fix: recover authenticated undergraduate full pages with session guards

mobile/README.md

@@ -1,8 +1,8 @@
 # TPSchedule Flutter工程
 
-当前版本0.7.2+20，安卓包名 `com.tpschedule.app`。Dart包名保留 `hepan_everyday`，兼容既有代码引用。
+当前版本0.7.3+21，安卓包名 `com.tpschedule.app`。Dart包名保留 `hepan_everyday`，兼容既有代码引用。
 
-学校浏览器沿用宽视口及第三方Cookie配置、Chromium版本显示和跳转重试；0.7.2细化脚本错误和页面依赖状态，258项单元测试通过。实际教务页面组件缺失仍未确认根因，见 `../docs/tpschedule-0.7.2-validation.md`。
+学校浏览器沿用宽视口及第三方Cookie配置。0.7.3新增本科已登录缺依赖页面的同会话完整页恢复，保留原学校地址与来源；失败或切页不覆盖旧页面和课表，真实账号仍需复测。见 `../docs/tpschedule-0.7.3-validation.md`。
 
 ## 本科使用
 

mobile/android/app/build.gradle.kts

@@ -27,6 +27,7 @@ android {
         // flag during build.
         versionCode = flutter.versionCode
         versionName = flutter.versionName
+        testInstrumentationRunner = "com.tpschedule.app.SchoolDocumentRenderInstrumentation"
     }
 
     buildTypes {
@@ -40,6 +41,7 @@ android {
 
 dependencies {
     coreLibraryDesugaring("com.android.tools:desugar_jdk_libs:2.1.4")
+    testImplementation("junit:junit:4.12")
 }
 
 kotlin {

mobile/android/app/src/androidTest/java/com/tpschedule/app/SchoolDocumentRenderInstrumentation.java

@@ -0,0 +1,97 @@
+package com.tpschedule.app;
+
+import android.app.Activity;
+import android.app.Instrumentation;
+import android.os.Bundle;
+import android.webkit.*;
+import java.io.ByteArrayInputStream;
+import java.nio.charset.StandardCharsets;
+import java.util.concurrent.*;
+import java.util.concurrent.atomic.*;
+import org.json.*;
+
+/** Device-only check using public, local fixtures; no school requests or credentials. */
+public final class SchoolDocumentRenderInstrumentation extends Instrumentation {
+  private static final String URL = "https://eams.uestc.edu.cn/eams/home!main.action";
+  private WebView view;
+  private volatile CountDownLatch loaded;
+  private volatile String failureCode = "initial_fixture";
+  private final AtomicInteger fixtures = new AtomicInteger();
+  @Override public void onCreate(Bundle arguments) { super.onCreate(arguments); start(); }
+  private void require(boolean value, String code) { if (!value) { failureCode = code; throw new AssertionError(code); } }
+  private void waitFor(CountDownLatch latch) throws Exception { require(latch.await(12, TimeUnit.SECONDS), "fixture_timeout"); }
+  private JSONObject evaluate(String expression) throws Exception {
+    CountDownLatch done = new CountDownLatch(1);
+    AtomicReference<String> result = new AtomicReference<>();
+    runOnMainSync(() -> view.evaluateJavascript(expression, value -> { result.set(value); done.countDown(); }));
+    waitFor(done);
+    return new JSONObject(new JSONArray("[" + result.get() + "]").getString(0));
+  }
+  private boolean checkDocument(String nonce) throws Exception {
+    CountDownLatch done = new CountDownLatch(1);
+    AtomicBoolean result = new AtomicBoolean();
+    runOnMainSync(() -> SchoolDocumentRenderer.checkDocument(view, URL, nonce, valid -> { result.set(valid); done.countDown(); }));
+    waitFor(done);
+    return result.get();
+  }
+  @Override public void onStart() {
+    Bundle result = new Bundle();
+    int finishCode = Activity.RESULT_CANCELED;
+    try {
+      loaded = new CountDownLatch(1);
+      runOnMainSync(() -> {
+        view = new WebView(getTargetContext());
+        view.getSettings().setJavaScriptEnabled(true);
+        view.setWebViewClient(new WebViewClient() {
+          @Override public void onPageFinished(WebView webView, String url) { loaded.countDown(); }
+          @Override public WebResourceResponse shouldInterceptRequest(WebView webView, WebResourceRequest request) {
+            String path = request.getUrl().getPath();
+            if (path == null) path = "";
+            String body = "";
+            String mime = "text/plain";
+            if (path.endsWith("fixture.js")) { body = "window.fixtureReady='external-script';"; mime = "application/javascript"; fixtures.incrementAndGet(); }
+            if (path.endsWith("fixture.css")) { body = "#probe {color:rgb(12, 34, 56)}"; mime = "text/css"; fixtures.incrementAndGet(); }
+            return new WebResourceResponse(mime,"UTF-8",new ByteArrayInputStream(body.getBytes(StandardCharsets.UTF_8)));
+          }
+        });
+        CookieManager.getInstance().setCookie(URL, "SchoolDocumentFixture=public; Path=/eams; Secure");
+        view.loadDataWithBaseURL(URL,"<html><script>Object.defineProperty(window,'__tpscheduleDocumentToken',{value:'fixture-old',enumerable:false})</script><body>old-public-fixture</body></html>","text/html","UTF-8",URL);
+      });
+      waitFor(loaded);
+      require(checkDocument("fixture-old"), "current_document_rejected");
+      loaded = new CountDownLatch(1);
+      runOnMainSync(() -> view.loadDataWithBaseURL(URL,"<html><script>Object.defineProperty(window,'__tpscheduleDocumentToken',{value:'fixture-new',enumerable:false})</script><body>same-url-new-document</body></html>","text/html","UTF-8",URL));
+      waitFor(loaded);
+      require(!checkDocument("fixture-old"), "same_url_new_document_accepted");
+      require(checkDocument("fixture-new"), "new_document_rejected");
+      String html = "<!doctype html><html><head><meta charset='UTF-8'><link rel='stylesheet' href='fixture.css'><script src='fixture.js'></script></head><body><p id='probe'>电子科技大学 • 课表 ✓</p></body></html>";
+      loaded = new CountDownLatch(1);
+      AtomicBoolean applied = new AtomicBoolean();
+      runOnMainSync(() -> applied.set(SchoolDocumentRenderer.render(view, URL, CookieManager.getInstance().getCookie(URL), new SchoolDocumentReader.Document(html, java.util.Collections.emptyList()))));
+      require(applied.get(), "render_not_applied"); waitFor(loaded);
+      JSONObject actual = evaluate("JSON.stringify({href:location.href,origin:location.origin,text:document.getElementById('probe').textContent,script:window.fixtureReady,color:getComputedStyle(document.getElementById('probe')).color})");
+      require(URL.equals(actual.getString("href")), "visible_url_changed");
+      require("https://eams.uestc.edu.cn".equals(actual.getString("origin")), "origin_changed");
+      require("电子科技大学 • 课表 ✓".equals(actual.getString("text")), "unicode_changed");
+      require("external-script".equals(actual.getString("script")), "external_script_missing");
+      require("rgb(12, 34, 56)".equals(actual.getString("color")), "external_css_missing");
+      require(fixtures.get() == 2, "relative_asset_resolution_failed");
+      runOnMainSync(() -> applied.set(SchoolDocumentRenderer.render(view, "https://eams.uestc.edu.cn/eams/index.action", CookieManager.getInstance().getCookie(URL), new SchoolDocumentReader.Document("bad",java.util.Collections.emptyList()))));
+      require(!applied.get(), "stale_url_accepted");
+      runOnMainSync(() -> applied.set(SchoolDocumentRenderer.render(view, URL, "SchoolDocumentFixture=wrong", new SchoolDocumentReader.Document("bad",java.util.Collections.emptyList()))));
+      require(!applied.get(), "changed_session_accepted");
+      JSONObject retained = evaluate("JSON.stringify({text:document.getElementById('probe').textContent})");
+      require("电子科技大学 • 课表 ✓".equals(retained.getString("text")), "failed_render_changed_dom");
+      result.putString("stream", "SchoolDocument render: URL/origin/Unicode/scripts/CSS/session/document guards passed\n");
+      sendStatus(0,result);
+      finishCode = Activity.RESULT_OK;
+    } catch (Throwable ignored) {
+      // Fixed output only: never print URI, cookie, page source or exception messages.
+      result.putString("stream", "SchoolDocument render fixture failed: " + failureCode + "\n");
+      sendStatus(-2,result);
+    } finally {
+      runOnMainSync(() -> { if (view != null) view.destroy(); });
+    }
+    finish(finishCode,result);
+  }
+}

