import os import glob from aiohttp import web dirname = os.path.dirname(os.path.realpath(__file__)) static_ui_path = os.path.join(dirname, "ui") METAFLOW_SERVICE = os.environ.get("METAFLOW_SERVICE", "/") METAFLOW_HEAD = os.environ.get("METAFLOW_HEAD", None) METAFLOW_BODY_BEFORE = os.environ.get("METAFLOW_BODY_BEFORE", None) METAFLOW_BODY_AFTER = os.environ.get("METAFLOW_BODY_AFTER", None) class Frontend(object): """ Provides routes for the static UI webpage. Require this as the last Api, as it is a catch-all route. """ def __init__(self, app): app.router.add_static('/static', path=os.path.join(static_ui_path, "static"), name='static') # serve the root static files separately. static_files = glob.glob(os.path.join(static_ui_path, "*.*")) for filepath in static_files: filename = filepath[len(static_ui_path) + 1:] app.router.add_route( 'GET', f'/{filename}', self.serve_file(filename)) # catch-all route that unfortunately messes with root static file serving. # Refreshing SPA pages won't work without the tail. app.router.add_route('GET', '/{tail:.*}', self.serve_index_html) def serve_file(self, filename: str): "Generator for single static file serving handlers" async def filehandler(request): return web.FileResponse(os.path.join(static_ui_path, filename)) return filehandler async def serve_index_html(self, request): "Serve index.html by injecting `METAFLOW_SERVICE` variable to define API base url." try: with open(os.path.join(static_ui_path, "index.html")) as f: content = f.read() \ .replace("", "".format(METAFLOW_SERVICE=METAFLOW_SERVICE)) if METAFLOW_HEAD: content = content.replace("", "{METAFLOW_HEAD}" .format(METAFLOW_HEAD=METAFLOW_HEAD)) if METAFLOW_BODY_BEFORE: content = content.replace("", "{METAFLOW_BODY_BEFORE}" .format(METAFLOW_BODY_BEFORE=METAFLOW_BODY_BEFORE)) if METAFLOW_BODY_AFTER: content = content.replace("", "{METAFLOW_BODY_AFTER}" .format(METAFLOW_BODY_AFTER=METAFLOW_BODY_AFTER)) return web.Response(text=content, content_type='text/html') except Exception as err: return web.Response(text=str(err), status=500, content_type='text/plain')