views.py

__author__ = "Gina Häußge <osd@foosel.net>"
__license__ = "GNU Affero General Public License http://www.gnu.org/licenses/agpl.html"
__copyright__ = "Copyright (C) 2015 The OctoPrint Project - Released under terms of the AGPLv3 License"

import base64
import datetime
import logging
import os
import re
from collections import defaultdict

from flask import (
    Response,
    abort,
    g,
    make_response,
    redirect,
    render_template,
    request,
    send_from_directory,
    url_for,
)

import octoprint.plugin
from octoprint.access.permissions import OctoPrintPermission, Permissions
from octoprint.filemanager import full_extension_tree, get_all_extensions
from octoprint.server import (  # noqa: F401
    BRANCH,
    DISPLAY_VERSION,
    LOCALES,
    NOT_MODIFIED,
    VERSION,
    app,
    debug,
    gettext,
    groupManager,
    pluginManager,
    preemptiveCache,
    userManager,
)
from octoprint.server.util import (
    has_permissions,
    require_login_with,
    validate_local_redirect,
)
from octoprint.settings import settings
from octoprint.util import sv, to_bytes, to_unicode
from octoprint.util.version import get_python_version_string

from . import util

_logger = logging.getLogger(__name__)

_templates = {}
_plugin_names = None
_plugin_vars = None

_valid_id_re = re.compile("[a-z_]+")
_valid_div_re = re.compile("[a-zA-Z_-]+")


def _preemptive_unless(base_url=None, additional_unless=None):
    if base_url is None:
        base_url = request.url_root

    disabled_for_root = (
        not settings().getBoolean(["devel", "cache", "preemptive"])
        or base_url in settings().get(["server", "preemptiveCache", "exceptions"])
        or not (base_url.startswith("http://") or base_url.startswith("https://"))
    )

    recording_disabled = request.headers.get("X-Preemptive-Recording", "no") == "yes"

    if callable(additional_unless):
        return recording_disabled or disabled_for_root or additional_unless()
    else:
        return recording_disabled or disabled_for_root


def _preemptive_data(
    key, path=None, base_url=None, data=None, additional_request_data=None
):
    if path is None:
        path = request.path
    if base_url is None:
        base_url = request.url_root

    d = {
        "path": path,
        "base_url": base_url,
        "query_string": "l10n={}".format(g.locale.language if g.locale else "en"),
    }

    if key != "_default":
        d["plugin"] = key

    # add data if we have any
    if data is not None:
        try:
            if callable(data):
                data = data()
            if data:
                if "query_string" in data:
                    data["query_string"] = "l10n={}&{}".format(
                        g.locale.language, data["query_string"]
                    )
                d.update(data)
        except Exception:
            _logger.exception(
                f"Error collecting data for preemptive cache from plugin {key}"
            )

    # add additional request data if we have any
    if callable(additional_request_data):
        try:
            ard = additional_request_data()
            if ard:
                d.update({"_additional_request_data": ard})
        except Exception:
            _logger.exception(
                "Error retrieving additional data for preemptive cache from plugin {}".format(
                    key
                )
            )

    return d


def _cache_key(ui, url=None, locale=None, additional_key_data=None):
    if url is None:
        url = request.base_url
    if locale is None:
        locale = g.locale.language if g.locale else "en"

    k = f"ui:{ui}:{url}:{locale}"
    if callable(additional_key_data):
        try:
            ak = additional_key_data()
            if ak:
                # we have some additional key components, let's attach them
                if not isinstance(ak, (list, tuple)):
                    ak = [ak]
                k = "{}:{}".format(k, ":".join(ak))
        except Exception:
            _logger.exception(
                "Error while trying to retrieve additional cache key parts for ui {}".format(
                    ui
                )
            )
    return k


def _valid_status_for_cache(status_code):
    return 200 <= status_code < 400


def _add_additional_assets(hook):
    result = []
    for name, hook in pluginManager.get_hooks(hook).items():
        try:
            assets = hook()
            if isinstance(assets, (tuple, list)):
                result += assets
        except Exception:
            _logger.exception(
                f"Error fetching theming CSS to include from plugin {name}",
                extra={"plugin": name},
            )
    return result


@app.route("/login")
@app.route("/login/")
def login():
    from flask_login import current_user

    default_redirect_url = request.script_root + url_for("index")
    redirect_url = request.args.get("redirect", default_redirect_url)
    allowed_paths = [url_for("index"), url_for("recovery")]

    if not validate_local_redirect(redirect_url, allowed_paths):
        _logger.warning(
            f"Got an invalid redirect URL with the login attempt, misconfiguration or attack attempt: {redirect_url}"
        )
        redirect_url = default_redirect_url

    permissions = sorted(
        filter(
            lambda x: x is not None and isinstance(x, OctoPrintPermission),
            map(
                lambda x: getattr(Permissions, x.strip()),
                request.args.get("permissions", "").split(","),
            ),
        ),
        key=lambda x: x.get_name(),
    )
    if not permissions:
        permissions = [Permissions.STATUS, Permissions.SETTINGS_READ]

    user_id = request.args.get("user_id", "")

    if (not user_id or current_user.get_id() == user_id) and has_permissions(
        *permissions
    ):
        return redirect(redirect_url)

    render_kwargs = {
        "theming": [],
        "redirect_url": redirect_url,
        "permission_names": map(lambda x: x.get_name(), permissions),
        "user_id": user_id,
        "logged_in": not current_user.is_anonymous,
    }

    try:
        additional_assets = _add_additional_assets("octoprint.theming.login")

        # backwards compatibility to forcelogin & loginui plugins which were replaced by this built-in dialog
        additional_assets += _add_additional_assets("octoprint.plugin.forcelogin.theming")
        additional_assets += _add_additional_assets("octoprint.plugin.loginui.theming")

        render_kwargs.update({"theming": additional_assets})
    except Exception:
        _logger.exception("Error processing theming CSS, ignoring")

    return render_template("login.jinja2", **render_kwargs)


