more on the linkedin oauth refactoring. need to test the changes, though.

1 files changed, 121 insertions, 0 deletions

diff --git a/internal/platforms/linkedin/oauth2/oauth2.go b/internal/platforms/linkedin/oauth2/oauth2.go
new file mode 100644
index 0000000..6a692b3
--- /dev/null
+++ b/internal/platforms/linkedin/oauth2/oauth2.go
@@ -0,0 +1,121 @@
+package oauth2
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+
+	"codeberg.org/snonux/gos/internal/config"
+	"golang.org/x/oauth2"
+	"golang.org/x/oauth2/linkedin"
+)
+
+var (
+	oauthConfig      *oauth2.Config
+	oauthAccessToken string
+	oauthPersonID    string
+	errCh            chan error
+)
+
+func getOauthPersonID(token *oauth2.Token) (string, error) {
+	const url = "https://api.linkedin.com/v2/userinfo"
+
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return "", fmt.Errorf("Error creating request:%w", err)
+	}
+
+	req.Header.Set("Authorization", "Bearer "+token.AccessToken)
+	req.Header.Set("X-RestLi-Protocol-Version", "2.0.0")
+
+	client := &http.Client{}
+	resp, err := client.Do(req)
+	if err != nil {
+		return "", fmt.Errorf("Error making the request:%w", err)
+	}
+	defer resp.Body.Close()
+
+	body, _ := io.ReadAll(resp.Body)
+	if resp.StatusCode != http.StatusOK {
+		return "", fmt.Errorf("Failed to retrieve user profile. Status: %s\n%s\n", resp.Status, string(body))
+	}
+
+	type User struct {
+		Sub string `json:"sub"`
+	}
+	var user User
+	if err := json.Unmarshal(body, &user); err != nil {
+		return "", fmt.Errorf("Error unmarshalling JSON: %w", err)
+	}
+
+	return user.Sub, nil
+}
+
+func oauthIndexHandler(w http.ResponseWriter, r *http.Request) {
+	url := oauthConfig.AuthCodeURL("state", oauth2.AccessTypeOffline)
+	http.Redirect(w, r, url, http.StatusTemporaryRedirect)
+}
+
+func oauthCallbackHandler(w http.ResponseWriter, r *http.Request) {
+	defer close(errCh)
+	code := r.URL.Query().Get("code")
+
+	token, err := oauthConfig.Exchange(context.Background(), code)
+	if err != nil {
+		_, _ = w.Write([]byte(err.Error()))
+		errCh <- err
+		return
+	}
+	oauthAccessToken = token.AccessToken
+	_, _ = w.Write([]byte("Successfully fetched LinkedIn access token\n"))
+
+	if oauthPersonID, err = getOauthPersonID(token); err != nil {
+		_, _ = w.Write([]byte(err.Error()))
+		errCh <- err
+		return
+	}
+	_, _ = w.Write([]byte("Successfully fetched LinkedIn person ID\n"))
+}
+
+func LinkedInOauth2Creds(args config.Args) (string, string, error) {
+	secrets := args.Secrets
+	if secrets.LinkedInAccessToken != "" && secrets.LinkedInPersonID != "" {
+		// TODO: Check, whether the access token is still valid. If not, get a new one.
+		return secrets.LinkedInPersonID, secrets.MastodonAccessToken, nil
+	}
+
+	oauthConfig = &oauth2.Config{
+		ClientID:     secrets.LinkedInClientID,
+		ClientSecret: secrets.LinkedInSecret,
+		RedirectURL:  secrets.LinkedInRedirectURL,
+		Scopes:       []string{"openid", "profile", "w_member_social"},
+		Endpoint:     linkedin.Endpoint,
+	}
+	errCh := make(chan error)
+
+	http.HandleFunc("/", oauthIndexHandler)
+	http.HandleFunc("/callback", oauthCallbackHandler)
+
+	go func() {
+		log.Println("Listening on http://localhost:8080 for LinkedIn oauth2")
+		if err := http.ListenAndServe(":8080", nil); err != nil {
+			errCh <- err
+		}
+	}()
+
+	var errs error
+	for err := range errCh {
+		errs = errors.Join(errs, err)
+	}
+	if errs != nil {
+		return "", "", errs
+	}
+
+	secrets.MastodonAccessToken = oauthAccessToken
+	secrets.LinkedInPersonID = oauthPersonID
+	return oauthPersonID, oauthAccessToken, secrets.WriteToDisk(args.SecretsConfigPath)
+}