[feature] Add HTTP header permission section to frontend (#2893)

* [feature] Add HTTP header filter section to frontend

* tweak naming a bit

web/source/settings/views/admin/http-header-permissions/overview.tsx

@@ -0,0 +1,169 @@
+/*
+	GoToSocial
+	Copyright (C) GoToSocial Authors admin@gotosocial.org
+	SPDX-License-Identifier: AGPL-3.0-or-later
+
+	This program is free software: you can redistribute it and/or modify
+	it under the terms of the GNU Affero General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU Affero General Public License for more details.
+
+	You should have received a copy of the GNU Affero General Public License
+	along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+import React, { useMemo } from "react";
+import { useGetHeaderAllowsQuery, useGetHeaderBlocksQuery } from "../../../lib/query/admin/http-header-permissions";
+import { NoArg } from "../../../lib/types/query";
+import { PageableList } from "../../../components/pageable-list";
+import { HeaderPermission } from "../../../lib/types/http-header-permissions";
+import { useLocation, useParams } from "wouter";
+import { PermType } from "../../../lib/types/perm";
+import { FetchBaseQueryError } from "@reduxjs/toolkit/query";
+import { SerializedError } from "@reduxjs/toolkit";
+import HeaderPermCreateForm from "./create";
+
+export default function HeaderPermsOverview() {
+	const [ location, setLocation ] = useLocation();
+	
+	// Parse perm type from routing params.
+	let params = useParams();
+	if (params.permType !== "blocks" && params.permType !== "allows") {
+		throw "unrecognized perm type " + params.permType;
+	}
+	const permType = useMemo(() => {
+		return params.permType?.slice(0, -1) as PermType;
+	}, [params]);
+
+	// Uppercase first letter of given permType.
+	const permTypeUpper = useMemo(() => {
+		return permType.charAt(0).toUpperCase() + permType.slice(1); 
+	}, [permType]);
+	
+	// Fetch desired perms, skipping
+	// the ones we don't want.
+	const {
+		data: blocks,
+		isLoading: isLoadingBlocks,
+		isFetching: isFetchingBlocks,
+		isSuccess: isSuccessBlocks,
+		isError: isErrorBlocks,
+		error: errorBlocks
+	} = useGetHeaderBlocksQuery(NoArg, { skip: permType !== "block" });
+
+	const {
+		data: allows,
+		isLoading: isLoadingAllows,
+		isFetching: isFetchingAllows,
+		isSuccess: isSuccessAllows,
+		isError: isErrorAllows,
+		error: errorAllows
+	} = useGetHeaderAllowsQuery(NoArg, { skip: permType !== "allow" });
+
+	const itemToEntry = (perm: HeaderPermission) => {
+		return (
+			<dl
+				key={perm.id}
+				className="entry spanlink"
+				onClick={() => {
+					// When clicking on a header perm,
+					// go to the detail view for perm.
+					setLocation(`/${permType}s/${perm.id}`, {
+						// Store the back location in
+						// history so the detail view
+						// can use it to return here.
+						state: { backLocation: location }
+					});
+				}}
+				role="link"
+				tabIndex={0}
+			>
+				<dt>{perm.header}</dt>
+				<dd>{perm.regex}</dd>
+			</dl>
+		);
+	};
+
+	const emptyMessage = (
+		<div className="info">
+			<i className="fa fa-fw fa-info-circle" aria-hidden="true"></i>
+			<b>
+				No HTTP header {permType}s exist yet.
+				You can create one using the form below.
+			</b>
+		</div>
+	);
+
+	let isLoading: boolean;
+	let isFetching: boolean;
+	let isSuccess: boolean; 
+	let isError: boolean;
+	let error: FetchBaseQueryError | SerializedError | undefined;
+	let items: HeaderPermission[] | undefined;
+
+	if (permType === "block") {
+		isLoading = isLoadingBlocks;
+		isFetching = isFetchingBlocks;
+		isSuccess = isSuccessBlocks;
+		isError = isErrorBlocks;
+		error = errorBlocks;
+		items = blocks;
+	} else {
+		isLoading = isLoadingAllows;
+		isFetching = isFetchingAllows;
+		isSuccess = isSuccessAllows;
+		isError = isErrorAllows;
+		error = errorAllows;
+		items = allows;
+	}
+
+	return (
+		<div className="http-header-permissions">
+			<div className="form-section-docs">
+				<h1>HTTP Header {permTypeUpper}s</h1>
+				<p>
+					On this page, you can view, create, and remove HTTP header {permType} entries,
+					<br/>
+					Blocks and allows have different effects depending on the value you've set
+					for <code>advanced-header-filter-mode</code> in your instance configuration.
+					<br/>
+					{ permType === "block" && <>
+						<strong>
+							When running in <code>block</code> mode, be very careful when creating
+							your value regexes, as a too-broad match can cause your instance to
+							deny all requests, locking you out of this settings panel.
+						</strong>
+						<br/>
+						If you do this by accident, you can fix it by stopping your instance,
+						changing <code>advanced-header-filter-mode</code> to an empty string
+						(disabled), starting your instance again, and removing the block.
+					</> }
+				</p>
+				<a
+					href="https://docs.gotosocial.org/en/latest/admin/request_filtering_modes/"
+					target="_blank"
+					className="docslink"
+					rel="noreferrer"
+				>
+					Learn more about HTTP request filtering (opens in a new tab)
+				</a>
+			</div>
+			<PageableList
+				isLoading={isLoading}
+				isFetching={isFetching}
+				isSuccess={isSuccess}
+				isError={isError}
+				error={error}
+				items={items}
+				itemToEntry={itemToEntry}
+				emptyMessage={emptyMessage}
+			/>
+			<HeaderPermCreateForm permType={permType} />
+		</div>
+	);
+}