mobile/android/app/src/main/java/com/tpschedule/app/SchoolDocumentPending.java

@@ -0,0 +1,56 @@
+package com.tpschedule.app;
+
+import java.util.function.LongSupplier;
+import java.util.*;
+import java.util.concurrent.Semaphore;
+
+/** UI-thread confined registry. Contents never cross the Flutter channel. */
+public final class SchoolDocumentPending<T> {
+  private static final Semaphore SLOTS = new Semaphore(4);
+  private static final long TTL = 20000;
+  private static final class Entry<T> {
+    final long viewId, created;
+    final T value;
+    Entry(long viewId, long created, T value) { this.viewId = viewId; this.created = created; this.value = value; }
+  }
+  private final LongSupplier clock;
+  private final Map<String,Entry<T>> entries = new HashMap<>();
+  private boolean closed;
+  public SchoolDocumentPending(LongSupplier clock) { this.clock = clock; }
+  public String put(long viewId, T value) {
+    expire();
+    if (closed) return null;
+    Iterator<Entry<T>> old = entries.values().iterator();
+    while (old.hasNext()) if (old.next().viewId == viewId) { old.remove(); SLOTS.release(); }
+    if (!SLOTS.tryAcquire()) return null;
+    String token = UUID.randomUUID().toString();
+    entries.put(token, new Entry<>(viewId, clock.getAsLong(), value));
+    return token;
+  }
+  public T get(String token) {
+    expire();
+    Entry<T> entry = entries.get(token);
+    return entry == null ? null : entry.value;
+  }
+  public T remove(String token) {
+    Entry<T> removed = entries.remove(token);
+    if (removed == null) return null;
+    SLOTS.release();
+    return removed.value;
+  }
+  public void removeView(long viewId) {
+    Iterator<Entry<T>> current = entries.values().iterator();
+    while (current.hasNext()) if (current.next().viewId == viewId) { current.remove(); SLOTS.release(); }
+  }
+  private void expire() {
+    long now = clock.getAsLong();
+    Iterator<Entry<T>> current = entries.values().iterator();
+    while (current.hasNext()) if (now - current.next().created >= TTL) { current.remove(); SLOTS.release(); }
+  }
+  public void close() {
+    if (closed) return;
+    closed = true;
+    SLOTS.release(entries.size());
+    entries.clear();
+  }
+}

mobile/android/app/src/main/java/com/tpschedule/app/SchoolDocumentReader.java

@@ -0,0 +1,162 @@
+package com.tpschedule.app;
+
+import java.io.*;
+import java.net.HttpURLConnection;
+import java.net.URI;
+import java.net.URL;
+import java.net.URLDecoder;
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+import java.util.*;
+import java.util.regex.*;
+import java.util.zip.GZIPInputStream;
+
+/** Bounded transport for an already visible read-only school document. */
+public final class SchoolDocumentReader {
+  public interface ConnectionFactory { HttpURLConnection open(URL url) throws IOException; }
+  public static final class Failure extends Exception {
+    public final String code;
+    public Failure(String code) { super(code); this.code = code; }
+  }
+  public static final class Document {
+    public final String html;
+    public final List<String> setCookies;
+    public Document(String html, List<String> setCookies) { this.html = html; this.setCookies = setCookies; }
+  }
+  private final ConnectionFactory connections;
+  public SchoolDocumentReader(ConnectionFactory connections) { this.connections = connections; }
+  public static URI validateUrl(String value) throws Failure {
+    try {
+      if (value == null || value.length() > 8192) throw new Failure("unsafe_url");
+      URI uri = new URI(value);
+      if (!"https".equalsIgnoreCase(uri.getScheme()) || uri.getUserInfo() != null ||
+          (uri.getPort() != -1 && uri.getPort() != 443)) throw new Failure("unsafe_url");
+      String path = uri.getRawPath();
+      boolean undergraduate = "eams.uestc.edu.cn".equalsIgnoreCase(uri.getHost()) && path != null &&
+          path.matches("/eams/?|/eams/(home(?:Ext)?(?:!(?:main|index|welcome))?|index|courseTableForStd(?:!courseTable)?|stdExamTable!examTable)\\.action");
+      boolean graduate = "yjsjy.uestc.edu.cn".equalsIgnoreCase(uri.getHost()) && path != null &&
+          path.matches("/pyxx/pygl/(xskbcx/index/[1-9][0-9]*|kskcxx/index)");
+      if (!undergraduate && !graduate) throw new Failure("unsafe_url");
+      if (uri.getRawQuery() != null) {
+        for (String parameter : uri.getRawQuery().split("[&;]")) {
+          String key = URLDecoder.decode(parameter.split("=", 2)[0], "UTF-8").toLowerCase(Locale.ROOT);
+          if (key.matches("x-requested-with|ticket|password|username|j_username|j_password|action|optype|operation|method|command|redirect|redirect_uri|service"))
+            throw new Failure("unsafe_url");
+        }
+      }
+      return uri;
+    } catch (Failure failure) { throw failure; }
+    catch (Exception ignored) { throw new Failure("unsafe_url"); }
+  }
+
+  public Document fetch(String url, String cookie, String userAgent) throws Failure {
+    URI uri = validateUrl(url);
+    if (cookie == null || cookie.trim().isEmpty() || cookie.length() > 16384 || hasControls(cookie)) throw new Failure("no_session");
+    HttpURLConnection connection = null;
+    long deadline = System.nanoTime() + 15_000_000_000L;
+    try {
+      connection = connections.open(uri.toURL());
+      connection.setInstanceFollowRedirects(false);
+      connection.setRequestMethod("GET");
+      connection.setConnectTimeout(8000);
+      connection.setReadTimeout(8000);
+      connection.setUseCaches(false);
+      connection.setRequestProperty("Cookie", cookie);
+      if (userAgent != null && userAgent.length() <= 4096 && !hasControls(userAgent)) connection.setRequestProperty("User-Agent", userAgent);
+      connection.setRequestProperty("Accept", "text/html,application/xhtml+xml");
+      connection.setRequestProperty("Accept-Encoding", "gzip");
+      if (connection.getResponseCode() != 200) throw new Failure("invalid_response");
+      String contentType = connection.getContentType();
+      if (contentType == null) throw new Failure("invalid_response");
+      String mime = contentType.split(";", 2)[0].trim().toLowerCase(Locale.ROOT);
+      if (!mime.equals("text/html") && !mime.equals("application/xhtml+xml")) throw new Failure("invalid_response");
+      Charset charset = StandardCharsets.UTF_8;
+      Matcher declared = Pattern.compile("(?:^|;)\\s*charset\\s*=\\s*[\"']?([^;\\s\"']+)", Pattern.CASE_INSENSITIVE).matcher(contentType);
+      if (declared.find()) {
+        try { charset = Charset.forName(declared.group(1)); }
+        catch (Exception ignored) { throw new Failure("invalid_response"); }
+      }
+      String encoding = connection.getContentEncoding();
+      if (encoding != null && !encoding.equalsIgnoreCase("gzip") && !encoding.equalsIgnoreCase("identity")) throw new Failure("invalid_response");
+      byte[] bytes;
+      try (InputStream raw = new BoundedInput(connection.getInputStream(), deadline);
+           InputStream decoded = "gzip".equalsIgnoreCase(encoding) ? new GZIPInputStream(raw) : raw;
+           ByteArrayOutputStream body = new ByteArrayOutputStream()) {
+        byte[] buffer = new byte[8192];
+        int count;
+        while ((count = decoded.read(buffer)) != -1) {
+          if (System.nanoTime() > deadline) throw new Failure("network_failed");
+          if (body.size() + count > 2 * 1024 * 1024) throw new Failure("too_large");
+          body.write(buffer, 0, count);
+        }
+        bytes = body.toByteArray();
+      }
+      return new Document(new String(bytes, charset), safeCookies(uri, connection.getHeaderFields()));
+    } catch (Failure failure) { throw failure; }
+    catch (BoundFailure failure) { throw new Failure(failure.code); }
+    catch (Exception ignored) { throw new Failure("network_failed"); }
+    finally { if (connection != null) connection.disconnect(); }
+  }
+
+  private static final class BoundFailure extends IOException {
+    final String code;
+    BoundFailure(String code) { super(code); this.code = code; }
+  }
+  /** Also bounds gzip metadata, which the decoder may read before emitting bytes. */
+  private static final class BoundedInput extends FilterInputStream {
+    final long deadline;
+    int total;
+    BoundedInput(InputStream source, long deadline) { super(source); this.deadline = deadline; }
+    private void check(int count) throws BoundFailure {
+      if (System.nanoTime() > deadline) throw new BoundFailure("network_failed");
+      if (count > 0) total += count;
+      if (total > 2 * 1024 * 1024) throw new BoundFailure("too_large");
+    }
+    @Override public int read() throws IOException {
+      check(0); int result = in.read(); check(result < 0 ? 0 : 1); return result;
+    }
+    @Override public int read(byte[] bytes, int offset, int length) throws IOException {
+      check(0); int count = in.read(bytes, offset, length); check(count); return count;
+    }
+  }
+
+  private static boolean hasControls(String value) {
+    for (int i = 0; i < value.length(); i++) if (value.charAt(i) < 32 || value.charAt(i) == 127) return true;
+    return false;
+  }
+
+  private static List<String> safeCookies(URI uri, Map<String,List<String>> headers) {
+    List<String> accepted = new ArrayList<>();
+    int total = 0;
+    if (headers == null) return accepted;
+    String root = uri.getHost().equalsIgnoreCase("eams.uestc.edu.cn") ? "/eams" : "/pyxx";
+    for (Map.Entry<String,List<String>> entry : headers.entrySet()) {
+      if (entry.getKey() == null || !entry.getKey().equalsIgnoreCase("Set-Cookie") || entry.getValue() == null) continue;
+      for (String cookie : entry.getValue()) {
+        if (cookie == null || cookie.length() > 4096 || hasControls(cookie)) continue;
+        String[] parts = cookie.split(";", -1);
+        if (!parts[0].trim().matches("[!#$%&'*+.^_`|~0-9A-Za-z-]+=[^;]*")) continue;
+        boolean safe = true, domainSeen = false, pathSeen = false;
+        for (int i = 1; i < parts.length; i++) {
+          String[] attr = parts[i].trim().split("=", 2);
+          if (attr[0].equalsIgnoreCase("Domain")) {
+            if (domainSeen || attr.length != 2 || !attr[1].equalsIgnoreCase(uri.getHost())) safe = false;
+            domainSeen = true;
+          }
+          if (attr[0].equalsIgnoreCase("Path")) {
+            if (pathSeen || attr.length != 2 || !(attr[1].equals(root) || attr[1].startsWith(root+"/")) || attr[1].contains("%") || attr[1].contains("\\") || attr[1].contains("..")) safe = false;
+            pathSeen = true;
+          }
+        }
+        if (safe && accepted.size() < 16 && total + cookie.length() <= 16384) {
+          accepted.add(cookie); total += cookie.length();
+        }
+      }
+    }
+    return Collections.unmodifiableList(accepted);
+  }
+
+  static List<String> cookiesForRender(String url, List<String> cookies) throws Failure {
+    return safeCookies(validateUrl(url), Collections.singletonMap("Set-Cookie", cookies));
+  }
+}

