feat: 集成漫画源并支持在线阅读

src/sources/http.js

@@ -38,6 +38,37 @@ function fetchWithElectron(url, options = {}) {
   return fetchWithProxy(url, options);
 }
 
+async function responseBytes(res, maxBytes) {
+  const declared = Number(res.headers && res.headers.get && res.headers.get('content-length'));
+  if (Number.isFinite(declared) && declared > maxBytes) {
+    try { if (res.body && res.body.cancel) await res.body.cancel(); } catch (e) { /* ignore */ }
+    return null;
+  }
+  if (!res.body || typeof res.body.getReader !== 'function') {
+    const bytes = Buffer.from(await res.arrayBuffer());
+    return bytes.length <= maxBytes ? bytes : null;
+  }
+  const reader = res.body.getReader();
+  const chunks = [];
+  let size = 0;
+  try {
+    for (;;) {
+      const { done, value } = await reader.read();
+      if (done) break;
+      const chunk = Buffer.from(value);
+      size += chunk.length;
+      if (size > maxBytes) {
+        await reader.cancel();
+        return null;
+      }
+      chunks.push(chunk);
+    }
+  } finally {
+    try { reader.releaseLock(); } catch (e) { /* ignore */ }
+  }
+  return Buffer.concat(chunks, size);
+}
+
 // 简易 cookie jar: Map<domain, Map<name, value>>
 const cookieJar = new Map();
 
@@ -218,4 +249,8 @@ async function withRetry(fn, { tries = 2, delay = 1000 } = {}) {
   }
 }
 
-module.exports = { UA, fetchRaw, fetchText, fetchJson, decodeEntities, stripTags, clampPage, tooShort, isRetryable, withRetry, getCookies, setCookies, clearCookies, setProxy, getProxy, fetchWithProxy };
+module.exports = {
+  UA, fetchRaw, fetchText, fetchJson, responseBytes, decodeEntities, stripTags,
+  clampPage, tooShort, isRetryable, withRetry, getCookies, setCookies, clearCookies,
+  setProxy, getProxy, fetchWithProxy
+};