairs(v) do
               if type(subk) == "number" then
                   table.insert(conf[k], subv)
               else
                   conf[k][subk] = subv
               end
           end
        else
           conf[k] = v
	end
    end
end

-- Default configuration values
default_conf = {
    portal_scheme             = "https",
    portal_path               = "/ssowat",
    domains                   = { conf["portal_domain"] },
    session_timeout           = 60 * 60 * 24,     -- one day
    session_max_timeout       = 60 * 60 * 24 * 7, -- one week
    login_arg                 = "sso_login",
    ldap_host                 = "localhost",
    ldap_group                = "ou=users,dc=yunohost,dc=org",
    ldap_identifier           = "uid",
    ldap_attributes           = {"uid", "givenname", "sn", "cn", "homedirectory", "mail", "maildrop"},
    allow_mail_authentication = true,
    default_language          = "en"
}

for param, default_value in pairs(default_conf) do
    conf[param] = conf[param] or default_value
end

local portal_url = conf["portal_scheme"].."://"..
                   conf["portal_domain"]..
                   conf["portal_path"]
table.insert(conf["skipped_urls"], conf["portal_domain"]..conf["portal_path"])

-- Dummy intructions
ngx.header["X-SSO-WAT"] = "You've just been SSOed"


--
--  Useful functions
--
function read_file(file)
    local f = io.open(file, "rb")
    if not f then return false end
    local content = f:read("*all")
    f:close()
    return content
end

function is_in_table (t, v)
    for key, value in ipairs(t) do
        if value == v then return key end
    end
end

function string.starts (String, Start)
   return string.sub(String, 1, string.len(Start)) == Start
end

function string.ends (String, End)
   return End=='' or string.sub(String, -string.len(End)) == End
end

function t (key)
   if lang and i18n[lang] then
       return i18n[lang][key] or ""
   else
       return i18n[conf["default_language"]][key] or ""
   end
end 

function cook (cookie_str)
    table.insert(cookies, cookie_str)
end

function flash (wat, message)
    if wat == "fail"
    or wat == "win"
    or wat == "info"
    then
        flashs[wat] = message
    end
end

function uri_args_string (args)
    if not args then
        args = ngx.req.get_uri_args()
    end
    String = "?"
    for k,v in pairs(args) do
        String = String..tostring(k).."="..tostring(v).."&"
    end
    return string.sub(String, 1, string.len(String) - 1)
end

function set_auth_cookie (user, domain)
    local maxAge = conf["session_max_timeout"]
    local expire = ngx.req.start_time() + maxAge
    local session_key = cache:get("session_"..user)
    if not session_key then
        session_key = tostring(math.random(1111111, 9999999))
        cache:add("session_"..user, session_key, conf["session_max_timeout"])
    end
    local hash = ngx.md5(srvkey..
               "|" ..ngx.var.remote_addr..
               "|"..user..
               "|"..expire..
               "|"..session_key)
    local cookie_str = "; Domain=."..domain..
                       "; Path=/"..
                       "; Max-Age="..maxAge
    cook("SSOwAuthUser="..user..cookie_str)
    cook("SSOwAuthHash="..hash..cookie_str)
    cook("SSOwAuthExpire="..expire..cookie_str)
end

function delete_cookie ()
    expired_time = "Thu, Jan 01 1970 00:00:00 UTC;"
    for _, domain in ipairs(conf["domains"]) do
        local cookie_str = "; Domain=."..domain..
                           "; Path=/"..
                           "; Max-Age="..expired_time
        cook("SSOwAuthUser=;"    ..cookie_str)
        cook("SSOwAuthHash=;"    ..cookie_str)
        cook("SSOwAuthExpire=;"  ..cookie_str)
    end
end

function delete_redirect_cookie ()
    expired_time = "Thu, Jan 01 1970 00:00:00 UTC;"
    local cookie_str = "; Path="..conf["portal_path"]..
                       "; Max-Age="..expired_time
    cook("SSOwAuthRedirect=;" ..cookie_str)
end

function is_logged_in ()

