feat(auth): add mini program test code endpoint (#51)

internal/common/auth/service/wechat_client.go

@@ -1,15 +1,19 @@
 package service
 
 import (
+	"bytes"
 	"context"
 	"encoding/json"
 	"fmt"
+	"io"
 	"net/http"
 	"net/url"
 	"time"
 )
 
 const weChatCode2SessionURL = "https://api.weixin.qq.com/sns/jscode2session"
+const weChatAccessTokenURL = "https://api.weixin.qq.com/cgi-bin/token"
+const weChatGetWXACodeURL = "https://api.weixin.qq.com/wxa/getwxacode"
 
 // WeChatClient 调用微信接口获取 session/openid。
 type WeChatClient struct {
@@ -30,6 +34,13 @@ type weChatSessionResponse struct {
 	ErrMsg  string `json:"errmsg"`
 }
 
+type weChatAccessTokenResponse struct {
+	AccessToken string `json:"access_token"`
+	ExpiresIn   int    `json:"expires_in"`
+	ErrCode     int    `json:"errcode"`
+	ErrMsg      string `json:"errmsg"`
+}
+
 // WeChatError 表示微信接口级错误。
 type WeChatError struct {
 	Code int
@@ -87,3 +98,98 @@ func (c *WeChatClient) Code2Session(ctx context.Context, code string) (*WeChatSe
 
 	return &raw.WeChatSession, nil
 }
+
+func (c *WeChatClient) GetAccessToken(ctx context.Context) (string, error) {
+	query := url.Values{}
+	query.Set("grant_type", "client_credential")
+	query.Set("appid", c.appID)
+	query.Set("secret", c.appSecret)
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, fmt.Sprintf("%s?%s", weChatAccessTokenURL, query.Encode()), nil)
+	if err != nil {
+		return "", fmt.Errorf("build access token request: %w", err)
+	}
+
+	resp, err := c.client.Do(req)
+	if err != nil {
+		return "", fmt.Errorf("call wechat access token api: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return "", fmt.Errorf("wechat access token api unexpected status: %s", resp.Status)
+	}
+
+	var raw weChatAccessTokenResponse
+	if err := json.NewDecoder(resp.Body).Decode(&raw); err != nil {
+		return "", fmt.Errorf("decode access token response: %w", err)
+	}
+	if raw.ErrCode != 0 {
+		return "", &WeChatError{Code: raw.ErrCode, Msg: raw.ErrMsg}
+	}
+	if raw.AccessToken == "" {
+		return "", fmt.Errorf("wechat access token missing")
+	}
+	return raw.AccessToken, nil
+}
+
+type getWXACodeRequest struct {
+	Path      string `json:"path"`
+	Width     int    `json:"width,omitempty"`
+	AutoColor bool   `json:"auto_color"`
+	IsHyaline bool   `json:"is_hyaline"`
+}
+
+type weChatAPIErrorResponse struct {
+	ErrCode int    `json:"errcode"`
+	ErrMsg  string `json:"errmsg"`
+}
+
+func (c *WeChatClient) GetWXACode(ctx context.Context, path string, width int) ([]byte, error) {
+	accessToken, err := c.GetAccessToken(ctx)
+	if err != nil {
+		return nil, err
+	}
+
+	body, err := json.Marshal(getWXACodeRequest{
+		Path:      path,
+		Width:     width,
+		AutoColor: false,
+		IsHyaline: true,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("marshal getwxacode request: %w", err)
+	}
+
+	req, err := http.NewRequestWithContext(
+		ctx,
+		http.MethodPost,
+		fmt.Sprintf("%s?access_token=%s", weChatGetWXACodeURL, url.QueryEscape(accessToken)),
+		bytes.NewReader(body),
+	)
+	if err != nil {
+		return nil, fmt.Errorf("build getwxacode request: %w", err)
+	}
+	req.Header.Set("Content-Type", "application/json")
+
+	resp, err := c.client.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("call wechat getwxacode api: %w", err)
+	}
+	defer resp.Body.Close()
+
+	payload, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("read getwxacode response: %w", err)
+	}
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("wechat getwxacode api unexpected status: %s", resp.Status)
+	}
+
+	var apiErr weChatAPIErrorResponse
+	if err := json.Unmarshal(payload, &apiErr); err == nil && apiErr.ErrCode != 0 {
+		return nil, &WeChatError{Code: apiErr.ErrCode, Msg: apiErr.ErrMsg}
+	}
+
+	return payload, nil
+}