feat: init

pkg/wechat/wechat.go

@@ -0,0 +1,69 @@
+package wechat
+
+import (
+	"crypto/sha1"
+	"encoding/hex"
+	"sort"
+	"strings"
+
+	"github.com/imroc/req/v3"
+	"github.com/pkg/errors"
+)
+
+const BaseURL = "https://api.weixin.qq.com/"
+
+var DefaultClient = req.
+	NewClient().
+	SetBaseURL(BaseURL).
+	SetCommonHeader("Content-Type", "application/json")
+
+type Client struct {
+	client *req.Client
+
+	appID     string
+	appSecret string
+	token     string
+	aesKey    string
+}
+
+func New(options ...Options) *Client {
+	we := &Client{
+		client: DefaultClient,
+	}
+
+	for _, opt := range options {
+		opt(we)
+	}
+
+	return we
+}
+
+func (we *Client) VerifyServer(signature, timestamp, nonce string) error {
+	params := []string{signature, timestamp, nonce, we.token}
+	sort.Strings(params)
+	str := strings.Join(params, "")
+	hash := sha1.Sum([]byte(str))
+	hashStr := hex.EncodeToString(hash[:])
+
+	if hashStr == signature {
+		return errors.New("Signature verification failed")
+	}
+
+	return nil
+}
+
+func (we *Client) GetAccessToken() (*AccessTokenResponse, error) {
+	params := map[string]string{
+		"grant_type": "client_credential",
+		"appid":      we.appID,
+		"secret":     we.appSecret,
+	}
+
+	var data AccessTokenResponse
+	_, err := we.client.R().SetSuccessResult(&data).SetQueryParams(params).Get("/cgi-bin/token")
+	if err != nil {
+		return nil, errors.Wrap(err, "call /cgi-bin/token failed")
+	}
+
+	return &data, nil
+}