Added oauth for gitea

internal/auth/oauth2.go

@@ -0,0 +1,98 @@
+package auth
+
+import (
+	"CatsOfMastodonBotGo/internal/config"
+	"bytes"
+	"encoding/json"
+	"io"
+	"net/http"
+	"net/url"
+)
+
+type GiteaOAuth2Handler struct {
+	ClientID     string
+	ClientSecret string
+	InstanceUrl  string
+}
+
+var GiteaOauth2HandlerInstance *GiteaOAuth2Handler
+
+func InitGiteaOauth2Token() {
+	GiteaOauth2HandlerInstance = &GiteaOAuth2Handler{
+		ClientID: config.Config.GiteaOauthClientID,
+		ClientSecret: config.Config.GiteaOauthClientSecret,
+		InstanceUrl: config.Config.GiteaOauthInstance,
+	}
+}
+
+func (g *GiteaOAuth2Handler) GetGiteaLoginURL (redirectHost string) (string) {
+	authUrl := g.InstanceUrl + "/login/oauth/authorize?client_id=" + g.ClientID + "&redirect_uri=" + redirectHost + "/oath/gitea&scope=openid&response_type=code&response_mode=form_post"
+	return authUrl
+}
+
+func (g *GiteaOAuth2Handler) GetGiteaUserEmailByCode(code string) (string, error) {
+    accessToken, err := getGiteaAccessTokenByCode(code)
+    if err != nil {
+        return "", err
+    }
+
+    req, err := http.NewRequest("POST", g.InstanceUrl+"/login/oauth/userinfo", nil)
+    if err != nil {
+        return "", err
+    }
+    req.Header.Set("Authorization", "Bearer " + accessToken)
+    req.Header.Set("Accept", "application/json")
+
+    resp, err := http.DefaultClient.Do(req)
+    if err != nil {
+        return "", err
+    }
+    defer resp.Body.Close()
+
+    body, err := io.ReadAll(resp.Body)
+    if err != nil {
+        return "", err
+    }
+
+    var userInfo struct {
+        Email string `json:"email"`
+    }
+    if err := json.Unmarshal(body, &userInfo); err != nil {
+        return "", err
+    }
+
+    return userInfo.Email, nil
+}
+
+
+
+func getGiteaAccessTokenByCode(code string) (string, error) {
+    form := url.Values{}
+    form.Add("client_id", GiteaOauth2HandlerInstance.ClientID)
+    form.Add("client_secret", GiteaOauth2HandlerInstance.ClientSecret)
+    form.Add("code", code)
+    form.Add("grant_type", "authorization_code")
+
+    req, err := http.NewRequest("POST", GiteaOauth2HandlerInstance.InstanceUrl+"/login/oauth/access_token", bytes.NewBufferString(form.Encode()))
+    if err != nil {
+        return "", err
+    }
+    req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+    req.Header.Set("Accept", "application/json")
+
+    resp, err := http.DefaultClient.Do(req)
+    if err != nil {
+        return "", err
+    }
+    defer resp.Body.Close()
+
+    body, _ := io.ReadAll(resp.Body)
+    var tokenResp struct {
+        AccessToken string `json:"access_token"`
+    }
+    if err := json.Unmarshal(body, &tokenResp); err != nil {
+        return "", err
+    }
+
+    return tokenResp.AccessToken, nil
+}