feat: WebSearch 接入百度搜索，DuckDuckGo 作为兜底

百度搜索失败或无结果时自动回退到 DuckDuckGo，不引入 Bing。

go.mod

@@ -5,6 +5,7 @@ go 1.25.0
 require (
 	codeberg.org/readeck/go-readability/v2 v2.1.1
 	connectrpc.com/connect v1.19.1
+	github.com/PuerkitoBio/goquery v1.9.2
 	github.com/denisbrodbeck/machineid v1.0.1
 	github.com/elazarl/goproxy v1.7.2
 	github.com/firecrawl/html-to-markdown v0.0.0-20260312013131-1af9901a5d61
@@ -29,7 +30,6 @@ require (
 	dario.cat/mergo v1.0.2 // indirect
 	github.com/Microsoft/go-winio v0.6.2 // indirect
 	github.com/ProtonMail/go-crypto v1.3.0 // indirect
-	github.com/PuerkitoBio/goquery v1.9.2 // indirect
 	github.com/adrg/xdg v0.5.3 // indirect
 	github.com/andybalholm/cascadia v1.3.3 // indirect
 	github.com/araddon/dateparse v0.0.0-20210429162001-6b43995a97de // indirect

internal/backend/agent/bridge/interaction/baidusearch.go

@@ -0,0 +1,212 @@
+package interaction
+
+import (
+	"net/http"
+	neturl "net/url"
+	"strings"
+	"time"
+
+	"github.com/PuerkitoBio/goquery"
+
+	"cursor/gen/agentv1"
+)
+
+const (
+	baiduWebSearchBaseURL     = "https://www.baidu.com/s?ie=utf-8&tn=baidu&wd="
+	baiduWebSearchHostURL     = "https://www.baidu.com"
+	baiduSearchAbstractLimit  = 300
+	baiduSearchReferenceLimit = 8
+)
+
+// extractBaiduWebSearchReferences 从百度搜索结果页 HTML 中解析出搜索结果列表。
+func extractBaiduWebSearchReferences(body string) []*agentv1.WebSearchReference {
+	document, err := goquery.NewDocumentFromReader(strings.NewReader(body))
+	if err != nil {
+		return nil
+	}
+	references := make([]*agentv1.WebSearchReference, 0, baiduSearchReferenceLimit)
+	document.Find("#content_left > div").EachWithBreak(func(_ int, selection *goquery.Selection) bool {
+		if len(references) >= baiduSearchReferenceLimit {
+			return false
+		}
+		if !selection.HasClass("c-container") {
+			return true
+		}
+		title, resultURL, abstract := extractBaiduSearchResult(selection)
+		if title == "" || resultURL == "" {
+			return true
+		}
+		references = append(references, &agentv1.WebSearchReference{
+			Title: title,
+			Url:   normalizeBaiduSearchURL(resultURL),
+			Chunk: truncateBaiduSearchAbstract(abstract),
+		})
+		return true
+	})
+	return references
+}
+
+// extractBaiduSearchResult 从单条百度搜索结果节点中提取标题、链接和摘要。
+func extractBaiduSearchResult(selection *goquery.Selection) (string, string, string) {
+	title := cleanBaiduSearchText(selection.Find("h3").First().Text())
+	resultURL, _ := selection.Find("h3 a").First().Attr("href")
+	if title == "" {
+		title = firstBaiduSearchLine(selection.Text())
+	}
+	if resultURL == "" {
+		resultURL, _ = selection.Find("a").First().Attr("href")
+	}
+	abstract := cleanBaiduSearchText(selection.Find(".c-abstract").First().Text())
+	if abstract == "" {
+		abstract = cleanBaiduSearchText(selection.ChildrenFiltered("div").First().Text())
+	}
+	if abstract == "" {
+		abstract = baiduSearchTextAfterFirstLine(selection.Text())
+	}
+	return title, strings.TrimSpace(resultURL), abstract
+}
+
+// normalizeBaiduSearchURL 把百度返回的相对或协议省略链接归一化为绝对 URL。
+func normalizeBaiduSearchURL(rawURL string) string {
+	rawURL = strings.TrimSpace(rawURL)
+	if strings.HasPrefix(rawURL, "//") {
+		return "https:" + rawURL
+	}
+	if strings.HasPrefix(rawURL, "/") {
+		return baiduWebSearchHostURL + rawURL
+	}
+	return rawURL
+}
+
+// resolveBaiduWebSearchRedirects 把百度跳转链接解析为最终目标地址，就地更新引用列表。
+func resolveBaiduWebSearchRedirects(client *http.Client, references []*agentv1.WebSearchReference) {
+	for _, reference := range references {
+		if reference == nil {
+			continue
+		}
+		reference.Url = resolveBaiduRedirectURL(client, reference.GetUrl())
+	}
+}
+
+// resolveBaiduRedirectURL 判断链接是否是百度跳转链接，并尝试解析出真实目标。
+func resolveBaiduRedirectURL(client *http.Client, rawURL string) string {