@app.route("/recovery")
@app.route("/recovery/")
def recovery():
    response = require_login_with(permissions=[Permissions.ADMIN])
    if response:
        return response

    render_kwargs = {"theming": []}

    try:
        additional_assets = _add_additional_assets("octoprint.theming.recovery")
        render_kwargs.update({"theming": additional_assets})
    except Exception:
        _logger.exception("Error processing theming CSS, ignoring")

    try:
        from octoprint.plugins.backup import MAX_UPLOAD_SIZE
        from octoprint.util import get_formatted_size

        render_kwargs.update(
            {
                "plugin_backup_max_upload_size": MAX_UPLOAD_SIZE,
                "plugin_backup_max_upload_size_str": get_formatted_size(MAX_UPLOAD_SIZE),
            }
        )
    except Exception:
        _logger.exception("Error adding backup upload size info, ignoring")

    return render_template("recovery.jinja2", **render_kwargs)


@app.route("/cached.gif")
def in_cache():
    url = request.base_url.replace("/cached.gif", "/")
    path = request.path.replace("/cached.gif", "/")
    base_url = request.url_root

    # select view from plugins and fall back on default view if no plugin will handle it
    ui_plugins = pluginManager.get_implementations(
        octoprint.plugin.UiPlugin, sorting_context="UiPlugin.on_ui_render"
    )
    for plugin in ui_plugins:
        try:
            if plugin.will_handle_ui(request):
                ui = plugin._identifier
                key = _cache_key(
                    plugin._identifier,
                    url=url,
                    additional_key_data=plugin.get_ui_additional_key_data_for_cache,
                )
                unless = _preemptive_unless(
                    url,
                    additional_unless=plugin.get_ui_preemptive_caching_additional_unless,
                )
                data = _preemptive_data(
                    plugin._identifier,
                    path=path,
                    base_url=base_url,
                    data=plugin.get_ui_data_for_preemptive_caching,
                    additional_request_data=plugin.get_ui_additional_request_data_for_preemptive_caching,
                )
                break
        except Exception:
            _logger.exception(
                f"Error while calling plugin {plugin._identifier}, skipping it",
                extra={"plugin": plugin._identifier},
            )
    else:
        ui = "_default"
        key = _cache_key("_default", url=url)
        unless = _preemptive_unless(url)
        data = _preemptive_data("_default", path=path, base_url=base_url)

    response = make_response(
        bytes(
            base64.b64decode("R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7")
        )
    )
    response.headers["Content-Type"] = "image/gif"

    if unless or not preemptiveCache.has_record(data, root=path):
        _logger.info(
            "Preemptive cache not active for path {}, ui {} and data {!r}, signaling as cached".format(
                path, ui, data
            )
        )
        return response
    elif util.flask.is_in_cache(key):
        _logger.info(f"Found path {path} in cache (key: {key}), signaling as cached")
        return response
    elif util.flask.is_cache_bypassed(key):
        _logger.info(
            "Path {} was bypassed from cache (key: {}), signaling as cached".format(
                path, key
            )
        )
        return response
    else:
        _logger.debug(f"Path {path} not yet cached (key: {key}), signaling as missing")
        return abort(404)


@app.route("/")
def index():
    from octoprint.server import connectivityChecker, printer

    global _templates, _plugin_names, _plugin_vars

    preemptive_cache_enabled = settings().getBoolean(["devel", "cache", "preemptive"])

    locale = g.locale.language if g.locale else "en"

    # helper to check if wizards are active
    def wizard_active(templates):
        return templates is not None and bool(templates["wizard"]["order"])

    # we force a refresh if the client forces one and we are not printing or if we have wizards cached
    client_refresh = util.flask.cache_check_headers()
    request_refresh = "_refresh" in request.values
    printing = printer.is_printing()
    if client_refresh and printing:
        logging.getLogger(__name__).warning(
            "Client requested cache refresh via cache-control headers but we are printing. "
            "Not invalidating caches due to resource limitation. Append ?_refresh=true to "
            "the URL if you absolutely require a refresh now"
        )
    client_refresh = client_refresh and not printing
    force_refresh = (
        client_refresh or request_refresh or wizard_active(_templates.get(locale))
    )

    # if we need to refresh our template cache or it's not yet set, process it
    fetch_template_data(refresh=force_refresh)

    now = datetime.datetime.utcnow()

    enable_timelapse = settings().getBoolean(["webcam", "timelapseEnabled"])
    enable_loading_animation = settings().getBoolean(["devel", "showLoadingAnimation"])
    enable_sd_support = settings().get(["feature", "sdSupport"])
    enable_webcam = settings().getBoolean(["webcam", "webcamEnabled"]) and bool(
        settings().get(["webcam", "stream"])
    )
    enable_temperature_graph = settings().get(["feature", "temperatureGraph"])
    sockjs_connect_timeout = settings().getInt(["devel", "sockJsConnectTimeout"])

    def default_template_filter(template_type, template_key):
        if template_type == "tab":
            return template_key != "timelapse" or enable_timelapse
        else:
            return True

    default_additional_etag = [
        enable_timelapse,
        enable_loading_animation,
        enable_sd_support,
        enable_webcam,
        enable_temperature_graph,
        sockjs_connect_timeout,
        connectivityChecker.online,
        wizard_active(_templates.get(locale)),
    ] + sorted(
        "{}:{}".format(to_unicode(k, errors="replace"), to_unicode(v, errors="replace"))
        for k, v in _plugin_vars.items()
    )

    def get_preemptively_cached_view(
        key, view, data=None, additional_request_data=None, additional_unless=None
    ):
        if (data is None and additional_request_data is None) or g.locale is None:
            return view

        d = _preemptive_data(
            key, data=data, additional_request_data=additional_request_data
        )

        def unless():
            return _preemptive_unless(
                base_url=request.url_root, additional_unless=additional_unless
            )