mobile/android/app/src/main/java/com/tpschedule/app/SchoolDocumentRenderer.java

@@ -0,0 +1,39 @@
+package com.tpschedule.app;
+
+import android.webkit.WebView;
+import android.webkit.CookieManager;
+import android.webkit.ValueCallback;
+import android.os.Looper;
+import org.json.JSONObject;
+
+/** Same-turn final guards and WebView load, shared with device instrumentation. */
+public final class SchoolDocumentRenderer {
+  private SchoolDocumentRenderer() { }
+  /** Checks the live document; callers must recheck native state in this callback. */
+  public static void checkDocument(WebView view, String url, String documentToken, ValueCallback<Boolean> callback) {
+    if (Looper.myLooper() != Looper.getMainLooper() || view == null || documentToken == null ||
+        !documentToken.matches("[A-Za-z0-9-]{1,128}")) { callback.onReceiveValue(false); return; }
+    try {
+      SchoolDocumentReader.validateUrl(url);
+      view.evaluateJavascript("location.href === " + JSONObject.quote(url) +
+          " && window.__tpscheduleDocumentToken === " + JSONObject.quote(documentToken),
+          value -> callback.onReceiveValue("true".equals(value)));
+    } catch (Exception ignored) { callback.onReceiveValue(false); }
+  }
+  public static boolean render(WebView view, String url, String originalCookie, SchoolDocumentReader.Document document) {
+    if (Looper.myLooper() != Looper.getMainLooper()) return false;
+    try {
+      SchoolDocumentReader.validateUrl(url);
+      if (view == null || document == null || document.html == null || document.html.length() > 2 * 1024 * 1024 ||
+          originalCookie == null || originalCookie.trim().isEmpty() || !url.equals(view.getUrl())) return false;
+      CookieManager cookies = CookieManager.getInstance();
+      if (!originalCookie.equals(cookies.getCookie(url))) return false;
+      // The guards, scoped cookie application and load occur in one UI turn.
+      for (String cookie : SchoolDocumentReader.cookiesForRender(url, document.setCookies)) cookies.setCookie(url, cookie);
+      view.loadDataWithBaseURL(url, document.html, "text/html", "UTF-8", url);
+      return true;
+    } catch (Exception ignored) {
+      return false;
+    }
+  }
+}

mobile/android/app/src/main/kotlin/com/tpschedule/app/MainActivity.kt

@@ -8,6 +8,7 @@ import io.flutter.embedding.engine.FlutterEngine
 class MainActivity : FlutterActivity() {
     private var calendar: CalendarBridge? = null
     private var reminders: ReminderSystemBridge? = null
+    private var schoolDocuments: SchoolDocumentBridge? = null
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {
@@ -20,6 +21,13 @@ class MainActivity : FlutterActivity() {
         super.configureFlutterEngine(flutterEngine)
         calendar = CalendarBridge(this, flutterEngine.dartExecutor.binaryMessenger)
         reminders = ReminderSystemBridge(this, flutterEngine.dartExecutor.binaryMessenger)
+        schoolDocuments?.close()
+        schoolDocuments = SchoolDocumentBridge(flutterEngine)
+    }
+    override fun cleanUpFlutterEngine(flutterEngine: FlutterEngine) {
+        schoolDocuments?.close()
+        schoolDocuments = null
+        super.cleanUpFlutterEngine(flutterEngine)
     }
     override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<out String>, grantResults: IntArray) {
         super.onRequestPermissionsResult(requestCode, permissions, grantResults)
@@ -28,6 +36,7 @@ class MainActivity : FlutterActivity() {
     override fun onDestroy() {
         calendar?.close()
         reminders?.close()
+        schoolDocuments?.close()
         super.onDestroy()
     }
 }