+	resultURL := normalizeBaiduSearchURL(rawURL)
+	if !isBaiduRedirectURL(resultURL) {
+		return resultURL
+	}
+	redirectClient := baiduRedirectHTTPClient(client)
+	if location := requestBaiduRedirectLocation(redirectClient, http.MethodHead, resultURL); location != "" {
+		return location
+	}
+	if location := requestBaiduRedirectLocation(redirectClient, http.MethodGet, resultURL); location != "" {
+		return location
+	}
+	return resultURL
+}
+
+// baiduRedirectHTTPClient 基于基础 client 构造一个不自动跟随重定向的短超时客户端。
+func baiduRedirectHTTPClient(base *http.Client) *http.Client {
+	if base == nil {
+		base = http.DefaultClient
+	}
+	client := *base
+	if client.Timeout == 0 || client.Timeout > 6*time.Second {
+		client.Timeout = 6 * time.Second
+	}
+	client.CheckRedirect = func(_ *http.Request, _ []*http.Request) error {
+		return http.ErrUseLastResponse
+	}
+	return &client
+}
+
+// requestBaiduRedirectLocation 发起一次请求并读取响应头中的重定向目标地址。
+func requestBaiduRedirectLocation(client *http.Client, method string, rawURL string) string {
+	request, err := http.NewRequest(method, rawURL, nil)
+	if err != nil {
+		return ""
+	}
+	request.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) Chrome/120.0.0.0 Safari/537.36")
+	request.Header.Set("Accept-Language", "zh-CN,zh;q=0.9")
+	request.Header.Set("Referer", baiduWebSearchHostURL+"/")
+	response, err := client.Do(request)
+	if err != nil {
+		return ""
+	}
+	defer response.Body.Close()
+	location := strings.TrimSpace(response.Header.Get("Location"))
+	if location == "" {
+		return ""
+	}
+	return resolveBaiduLocationURL(rawURL, location)
+}
+
+// resolveBaiduLocationURL 把响应头里的相对重定向地址解析为绝对地址。
+func resolveBaiduLocationURL(baseURL string, location string) string {
+	parsedLocation, err := neturl.Parse(location)
+	if err != nil {
+		return location
+	}
+	if parsedLocation.IsAbs() {
+		return parsedLocation.String()
+	}
+	parsedBase, err := neturl.Parse(baseURL)
+	if err != nil {
+		return location
+	}
+	return parsedBase.ResolveReference(parsedLocation).String()
+}
+
+// isBaiduRedirectURL 判断给定地址是否是百度域名下的跳转链接。
+func isBaiduRedirectURL(rawURL string) bool {
+	parsedURL, err := neturl.Parse(strings.TrimSpace(rawURL))
+	if err != nil {
+		return false
+	}
+	host := strings.ToLower(parsedURL.Hostname())
+	path := strings.ToLower(parsedURL.EscapedPath())
+	return (host == "baidu.com" || strings.HasSuffix(host, ".baidu.com")) && strings.HasPrefix(path, "/link")
+}
+
+// truncateBaiduSearchAbstract 按字符数截断摘要文本，避免结果过长。
+func truncateBaiduSearchAbstract(value string) string {
+	value = cleanBaiduSearchText(value)
+	if baiduSearchAbstractLimit <= 0 {
+		return value
+	}
+	runes := []rune(value)
+	if len(runes) <= baiduSearchAbstractLimit {
+		return value
+	}
+	return string(runes[:baiduSearchAbstractLimit])
+}
+
+// firstBaiduSearchLine 返回文本中第一个非空行。
+func firstBaiduSearchLine(value string) string {
+	for _, line := range strings.Split(strings.ReplaceAll(value, "\r", "\n"), "\n") {
+		line = cleanBaiduSearchText(line)
+		if line != "" {
+			return line
+		}
+	}
+	return ""
+}
+
+// baiduSearchTextAfterFirstLine 返回除第一个非空行外剩余文本的拼接结果。
+func baiduSearchTextAfterFirstLine(value string) string {
+	nonEmpty := make([]string, 0, 8)
+	for _, line := range strings.Split(strings.ReplaceAll(value, "\r", "\n"), "\n") {
+		line = cleanBaiduSearchText(line)
+		if line != "" {
+			nonEmpty = append(nonEmpty, line)
+		}
+	}
+	if len(nonEmpty) <= 1 {
+		return ""
+	}
+	return cleanBaiduSearchText(strings.Join(nonEmpty[1:], " "))
+}
+
+// cleanBaiduSearchText 折叠多余空白并去除首尾空格。
+func cleanBaiduSearchText(value string) string {
+	return strings.Join(strings.Fields(strings.TrimSpace(value)), " ")
+}