        # finally decorate our view
        return util.flask.preemptively_cached(
            cache=preemptiveCache, data=d, unless=unless
        )(view)

    def get_cached_view(
        key,
        view,
        additional_key_data=None,
        additional_files=None,
        additional_etag=None,
        custom_files=None,
        custom_etag=None,
        custom_lastmodified=None,
    ):
        if additional_etag is None:
            additional_etag = []

        def cache_key():
            return _cache_key(key, additional_key_data=additional_key_data)

        def collect_files():
            if callable(custom_files):
                try:
                    files = custom_files()
                    if files:
                        return files
                except Exception:
                    _logger.exception(
                        "Error while trying to retrieve tracked files for plugin {}".format(
                            key
                        )
                    )

            files = _get_all_templates()
            files += _get_all_assets()
            files += _get_all_translationfiles(
                g.locale.language if g.locale else "en", "messages"
            )

            if callable(additional_files):
                try:
                    af = additional_files()
                    if af:
                        files += af
                except Exception:
                    _logger.exception(
                        "Error while trying to retrieve additional tracked files for plugin {}".format(
                            key
                        )
                    )

            return sorted(set(files))

        def compute_lastmodified(files):
            if callable(custom_lastmodified):
                try:
                    lastmodified = custom_lastmodified()
                    if lastmodified:
                        return lastmodified
                except Exception:
                    _logger.exception(
                        "Error while trying to retrieve custom LastModified value for plugin {}".format(
                            key
                        )
                    )

            return _compute_date(files)

        def compute_etag(files, lastmodified, additional=None):
            if callable(custom_etag):
                try:
                    etag = custom_etag()
                    if etag:
                        return etag
                except Exception:
                    _logger.exception(
                        "Error while trying to retrieve custom ETag value for plugin {}".format(
                            key
                        )
                    )

            if lastmodified and not isinstance(lastmodified, str):
                from werkzeug.http import http_date

                lastmodified = http_date(lastmodified)
            if additional is None:
                additional = []

            import hashlib

            hash = hashlib.sha1()

            def hash_update(value):
                hash.update(to_bytes(value, encoding="utf-8", errors="replace"))

            hash_update(octoprint.__version__)
            hash_update(get_python_version_string())
            hash_update(",".join(sorted(files)))
            if lastmodified:
                hash_update(lastmodified)
            for add in additional:
                hash_update(add)
            return hash.hexdigest()

        current_files = collect_files()
        current_lastmodified = compute_lastmodified(current_files)
        current_etag = compute_etag(
            files=current_files,
            lastmodified=current_lastmodified,
            additional=[cache_key()] + additional_etag,
        )

        def check_etag_and_lastmodified():
            lastmodified_ok = util.flask.check_lastmodified(current_lastmodified)
            etag_ok = util.flask.check_etag(current_etag)
            return lastmodified_ok and etag_ok

        def validate_cache(cached):
            return force_refresh or (current_etag != cached.get_etag()[0])

        decorated_view = view
        decorated_view = util.flask.lastmodified(lambda _: current_lastmodified)(
            decorated_view
        )
        decorated_view = util.flask.etagged(lambda _: current_etag)(decorated_view)
        decorated_view = util.flask.cached(
            timeout=-1,
            refreshif=validate_cache,
            key=cache_key,
            unless_response=lambda response: util.flask.cache_check_response_headers(
                response
            )
            or util.flask.cache_check_status_code(response, _valid_status_for_cache),
        )(decorated_view)
        decorated_view = util.flask.with_client_revalidation(decorated_view)
        decorated_view = util.flask.conditional(
            check_etag_and_lastmodified, NOT_MODIFIED
        )(decorated_view)
        return decorated_view

    def plugin_view(p):
        cached = get_cached_view(
            p._identifier,
            p.on_ui_render,
            additional_key_data=p.get_ui_additional_key_data_for_cache,
            additional_files=p.get_ui_additional_tracked_files,
            custom_files=p.get_ui_custom_tracked_files,
            custom_etag=p.get_ui_custom_etag,
            custom_lastmodified=p.get_ui_custom_lastmodified,
            additional_etag=p.get_ui_additional_etag(default_additional_etag),
        )

        if preemptive_cache_enabled and p.get_ui_preemptive_caching_enabled():
            view = get_preemptively_cached_view(
                p._identifier,
                cached,
                p.get_ui_data_for_preemptive_caching,
                p.get_ui_additional_request_data_for_preemptive_caching,
                p.get_ui_preemptive_caching_additional_unless,
            )
        else:
            view = cached

        template_filter = p.get_ui_custom_template_filter(default_template_filter)
        if template_filter is not None and callable(template_filter):
            filtered_templates = _filter_templates(_templates[locale], template_filter)
        else:
            filtered_templates = _templates[locale]

        render_kwargs = _get_render_kwargs(
            filtered_templates, _plugin_names, _plugin_vars, now
        )

        return view(now, request, render_kwargs)

    def default_view():
        filtered_templates = _filter_templates(
            _templates[locale], default_template_filter
        )

        wizard = wizard_active(filtered_templates)
        accesscontrol_active = userManager.has_been_customized()

        render_kwargs = _get_render_kwargs(
            filtered_templates, _plugin_names, _plugin_vars, now
        )
        render_kwargs.update(
            {
                "enableWebcam": enable_webcam,
                "enableTemperatureGraph": enable_temperature_graph,
                "enableAccessControl": True,
                "accessControlActive": accesscontrol_active,
                "enableLoadingAnimation": enable_loading_animation,
                "enableSdSupport": enable_sd_support,
                "sockJsConnectTimeout": sockjs_connect_timeout * 1000,
                "wizard": wizard,
                "online": connectivityChecker.online,
                "now": now,
            }
        )

        # no plugin took an interest, we'll use the default UI
        def make_default_ui():
            r = make_response(render_template("index.jinja2", **render_kwargs))
            if wizard:
                # if we have active wizard dialogs, set non caching headers
                r = util.flask.add_non_caching_response_headers(r)
            return r

        cached = get_cached_view(
            "_default", make_default_ui, additional_etag=default_additional_etag
        )
        preemptively_cached = get_preemptively_cached_view("_default", cached, {}, {})
        return preemptively_cached()

    default_permissions = [Permissions.STATUS, Permissions.SETTINGS_READ]

    response = None

    forced_view = request.headers.get("X-Force-View", None)

    if forced_view:
        # we have view forced by the preemptive cache
        _logger.debug(f"Forcing rendering of view {forced_view}")
        if forced_view != "_default":
            plugin = pluginManager.get_plugin_info(forced_view, require_enabled=True)
            if plugin is not None and isinstance(
                plugin.implementation, octoprint.plugin.UiPlugin
            ):
                permissions = plugin.implementation.get_ui_permissions()
                response = require_login_with(permissions=permissions)
                if not response:
                    response = plugin_view(plugin.implementation)
                    if _logger.isEnabledFor(logging.DEBUG) and isinstance(
                        response, Response
                    ):
                        response.headers[
                            "X-Ui-Plugin"
                        ] = plugin.implementation._identifier
        else:
            response = require_login_with(permissions=default_permissions)
            if not response:
                response = default_view()
                if _logger.isEnabledFor(logging.DEBUG) and isinstance(response, Response):
                    response.headers["X-Ui-Plugin"] = "_default"