    -- Check if cookie is set
    if  ngx.var.cookie_SSOwAuthExpire and ngx.var.cookie_SSOwAuthExpire ~= ""
    and ngx.var.cookie_SSOwAuthHash   and ngx.var.cookie_SSOwAuthHash   ~= ""
    and ngx.var.cookie_SSOwAuthUser   and ngx.var.cookie_SSOwAuthUser   ~= ""
    then
        -- Check expire time
        if (ngx.req.start_time() <= tonumber(ngx.var.cookie_SSOwAuthExpire)) then
            -- Check hash
            local session_key = cache:get("session_"..ngx.var.cookie_SSOwAuthUser)
            if session_key and session_key ~= "" then
                -- Check cache
                if cache:get(ngx.var.cookie_SSOwAuthUser.."-password") then
                    local hash = ngx.md5(srvkey..
                            "|"..ngx.var.remote_addr..
                            "|"..ngx.var.cookie_SSOwAuthUser..
                            "|"..ngx.var.cookie_SSOwAuthExpire..
                            "|"..session_key)
                    return hash == ngx.var.cookie_SSOwAuthHash
                end
            end
        end
    end

    return false
end

function has_access (user, url)
    user = user or ngx.var.cookie_SSOwAuthUser
    url = url or ngx.var.host..ngx.var.uri
    if not conf["users"] or not conf["users"][user] then
        return true
    end
    for u, _ in pairs(conf["users"][user]) do
        if string.starts(url, string.sub(u, 1, -2)) then return true end
    end
    return false
end

function authenticate (user, password)
    if conf["allow_mail_authentication"] and string.find(user, "@") then
        ldap = lualdap.open_simple(conf["ldap_host"])
        for dn, attribs in ldap:search {
            base = conf["ldap_group"],
            scope = "onelevel",
            sizelimit = 1,
            filter = "(mail="..user..")",
            attrs = {conf["ldap_identifier"]}
        } do
            if attribs[conf["ldap_identifier"]] then
                ngx.log(ngx.NOTICE, "Use email: "..user)
                user = attribs[conf["ldap_identifier"]]
            else
                ngx.log(ngx.ERR, "Unknown email: "..user)
                return false
            end
        end
        ldap:close()
    end
    connected = lualdap.open_simple (
        conf["ldap_host"],
        conf["ldap_identifier"].."=".. user ..","..conf["ldap_group"],
        password
    )

    cache:flush_expired()
    if connected then
        cache:add(user.."-password", password, conf["session_timeout"])
        ngx.log(ngx.NOTICE, "Connected as: "..user)
        return user
    else
        ngx.log(ngx.ERR, "Connection failed for: "..user)
        return false
    end
end

function set_headers (user)
    if ngx.var.scheme ~= "https" then
        return redirect("https://"..ngx.var.host..ngx.var.uri..uri_args_string())
    end
    user = user or ngx.var.cookie_SSOwAuthUser
    if not cache:get(user.."-password") then
        flash("info", t("please_login"))
        local back_url = ngx.var.scheme .. "://" .. ngx.var.host .. ngx.var.uri .. uri_args_string()
        return redirect(portal_url.."?r="..ngx.encode_base64(back_url))
    end
    if not cache:get(user.."-"..conf["ldap_identifier"]) then
        ldap = lualdap.open_simple(conf["ldap_host"])
        ngx.log(ngx.NOTICE, "Reloading LDAP values for: "..user)
        for dn, attribs in ldap:search {
            base = conf["ldap_identifier"].."=".. user ..","..conf["ldap_group"],
            scope = "base",
            sizelimit = 1,
            attrs = conf["ldap_attributes"]
        } do
            for k,v in pairs(attribs) do
                if type(v) == "table" then
                    for k2,v2 in ipairs(v) do
                        if k2 == 1 then cache:set(user.."-"..k, v2, conf["session_timeout"]) end
                        cache:set(user.."-"..k.."|"..k2, v2, conf["session_max_timeout"])
                    end
                else
                    cache:set(user.."-"..k, v, conf["session_timeout"])
                end
            end
        end
    else
        -- Revalidate session for another day by default
        password = cache:get(user.."-password")
        cache:set(user.."-password", password, conf["session_timeout"])
    end

    -- Set HTTP Auth header
    ngx.req.set_header("Authorization", "Basic "..ngx.encode_base64(
      user..":"..cache:get(user.."-password")
    ))

    -- Set Additional headers
    for k, v in pairs(conf["additional_headers"]) do
        ngx.req.set_header(k, cache:get(user.."-"..v))
    end

end

function get_mails(user)
    local mails = { mail = "", mailalias = {}, maildrop = {} }
    if cache:get(user.."-mail|2") then
        for _, v in ipairs({2, 3, 4, 5, 6, 7, 8, 9, 10}) do
            table.insert(mails["mailalias"], cache:get(user.."-mail|"..v))
        end
    end
    mails["mail"] = cache:get(user.."-mail")
    if cache:get(user.."-maildrop|2") then
        for _, v in ipairs({2, 3, 4, 5, 6, 7, 8, 9, 10}) do
            table.insert(mails["maildrop"], cache:get(user.."-maildrop|"..v))
        end
    end
    return mails
end

