feat(web_search_engine): adds google as a provider (#1226)

lua/avante/config.lua

@@ -55,8 +55,33 @@ M._defaults = {
                   }
                 end
               )
+              :take(5)
+              :totable()
+            return vim.json.encode(jsn), nil
+          end
+          return "", nil
+        end,
+      },
+      google = {
+        api_key_name = "GOOGLE_SEARCH_API_KEY",
+        engine_id_name = "GOOGLE_SEARCH_ENGINE_ID",
+        extra_request_body = {},
+        ---@type WebSearchEngineProviderResponseBodyFormatter
+        format_response_body = function(body)
+          if body.items ~= nil then
+            local jsn = vim
+              .iter(body.items)
+              :map(
+                function(result)
+                  return {
+                    title = result.title,
+                    link = result.link,
+                    snippet = result.snippet,
+                  }
+                end
+              )
+              :take(5)
               :totable()
-            if #jsn > 5 then jsn = vim.list_slice(jsn, 1, 5) end
             return vim.json.encode(jsn), nil
           end
           return "", nil

lua/avante/llm_tools.lua

@@ -327,6 +327,28 @@ function M.web_search(opts, on_log)
     if resp.status ~= 200 then return nil, "Error: " .. resp.body end
     local jsn = vim.json.decode(resp.body)
     return search_engine.format_response_body(jsn)
+  elseif provider_type == "google" then
+    local engine_id = os.getenv(search_engine.engine_id_name)
+    if engine_id == nil or engine_id == "" then
+      return nil, "Environment variable " .. search_engine.engine_id_namee .. " is not set"
+    end
+    local query_params = vim.tbl_deep_extend("force", {
+      key = api_key,
+      cx = engine_id,
+      q = opts.query,
+    }, search_engine.extra_request_body)
+    local query_string = ""
+    for key, value in pairs(query_params) do
+      query_string = query_string .. key .. "=" .. vim.uri_encode(value) .. "&"
+    end
+    local resp = curl.get("https://www.googleapis.com/customsearch/v1?" .. query_string, {
+      headers = {
+        ["Content-Type"] = "application/json",
+      },
+    })
+    if resp.status ~= 200 then return nil, "Error: " .. resp.body end
+    local jsn = vim.json.decode(resp.body)
+    return search_engine.format_response_body(jsn)
   end
 end