mobile/android/app/src/main/kotlin/com/tpschedule/app/SchoolDocumentBridge.kt

@@ -0,0 +1,165 @@
+package com.tpschedule.app
+
+import android.os.Handler
+import android.os.Looper
+import android.os.SystemClock
+import android.webkit.CookieManager
+import android.webkit.WebView
+import io.flutter.embedding.engine.FlutterEngine
+import io.flutter.plugin.common.MethodCall
+import io.flutter.plugin.common.MethodChannel
+import io.flutter.plugins.webviewflutter.WebViewFlutterAndroidExternalApi
+import java.lang.ref.WeakReference
+import java.util.concurrent.ArrayBlockingQueue
+import java.util.concurrent.RejectedExecutionException
+import java.util.concurrent.ThreadPoolExecutor
+import java.util.concurrent.TimeUnit
+import javax.net.ssl.HttpsURLConnection
+
+/** Fetches a bounded full document with the visible WebView's existing session. */
+class SchoolDocumentBridge(private val engine: FlutterEngine) {
+    private class Candidate(
+        val viewId: Long,
+        val url: String,
+        val cookie: String,
+        val documentToken: String,
+        val view: WeakReference<WebView>,
+        var document: SchoolDocumentReader.Document? = null,
+    )
+
+    private val ui = Handler(Looper.getMainLooper())
+    private val worker = ThreadPoolExecutor(
+        2, 2, 0L, TimeUnit.MILLISECONDS, ArrayBlockingQueue<Runnable>(2),
+    )
+    private val pending = SchoolDocumentPending<Candidate> { SystemClock.elapsedRealtime() }
+    private val reader = SchoolDocumentReader { url -> url.openConnection() as HttpsURLConnection }
+    private val channel = MethodChannel(engine.dartExecutor.binaryMessenger, "com.tpschedule.app/school_document")
+    private var closed = false
+
+    init {
+        channel.setMethodCallHandler { call, result ->
+            try {
+                if (closed || Looper.myLooper() != Looper.getMainLooper()) {
+                    fail(result, "unavailable")
+                } else {
+                    when (call.method) {
+                        "fetch" -> fetch(call, result)
+                        "render" -> render(call, result)
+                        "invalidate" -> {
+                            val viewId = call.argument<Number>("viewId")?.toLong()
+                            if (viewId != null) pending.removeView(viewId)
+                            result.success(null)
+                        }
+                        "discard" -> {
+                            call.argument<String>("token")?.let { pending.remove(it) }
+                            result.success(null)
+                        }
+                        else -> result.notImplemented()
+                    }
+                }
+            } catch (failure: SchoolDocumentReader.Failure) {
+                fail(result, failure.code)
+            } catch (_: Exception) {
+                fail(result, "unavailable")
+            }
+        }
+    }
+
+    @Suppress("DEPRECATION")
+    private fun webView(viewId: Long): WebView? =
+        WebViewFlutterAndroidExternalApi.getWebView(engine, viewId)
+
+    private fun fetch(call: MethodCall, result: MethodChannel.Result) {
+        val viewId = call.argument<Number>("viewId")?.toLong()
+            ?: return fail(result, "unavailable")
+        val url = call.argument<String>("url") ?: return fail(result, "unsafe_url")
+        val documentToken = call.argument<String>("documentToken")
+            ?.takeIf { it.matches(Regex("[A-Za-z0-9-]{1,128}")) }
+            ?: return fail(result, "stale_document")
+        SchoolDocumentReader.validateUrl(url)
+        val view = webView(viewId) ?: return fail(result, "unavailable")
+        if (view.url != url) return fail(result, "stale_document")
+        val cookie = CookieManager.getInstance().getCookie(url)
+        if (cookie.isNullOrBlank()) return fail(result, "no_session")
+        val userAgent = view.settings.userAgentString
+        val candidate = Candidate(viewId, url, cookie, documentToken, WeakReference(view))
+        val token = pending.put(viewId, candidate) ?: return fail(result, "unavailable")
+        // Expiration clears native bodies/cookies even when Dart never calls discard.
+        ui.postDelayed({ pending.remove(token) }, 20_000)
+        try {
+            worker.execute {
+                var document: SchoolDocumentReader.Document? = null
+                var error: String? = null
+                try {
+                    document = reader.fetch(url, cookie, userAgent)
+                } catch (failure: SchoolDocumentReader.Failure) {
+                    error = failure.code
+                } catch (_: Exception) {
+                    error = "network_failed"
+                }
+                ui.post {
+                    try {
+                        if (closed) {
+                            pending.remove(token)
+                            fail(result, "unavailable")
+                        } else if (pending.get(token) !== candidate || !matches(candidate)) {
+                            pending.remove(token)
+                            fail(result, "stale_document")
+                        } else if (error != null || document == null) {
+                            pending.remove(token)
+                            fail(result, error ?: "invalid_response")
+                        } else {
+                            candidate.document = document
+                            result.success(mapOf("token" to token, "html" to document!!.html))
+                        }
+                    } catch (_: Exception) {
+                        pending.remove(token)
+                        fail(result, "unavailable")
+                    }
+                }
+            }
+        } catch (_: RejectedExecutionException) {
+            pending.remove(token)
+            fail(result, "unavailable")
+        }
+    }
+
+    private fun matches(candidate: Candidate): Boolean {
+        val actual = webView(candidate.viewId) ?: return false
+        return actual === candidate.view.get() && actual.url == candidate.url &&
+            CookieManager.getInstance().getCookie(candidate.url) == candidate.cookie
+    }
+
+    private fun render(call: MethodCall, result: MethodChannel.Result) {
+        val token = call.argument<String>("token") ?: return result.success(false)
+        val candidate = pending.get(token) ?: return result.success(false)
+        val document = candidate.document ?: return result.success(false)
+        if (!matches(candidate)) return result.success(false)
+        val view = candidate.view.get() ?: return result.success(false)
+        SchoolDocumentRenderer.checkDocument(view, candidate.url, candidate.documentToken) { sameDocument ->
+            try {
+                // Invalidation, replacement or expiration during JS verification cancels this render.
+                if (closed || !sameDocument || pending.get(token) !== candidate || !matches(candidate)) {
+                    pending.remove(token)
+                    result.success(false)
+                } else {
+                    pending.remove(token)
+                    result.success(SchoolDocumentRenderer.render(view, candidate.url, candidate.cookie, document))
+                }
+            } catch (_: Exception) {
+                pending.remove(token)
+                result.success(false)
+            }
+        }
+    }
+
+    private fun fail(result: MethodChannel.Result, code: String) = result.error(code, code, null)
+
+    fun close() {
+        closed = true
+        channel.setMethodCallHandler(null)
+        pending.close()
+        worker.shutdownNow()
+        ui.removeCallbacksAndMessages(null)
+    }
+}

mobile/android/app/src/test/java/com/tpschedule/app/SchoolDocumentPendingTest.java