-- Yo dawg
function serve(uri)
    rel_path = string.gsub(uri, conf["portal_path"], "/")

    -- Load login.html as index
    if rel_path == "/" then
        if is_logged_in() then
            rel_path = "/info.html"
        else
            rel_path = "/login.html"
        end
    end

    -- Access to directory root: forbidden
    if string.ends(rel_path, "/") then
        return ngx.exit(403)
    end

    -- Try to get file content
    local content = read_file(script_path.."portal"..rel_path)
    if not content then
        return ngx.exit(ngx.HTTP_NOT_FOUND)
    end

    -- Extract file extension
    _, file, ext = string.match(rel_path, "(.-)([^\\/]-%.?([^%.\\/]*))$")

    -- Associate to MIME type
    mime_types = {
        html = "text/html",
        ms   = "text/html",
        js   = "text/javascript",
        map  = "text/javascript",
        css  = "text/css",
        gif  = "image/gif",
        jpg  = "image/jpeg",
        png  = "image/png",
        svg  = "image/svg+xml",
        ico  = "image/vnd.microsoft.icon",
        woff = "application/x-font-woff",
        json = "application/json"
    }

    -- Set Content-Type
    if mime_types[ext] then
        ngx.header["Content-Type"] = mime_types[ext]
    else
        ngx.header["Content-Type"] = "text/plain"
    end

    -- Render as mustache
    if ext == "html" then
        local data = get_data_for(file)
        local rendered = hige.render(read_file(script_path.."portal/header.ms"), data)
        rendered = rendered..hige.render(content, data)
        content = rendered..hige.render(read_file(script_path.."portal/footer.ms"), data)
    elseif ext == "ms" then
        local data = get_data_for(file)
        content = hige.render(content, data)
    elseif ext == "json" then
        local data = get_data_for(file)
        content = json.encode(data)
    end

    -- Reset flash messages
    flashs["fail"] = nil
    flashs["win"] = nil
    flashs["info"] = nil

    -- Ain't nobody got time for cache
    ngx.header["Cache-Control"] = "no-cache"
    ngx.say(content)
    return ngx.exit(ngx.HTTP_OK)
end

function get_data_for(view)
    local user = ngx.var.cookie_SSOwAuthUser
    local data = {}

    if view == "login.html" then
        data = {
            title = t("login"),
            connected = false
        }

    elseif view == "info.html"
        or view == "edit.html"
        or view == "password.html"
        or view == "ynhpanel.json" then
        set_headers(user)

        local mails = get_mails(user)
        data = {
            title      = user.." <small>"..cache:get(user.."-cn").."</small>",
            connected  = true,
            portal_url = portal_url,
            uid        = user,
            cn         = cache:get(user.."-cn"),
            sn         = cache:get(user.."-sn"),
            givenName  = cache:get(user.."-givenName"),
            mail       = mails["mail"],
            mailalias  = mails["mailalias"],
            maildrop   = mails["maildrop"],
            app = {}
        }

        for url, name in pairs(conf["users"][user]) do
            table.insert(data["app"], { url = url, name = name })
        end
    end

    -- View translation (use "t_key")
    if lang and i18n[lang] then
        translate_table = i18n[lang]
    else
        translate_table = i18n[conf["default_language"]]
    end
    for k, v in pairs(translate_table) do
        data["t_"..k] = v
    end

    data['flash_fail'] = {flashs["fail"]}
    data['flash_win']  = {flashs["win"] }
    data['flash_info'] = {flashs["info"]}
    return data
end

function do_edit ()
    ngx.req.read_body()
    local args = ngx.req.get_post_args()

    if is_logged_in() and args
    then
        ngx.status = ngx.HTTP_CREATED
        local user = ngx.var.cookie_SSOwAuthUser

