275 lines
7.4 KiB
Go
275 lines
7.4 KiB
Go
// Package translator 提供文本翻译功能
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package translator
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import (
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"bytes"
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"context"
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"encoding/json"
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"errors"
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"fmt"
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"io"
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"net/http"
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"net/url"
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"strings"
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"time"
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"golang.org/x/text/language"
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)
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// BingTranslator Bing翻译器结构体
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type BingTranslator struct {
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httpClient *http.Client // HTTP客户端
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Timeout time.Duration // 请求超时时间
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token *tokenInfo // Token信息
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languages map[string]LanguageInfo // 支持的语言列表
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}
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// tokenInfo 存储token信息
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type tokenInfo struct {
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Value string
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ExpiresAt time.Time
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}
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// TranslateRequest 翻译请求结构
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type TranslateRequest struct {
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Text string `json:"Text"`
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}
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// TranslateResponse 翻译响应结构
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type TranslateResponse struct {
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Translations []struct {
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Text string `json:"text"`
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} `json:"translations"`
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}
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// ErrorResponse 错误响应结构
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type ErrorResponse struct {
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Error struct {
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Code int `json:"code"`
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Message string `json:"message"`
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} `json:"error"`
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}
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// 常量定义
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const (
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bingDefaultTimeout = 30 * time.Second
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bingTokenURL = "https://edge.microsoft.com/translate/auth"
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bingTranslateAPIURL = "https://api-edge.cognitive.microsofttranslator.com/translate"
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tokenValidDuration = 25 * time.Minute // Token有效期，比实际30分钟稍短以确保安全
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)
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// 错误定义
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var (
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ErrBingNetworkError = errors.New("bing translator network error")
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ErrBingParseError = errors.New("bing translator parse error")
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ErrBingEmptyResponse = errors.New("empty response from bing translator")
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)
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// NewBingTranslator 创建一个新的Bing翻译器实例
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func NewBingTranslator() *BingTranslator {
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translator := &BingTranslator{
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httpClient: &http.Client{
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Timeout: bingDefaultTimeout,
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},
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Timeout: bingDefaultTimeout,
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languages: initBingLanguages(),
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}
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return translator
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}
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// initBingLanguages 初始化Bing翻译器支持的语言列表
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func initBingLanguages() map[string]LanguageInfo {
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// 创建语言映射表
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languages := make(map[string]LanguageInfo)
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// 添加支持的语言
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// 基于 Microsoft Translator API 支持的语言列表
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// 参考: https://docs.microsoft.com/en-us/azure/cognitive-services/translator/language-support
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languages["en"] = LanguageInfo{Code: "en", Name: "English"}
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languages["zh-Hans"] = LanguageInfo{Code: "zh-Hans", Name: "Chinese (Simplified)"}
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languages["zh-Hant"] = LanguageInfo{Code: "zh-Hant", Name: "Chinese (Traditional)"}
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return languages
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}
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// SetTimeout 设置请求超时时间
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func (t *BingTranslator) SetTimeout(timeout time.Duration) {
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t.Timeout = timeout
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t.httpClient.Timeout = timeout
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}
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// getToken 获取访问token
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func (t *BingTranslator) getToken(ctx context.Context) (string, error) {
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// 检查token是否有效
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if t.token != nil && time.Now().Before(t.token.ExpiresAt) {
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return t.token.Value, nil
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}
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// 创建请求
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req, err := http.NewRequestWithContext(ctx, "GET", bingTokenURL, nil)
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if err != nil {
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return "", fmt.Errorf("failed to create token request: %w", err)
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}
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// 设置请求头
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req.Header.Set("Accept", "*/*")
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req.Header.Set("Accept-Language", "zh-TW,zh;q=0.9,ja;q=0.8,zh-CN;q=0.7,en-US;q=0.6,en;q=0.5")
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req.Header.Set("Cache-Control", "no-cache")
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req.Header.Set("Pragma", "no-cache")
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req.Header.Set("Referrer-Policy", "strict-origin-when-cross-origin")
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req.Header.Set("Sec-Fetch-Dest", "empty")
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req.Header.Set("Sec-Fetch-Mode", "cors")
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req.Header.Set("Sec-Fetch-Site", "none")
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// 发送请求
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resp, err := t.httpClient.Do(req)
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if err != nil {
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return "", fmt.Errorf("failed to get token: %w", err)
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}
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defer resp.Body.Close()
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// 检查状态码
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if resp.StatusCode != http.StatusOK {
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return "", fmt.Errorf("token request failed with status %d", resp.StatusCode)
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}
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// 读取响应