internal/backend/agent/bridge/interaction/bridge.go

@@ -577,13 +577,68 @@ const (
 )
 
 func (bridge *Bridge) executeWebSearch(searchTerm string) ([]*agentv1.WebSearchReference, string, error) {
-	if strings.TrimSpace(searchTerm) == "" {
+	searchTerm = strings.TrimSpace(searchTerm)
+	if searchTerm == "" {
 		return nil, "", fmt.Errorf("web search search_term is required")
 	}
 	client := bridge.httpClient
 	if client == nil {
 		client = netproxy.NewHTTPClient(15 * time.Second)
 	}
+
+	// 先尝试百度搜索
+	baiduReferences, baiduPayload, baiduErr := bridge.tryBaiduWebSearch(client, searchTerm)
+	if baiduErr == nil && len(baiduReferences) > 0 {
+		return baiduReferences, baiduPayload, nil
+	}
+
+	// 百度失败，回退到 DuckDuckGo
+	duckReferences, duckPayload, duckErr := bridge.tryDuckDuckGoWebSearch(client, searchTerm)
+	if duckErr == nil && len(duckReferences) > 0 {
+		return duckReferences, duckPayload, nil
+	}
+
+	// 两者都失败，返回综合错误
+	if baiduErr != nil && duckErr != nil {
+		return nil, "", fmt.Errorf("web search failed: baidu=%v, duckduckgo=%v", baiduErr, duckErr)
+	}
+	return nil, "", fmt.Errorf("web search returned no parseable results")
+}
+
+func (bridge *Bridge) tryBaiduWebSearch(client *http.Client, searchTerm string) ([]*agentv1.WebSearchReference, string, error) {
+	requestURL := baiduWebSearchBaseURL + neturl.QueryEscape(searchTerm)
+	request, err := http.NewRequest(http.MethodGet, requestURL, nil)
+	if err != nil {
+		return nil, "", err
+	}
+	request.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36")
+	request.Header.Set("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8")
+	request.Header.Set("Accept-Language", "zh-CN,zh;q=0.9,en;q=0.8")
+	request.Header.Set("Referer", baiduWebSearchHostURL+"/")
+	response, err := client.Do(request)
+	if err != nil {
+		return nil, "", err
+	}
+	defer response.Body.Close()
+	if response.StatusCode < 200 || response.StatusCode >= 300 {
+		return nil, "", fmt.Errorf("baidu http status %d", response.StatusCode)
+	}
+	body, err := io.ReadAll(io.LimitReader(response.Body, 2*1024*1024))
+	if err != nil {
+		return nil, "", err
+	}
+	references := extractBaiduWebSearchReferences(string(body))
+	if len(references) == 0 {
+		return nil, "", fmt.Errorf("baidu returned no parseable results")
+	}
+	if len(references) > 5 {
+		references = references[:5]
+	}
+	resolveBaiduWebSearchRedirects(client, references)
+	return references, formatWebSearchPayload(searchTerm, references), nil
+}
+
+func (bridge *Bridge) tryDuckDuckGoWebSearch(client *http.Client, searchTerm string) ([]*agentv1.WebSearchReference, string, error) {
 	requestURL := webSearchURLOverride + neturl.QueryEscape(searchTerm)
 	request, err := http.NewRequest(http.MethodGet, requestURL, nil)
 	if err != nil {