        -- Change password
        if string.ends(ngx.var.uri, "password.html") then
            if args.currentpassword
            and args.currentpassword == cache:get(user.."-password")
            then
                if args.newpassword == args.confirm then
                    local dn = conf["ldap_identifier"].."="..user..","..conf["ldap_group"]
                    local ldap = lualdap.open_simple(conf["ldap_host"], dn, args.currentpassword)
                    local password = "{SHA}"..ngx.encode_base64(ngx.sha1_bin(args.newpassword))
                    if ldap:modify(dn, {'=', userPassword = password }) then
                        flash("win", t("password_changed"))
                        cache:set(user.."-password", args.newpassword, conf["session_timeout"])
                        return redirect(portal_url.."info.html")
                    else
                        flash("fail", t("password_changed_error"))
                    end
                else
                    flash("fail", t("password_not_match"))
                end
             else
                flash("fail", t("wrong_current_password"))
             end
             return redirect(portal_url.."password.html")

         -- Edit user informations
         elseif string.ends(ngx.var.uri, "edit.html") then
             if args.givenName and args.sn and args.mail then

                 local mailalias = {}
                 if args["mailalias[]"] then
                     if type(args["mailalias[]"]) == "string" then
                         args["mailalias[]"] = {args["mailalias[]"]}
                     end
                     mailalias = args["mailalias[]"]
                 end

                 local maildrop = {}
                 if args["maildrop[]"] then
                     if type(args["maildrop[]"]) == "string" then
                         args["maildrop[]"] = {args["maildrop[]"]}
                     end
                     maildrop = args["maildrop[]"]
                 end

                 local mail_pattern = "[A-Za-z0-9%.%%%+%-]+@[A-Za-z0-9%.%%%+%-]+%.%w%w%w?%w?"
                 local domains = conf["domains"]
                 local mails = {}
                 local filter = "(|"
                 table.insert(mailalias, 1, args.mail)
                 for k, mail in ipairs(mailalias) do
                     if mail ~= "" then
                         if not mail:match(mail_pattern) then
                             flash("fail", t("invalid_mail")..": "..mail)
                             return redirect(portal_url.."edit.html")
                         else
                             local domain_valid = false
                             for _, domain in ipairs(domains) do
                                 if string.ends(mail, "@"..domain) then
                                     domain_valid = true
                                     break
                                 end
                             end
                             if domain_valid then
                                 table.insert(mails, mail)
                                 filter = filter.."(mail="..mail..")"
                             else
                                 flash("fail", t("invalid_domain").." "..mail)
                                 return redirect(portal_url.."edit.html")
                             end
                         end
                     end
                 end
                 filter = filter..")"

                 local drops = {}
                 for k, mail in ipairs(maildrop) do
                     if mail ~= "" then
                         if not mail:match(mail_pattern) then
                             flash("fail", t("invalid_mailforward")..": "..mail)
                             return redirect(portal_url.."edit.html")
                         end
                         table.insert(drops, mail)
                     end
                 end
                 table.insert(drops, 1, user)

                 local dn = conf["ldap_identifier"].."="..user..","..conf["ldap_group"]
                 local ldap = lualdap.open_simple(conf["ldap_host"], dn, cache:get(user.."-password"))
                 local cn = args.givenName.." "..args.sn
                 for dn, attribs in ldap:search {
                     base = conf["ldap_group"],
                     scope = "onelevel",
                     filter = filter,
                     attrs = {conf["ldap_identifier"], "mail"}
                 } do
                     ngx.log(4, filter)
                     ngx.log(4, attribs[conf["ldap_identifier"]])
                     if attribs[conf["ldap_identifier"]] and attribs[conf["ldap_identifier"]] ~= user then
                         if type(attribs["mail"]) == "string" then
                             attribs["mail"] = {attribs["mail"]}
                         end
                         for _, mail in ipairs(attribs["mail"]) do
                             if is_in_table(mails, mail) then
                                 flash("fail", t("mail_already_used").." "..mail)
                             end
                         end
                         return redirect(portal_url.."edit.html")
                     end
                 end
                 if ldap:modify(dn, {'=', cn = cn,
                                          givenName = args.givenName,
                                          sn = args.sn,
                                          mail = mails,
                                          maildrop = drops })
                 then
                     cache:delete(user.."-"..conf["ldap_identifier"])
                     for _, v in ipairs({2, 3, 4, 5, 6, 7, 8, 9, 10}) do
                         cache:delete(user.."-maildrop|"..v)
                         cache:delete(user.."-mail|"..v)
                     end
                     set_headers(user) -- Ugly trick to reload cache
                     flash("win", t("informations_updated"))
                     return redirect(portal_url.."info.html")
                 else
                     flash("fail", t("user_saving_fail"))
                 end
             else
                 flash("fail", t("missing_required_fields"))
             end
             return redirect(portal_url.."edit.html")
         end
    end
end