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body, err := io.ReadAll(resp.Body)
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if err != nil {
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return "", fmt.Errorf("failed to read token response: %w", err)
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}
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token := strings.TrimSpace(string(body))
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if token == "" {
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return "", fmt.Errorf("empty token received")
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}
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// 缓存token
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t.token = &tokenInfo{
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Value: token,
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ExpiresAt: time.Now().Add(tokenValidDuration),
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}
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return token, nil
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}
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// Translate 使用标准语言标签进行文本翻译
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func (t *BingTranslator) Translate(text string, from language.Tag, to language.Tag) (string, error) {
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return t.translate(text, from.String(), to.String())
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}
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// TranslateWithParams 使用简单字符串参数进行文本翻译
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func (t *BingTranslator) TranslateWithParams(text string, params TranslationParams) (string, error) {
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// 设置超时时间（如果有指定）
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if params.Timeout > 0 {
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t.SetTimeout(params.Timeout)
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}
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return t.translate(text, params.From, params.To)
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}
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// translate 执行实际翻译操作
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func (t *BingTranslator) translate(text, from, to string) (string, error) {
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if text == "" {
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return "", fmt.Errorf("text cannot be empty")
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}
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// 创建带超时的context
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ctx, cancel := context.WithTimeout(context.Background(), t.Timeout)
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defer cancel()
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// 获取token
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token, err := t.getToken(ctx)
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if err != nil {
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return "", fmt.Errorf("failed to get token: %w", err)
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}
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// 构建请求URL
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params := url.Values{}
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if from != "auto" {
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params.Set("from", from)
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}
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params.Set("to", to)
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params.Set("api-version", "3.0")
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params.Set("includeSentenceLength", "true")
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fullURL := fmt.Sprintf("%s?%s", bingTranslateAPIURL, params.Encode())
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// 构建请求体
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requestBody := []TranslateRequest{{Text: text}}
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jsonBody, err := json.Marshal(requestBody)
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if err != nil {
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return "", fmt.Errorf("failed to marshal request: %w", err)
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}
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// 创建HTTP请求
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req, err := http.NewRequestWithContext(ctx, "POST", fullURL, bytes.NewBuffer(jsonBody))
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if err != nil {
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return "", fmt.Errorf("failed to create request: %w", err)
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}
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// 设置请求头
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req.Header.Set("Accept", "application/json")
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req.Header.Set("Authorization", "Bearer "+token)
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req.Header.Set("Content-Type", "application/json")
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req.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36")
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// 发送请求
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resp, err := t.httpClient.Do(req)
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if err != nil {
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return "", fmt.Errorf("%w: %v", ErrBingNetworkError, err)
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}
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defer resp.Body.Close()
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// 读取响应
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body, err := io.ReadAll(resp.Body)
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if err != nil {
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return "", fmt.Errorf("failed to read response: %w", err)
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}
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// 检查HTTP状态码
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if resp.StatusCode != http.StatusOK {
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return "", fmt.Errorf("HTTP error %d: %s", resp.StatusCode, string(body))
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}
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// 首先尝试解析为错误响应
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var errorResp ErrorResponse
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if err := json.Unmarshal(body, &errorResp); err == nil && errorResp.Error.Code != 0 {
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return "", fmt.Errorf("translation error %d: %s", errorResp.Error.Code, errorResp.Error.Message)
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}
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// 解析翻译响应
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var translateResp []TranslateResponse
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if err := json.Unmarshal(body, &translateResp); err != nil {
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return "", fmt.Errorf("%w: %v", ErrBingParseError, err)
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}
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if len(translateResp) == 0 || len(translateResp[0].Translations) == 0 {
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return "", ErrBingEmptyResponse
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}
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// 合并所有翻译片段
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var result strings.Builder
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for i, translation := range translateResp[0].Translations {
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if i > 0 {
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result.WriteString(" ")
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}
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result.WriteString(translation.Text)
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}
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return result.String(), nil
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}
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// GetSupportedLanguages 获取翻译器支持的语言列表
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func (t *BingTranslator) GetSupportedLanguages() map[string]LanguageInfo {
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return t.languages
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}
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// IsLanguageSupported 检查指定的语言代码是否受支持
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func (t *BingTranslator) IsLanguageSupported(languageCode string) bool {
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_, exists := t.languages[languageCode]
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return exists
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}
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