"""General page functionality. SPDX-FileCopyrightText: © 2020 Brian S. Stephan SPDX-License-Identifier: AGPL-3.0-or-later """ import logging import os from flask import Blueprint, abort from flask import current_app as app from flask import redirect, request, send_from_directory from markupsafe import Markup from werkzeug.security import safe_join from incorporealcms.lib import get_meta_str, init_md, instance_resource_path_to_request_path, parse_md, render logger = logging.getLogger(__name__) bp = Blueprint('pages', __name__, url_prefix='/') @bp.route('/', defaults={'path': 'index'}) @bp.route('/') def display_page(path): """Get the file contents of the requested path and render the file.""" try: resolved_path, render_type = request_path_to_instance_resource_path(path) logger.debug("received request for path '%s', resolved to '%s', type '%s'", path, resolved_path, render_type) except PermissionError: abort(400) except IsADirectoryError: return redirect(f'/{path}/', code=301) except FileNotFoundError: abort(404) if render_type == 'file': return send_from_directory(app.instance_path, resolved_path) elif render_type == 'symlink': logger.debug("attempting to redirect path '%s' to reverse of resource '%s'", path, resolved_path) redirect_path = f'/{instance_resource_path_to_request_path(resolved_path)}' logger.debug("redirect path: '%s'", redirect_path) return redirect(redirect_path, code=301) elif render_type == 'markdown': logger.debug("treating path '%s' as markdown '%s'", path, resolved_path) return handle_markdown_file_path(resolved_path) else: logger.exception("unsupported render_type '%s'!?", render_type) abort(500) def handle_markdown_file_path(resolved_path): """Given a location on disk, attempt to open it and render the markdown within.""" try: content, md, page_name, page_title, mtime = parse_md(resolved_path) except OSError: logger.exception("resolved path '%s' could not be opened!", resolved_path) abort(500) except ValueError: logger.exception("error parsing/rendering markdown!") abort(500) except TypeError: logger.exception("error loading/rendering markdown!") abort(500) else: parent_navs = generate_parent_navs(resolved_path) extra_footer = get_meta_str(md, 'footer') if md.Meta.get('footer') else None template = get_meta_str(md, 'template') if md.Meta.get('template') else 'base.html' # check if this has a HTTP redirect redirect_url = get_meta_str(md, 'redirect') if md.Meta.get('redirect') else None if redirect_url: logger.debug("redirecting via meta tag to '%s'", redirect_url) return redirect(redirect_url, code=301) return render(template, title=page_title, description=get_meta_str(md, 'description'), image=get_meta_str(md, 'image'), base_url=request.base_url, content=content, navs=parent_navs, mtime=mtime.strftime('%Y-%m-%d %H:%M:%S %Z'), extra_footer=extra_footer) def request_path_to_instance_resource_path(path): """Turn a request URL path to the full page path. flask.Flask.open_instance_resource will open a file like /etc/hosts if you tell it to, which sucks, so we do a lot of work here to make sure we have a valid request to something inside the pages dir. """ # check if the path is allowed base_dir = os.path.realpath(f'{app.instance_path}/pages/') safe_path = safe_join(base_dir, path) # bail if the requested real path isn't inside the base directory if not safe_path: logger.warning("client tried to request a path '%s' outside of the base_dir!", path) raise PermissionError verbatim_path = os.path.abspath(safe_path) resolved_path = os.path.realpath(verbatim_path) logger.debug("base_dir '%s', constructed resolved_path '%s' for path '%s'", base_dir, resolved_path, path) # see if we have a real file or if we should infer markdown rendering if os.path.exists(resolved_path): # if this is a file-like request but actually a directory, redirect the user if os.path.isdir(resolved_path) and not path.endswith('/'): logger.info("client requested a path '%s' that is actually a directory", path) raise IsADirectoryError # if the requested path contains a symlink, redirect the user if verbatim_path != resolved_path: logger.info("client requested a path '%s' that is actually a symlink to file '%s'", path, resolved_path) return resolved_path.replace(f'{app.instance_path}{os.path.sep}', ''), 'symlink' # derive the proper markdown or actual file depending on if this is a dir or file if os.path.isdir(resolved_path): resolved_path = os.path.join(resolved_path, 'index.md') return resolved_path.replace(f'{app.instance_path}{os.path.sep}', ''), 'markdown' logger.info("final DIRECT path = '%s' for request '%s'", resolved_path, path) return resolved_path.replace(f'{app.instance_path}{os.path.sep}', ''), 'file' # if we're here, this isn't direct file access, so try markdown inference verbatim_path = f'{safe_path}.md' resolved_path = os.path.realpath(verbatim_path) # does the final file actually exist? if not os.path.exists(resolved_path): logger.warning("requested final path '%s' does not exist!", resolved_path) raise FileNotFoundError # check for symlinks if verbatim_path != resolved_path: logger.info("client requested a path '%s' that is actually a symlink to file '%s'", path, resolved_path) return resolved_path.replace(f'{app.instance_path}{os.path.sep}', ''), 'symlink' logger.info("final path = '%s' for request '%s'", resolved_path, path) # we checked that the file exists via absolute path, but now we need to give the path relative to instance dir return resolved_path.replace(f'{app.instance_path}{os.path.sep}', ''), 'markdown' def generate_parent_navs(path): """Create a series of paths/links to navigate up from the given resource path.""" if path == 'pages/index.md': # bail and return the domain name as a terminal case return [(app.config['DOMAIN_NAME'], '/')] else: if path.endswith('index.md'): # index case: one dirname for foo/bar/index.md -> foo/bar, one for foo/bar -> foo parent_resource_dir = os.path.dirname(os.path.dirname(path)) else: # usual case: foo/buh.md -> foo parent_resource_dir = os.path.dirname(path) # generate the request path (i.e. what the link will be) for this path, and # also the resource path of this parent (which is always a dir, so always index.md) request_path = f'/{instance_resource_path_to_request_path(path)}' parent_resource_path = os.path.join(parent_resource_dir, 'index.md') logger.debug("resource path: '%s'; request path: '%s'; parent resource path: '%s'", path, request_path, parent_resource_path) # for issues regarding parser reuse (see lib.init_md) we reinitialize the parser here md = init_md() # read the resource try: with app.open_instance_resource(path, 'r') as entry_file: entry = entry_file.read() _ = Markup(md.convert(entry)) page_name = (" ".join(md.Meta.get('title')) if md.Meta.get('title') else request_path_to_breadcrumb_display(request_path)) return generate_parent_navs(parent_resource_path) + [(page_name, request_path)] except FileNotFoundError: return generate_parent_navs(parent_resource_path) + [(request_path, request_path)] def request_path_to_breadcrumb_display(path): """Given a request path, e.g. "/foo/bar/baz/", turn it into breadcrumby text "baz".""" undired = path.rstrip('/') leaf = undired[undired.rfind('/'):] return leaf.strip('/')