function do_login ()
    ngx.req.read_body()
    local args = ngx.req.get_post_args()
    local uri_args = ngx.req.get_uri_args()

    user = authenticate(args.user, args.password)
    if user then
        ngx.status = ngx.HTTP_CREATED
        set_auth_cookie(user, ngx.var.host)
        if uri_args.r then
            return redirect(portal_url.."?r="..uri_args.r)
        else
            return redirect(portal_url)
        end
    else
        ngx.status = ngx.HTTP_UNAUTHORIZED
        flash("fail", t("wrong_username_password"))
        return redirect(portal_url)
    end
end

function do_logout()
    local args = ngx.req.get_uri_args()
    if is_logged_in() then
        cache:delete("session_"..ngx.var.cookie_SSOwAuthUser)
        cache:delete(ngx.var.cookie_SSOwAuthUser.."-"..conf["ldap_identifier"]) -- Ugly trick to reload cache
        flash("info", t("logged_out"))
        return redirect(portal_url)
    end
end

function redirect (url)
    ngx.header["Set-Cookie"] = cookies
    ngx.log(ngx.INFO, "Redirect to: "..url)
    return ngx.redirect(url)
end

function pass ()
    delete_redirect_cookie()
    ngx.req.set_header("Set-Cookie", cookies)
    if string.ends(ngx.var.uri, "/")
    or string.ends(ngx.var.uri, ".html")
    or string.ends(ngx.var.uri, ".htm")
    then
        ngx.header["Content-Type"] = "text/html"
    end
    return
end


--------------------------------------------------
-- Routing
--

-- Logging in
--   i.e. http://mydomain.org/?sso_login=a6e5320f

if ngx.var.host ~= conf["portal_domain"] and ngx.var.request_method == "GET" then
    uri_args = ngx.req.get_uri_args()
    if uri_args[conf.login_arg] then
        cda_key = uri_args[conf.login_arg]
        if login[cda_key] then
            set_auth_cookie(login[cda_key], ngx.var.host)
            ngx.log(ngx.NOTICE, "Cross-domain authentication: "..login[cda_key].." connected on "..ngx.var.host)
            login[cda_key] = nil
            uri_args[conf.login_arg] = nil
            return redirect(ngx.var.uri..uri_args_string(uri_args))
        end
    end
end


-- Portal
--   i.e. http://mydomain.org/ssowat/*

if ngx.var.host == conf["portal_domain"]
   and string.starts(ngx.var.uri, string.sub(conf["portal_path"], 1, -2))
then
    if ngx.var.request_method == "GET" then

        -- http://mydomain.org/ssowat
        if ngx.var.uri.."/" == conf["portal_path"] then
            return redirect(portal_url)
        end

        uri_args = ngx.req.get_uri_args()
        if uri_args.action and uri_args.action == 'logout' then
            -- Logout
            return do_logout()

        elseif is_logged_in() and uri_args.r then
            back_url = ngx.decode_base64(uri_args.r)
            if  not string.match(back_url, "^http[s]?://"..ngx.var.host.."/")
            and not string.match(back_url, ".*"..conf.login_arg.."=%d+$") then
                cda_key = tostring(math.random(1111111, 9999999))
                login[cda_key] = ngx.var.cookie_SSOwAuthUser
                if string.match(back_url, ".*?.*") then
                    back_url = back_url.."&"
                else
                    back_url = back_url.."?"
                end
                back_url = back_url.."sso_login="..cda_key
            end
            return redirect(back_url)

        elseif is_logged_in()                                             -- Authenticated
            or ngx.var.uri == conf["portal_path"]                         -- OR Want to serve portal login
            or (string.starts(ngx.var.uri, conf["portal_path"].."assets")
               and (not ngx.var.http_referer
                    or string.starts(ngx.var.http_referer, portal_url)))  -- OR Want to serve assets for portal login
        then
            -- Serve normal portal
            return serve(ngx.var.uri)

        else
            -- Redirect to portal
            flash("info", t("please_login"))
            return redirect(portal_url)
        end

    elseif ngx.var.request_method == "POST" then

        -- CSRF protection
        if string.starts(ngx.var.http_referer, portal_url) then
            if string.ends(ngx.var.uri, conf["portal_path"].."password.html")
            or string.ends(ngx.var.uri, conf["portal_path"].."edit.html")
            then
               return do_edit()
            else
               return do_login()
            end
        else
            -- Redirect to portal
            flash("fail", t("please_login_from_portal"))
            return redirect(portal_url)
        end
    end
end