    else:
        # select view from plugins and fall back on default view if no plugin will handle it
        ui_plugins = pluginManager.get_implementations(
            octoprint.plugin.UiPlugin, sorting_context="UiPlugin.on_ui_render"
        )
        for plugin in ui_plugins:
            try:
                if plugin.will_handle_ui(request):
                    # plugin claims responsibility, let it render the UI
                    permissions = plugin.get_ui_permissions()
                    response = require_login_with(permissions=permissions)
                    if not response:
                        response = plugin_view(plugin)
                        if response is not None:
                            if _logger.isEnabledFor(logging.DEBUG) and isinstance(
                                response, Response
                            ):
                                response.headers["X-Ui-Plugin"] = plugin._identifier
                            break
                        else:
                            _logger.warning(
                                "UiPlugin {} returned an empty response".format(
                                    plugin._identifier
                                )
                            )
            except Exception:
                _logger.exception(
                    "Error while calling plugin {}, skipping it".format(
                        plugin._identifier
                    ),
                    extra={"plugin": plugin._identifier},
                )
        else:
            response = require_login_with(permissions=default_permissions)
            if not response:
                response = default_view()
                if _logger.isEnabledFor(logging.DEBUG) and isinstance(response, Response):
                    response.headers["X-Ui-Plugin"] = "_default"

    if response is None:
        return abort(404)
    return response


def _get_render_kwargs(templates, plugin_names, plugin_vars, now):
    global _logger

    # ~~ a bunch of settings

    first_run = settings().getBoolean(["server", "firstRun"])

    locales = {}
    for loc in LOCALES:
        try:
            locales[loc.language] = {
                "language": loc.language,
                "display": loc.display_name,
                "english": loc.english_name,
            }
        except Exception:
            _logger.exception("Error while collecting available locales")

    permissions = [permission.as_dict() for permission in Permissions.all()]
    filetypes = list(sorted(full_extension_tree().keys()))
    extensions = list(map(lambda ext: f".{ext}", get_all_extensions()))

    # ~~ prepare full set of template vars for rendering

    render_kwargs = {
        "debug": debug,
        "firstRun": first_run,
        "version": {"number": VERSION, "display": DISPLAY_VERSION, "branch": BRANCH},
        "python_version": get_python_version_string(),
        "templates": templates,
        "pluginNames": plugin_names,
        "locales": locales,
        "permissions": permissions,
        "supportedFiletypes": filetypes,
        "supportedExtensions": extensions,
    }
    render_kwargs.update(plugin_vars)

    return render_kwargs


def fetch_template_data(refresh=False):
    global _templates, _plugin_names, _plugin_vars

    locale = g.locale.language if g.locale else "en"

    if (
        not refresh
        and _templates.get(locale) is not None
        and _plugin_names is not None
        and _plugin_vars is not None
    ):
        return _templates[locale], _plugin_names, _plugin_vars

    first_run = settings().getBoolean(["server", "firstRun"])

    ##~~ prepare templates

    templates = defaultdict(lambda: {"order": [], "entries": {}})

    # rules for transforming template configs to template entries
    template_rules = {
        "navbar": {
            "div": lambda x: "navbar_plugin_" + x,
            "template": lambda x: x + "_navbar.jinja2",
            "to_entry": lambda data: data,
        },
        "sidebar": {
            "div": lambda x: "sidebar_plugin_" + x,
            "template": lambda x: x + "_sidebar.jinja2",
            "to_entry": lambda data: (data["name"], data),
        },
        "tab": {
            "div": lambda x: "tab_plugin_" + x,
            "template": lambda x: x + "_tab.jinja2",
            "to_entry": lambda data: (data["name"], data),
        },
        "settings": {
            "div": lambda x: "settings_plugin_" + x,
            "template": lambda x: x + "_settings.jinja2",
            "to_entry": lambda data: (data["name"], data),
        },
        "usersettings": {
            "div": lambda x: "usersettings_plugin_" + x,
            "template": lambda x: x + "_usersettings.jinja2",
            "to_entry": lambda data: (data["name"], data),
        },
        "wizard": {
            "div": lambda x: "wizard_plugin_" + x,
            "template": lambda x: x + "_wizard.jinja2",
            "to_entry": lambda data: (data["name"], data),
        },
        "about": {
            "div": lambda x: "about_plugin_" + x,
            "template": lambda x: x + "_about.jinja2",
            "to_entry": lambda data: (data["name"], data),
        },
        "generic": {"template": lambda x: x + ".jinja2", "to_entry": lambda data: data},
    }

    # sorting orders
    def wizard_key_extractor(d, k):
        if d[1].get("_key", None) == "plugin_corewizard_acl":
            # Ultra special case - we MUST always have the ACL wizard first since otherwise any steps that follow and
            # that require to access APIs to function will run into errors since those APIs won't work before ACL
            # has been configured. See also #2140
            return f"0:{to_unicode(d[0])}"
        elif d[1].get("mandatory", False):
            # Other mandatory steps come before the optional ones
            return f"1:{to_unicode(d[0])}"
        else:
            # Finally everything else
            return f"2:{to_unicode(d[0])}"

    template_sorting = {
        "navbar": {"add": "prepend", "key": None},
        "sidebar": {"add": "append", "key": "name"},
        "tab": {"add": "append", "key": "name"},
        "settings": {
            "add": "custom_append",
            "key": "name",
            "custom_add_entries": lambda missing: {
                "section_plugins": (gettext("Plugins"), None)
            },
            "custom_add_order": lambda missing: ["section_plugins"] + missing,
        },
        "usersettings": {"add": "append", "key": "name"},
        "wizard": {"add": "append", "key": "name", "key_extractor": wizard_key_extractor},
        "about": {"add": "append", "key": "name"},
        "generic": {"add": "append", "key": None},
    }

    hooks = pluginManager.get_hooks("octoprint.ui.web.templatetypes")
    for name, hook in hooks.items():
        try:
            result = hook(dict(template_sorting), dict(template_rules))
        except Exception:
            _logger.exception(
                f"Error while retrieving custom template type "
                f"definitions from plugin {name}",
                extra={"plugin": name},
            )
        else:
            if not isinstance(result, list):
                continue

            for entry in result:
                if not isinstance(entry, tuple) or not len(entry) == 3:
                    continue

                key, order, rule = entry

                # order defaults
                if "add" not in order:
                    order["add"] = "prepend"
                if "key" not in order:
                    order["key"] = "name"