@@ -0,0 +1,53 @@
+package com.tpschedule.app;
+
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+public class SchoolDocumentPendingTest {
+  @Test public void invalidateViewRemovesCandidateAwaitingDocumentVerification() {
+    SchoolDocumentPending<String> store = new SchoolDocumentPending<>(() -> 0);
+    try {
+      String waiting = store.put(42, "awaiting-verification"), other = store.put(43, "other-view");
+      store.removeView(42);
+      assertNull(store.get(waiting));
+      assertEquals("other-view", store.get(other));
+      assertNotNull(store.put(42, "new-document"));
+      assertNull(store.get(waiting));
+    } finally { store.close(); }
+  }
+  @Test public void capsPendingAcrossViewsAndReleasesOnDiscard() {
+    long[] now = {0};
+    SchoolDocumentPending<String> store = new SchoolDocumentPending<>(() -> now[0]);
+    for (int i=0;i<4;i++) assertNotNull(store.put(i, "doc"));
+    assertNull(store.put(5, "over-cap"));
+    String removed = store.put(0, "replacement");
+    assertNotNull(removed);
+    store.remove(removed);
+    assertNotNull(store.put(5, "after-discard"));
+    store.close();
+  }
+  @Test public void expiresAtTwentySecondsAndDoesNotReviveAfterClose() {
+    long[] now = {100};
+    SchoolDocumentPending<String> store = new SchoolDocumentPending<>(() -> now[0]);
+    String token = store.put(42, "private");
+    now[0] = 20099; assertEquals("private", store.get(token));
+    now[0] = 20100; assertNull(store.get(token));
+    String next = store.put(43, "private"); store.close();
+    assertNull(store.get(next)); assertNull(store.put(44, "late"));
+  }
+  @Test public void newFetchReplacesOnlyTheSameViewAndInvalidatesOldToken() {
+    SchoolDocumentPending<String> store = new SchoolDocumentPending<>(() -> 0);
+    String first = store.put(1,"old"), other = store.put(2,"other"), latest = store.put(1,"latest");
+    assertNull(store.get(first)); assertEquals("other",store.get(other)); assertEquals("latest",store.get(latest));
+    assertEquals("latest",store.remove(latest)); assertNull(store.remove(latest));
+    store.close();
+  }
+  @Test public void fourSlotLimitIsSharedAcrossRegistries() {
+    SchoolDocumentPending<String> a = new SchoolDocumentPending<>(() -> 0), b = new SchoolDocumentPending<>(() -> 0);
+    try {
+      for(int i=0;i<4;i++) assertNotNull(a.put(i,"private"));
+      assertNull(b.put(7,"over-cap"));
+      a.close(); assertNotNull(b.put(7,"released"));
+    } finally { a.close(); b.close(); }
+  }
+}

mobile/android/app/src/test/java/com/tpschedule/app/SchoolDocumentReaderTest.java

@@ -0,0 +1,111 @@
+package com.tpschedule.app;
+
+import org.junit.Test;
+import static org.junit.Assert.*;
+import java.io.*;
+import java.net.*;
+import java.nio.charset.StandardCharsets;
+import java.util.*;
+import java.util.zip.GZIPOutputStream;
+
+public class SchoolDocumentReaderTest {
+  private static final String URL = "https://eams.uestc.edu.cn/eams/home!main.action";
+  // Mimics beangle3 head.ftl: presence of XRW suppresses the complete head.
+  static class Backend extends HttpURLConnection {
+    int status = 200;
+    String mime = "text/html; charset=UTF-8";
+    byte[] body;
+    String encoding;
+    List<String> cookies = new ArrayList<>();
+    boolean disconnected;
+    Backend() throws Exception { super(new URL(URL)); }
+    public void connect() { }
+    public boolean usingProxy() { return false; }
+    public void disconnect() { disconnected = true; }
+    public int getResponseCode() { return status; }
+    public String getContentType() { return mime; }
+    public String getContentEncoding() { return encoding; }
+    public Map<String,List<String>> getHeaderFields() { return Collections.singletonMap("Set-Cookie", cookies); }
+    public InputStream getInputStream() {
+      if (body != null) return new ByteArrayInputStream(body);
+      boolean fragment = getRequestProperty("X-Requested-With") != null;
+      return new ByteArrayInputStream((fragment ? "<div>课表</div>" : "<html><head><script src='jquery.js'></script><link rel='stylesheet' href='site.css'></head><body>课表</body></html>").getBytes(StandardCharsets.UTF_8));
+    }
+  }
+  private SchoolDocumentReader reader(Backend backend) { return new SchoolDocumentReader(url -> backend); }
+  private void reject(String code, Throwing action) throws Exception {
+    try { action.run(); fail("expected " + code); }
+    catch (SchoolDocumentReader.Failure failure) { assertEquals(code, failure.code); assertEquals(code, failure.getMessage()); }
+  }
+  interface Throwing { void run() throws Exception; }
+
+  @Test public void missingXrwRestoresFullHeadWithSameSessionGet() throws Exception {
+    Backend backend = new Backend();
+    SchoolDocumentReader.Document document = reader(backend).fetch(URL, "SESSION=private", "fixture-agent");
+    assertTrue(document.html.contains("jquery.js"));
+    assertTrue(document.html.contains("site.css"));
+    assertTrue(document.html.contains("课表"));
+    assertEquals("GET", backend.getRequestMethod());
+    assertEquals("SESSION=private", backend.getRequestProperty("Cookie"));
+    assertEquals("fixture-agent", backend.getRequestProperty("User-Agent"));
+    assertNull(backend.getRequestProperty("X-Requested-With"));
+    assertFalse(backend.getInstanceFollowRedirects());
+    assertTrue(backend.disconnected);
+  }
+  @Test public void missingSessionMakesNoRequest() throws Exception {
+    reject("no_session", () -> new SchoolDocumentReader(url -> { fail("request before session validation"); return null; }).fetch(URL, "", "ua"));
+  }
+  @Test public void rejectsUnsafeTargetsAndDecodedCredentialQuery() throws Exception {
+    String[] urls = {"http://eams.uestc.edu.cn/eams/", "https://eams.uestc.edu.cn:444/eams/", "https://eams.uestc.edu.cn.evil/eams/", "https://user@eams.uestc.edu.cn/eams/", "https://eams.uestc.edu.cn/eams/logout.action", "https://eams.uestc.edu.cn/eams/home!save.action", URL+"?%74icket=secret", URL+"?X-Requested-With=a", URL+"?action=delete", URL+"?opType=save", "https://eams.uestc.edu.cn/eams/%2e%2e/eams/"};
+    for (String url : urls) reject("unsafe_url", () -> reader(new Backend()).fetch(url, "S=x", "ua"));
+  }
+  @Test public void allowsOnlySettledReadonlyRoutes() throws Exception {
+    String[] urls = {"https://eams.uestc.edu.cn/eams", "https://eams.uestc.edu.cn/eams/", "https://eams.uestc.edu.cn/eams/homeExt!index.action", "https://eams.uestc.edu.cn/eams/courseTableForStd!courseTable.action?semester.id=42", "https://eams.uestc.edu.cn/eams/stdExamTable!examTable.action", "https://yjsjy.uestc.edu.cn/pyxx/pygl/xskbcx/index/42", "https://yjsjy.uestc.edu.cn/pyxx/pygl/kskcxx/index"};
+    for (String url : urls) assertNotNull(reader(new Backend()).fetch(url, "S=x", "ua"));
+  }
+  @Test public void neverFollowsRedirectsIncludingSameHost() throws Exception {
+    Backend backend = new Backend(); backend.status = 302;
+    reject("invalid_response", () -> reader(backend).fetch(URL, "S=x", "ua"));
+    assertFalse(backend.getInstanceFollowRedirects()); assertTrue(backend.disconnected);
+  }
+  @Test public void rejectsNonHtmlOrNonSuccess() throws Exception {
+    for (String mime : new String[]{"application/json", "text/plain", null}) {
+      Backend backend = new Backend(); backend.mime = mime;
+      reject("invalid_response", () -> reader(backend).fetch(URL, "S=x", "ua"));
+    }
+    for (int status : new int[]{201,204,401,403,500}) {
+      Backend backend = new Backend(); backend.status = status;
+      reject("invalid_response", () -> reader(backend).fetch(URL, "S=x", "ua"));
+    }
+  }
+  @Test public void enforcesDecodedLimitEvenForGzip() throws Exception {
+    byte[] oversized = new byte[2*1024*1024+1]; Arrays.fill(oversized, (byte)'a');
+    Backend plain = new Backend(); plain.body = oversized;
+    reject("too_large", () -> reader(plain).fetch(URL, "S=x", "ua"));
+    Backend zipped = new Backend(); zipped.encoding = "gzip";
+    ByteArrayOutputStream buffer = new ByteArrayOutputStream();
+    try (GZIPOutputStream gzip = new GZIPOutputStream(buffer)) { gzip.write(oversized); }
+    zipped.body = buffer.toByteArray();
+    reject("too_large", () -> reader(zipped).fetch(URL, "S=x", "ua"));
+  }
+  @Test public void acceptsHtmlCharsetAndGzip() throws Exception {
+    Backend backend = new Backend(); backend.mime = "application/xhtml+xml; charset=GB18030";
+    backend.body = "<html>中文</html>".getBytes("GB18030");
+    assertEquals("<html>中文</html>", reader(backend).fetch(URL,"S=x","ua").html);
+  }
+  @Test public void boundsCompressedHeadersBeforeDecoderProducesOutput() throws Exception {
+    Backend backend = new Backend(); backend.encoding = "gzip";
+    backend.body = new byte[2*1024*1024+1]; Arrays.fill(backend.body,(byte)'a');
+    byte[] gzipHeader = {(byte)0x1f,(byte)0x8b,8,8,0,0,0,0,0,3};
+    System.arraycopy(gzipHeader,0,backend.body,0,gzipHeader.length);
+    reject("too_large", () -> reader(backend).fetch(URL,"S=x","ua"));
+  }
+  @Test public void onlyKeepsBoundedSameSchoolCookieScope() throws Exception {
+    Backend backend = new Backend();
+    backend.cookies = Arrays.asList("SID=next; Path=/eams; Secure; HttpOnly", "A=b; Domain=eams.uestc.edu.cn; Path=/eams/", "BAD=x; Domain=.uestc.edu.cn; Path=/eams", "BAD=x; Domain=eams.uestc.edu.cn.evil; Path=/eams", "BAD=x; Path=/", "BAD=x; Path=/eamsOther", "BAD=x\r\nInjected: yes", "BAD=x; Domain=eams.uestc.edu.cn; Domain=evil", "z="+String.join("", Collections.nCopies(4097,"a")));
+    assertEquals(Arrays.asList("SID=next; Path=/eams; Secure; HttpOnly", "A=b; Domain=eams.uestc.edu.cn; Path=/eams/"),reader(backend).fetch(URL,"S=x","ua").setCookies);
+  }
+  @Test public void sanitizesTransportFailure() throws Exception {
+    reject("network_failed", () -> new SchoolDocumentReader(url -> { throw new IOException("secret-cookie-and-url"); }).fetch(URL,"S=x","ua"));
+  }
+}