-- Redirected urls

function detect_redirection(redirect_url)
    if string.starts(redirect_url, "http://")
    or string.starts(redirect_url, "https://") then
        return redirect(redirect_url)
    elseif  string.starts(redirect_url, "/") then
        return redirect(ngx.var.scheme.."://"..ngx.var.host..redirect_url)
    else
        return redirect(ngx.var.scheme.."://"..redirect_url)
    end
end

if conf["redirected_urls"] then
    for url, redirect_url in pairs(conf["redirected_urls"]) do
        if url == ngx.var.host..ngx.var.uri
        or url == ngx.var.scheme.."://"..ngx.var.host..ngx.var.uri
        or url == ngx.var.uri then
            detect_redirection(redirect_url)
        end
    end
end

if conf["redirected_regex"] then
    for regex, redirect_url in pairs(conf["redirected_regex"]) do
        if string.match(ngx.var.host..ngx.var.uri, regex)
        or string.match(ngx.var.scheme.."://"..ngx.var.host..ngx.var.uri, regex)
        or string.match(ngx.var.uri, regex) then
            detect_redirection(redirect_url)
        end
    end
end

-- URL that must be protected
function is_protected()
    if not conf["protected_urls"] then
        conf["protected_urls"] = {}
    end
    if not conf["protected_regex"] then
        conf["protected_regex"] = {}
    end

    for _, url in ipairs(conf["protected_urls"]) do
        if string.starts(ngx.var.host..ngx.var.uri, url)
        or string.starts(ngx.var.uri, url) then
            return true
        end
    end
    for _, regex in ipairs(conf["protected_regex"]) do
        if string.match(ngx.var.host..ngx.var.uri, regex)
        or string.match(ngx.var.uri, regex) then
            return true
        end
    end

    return false
end

-- Skipped urls
--  i.e. http://mydomain.org/no_protection/

if conf["skipped_urls"] then
    for _, url in ipairs(conf["skipped_urls"]) do
        if (string.starts(ngx.var.host..ngx.var.uri, url)
        or  string.starts(ngx.var.uri, url))
        and not is_protected() then
            return pass()
        end
    end
end

if conf["skipped_regex"] then
    for _, regex in ipairs(conf["skipped_regex"]) do
        if (string.match(ngx.var.host..ngx.var.uri, regex)
        or  string.match(ngx.var.uri, regex))
        and not is_protected() then
            return pass()
        end
    end
end



-- Unprotected urls
--  i.e. http://mydomain.org/no_protection+headers/

if conf["unprotected_urls"] then
    for _, url in ipairs(conf["unprotected_urls"]) do
        if (string.starts(ngx.var.host..ngx.var.uri, url)
        or  string.starts(ngx.var.uri, url))
        and not is_protected() then
            if is_logged_in() then
                set_headers()
            end
            return pass()
        end
    end
end

if conf["unprotected_regex"] then
    for _, regex in ipairs(conf["unprotected_regex"]) do
        if (string.match(ngx.var.host..ngx.var.uri, regex)
        or  string.match(ngx.var.uri, regex))
        and not is_protected() then
            if is_logged_in() then
                set_headers()
            end
            return pass()
        end
    end
end

-- Cookie validation
--

if is_logged_in() then
    if string.match(ngx.var.uri, "^/ynhpanel.js$") then
        serve("/yunohost/sso/assets/js/ynhpanel.js")
    end
    if string.match(ngx.var.uri, "^/ynhpanel.css$") then
        serve("/yunohost/sso/assets/css/ynhpanel.css")
    end
    if string.match(ngx.var.uri, "^/ynhpanel.json$") then
        serve("/yunohost/sso/assets/js/ynhpanel.json")
    end
    if not has_access() then
        return redirect(portal_url)
    end
    set_headers()
    return pass()
end


-- Login with HTTP Auth if credentials are brought
--

local auth_header = ngx.req.get_headers()["Authorization"]
if auth_header then
    _, _, b64_cred = string.find(auth_header, "^Basic%s+(.+)$")
    _, _, user, password = string.find(ngx.decode_base64(b64_cred), "^(.+):(.+)$")
    user = authenticate(user, password)
    if user then
        set_headers(user)
        return pass()
    end
end

-- Else redirect to portal
--

flash("info", t("please_login"))
local back_url = ngx.var.scheme .. "://" .. ngx.var.host .. ngx.var.uri .. uri_args_string()
return redirect(portal_url.."?r="..ngx.encode_base64(back_url))