                # rule defaults
                if "div" not in rule:
                    # default div name: <hook plugin>_<template_key>_plugin_<plugin>
                    div = f"{name}_{key}_plugin_"
                    rule["div"] = lambda x: div + x
                if "template" not in rule:
                    # default template name: <plugin>_plugin_<hook plugin>_<template key>.jinja2
                    template = f"_plugin_{name}_{key}.jinja2"
                    rule["template"] = lambda x: x + template
                if "to_entry" not in rule:
                    # default to_entry assumes existing "name" property to be used as label for 2-tuple entry data structure (<name>, <properties>)
                    rule["to_entry"] = lambda data: (data["name"], data)

                template_rules["plugin_" + name + "_" + key] = rule
                template_sorting["plugin_" + name + "_" + key] = order
    template_types = list(template_rules.keys())

    # navbar

    templates["navbar"]["entries"] = {
        "offlineindicator": {
            "template": "navbar/offlineindicator.jinja2",
            "_div": "navbar_offlineindicator",
            "custom_bindings": False,
        },
        "settings": {
            "template": "navbar/settings.jinja2",
            "_div": "navbar_settings",
            "styles": ["display: none;"],
            "data_bind": "visible: loginState.hasPermissionKo(access.permissions.SETTINGS)",
        },
        "systemmenu": {
            "template": "navbar/systemmenu.jinja2",
            "_div": "navbar_systemmenu",
            "classes": ["dropdown"],
            "styles": ["display: none;"],
            "data_bind": "visible: loginState.hasPermissionKo(access.permissions.SYSTEM)",
            "custom_bindings": False,
        },
        "login": {
            "template": "navbar/login.jinja2",
            "_div": "navbar_login",
            "classes": ["dropdown"],
            "custom_bindings": False,
        },
    }

    # sidebar

    templates["sidebar"]["entries"] = {
        "connection": (
            gettext("Connection"),
            {
                "template": "sidebar/connection.jinja2",
                "_div": "connection",
                "icon": "signal",
                "styles_wrapper": ["display: none;"],
                "data_bind": "visible: loginState.hasPermissionKo(access.permissions.CONNECTION)",
                "template_header": "sidebar/connection_header.jinja2",
            },
        ),
        "state": (
            gettext("State"),
            {
                "template": "sidebar/state.jinja2",
                "_div": "state",
                "icon": "info-circle",
                "styles_wrapper": ["display: none;"],
                "data_bind": "visible: loginState.hasPermissionKo(access.permissions.STATUS)",
            },
        ),
        "files": (
            gettext("Files"),
            {
                "template": "sidebar/files.jinja2",
                "_div": "files",
                "icon": "list",
                "classes_content": ["overflow_visible"],
                "template_header": "sidebar/files_header.jinja2",
                "styles_wrapper": ["display: none;"],
                "data_bind": "visible: loginState.hasPermissionKo(access.permissions.FILES_LIST)",
            },
        ),
    }

    # tabs

    templates["tab"]["entries"] = {
        "temperature": (
            gettext("Temperature"),
            {
                "template": "tabs/temperature.jinja2",
                "_div": "temp",
                "styles": ["display: none;"],
                "data_bind": "visible: loginState.hasAnyPermissionKo(access.permissions.STATUS, access.permissions.CONTROL)() && visible()",
            },
        ),
        "control": (
            gettext("Control"),
            {
                "template": "tabs/control.jinja2",
                "_div": "control",
                "styles": ["display: none;"],
                "data_bind": "visible: loginState.hasAnyPermissionKo(access.permissions.WEBCAM, access.permissions.CONTROL)",
            },
        ),
        "terminal": (
            gettext("Terminal"),
            {
                "template": "tabs/terminal.jinja2",
                "_div": "term",
                "styles": ["display: none;"],
                "data_bind": "visible: loginState.hasPermissionKo(access.permissions.MONITOR_TERMINAL)",
            },
        ),
        "timelapse": (
            gettext("Timelapse"),
            {
                "template": "tabs/timelapse.jinja2",
                "_div": "timelapse",
                "styles": ["display: none;"],
                "data_bind": "visible: loginState.hasPermissionKo(access.permissions.TIMELAPSE_LIST)",
            },
        ),
    }

    # settings dialog

    templates["settings"]["entries"] = {
        "section_printer": (gettext("Printer"), None),
        "serial": (
            gettext("Serial Connection"),
            {
                "template": "dialogs/settings/serialconnection.jinja2",
                "_div": "settings_serialConnection",
                "custom_bindings": False,
            },
        ),
        "printerprofiles": (
            gettext("Printer Profiles"),
            {
                "template": "dialogs/settings/printerprofiles.jinja2",
                "_div": "settings_printerProfiles",
                "custom_bindings": False,
            },
        ),
        "temperatures": (
            gettext("Temperatures"),
            {
                "template": "dialogs/settings/temperatures.jinja2",
                "_div": "settings_temperature",
                "custom_bindings": False,
            },
        ),
        "terminalfilters": (
            gettext("Terminal Filters"),
            {
                "template": "dialogs/settings/terminalfilters.jinja2",
                "_div": "settings_terminalFilters",
                "custom_bindings": False,
            },
        ),
        "gcodescripts": (
            gettext("GCODE Scripts"),
            {
                "template": "dialogs/settings/gcodescripts.jinja2",
                "_div": "settings_gcodeScripts",
                "custom_bindings": False,
            },
        ),
        "section_features": (gettext("Features"), None),
        "features": (
            gettext("Features"),
            {
                "template": "dialogs/settings/features.jinja2",
                "_div": "settings_features",
                "custom_bindings": False,
            },
        ),
        "webcam": (
            gettext("Webcam & Timelapse"),
            {
                "template": "dialogs/settings/webcam.jinja2",
                "_div": "settings_webcam",
                "custom_bindings": False,
            },
        ),
        "api": (
            gettext("API"),
            {
                "template": "dialogs/settings/api.jinja2",
                "_div": "settings_api",
                "custom_bindings": False,
            },
        ),
        "section_octoprint": (gettext("OctoPrint"), None),
        "accesscontrol": (
            gettext("Access Control"),
            {
                "template": "dialogs/settings/accesscontrol.jinja2",
                "_div": "settings_users",
                "custom_bindings": False,
            },
        ),
        "folders": (
            gettext("Folders"),
            {
                "template": "dialogs/settings/folders.jinja2",
                "_div": "settings_folders",
                "custom_bindings": False,
            },
        ),
        "appearance": (
            gettext("Appearance"),
            {
                "template": "dialogs/settings/appearance.jinja2",
                "_div": "settings_appearance",
                "custom_bindings": False,
            },
        ),
        "server": (
            gettext("Server"),
            {
                "template": "dialogs/settings/server.jinja2",
                "_div": "settings_server",
                "custom_bindings": False,
            },
        ),
    }