mobile/lib/app/app_version.dart

@@ -1,2 +1,2 @@
-const appVersion = '0.7.2';
-const appBuildNumber = 20;
+const appVersion = '0.7.3';
+const appBuildNumber = 21;

mobile/lib/features/school/school_full_page_recovery.dart

@@ -0,0 +1,295 @@
+import 'dart:async';
+import 'dart:convert';
+import 'dart:math';
+
+import 'package:flutter/services.dart';
+import 'package:html/parser.dart' as html;
+import 'package:webview_flutter/webview_flutter.dart';
+import 'package:webview_flutter_android/webview_flutter_android.dart';
+
+import '../../services/diagnostic_log.dart';
+import 'school_browser_diagnostics.dart';
+
+class SchoolPageCandidate {
+  const SchoolPageCandidate(this.token, this.html);
+  final String token, html;
+}
+
+abstract interface class SchoolFullPageGateway {
+  bool supports(WebViewController web);
+  Future<SchoolPageCandidate> fetch(
+    WebViewController web,
+    Uri url,
+    String documentToken,
+  );
+  Future<bool> render(String token);
+  Future<void> discard(String token);
+  Future<void> invalidate(WebViewController web);
+}
+
+enum FullPageRecoveryResult { unchanged, restored, failed, cancelled }
+
+class AndroidSchoolFullPageGateway implements SchoolFullPageGateway {
+  const AndroidSchoolFullPageGateway();
+  static const _channel = MethodChannel('com.tpschedule.app/school_document');
+  @override
+  bool supports(WebViewController web) =>
+      web.platform is AndroidWebViewController;
+  @override
+  Future<SchoolPageCandidate> fetch(
+    WebViewController web,
+    Uri url,
+    String documentToken,
+  ) async {
+    final response = await _channel.invokeMapMethod<String, dynamic>('fetch', {
+      'viewId': (web.platform as AndroidWebViewController).webViewIdentifier,
+      'url': url.toString(),
+      'documentToken': documentToken,
+    });
+    final token = response?['token'], page = response?['html'];
+    if (token is! String ||
+        !RegExp(r'^[A-Za-z0-9-]{1,128}$').hasMatch(token) ||
+        page is! String) {
+      throw const FormatException('Invalid page response');
+    }
+    return SchoolPageCandidate(token, page);
+  }
+
+  @override
+  Future<bool> render(String token) async =>
+      await _channel.invokeMethod<bool>('render', {'token': token}) == true;
+  @override
+  Future<void> discard(String token) =>
+      _channel.invokeMethod<void>('discard', {'token': token});
+  @override
+  Future<void> invalidate(WebViewController web) => _channel.invokeMethod<void>(
+    'invalidate',
+    {'viewId': (web.platform as AndroidWebViewController).webViewIdentifier},
+  );
+}
+
+class SchoolFullPageRecovery {
+  SchoolFullPageRecovery({SchoolFullPageGateway? gateway})
+    : gateway = gateway ?? const AndroidSchoolFullPageGateway();
+  final SchoolFullPageGateway gateway;
+  final _attempted = <String>{};
+  int _epoch = 0;
+  WebViewController? _lastWeb;
+  void reset() {
+    invalidateDocument();
+    _attempted.clear();
+  }
+
+  void invalidateDocument() {
+    _epoch++;
+    final web = _lastWeb;
+    if (web != null && gateway.supports(web)) {
+      unawaited(gateway.invalidate(web).catchError((Object _) {}));
+    }
+  }
+
+  static bool canRestore(Uri uri) {
+    if (uri.scheme != 'https' ||
+        uri.host != 'eams.uestc.edu.cn' ||
+        uri.port != 443 ||
+        uri.userInfo.isNotEmpty) {
+      return false;
+    }
+    if (uri.queryParametersAll.keys.any(
+      (key) => const {
+        'x-requested-with',
+        'ticket',
+        'password',
+        'username',
+        'j_username',
+        'j_password',
+        'optype',
+        'operation',
+        'action',
+        'method',
+      }.contains(key.toLowerCase()),
+    )) {
+      return false;
+    }
+    return uri.path == '/eams' ||
+        uri.path == '/eams/' ||
+        RegExp(
+          r'^/eams/(home(?:Ext)?(?:!(?:main|index|welcome))?|index|courseTableForStd(?:!courseTable)?|stdExamTable!examTable)\.action$',
+        ).hasMatch(uri.path);
+  }
+
+  Map? _pageState(Object raw) {
+    dynamic value = raw;
+    for (var i = 0; i < 2 && value is String; i++) {
+      value = jsonDecode(value);
+    }
+    return value is Map &&
+            value['scripts'] is int &&
+            value['scripts'] >= 0 &&
+            value['scripts'] <= 4 &&
+            value['styles'] == 0 &&
+            value['links'] == 0 &&
+            value['jquery'] == false &&
+            value['documentToken'] is String &&
+            RegExp(r'^[A-Za-z0-9-]{1,128}$').hasMatch(value['documentToken'])
+        ? value
+        : null;
+  }
+
+  bool _completePage(String source, Uri uri) {
+    if (source.length > 2 * 1024 * 1024 ||
+        utf8.encode(source).length > 2 * 1024 * 1024 ||
+        !RegExp(r'<head(?:\s|>)', caseSensitive: false).hasMatch(source)) {
+      return false;
+    }
+    final document = html.parse(source);
+    final head = document.head;
+    if (document.querySelector('input[type="password"]') != null ||
+        head == null ||
+        !head
+            .querySelectorAll('script[src]')
+            .any((e) => e.attributes['src']!.trim().isNotEmpty) ||
+        !head
+            .querySelectorAll('link[rel~="stylesheet"][href]')
+            .any((e) => e.attributes['href']!.trim().isNotEmpty)) {
+      return false;
+    }
+    if (head
+        .querySelectorAll('meta[http-equiv]')
+        .any((e) => e.attributes['http-equiv']!.toLowerCase() == 'refresh')) {
+      return false;
+    }
+    for (final base in head.querySelectorAll('base[href]')) {
+      if (uri.resolve(base.attributes['href']!).origin != uri.origin) {
+        return false;
+      }
+    }
+    return document.querySelector(
+              '#manualArrangeCourseTable, #stdExamTableForm',
+            ) !=
+            null ||
+        document.querySelectorAll('a[href]').any((a) {
+          final target = uri.resolve(a.attributes['href']!);
+          return target.scheme == 'https' &&
