server: add Brave search provider

2026-07-19 21:35:47 -07:00
parent 1952f4f358
commit 87b7d9502f
8 changed files with 317 additions and 4 deletions
@@ -0,0 +1,168 @@
+import { buildBrowserLikeRequestHeaders } from "../browser-fetch-headers.js";
+import { env } from "../env.js";
+
+const BRAVE_WEB_SEARCH_URL = "https://api.search.brave.com/res/v1/web/search";
+const BRAVE_SEARCH_TIMEOUT_MS = 12_000;
+
+export type BraveSearchOptions = {
+  numResults: number;
+  includeDomains?: string[];
+  excludeDomains?: string[];
+};
+
+export type BraveSearchResult = {
+  title: string | null;
+  url: string | null;
+  publishedDate: string | null;
+  author: string | null;
+  summary: string | null;
+  text: string | null;
+  highlights: string[];
+};
+
+export type BraveSearchResponse = {
+  query: string;
+  requestId: string | null;
+  results: BraveSearchResult[];
+};
+
+function clipText(input: string, maxCharacters: number) {
+  return input.length <= maxCharacters ? input : `${input.slice(0, maxCharacters)}...`;
+}
+
+function compactWhitespace(input: string) {
+  return input.replace(/\r/g, "").replace(/[ \t]+\n/g, "\n").replace(/\n{3,}/g, "\n\n").replace(/\s+/g, " ").trim();
+}
+
+function requireBraveSearchApiKey() {
+  if (!env.BRAVE_SEARCH_API_KEY) {
+    throw new Error("BRAVE_SEARCH_API_KEY not set");
+  }
+  return env.BRAVE_SEARCH_API_KEY;
+}
+
+function normalizeDomain(input: string) {
+  const trimmed = input.trim().toLowerCase();
+  if (!trimmed) return null;
+
+  try {
+    const parsed = new URL(trimmed.includes("://") ? trimmed : `https://${trimmed}`);
+    return parsed.hostname.replace(/^www\./, "");
+  } catch {
+    return trimmed.split(/[/?#]/, 1)[0]?.replace(/^www\./, "") || null;
+  }
+}
+
+function normalizeDomains(input: string[] | undefined) {
+  return Array.from(new Set((input ?? []).map(normalizeDomain).filter((domain): domain is string => Boolean(domain))));
+}
+
+function hostnameMatchesDomain(urlRaw: string | null, domain: string) {
+  if (!urlRaw) return false;
+  try {
+    const hostname = new URL(urlRaw).hostname.toLowerCase().replace(/^www\./, "");
+    return hostname === domain || hostname.endsWith(`.${domain}`);
+  } catch {
+    return false;
+  }
+}
+
+function filterResultsByDomains(results: BraveSearchResult[], options: BraveSearchOptions) {
+  const includeDomains = normalizeDomains(options.includeDomains);
+  const excludeDomains = normalizeDomains(options.excludeDomains);
+  return results.filter((result) => {
+    if (includeDomains.length && !includeDomains.some((domain) => hostnameMatchesDomain(result.url, domain))) return false;
+    if (excludeDomains.some((domain) => hostnameMatchesDomain(result.url, domain))) return false;
+    return true;
+  });
+}
+
+function buildBraveQuery(query: string, options: BraveSearchOptions) {
+  const includeDomains = normalizeDomains(options.includeDomains);
+  const excludeDomains = normalizeDomains(options.excludeDomains);
+  const includeClause =
+    includeDomains.length === 0
+      ? ""
+      : includeDomains.length === 1
+        ? `site:${includeDomains[0]}`
+        : `(${includeDomains.map((domain) => `site:${domain}`).join(" OR ")})`;
+  const excludeClause = excludeDomains.map((domain) => `-site:${domain}`).join(" ");
+  return [query, includeClause, excludeClause].filter(Boolean).join(" ");
+}
+
+function buildSearchUrl(query: string, options: BraveSearchOptions) {
+  const url = new URL(BRAVE_WEB_SEARCH_URL);
+  url.searchParams.set("q", buildBraveQuery(query, options));
+  url.searchParams.set("count", String(options.numResults));
+  url.searchParams.set("safesearch", "moderate");
+  url.searchParams.set("result_filter", "web");
+  url.searchParams.set("text_decorations", "false");
+  url.searchParams.set("extra_snippets", "true");
+  return url;
+}
+
+function stringOrNull(value: unknown) {
+  if (typeof value !== "string") return null;
+  const normalized = compactWhitespace(value);
+  return normalized || null;
+}
+
+function stringArray(value: unknown) {
+  if (!Array.isArray(value)) return [];
+  return value.filter((item): item is string => typeof item === "string").map(compactWhitespace).filter(Boolean);
+}
+
+function mapWebResult(result: any): BraveSearchResult {
+  const description = stringOrNull(result?.description);
+  const extraSnippets = stringArray(result?.extra_snippets);
+  const snippets = [description, ...extraSnippets].filter((snippet): snippet is string => Boolean(snippet));
+  const combinedText = snippets.join("\n\n");
+
+  return {
+    title: stringOrNull(result?.title),
+    url: stringOrNull(result?.url),
+    publishedDate: stringOrNull(result?.page_age),
+    author: stringOrNull(result?.profile?.name) ?? stringOrNull(result?.article?.author),
+    summary: description ? clipText(description, 1_400) : null,
+    text: combinedText ? clipText(combinedText, 700) : null,
+    highlights: snippets.slice(0, 3).map((snippet) => clipText(snippet, 280)),
+  };
+}
+
+export async function searchBrave(query: string, options: BraveSearchOptions): Promise<BraveSearchResponse> {
+  const url = buildSearchUrl(query, options);
+  const controller = new AbortController();
+  const timeout = setTimeout(() => controller.abort(), BRAVE_SEARCH_TIMEOUT_MS);
+
+  let response: Response;
+  try {
+    response = await fetch(url, {
+      signal: controller.signal,
+      headers: {
+        ...buildBrowserLikeRequestHeaders("application/json"),
+        "X-Subscription-Token": requireBraveSearchApiKey(),
+      },
+    });
+  } finally {
+    clearTimeout(timeout);
+  }
+
+  if (!response.ok) {
+    await response.arrayBuffer();
+    throw new Error(`Brave Search API request failed with status ${response.status}.`);
+  }
+
+  const contentType = response.headers.get("content-type")?.toLowerCase() ?? "";
+  if (!contentType.includes("application/json")) {
+    await response.arrayBuffer();
+    throw new Error(`Brave Search API returned ${contentType || "unknown content type"}.`);
+  }
+
+  const data: any = await response.json();
+  const results = Array.isArray(data?.web?.results) ? data.web.results.map(mapWebResult) : [];
+  return {
+    query,
+    requestId: response.headers.get("x-request-id"),
+    results: filterResultsByDomains(results, options).slice(0, options.numResults),
+  };
+}