    # user settings dialog

    templates["usersettings"]["entries"] = {
        "access": (
            gettext("Access"),
            {
                "template": "dialogs/usersettings/access.jinja2",
                "_div": "usersettings_access",
                "custom_bindings": False,
            },
        ),
        "interface": (
            gettext("Interface"),
            {
                "template": "dialogs/usersettings/interface.jinja2",
                "_div": "usersettings_interface",
                "custom_bindings": False,
            },
        ),
    }

    # wizard

    if first_run:

        def custom_insert_order(existing, missing):
            if "firstrunstart" in missing:
                missing.remove("firstrunstart")
            if "firstrunend" in missing:
                missing.remove("firstrunend")

            return ["firstrunstart"] + existing + missing + ["firstrunend"]

        template_sorting["wizard"].update(
            {
                "add": "custom_insert",
                "custom_insert_entries": lambda missing: {},
                "custom_insert_order": custom_insert_order,
            }
        )
        templates["wizard"]["entries"] = {
            "firstrunstart": (
                gettext("Start"),
                {
                    "template": "dialogs/wizard/firstrun_start.jinja2",
                    "_div": "wizard_firstrun_start",
                },
            ),
            "firstrunend": (
                gettext("Finish"),
                {
                    "template": "dialogs/wizard/firstrun_end.jinja2",
                    "_div": "wizard_firstrun_end",
                },
            ),
        }

    # about dialog

    templates["about"]["entries"] = {
        "about": (
            "About OctoPrint",
            {
                "template": "dialogs/about/about.jinja2",
                "_div": "about_about",
                "custom_bindings": False,
            },
        ),
        "license": (
            "OctoPrint License",
            {
                "template": "dialogs/about/license.jinja2",
                "_div": "about_license",
                "custom_bindings": False,
            },
        ),
        "thirdparty": (
            "Third Party Licenses",
            {
                "template": "dialogs/about/thirdparty.jinja2",
                "_div": "about_thirdparty",
                "custom_bindings": False,
            },
        ),
        "authors": (
            "Authors",
            {
                "template": "dialogs/about/authors.jinja2",
                "_div": "about_authors",
                "custom_bindings": False,
            },
        ),
        "supporters": (
            "Supporters",
            {
                "template": "dialogs/about/supporters.jinja2",
                "_div": "about_sponsors",
                "custom_bindings": False,
            },
        ),
        "systeminfo": (
            "System Information",
            {
                "template": "dialogs/about/systeminfo.jinja2",
                "_div": "about_systeminfo",
                "custom_bindings": False,
                "styles": ["display: none;"],
                "data_bind": "visible: loginState.hasPermissionKo(access.permissions.SYSTEM)",
            },
        ),
    }

    # extract data from template plugins

    template_plugins = pluginManager.get_implementations(octoprint.plugin.TemplatePlugin)

    plugin_vars = {}
    plugin_names = set()
    plugin_aliases = {}
    seen_wizards = settings().get(["server", "seenWizards"]) if not first_run else {}
    for implementation in template_plugins:
        name = implementation._identifier
        plugin_names.add(name)
        wizard_required = False
        wizard_ignored = False

        try:
            vars = implementation.get_template_vars()
            configs = implementation.get_template_configs()
            if isinstance(implementation, octoprint.plugin.WizardPlugin):
                wizard_required = implementation.is_wizard_required()
                wizard_ignored = octoprint.plugin.WizardPlugin.is_wizard_ignored(
                    seen_wizards, implementation
                )
        except Exception:
            _logger.exception(
                "Error while retrieving template data for plugin {}, ignoring it".format(
                    name
                ),
                extra={"plugin": name},
            )
            continue

        if not isinstance(vars, dict):
            vars = {}
        if not isinstance(configs, (list, tuple)):
            configs = []

        for var_name, var_value in vars.items():
            plugin_vars["plugin_" + name + "_" + var_name] = var_value

        try:
            includes = _process_template_configs(
                name, implementation, configs, template_rules
            )
        except Exception:
            _logger.exception(
                "Error while processing template configs for plugin {}, ignoring it".format(
                    name
                ),
                extra={"plugin": name},
            )

        if not wizard_required or wizard_ignored:
            includes["wizard"] = list()

        for t in template_types:
            plugin_aliases[t] = {}
            for include in includes[t]:
                if t == "navbar" or t == "generic":
                    data = include
                else:
                    data = include[1]

                key = data["_key"]
                if "replaces" in data:
                    key = data["replaces"]
                    plugin_aliases[t][data["_key"]] = data["replaces"]
                templates[t]["entries"][key] = include

    # ~~ order internal templates and plugins

    # make sure that
    # 1) we only have keys in our ordered list that we have entries for and
    # 2) we have all entries located somewhere within the order

    for t in template_types:
        default_order = (
            settings().get(
                ["appearance", "components", "order", t], merged=True, config={}
            )
            or []
        )
        configured_order = (
            settings().get(["appearance", "components", "order", t], merged=True) or []
        )
        configured_disabled = (
            settings().get(["appearance", "components", "disabled", t]) or []
        )

        # first create the ordered list of all component ids according to the configured order
        result = []
        for x in configured_order:
            if x in plugin_aliases[t]:
                x = plugin_aliases[t][x]
            if (
                x in templates[t]["entries"]
                and x not in configured_disabled
                and x not in result
            ):
                result.append(x)
        templates[t]["order"] = result