+              target.host == uri.host &&
+              target.port == 443 &&
+              target.userInfo.isEmpty &&
+              target.path == '/eams/logout.action';
+        });
+  }
+
+  void _record(String phase, [String? code]) => DiagnosticLog.instance.add(
+    'school_full_page_restore',
+    fields: {'school': 'undergraduate', 'phase': phase, 'code': code},
+  );
+
+  Future<FullPageRecoveryResult> tryRestore(
+    WebViewController web,
+    Uri url, {
+    required bool authenticated,
+    required String documentKey,
+    required bool Function() isCurrent,
+    void Function()? onStarted,
+  }) async {
+    if (!authenticated ||
+        !canRestore(url) ||
+        !gateway.supports(web) ||
+        _attempted.contains(documentKey)) {
+      return FullPageRecoveryResult.unchanged;
+    }
+    final epoch = _epoch;
+    _lastWeb = web;
+    bool valid() => isCurrent() && epoch == _epoch;
+    SchoolPageCandidate? candidate;
+    try {
+      if (!valid() || await web.currentUrl() != url.toString() || !valid()) {
+        return FullPageRecoveryResult.cancelled;
+      }
+      final nonce = List.generate(
+        4,
+        (_) => Random.secure()
+            .nextInt(0x100000000)
+            .toRadixString(16)
+            .padLeft(8, '0'),
+      ).join();
+      final diagnostic = schoolPageDiagnosticsScript.replaceAll(
+        '__EXPECTED_URL__',
+        jsonEncode(url.toString()),
+      );
+      final raw = await web.runJavaScriptReturningResult('''(() => {
+        const state=JSON.parse($diagnostic);
+        if(!state)return 'null';
+        if(typeof window.__tpscheduleDocumentToken!=='string')Object.defineProperty(window,'__tpscheduleDocumentToken',{value:'$nonce',configurable:true});
+        state.documentToken=window.__tpscheduleDocumentToken;
+        return JSON.stringify(state);
+      })()''');
+      if (!valid() || await web.currentUrl() != url.toString() || !valid()) {
+        return FullPageRecoveryResult.cancelled;
+      }
+      final state = _pageState(raw);
+      if (state == null) return FullPageRecoveryResult.unchanged;
+      if (_attempted.length >= 4) return FullPageRecoveryResult.failed;
+      _attempted.add(documentKey);
+      onStarted?.call();
+      if (!valid()) return FullPageRecoveryResult.cancelled;
+      _record('requested', 'missing_head');
+      candidate = await gateway
+          .fetch(web, url, state['documentToken'] as String)
+          .timeout(const Duration(seconds: 35));
+      if (!valid() || await web.currentUrl() != url.toString() || !valid()) {
+        _record('cancelled', 'document_changed');
+        return FullPageRecoveryResult.cancelled;
+      }
+      if (!_completePage(candidate.html, url)) {
+        _record('rejected', 'incomplete_head');
+        return FullPageRecoveryResult.failed;
+      }
+      if (!valid()) return FullPageRecoveryResult.cancelled;
+      final rendered = await gateway
+          .render(candidate.token)
+          .timeout(const Duration(seconds: 10));
+      _record(
+        rendered ? 'applied' : 'cancelled',
+        rendered ? null : 'document_changed',
+      );
+      return rendered
+          ? FullPageRecoveryResult.restored
+          : FullPageRecoveryResult.cancelled;
+    } catch (error) {
+      if (!valid()) return FullPageRecoveryResult.cancelled;
+      const codes = {
+        'invalid_url',
+        'no_session',
+        'document_changed',
+        'unexpected_status',
+        'redirect_rejected',
+        'invalid_content_type',
+        'too_large',
+        'network_failed',
+        'tls_failed',
+        'invalid_cookie',
+        'cookie_scope',
+        'unsupported_encoding',
+        'unsafe_url',
+        'stale_document',
+        'invalid_response',
+        'unavailable',
+      };
+      final code = error is PlatformException && codes.contains(error.code)
+          ? error.code
+          : error is TimeoutException
+          ? 'timeout'
+          : 'capture_failed';
+      _record('failed', code);
+      return FullPageRecoveryResult.failed;
+    } finally {
+      if (candidate != null) {
+        try {
+          await gateway.discard(candidate.token);
+        } catch (_) {
+          /* No pending private page is persisted. */
+        }
+      }
+    }
+  }
+}

mobile/lib/features/school/undergraduate/session.dart

@@ -13,9 +13,14 @@ import 'timetable_adapter.dart';
 import 'exam_adapter.dart';
 import '../school_browser.dart';
 import '../school_browser_diagnostics.dart';
+import '../school_full_page_recovery.dart';
 
 class UndergraduateSession extends ChangeNotifier {
-  UndergraduateSession({this.configureBrowser = configureSchoolBrowser});
+  UndergraduateSession({
+    this.configureBrowser = configureSchoolBrowser,
+    SchoolFullPageRecovery? pageRecovery,
+  }) : _pageRecovery = pageRecovery ?? SchoolFullPageRecovery();
+  final SchoolFullPageRecovery _pageRecovery;
   final SchoolBrowserConfigurator configureBrowser;
   Future<SchoolBrowserInfo>? _browserReady;
   String? browserVersion;
@@ -28,6 +33,7 @@ class UndergraduateSession extends ChangeNotifier {
       _connected = false,
       _loading = false,
       _manualCapture = false,
+      _recoveringPage = false,
       _failed = false,
       _complete = false;
   bool hasOpened = false, awaitingAuthentication = false, logoutFailed = false;
@@ -44,7 +50,8 @@ class UndergraduateSession extends ChangeNotifier {
   int get pageGeneration => _generation;
   bool get requestingExams => query != null;
   bool get canLogout => hasOpened || logoutFailed;
-  bool get busy => _loading || _manualCapture || _itemTimeout != null;
+  bool get busy =>
+      _loading || _manualCapture || _recoveringPage || _itemTimeout != null;
   String get statusLabel => logoutFailed
       ? '退出未完成'
       : _failed
@@ -70,6 +77,8 @@ class UndergraduateSession extends ChangeNotifier {
 
