更新若干功能

2026-08-15 17:18:00 +08:00
parent 4954295961
commit 6a81e479ef
77 changed files with 8165 additions and 2372 deletions
--- a/imgproxy.go
+++ b/imgproxy.go
@@ -0,0 +1,157 @@
+package main
+
+// imgproxy.go：远程图片拉取。
+// WebView 页面源是 http://wails.localhost，直接加载外站 HTTPS 图常会破图。
+// 优先经 Go 拉成 dataURL（FetchRemoteImageAsDataURL）；AssetServer /__ccimg 作兜底。
+
+import (
+	"context"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strings"
+	"sync"
+	"time"
+)
+
+const (
+	imgProxyPath     = "/__ccimg"
+	imgProxyMaxBytes = 12 << 20 // 12MB
+)
+
+var imgProxyClient = &http.Client{Timeout: 20 * time.Second}
+
+var (
+	imgDataURLMu    sync.Mutex
+	imgDataURLCache = map[string]string{}
+	errBadImageURL  = errors.New("bad url")
+)
+
+// remoteImageMiddleware 拦截 /__ccimg?u=<urlencoded http(s) URL>，拉取上游图片并回传。
+func remoteImageMiddleware(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		path := strings.TrimSuffix(r.URL.Path, "/")
+		if path != imgProxyPath {
+			next.ServeHTTP(w, r)
+			return
+		}
+		raw := strings.TrimSpace(r.URL.Query().Get("u"))
+		data, ct, err := fetchRemoteImage(r.Context(), raw)
+		if err != nil {
+			code := http.StatusBadGateway
+			if errors.Is(err, errBadImageURL) {
+				code = http.StatusBadRequest
+			}
+			http.Error(w, err.Error(), code)
+			return
+		}
+		w.Header().Set("Content-Type", ct)
+		w.Header().Set("Cache-Control", "private, max-age=86400")
+		_, _ = w.Write(data)
+	})
+}
+
+func fetchRemoteImage(ctx context.Context, raw string) ([]byte, string, error) {
+	raw = strings.TrimSpace(raw)
+	u, err := url.Parse(raw)
+	if err != nil || u.Host == "" || (u.Scheme != "http" && u.Scheme != "https") {
+		return nil, "", errBadImageURL
+	}
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, u.String(), nil)
+	if err != nil {
+		return nil, "", errBadImageURL
+	}
+	req.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36")
+	req.Header.Set("Accept", "image/avif,image/webp,image/apng,image/*,*/*;q=0.8")
+	resp, err := imgProxyClient.Do(req)
+	if err != nil {
+		return nil, "", errors.New("upstream unreachable")
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		return nil, "", errors.New("upstream error")
+	}
+	ct := resp.Header.Get("Content-Type")
+	if i := strings.Index(ct, ";"); i >= 0 {
+		ct = strings.TrimSpace(ct[:i])
+	}
+	data, err := io.ReadAll(io.LimitReader(resp.Body, imgProxyMaxBytes+1))
+	if err != nil {
+		return nil, "", errors.New("upstream read failed")
+	}
+	if len(data) > imgProxyMaxBytes {
+		return nil, "", errors.New("image too large")
+	}
+	if len(data) == 0 {
+		return nil, "", errors.New("empty image")
+	}
+	if ct == "" || (!strings.HasPrefix(ct, "image/") && !strings.Contains(ct, "octet-stream")) {
+		if sniffed := sniffImageMIME(data); sniffed != "" {
+			ct = sniffed
+		}
+	}
+	if ct == "" {
+		ct = "application/octet-stream"
+	}
+	return data, ct, nil
+}
+
+func sniffImageMIME(b []byte) string {
+	if len(b) >= 3 && b[0] == 0xff && b[1] == 0xd8 && b[2] == 0xff {
+		return "image/jpeg"
+	}
+	if len(b) >= 8 && string(b[:8]) == "\x89PNG\r\n\x1a\n" {
+		return "image/png"
+	}
+	if len(b) >= 6 && (string(b[:6]) == "GIF87a" || string(b[:6]) == "GIF89a") {
+		return "image/gif"
+	}
+	if len(b) >= 12 && string(b[:4]) == "RIFF" && string(b[8:12]) == "WEBP" {
+		return "image/webp"
+	}
+	return ""
+}
+
+// FetchRemoteImageAsDataURL 由 Go 拉取远程图片并返回 dataURL，绕过 WebView 外站限制。
+func (a *App) FetchRemoteImageAsDataURL(rawURL string) (string, error) {
+	rawURL = strings.TrimSpace(rawURL)
+	if rawURL == "" {
+		return "", errors.New("EMPTY_URL")
+	}
+	if strings.HasPrefix(rawURL, "data:") {
+		return rawURL, nil
+	}
+	imgDataURLMu.Lock()
+	if cached, ok := imgDataURLCache[rawURL]; ok {
+		imgDataURLMu.Unlock()
+		return cached, nil
+	}
+	imgDataURLMu.Unlock()
+
+	ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
+	defer cancel()
+	data, ct, err := fetchRemoteImage(ctx, rawURL)
+	if err != nil {
+		return "", err
+	}
+	if !strings.HasPrefix(ct, "image/") {
+		ct = "image/png"
+		if sniffed := sniffImageMIME(data); sniffed != "" {
+			ct = sniffed
+		}
+	}
+	out := fmt.Sprintf("data:%s;base64,%s", ct, base64.StdEncoding.EncodeToString(data))
+	imgDataURLMu.Lock()
+	if len(imgDataURLCache) > 128 {
+		imgDataURLCache = map[string]string{}
+	}
+	imgDataURLCache[rawURL] = out
+	imgDataURLMu.Unlock()
+	return out, nil
+}