        # now append the entries from the default order that are not already in there
        templates[t]["order"] += [
            x
            for x in default_order
            if x not in templates[t]["order"]
            and x in templates[t]["entries"]
            and x not in configured_disabled
        ]

        all_ordered = set(templates[t]["order"])
        all_disabled = set(configured_disabled)

        # check if anything is missing, if not we are done here
        missing_in_order = (
            set(templates[t]["entries"].keys())
            .difference(all_ordered)
            .difference(all_disabled)
        )
        if len(missing_in_order) == 0:
            continue

        # works with entries that are dicts and entries that are 2-tuples with the
        # entry data at index 1
        def config_extractor(item, key, default_value=None):
            if isinstance(item, dict) and key in item:
                return item[key] if key in item else default_value
            elif (
                isinstance(item, tuple)
                and len(item) > 1
                and isinstance(item[1], dict)
                and key in item[1]
            ):
                return item[1][key] if key in item[1] else default_value

            return default_value

        # finally add anything that's not included in our order yet
        if template_sorting[t]["key"] is not None:
            # we'll use our config extractor as default key extractor
            extractor = config_extractor

            # if template type provides custom extractor, make sure its exceptions are handled
            if "key_extractor" in template_sorting[t] and callable(
                template_sorting[t]["key_extractor"]
            ):

                def create_safe_extractor(extractor):
                    def f(x, k):
                        try:
                            return extractor(x, k)
                        except Exception:
                            _logger.exception(
                                "Error while extracting sorting keys for template {}".format(
                                    t
                                )
                            )
                            return None

                    return f

                extractor = create_safe_extractor(template_sorting[t]["key_extractor"])

            sort_key = template_sorting[t]["key"]

            def key_func(x):
                config = templates[t]["entries"][x]
                entry_order = config_extractor(config, "order", default_value=None)
                return (
                    entry_order is None,
                    sv(entry_order),
                    sv(extractor(config, sort_key)),
                )

            sorted_missing = sorted(missing_in_order, key=key_func)
        else:

            def key_func(x):
                config = templates[t]["entries"][x]
                entry_order = config_extractor(config, "order", default_value=None)
                return entry_order is None, sv(entry_order)

            sorted_missing = sorted(missing_in_order, key=key_func)

        if template_sorting[t]["add"] == "prepend":
            templates[t]["order"] = sorted_missing + templates[t]["order"]
        elif template_sorting[t]["add"] == "append":
            templates[t]["order"] += sorted_missing
        elif (
            template_sorting[t]["add"] == "custom_prepend"
            and "custom_add_entries" in template_sorting[t]
            and "custom_add_order" in template_sorting[t]
        ):
            templates[t]["entries"].update(
                template_sorting[t]["custom_add_entries"](sorted_missing)
            )
            templates[t]["order"] = (
                template_sorting[t]["custom_add_order"](sorted_missing)
                + templates[t]["order"]
            )
        elif (
            template_sorting[t]["add"] == "custom_append"
            and "custom_add_entries" in template_sorting[t]
            and "custom_add_order" in template_sorting[t]
        ):
            templates[t]["entries"].update(
                template_sorting[t]["custom_add_entries"](sorted_missing)
            )
            templates[t]["order"] += template_sorting[t]["custom_add_order"](
                sorted_missing
            )
        elif (
            template_sorting[t]["add"] == "custom_insert"
            and "custom_insert_entries" in template_sorting[t]
            and "custom_insert_order" in template_sorting[t]
        ):
            templates[t]["entries"].update(
                template_sorting[t]["custom_insert_entries"](sorted_missing)
            )
            templates[t]["order"] = template_sorting[t]["custom_insert_order"](
                templates[t]["order"], sorted_missing
            )

    _templates[locale] = templates
    _plugin_names = plugin_names
    _plugin_vars = plugin_vars

    return templates, plugin_names, plugin_vars


def _process_template_configs(name, implementation, configs, rules):
    from jinja2.exceptions import TemplateNotFound

    counters = defaultdict(lambda: 1)
    includes = defaultdict(list)

    for config in configs:
        if not isinstance(config, dict):
            continue
        if "type" not in config:
            continue

        template_type = config["type"]
        del config["type"]

        if template_type not in rules:
            continue
        rule = rules[template_type]

        data = _process_template_config(
            name, implementation, rule, config=config, counter=counters[template_type]
        )
        if data is None:
            continue

        includes[template_type].append(rule["to_entry"](data))
        counters[template_type] += 1

    for template_type in rules:
        if len(includes[template_type]) == 0:
            # if no template of that type was added by the config, we'll try to use the default template name
            rule = rules[template_type]
            data = _process_template_config(name, implementation, rule)
            if data is not None:
                try:
                    app.jinja_env.get_or_select_template(data["template"])
                except TemplateNotFound:
                    pass
                except Exception:
                    _logger.exception(
                        "Error in template {}, not going to include it".format(
                            data["template"]
                        )
                    )
                else:
                    includes[template_type].append(rule["to_entry"](data))

    return includes


def _process_template_config(name, implementation, rule, config=None, counter=1):
    if "mandatory" in rule:
        for mandatory in rule["mandatory"]:
            if mandatory not in config:
                return None

    if config is None:
        config = {}
    data = dict(config)

    if "suffix" not in data and counter > 1:
        data["suffix"] = "_%d" % counter

    if "div" in data:
        data["_div"] = data["div"]
    elif "div" in rule:
        data["_div"] = rule["div"](name)
        if "suffix" in data:
            data["_div"] = data["_div"] + data["suffix"]
        if not _valid_div_re.match(data["_div"]):
            _logger.warning(
                "Template config {} contains invalid div identifier {}, skipping it".format(
                    name, data["_div"]
                )
            )
            return None

    if data.get("template"):
        data["template"] = implementation.template_folder_key + "/" + data["template"]
    else:
        data["template"] = (
            implementation.template_folder_key + "/" + rule["template"](name)
        )

    if data.get("template_header"):
        data["template_header"] = (
            implementation.template_folder_key + "/" + data["template_header"]
        )

    if "name" not in data:
        data["name"] = implementation._plugin_name

    if "custom_bindings" not in data or data["custom_bindings"]:
        data_bind = "allowBindings: true"
        if "data_bind" in data:
            data_bind = data_bind + ", " + data["data_bind"]
        data_bind = data_bind.replace('"', '\\"')
        data["data_bind"] = data_bind

    data["_key"] = "plugin_" + name
    if "suffix" in data:
        data["_key"] += data["suffix"]

    data["_plugin"] = name

    return data


def _filter_templates(templates, template_filter):
    filtered_templates = {}
    for template_type, template_collection in templates.items():
        filtered_entries = {}
        for template_key, template_entry in template_collection["entries"].items():
            if template_filter(template_type, template_key):
                filtered_entries[template_key] = template_entry
        filtered_templates[template_type] = {
            "order": list(
                filter(lambda x: x in filtered_entries, template_collection["order"])
            ),
            "entries": filtered_entries,
        }
    return filtered_templates


