feat: #313

app/api/langchain-tools/google_custom_search.ts

@@ -0,0 +1,85 @@
+import { getEnvironmentVariable } from "@langchain/core/utils/env";
+import { Tool } from "@langchain/core/tools";
+
+const API_PROXY_PREFIX = process.env.GOOGLE_PLUGIN_API_PROXY_PREFIX ?? "";
+
+/**
+ * Interface for parameters required by GoogleCustomSearch class.
+ */
+export interface GoogleCustomSearchParams {
+  apiKey?: string;
+  googleCSEId?: string;
+}
+
+/**
+ * Class that uses the Google Search API to perform custom searches.
+ * Requires environment variables `GOOGLE_API_KEY` and `GOOGLE_CSE_ID` to
+ * be set.
+ */
+export class GoogleCustomSearch extends Tool {
+  static lc_name() {
+    return "GoogleCustomSearch";
+  }
+
+  get lc_secrets(): { [key: string]: string } | undefined {
+    return {
+      apiKey: "GOOGLE_API_KEY",
+    };
+  }
+
+  name = "google-custom-search";
+
+  protected apiKey: string;
+
+  protected googleCSEId: string;
+
+  description =
+    "a custom search engine. useful for when you need to answer questions about current events. input should be a search query. outputs a JSON array of results.";
+
+  constructor(
+    fields: GoogleCustomSearchParams = {
+      apiKey: getEnvironmentVariable("GOOGLE_API_KEY"),
+      googleCSEId: getEnvironmentVariable("GOOGLE_CSE_ID"),
+    },
+  ) {
+    super(...arguments);
+    if (!fields.apiKey) {
+      throw new Error(
+        `Google API key not set. You can set it as "GOOGLE_API_KEY" in your environment variables.`,
+      );
+    }
+    if (!fields.googleCSEId) {
+      throw new Error(
+        `Google custom search engine id not set. You can set it as "GOOGLE_CSE_ID" in your environment variables.`,
+      );
+    }
+    this.apiKey = fields.apiKey;
+    this.googleCSEId = fields.googleCSEId;
+  }
+
+  async _call(input: string) {
+    const res = await fetch(
+      `${API_PROXY_PREFIX}https://www.googleapis.com/customsearch/v1?key=${this.apiKey}&cx=${
+        this.googleCSEId
+      }&q=${encodeURIComponent(input)}`,
+    );
+
+    if (!res.ok) {
+      throw new Error(
+        `Got ${res.status} error from Google custom search: ${res.statusText}`,
+      );
+    }
+
+    const json = await res.json();
+
+    const results =
+      json?.items?.map(
+        (item: { title?: string; link?: string; snippet?: string }) => ({
+          title: item.title,
+          link: item.link,
+          snippet: item.snippet,
+        }),
+      ) ?? [];
+    return JSON.stringify(results);
+  }
+}

app/api/langchain-tools/google_search.ts

@@ -4,6 +4,8 @@ import { Tool } from "@langchain/core/tools";
 import * as cheerio from "cheerio";
 import { getRandomUserAgent } from "./ua_tools";
 
+const API_PROXY_PREFIX = process.env.GOOGLE_PLUGIN_API_PROXY_PREFIX ?? "";
+
 interface SearchResults {
   /** The web results of the search. */
   results: SearchResult[];
@@ -31,7 +33,7 @@ async function search(
   const headers = new Headers();
   headers.append("User-Agent", getRandomUserAgent());
   const resp = await fetch(
-    `https://www.google.com/search?nfpr=1&num=${maxResults}&pws=0&q=${encodeURIComponent(
+    `${API_PROXY_PREFIX}https://www.google.com/search?nfpr=1&num=${maxResults}&pws=0&q=${encodeURIComponent(
       input,
     )}`,
     {

app/api/langchain-tools/langchian-tool-index.ts

@@ -8,10 +8,6 @@ export {
   Serper,
   type SerperParameters,
 } from "@langchain/community/tools/serper";
-export {
-  GoogleCustomSearch,
-  type GoogleCustomSearchParams,
-} from "@langchain/community/tools/google_custom_search";
 export { AIPluginTool } from "@langchain/community/tools/aiplugin";
 export {
   WikipediaQueryRun,