search: add nick keyword search

- search messages by author with `from:nick`
- add section to Help.vue
- should be easy to adapt this into global keyword-based search

https://github.com/thelounge/thelounge/issues/4209

client/components/Windows/Help.vue

@@ -825,6 +825,23 @@
 					<p>Retrieve information about the given user on the current network.</p>
 				</div>
 			</div>
+
+			<h2>Search</h2>
+
+			<p>
+				You can search messages simply by clicking the magnifying glass icon on the right
+				side of a channel's titlebar and entering a search term. Here are some additional
+				keywords you can use to fine-tune your search.
+			</p>
+
+			<div class="help-item">
+				<div class="subject">
+					<code>from:<em>nick</em></code>
+				</div>
+				<div class="description">
+					<p>Search messages by author.</p>
+				</div>
+			</div>
 		</div>
 	</div>
 </template>

src/plugins/messageStorage/sqlite.js

@@ -208,9 +208,41 @@ class MessageStorage {
 		// Using the '@' character to escape '%' and '_' in patterns.
 		const escapedSearchTerm = query.searchTerm.replace(/([%_@])/g, "@$1");
 
+		// Additional filtering:
+		// - "from:nick" to find messages sent by a given nick
+		const keywords = ["from"];
+		const joinedKeywords = keywords.map((kw) => kw + ":").join("|");
+		const filterExp = RegExp(`((${joinedKeywords})(\\S+))+`, "g");
+
+		let filters;
+		const filterMatch = escapedSearchTerm.match(filterExp);
+
+		if (filterMatch && filterMatch.length) {
+			filters = filterMatch.reduce((params, filter) => {
+				const [key, value] = filter.split(":");
+				params[key] = value;
+				return params;
+			}, {});
+		}
+
+		// strip "key:value" filter pairs out of search string
+		const mainSearchTerm = escapedSearchTerm.replace(filterExp, "").trim();
+
 		let select =
-			'SELECT msg, type, time, network, channel FROM messages WHERE type = "message" AND json_extract(msg, "$.text") LIKE ? ESCAPE \'@\'';
-		const params = [`%${escapedSearchTerm}%`];
+			'SELECT msg, type, time, network, channel FROM messages WHERE type = "message"';
+		const params = [];
+
+		if (mainSearchTerm.length) {
+			select += " AND json_extract(msg, \"$.text\") LIKE ? ESCAPE '@'";
+			params.push(`%${mainSearchTerm}%`);
+		}
+
+		if (filters && Object.keys(filters).length) {
+			if (filters.from) {
+				select += ' AND json_extract(msg, "$.from.nick") LIKE ?';
+				params.push(filters.from);
+			}
+		}
 
 		if (query.networkUuid) {
 			select += " AND network = ? ";

test/plugins/sqlite.js

@@ -243,6 +243,83 @@ describe("SQLite Message Storage", function () {
 		}
 	});
 
+	it("should search messages with keyword queries", function () {
+		function assertResults(query, expected) {
+			return store
+				.search({
+					searchTerm: query,
+					networkUuid: "this-is-a-network-guid3",
+				})
+				.then((messages) => {
+					expect(messages.results.map((i) => i.text)).to.deep.equal(expected);
+				});
+		}
+
+		const originalMaxHistory = Config.values.maxHistory;
+
+		try {
+			Config.values.maxHistory = 3;
+
+			store.index(
+				{uuid: "this-is-a-network-guid3"},
+				{name: "#channel"},
+				new Msg({
+					time: 123456793,
+					text: "my first message",
+					from: {
+						mode: "",
+						nick: "thelounge007",
+					},
+				})
+			);
+
+			store.index(
+				{uuid: "this-is-a-network-guid3"},
+				{name: "#channel"},
+				new Msg({
+					time: 123456794,
+					text: "no, my first message!",
+					from: {
+						mode: "",
+						nick: "thelounge008",
+					},
+				})
+			);
+
+			store.index(
+				{uuid: "this-is-a-network-guid3"},
+				{name: "#channel"},
+				new Msg({
+					time: 123456795,
+					text: "another unrelated message",
+					from: {
+						mode: "",
+						nick: "thelounge007",
+					},
+				})
+			);
+
+			return (
+				store
+					.getMessages({uuid: "this-is-a-network-guid3"}, {name: "#channel"})
+					// .getMessages() waits for store.index() transactions to commit
+					.then(() =>
+						assertResults("from:thelounge007", [
+							"my first message",
+							"another unrelated message",
+						])
+					)
+					.then(() => assertResults("from:thelounge007 first", ["my first message"]))
+					.then(() =>
+						assertResults("first", ["my first message", "no, my first message!"])
+					)
+					.then(() => assertResults("from:nobody", []))
+			);
+		} finally {
+			Config.values.maxHistory = originalMaxHistory;
+		}
+	});
+
 	it("should close database", function (done) {
 		store.close((err) => {
 			expect(err).to.be.null;