@app.route("/robots.txt")
def robotsTxt():
    return send_from_directory(app.static_folder, "robots.txt")


@app.route("/i18n/<string:locale>/<string:domain>.js")
@util.flask.conditional(lambda: _check_etag_and_lastmodified_for_i18n(), NOT_MODIFIED)
@util.flask.etagged(
    lambda _: _compute_etag_for_i18n(
        request.view_args["locale"], request.view_args["domain"]
    )
)
@util.flask.lastmodified(
    lambda _: _compute_date_for_i18n(
        request.view_args["locale"], request.view_args["domain"]
    )
)
def localeJs(locale, domain):
    messages = {}
    plural_expr = None

    if locale != "en":
        messages, plural_expr = _get_translations(locale, domain)

    catalog = {
        "messages": messages,
        "plural_expr": plural_expr,
        "locale": locale,
        "domain": domain,
    }

    from flask import Response

    return Response(
        render_template("i18n.js.jinja2", catalog=catalog),
        content_type="application/x-javascript; charset=utf-8",
    )


@app.route("/plugin_assets/<string:name>/<path:filename>")
def plugin_assets(name, filename):
    return redirect(url_for("plugin." + name + ".static", filename=filename))


def _compute_etag_for_i18n(locale, domain, files=None, lastmodified=None):
    if files is None:
        files = _get_all_translationfiles(locale, domain)
    if lastmodified is None:
        lastmodified = _compute_date(files)
    if lastmodified and not isinstance(lastmodified, str):
        from werkzeug.http import http_date

        lastmodified = http_date(lastmodified)

    import hashlib

    hash = hashlib.sha1()

    def hash_update(value):
        hash.update(value.encode("utf-8"))

    hash_update(",".join(sorted(files)))
    if lastmodified:
        hash_update(lastmodified)
    return hash.hexdigest()


def _compute_date_for_i18n(locale, domain):
    return _compute_date(_get_all_translationfiles(locale, domain))


def _compute_date(files):
    # Note, we do not expect everything in 'files' to exist.
    import stat
    from datetime import datetime

    from octoprint.util.tz import UTC_TZ

    max_timestamp = 0
    for path in files:
        try:
            # try to stat file. If an exception is thrown, its because it does not exist.
            s = os.stat(path)
            if stat.S_ISREG(s.st_mode) and s.st_mtime > max_timestamp:
                # is a regular file and has a newer timestamp
                max_timestamp = s.st_mtime
        except Exception:
            # path does not exist.
            continue

    if max_timestamp:
        # we set the micros to 0 since microseconds are not speced for HTTP
        max_timestamp = (
            datetime.fromtimestamp(max_timestamp)
            .replace(microsecond=0)
            .replace(tzinfo=UTC_TZ)
        )
    return max_timestamp


def _check_etag_and_lastmodified_for_i18n():
    locale = request.view_args["locale"]
    domain = request.view_args["domain"]

    etag_ok = util.flask.check_etag(
        _compute_etag_for_i18n(request.view_args["locale"], request.view_args["domain"])
    )

    lastmodified = _compute_date_for_i18n(locale, domain)
    lastmodified_ok = lastmodified is None or util.flask.check_lastmodified(lastmodified)

    return etag_ok and lastmodified_ok


def _get_all_templates():
    from octoprint.util.jinja import get_all_template_paths

    return get_all_template_paths(app.jinja_loader)


def _get_all_assets():
    from octoprint.util.jinja import get_all_asset_paths

    return get_all_asset_paths(app.jinja_env.assets_environment, verifyExist=False)


def _get_all_translationfiles(locale, domain):
    from flask import _request_ctx_stack

    def get_po_path(basedir, locale, domain):
        return os.path.join(basedir, locale, "LC_MESSAGES", f"{domain}.po")

    po_files = []

    user_base_path = os.path.join(
        settings().getBaseFolder("translations", check_writable=False)
    )
    user_plugin_path = os.path.join(user_base_path, "_plugins")

    # plugin translations
    plugins = octoprint.plugin.plugin_manager().enabled_plugins
    for name, plugin in plugins.items():
        dirs = [
            os.path.join(user_plugin_path, name),
            os.path.join(plugin.location, "translations"),
        ]
        for dirname in dirs:
            po_files.append(get_po_path(dirname, locale, domain))

    # core translations
    ctx = _request_ctx_stack.top
    base_path = os.path.join(ctx.app.root_path, "translations")

    dirs = [user_base_path, base_path]
    for dirname in dirs:
        po_files.append(get_po_path(dirname, locale, domain))

    return po_files


def _get_translations(locale, domain):
    from babel.messages.pofile import read_po

    from octoprint.util import dict_merge

    messages = {}
    plural_expr = None

    def messages_from_po(path, locale, domain):
        messages = {}
        with open(path, encoding="utf-8") as f:
            catalog = read_po(f, locale=locale, domain=domain)

            for message in catalog:
                message_id = message.id
                if isinstance(message_id, (list, tuple)):
                    message_id = message_id[0]
                if message.string:
                    messages[message_id] = message.string

        return messages, catalog.plural_expr

    po_files = _get_all_translationfiles(locale, domain)
    for po_file in po_files:
        if not os.path.exists(po_file):
            continue
        po_messages, plural_expr = messages_from_po(po_file, locale, domain)
        if po_messages is not None:
            messages = dict_merge(messages, po_messages, in_place=True)

    return messages, plural_expr