   void _reset() {
     _generation++;
+    _pageRecovery.reset();
+    _recoveringPage = false;
     _cancelTimers();
     _parts.clear();
     _index = 0;
@@ -123,6 +132,7 @@ class UndergraduateSession extends ChangeNotifier {
           return NavigationDecision.navigate;
         },
         onPageStarted: (url) {
+          _pageRecovery.invalidateDocument();
           DiagnosticLog.instance.navigation('undergraduate', 'started', url);
           // Within a batch, type-to-type loads retain their generation. Once
           // published, any new document invalidates the deferred save result.
@@ -130,6 +140,7 @@ class UndergraduateSession extends ChangeNotifier {
             _reset();
           }
           _document++;
+          _recoveringPage = false;
           _poll?.cancel();
           _probeKey = null;
           pendingDraft = null;
@@ -350,6 +361,37 @@ class UndergraduateSession extends ChangeNotifier {
       }
       _connected = true;
       awaitingAuthentication = false;
+      final recovery = await _pageRecovery.tryRestore(
+        web,
+        uri,
+        authenticated: true,
+        documentKey: '$g:$d',
+        isCurrent: () => _valid(g) && d == _document,
+        onStarted: () {
+          _recoveringPage = true;
+          message = '已登录，正在恢复完整教务页面…';
+          _emit();
+        },
+      );
+      if (!_valid(g) || d != _document) return;
+      _recoveringPage = false;
+      if (recovery == FullPageRecoveryResult.restored) {
+        _loading = true;
+        message = '完整页面已恢复，正在检查…';
+        _schedulePoll(g, d, url);
+        _emit();
+        return;
+      }
+      if (recovery == FullPageRecoveryResult.cancelled) {
+        message = '页面已变化，请等待加载完成或重新认证。';
+        _emit();
+        return;
+      }
+      if (recovery == FullPageRecoveryResult.failed) {
+        message = '已登录，但完整教务页面暂未恢复，请重新认证后重试。';
+        _emit();
+        return;
+      }
       if (!requestingExams) {
         message = manualMessage;
         _emit();
@@ -438,7 +480,9 @@ class UndergraduateSession extends ChangeNotifier {
   }
 
   Future<void> readCurrentTimetable() async {
-    if (requestingExams || _manualCapture || !_active) return;
+    if (requestingExams || _manualCapture || _recoveringPage || !_active) {
+      return;
+    }
     final g = _generation, d = _document;
     _manualCapture = true;
     _emit();
@@ -535,6 +579,7 @@ class UndergraduateSession extends ChangeNotifier {
     _disposed = true;
     _active = false;
     _generation++;
+    _pageRecovery.reset();
     _cancelTimers();
     super.dispose();
   }

mobile/pubspec.yaml

@@ -1,7 +1,7 @@
 name: hepan_everyday
 description: TPSchedule 学生课表
 publish_to: none
-version: 0.7.2+20
+version: 0.7.3+21
 environment:
   sdk: ^3.13.5
 dependencies:

mobile/test/school/full_page_recovery_js_test.cjs

@@ -0,0 +1,25 @@
+const assert = require('node:assert/strict');
+const fs = require('node:fs');
+const vm = require('node:vm');
+const path = require('node:path');
+const root = path.join(__dirname, '../../lib/features/school');
+const diagnostic = fs.readFileSync(path.join(root, 'school_browser_diagnostics.dart'), 'utf8').match(/schoolPageDiagnosticsScript = r'''([\s\S]*?)''';/)[1];
+const wrapper = fs.readFileSync(path.join(root, 'school_full_page_recovery.dart'), 'utf8').match(/'''(\(\(\) => \{[\s\S]*?)'''/)[1];
+const url = 'https://eams.uestc.edu.cn/eams/home.action';
+function context(password = false) {
+  const document = {scripts: Array(2), styleSheets: [], querySelector: () => password ? {} : null, querySelectorAll: () => []};
+  for (const key of ['cookie', 'body', 'forms']) Object.defineProperty(document, key, {get() {throw Error('private_data_read');}});
+  return vm.createContext({document, location: {href: url}, window: {}, performance: {getEntriesByType: () => []}});
+}
+function run(ctx, nonce) {
+  return JSON.parse(vm.runInContext(wrapper.replace('$diagnostic', diagnostic.replace('__EXPECTED_URL__', JSON.stringify(url))).replace('$nonce', nonce), ctx));
+}
+const ctx = context();
+assert.equal(run(ctx, 'first-document').documentToken, 'first-document');
+assert.equal(run(ctx, 'unused-token').documentToken, 'first-document');
+assert.equal(Object.keys(ctx.window).includes('__tpscheduleDocumentToken'), false);
+assert.equal(run(context(), 'new-document').documentToken, 'new-document');
+assert.equal(run(context(true), 'ignored'), null);
+const moved = context(); moved.location.href = 'https://idas.uestc.edu.cn/authserver/login';
+assert.equal(run(moved, 'ignored'), null);
+console.log('Recovery snapshot: actual wrapper, stable document nonce, new-document change, password/redirect guards and no private reads passed.');

mobile/test/school/school_full_page_recovery_test.dart

@@ -0,0 +1,259 @@
+import 'dart:async';
+import 'dart:convert';
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:webview_flutter/webview_flutter.dart';
+import 'package:hepan_everyday/features/school/school_full_page_recovery.dart';
+import 'package:hepan_everyday/features/school/undergraduate/session.dart';
+import 'package:hepan_everyday/features/school/undergraduate/page_probe.dart';
+
+import '../support/fake_school_web.dart';
+
+const _complete = '''<!doctype html><html><head>
+<script src="/eams/static/jquery.js"></script>
+<link rel="stylesheet" href="/eams/static/site.css"></head>
+<body><a href="/eams/logout.action">退出</a>PRIVATE_PAGE_CONTENT</body></html>''';
+const _fragment =
+    '<a href="/eams/logout.action">退出</a><script>jQuery(document);</script>';
+
+class Gateway implements SchoolFullPageGateway {
+  int requests = 0, renders = 0, discards = 0;
+  String html = _complete;
+  Completer<SchoolPageCandidate>? pending;
+  Completer<bool>? pendingRender;
+  bool live = false;
+  void Function()? onRender;
+  @override
+  bool supports(WebViewController web) => true;
+  @override
+  Future<SchoolPageCandidate> fetch(
+    WebViewController web,
+    Uri uri,
+    String documentToken,
+  ) async {
+    requests++;
+    live = true;
+    return pending == null
+        ? SchoolPageCandidate('opaque-token', html)
+        : pending!.future;
+  }
+
+  @override
+  Future<bool> render(String token) async {
+    renders++;
+    if (pendingRender != null) {
+      return await pendingRender!.future && live;
+    }
+    final accepted = live;
+    onRender?.call();
+    return accepted;
+  }
+
+  @override
+  Future<void> discard(String token) async {
+    discards++;
+  }
+
+  @override
+  Future<void> invalidate(WebViewController web) async {
+    live = false;
+  }
+}
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+  late FakeSchoolPlatform platform;
+  late WebViewController web;
+  late Gateway gateway;
+  late SchoolFullPageRecovery recovery;
+  final url = Uri.parse('https://eams.uestc.edu.cn/eams/home.action');
+  setUp(() {
+    platform = FakeSchoolPlatform();
+    WebViewPlatform.instance = platform;
+    web = WebViewController();
+    platform.web.url = url.toString();
+    platform.web.javascript = (_) async => jsonEncode({
+      'scripts': 2,
+      'styles': 0,
+      'links': 0,
+      'loaded': 0,
+      'jquery': false,
+      'documentToken': 'fixture-document-token',
+      'beangle': false,
+      'require': false,
+      'script202': 0,
+      'style202': 0,
+    });
+    gateway = Gateway();
+    recovery = SchoolFullPageRecovery(gateway: gateway);
+  });
+  Future<FullPageRecoveryResult> restore({
+    bool authenticated = true,
+    bool Function()? current,
+  }) => recovery.tryRestore(
+    web,
+    url,
+    authenticated: authenticated,
+    documentKey: 'visit:document',
+    isCurrent: current ?? () => true,
+  );
+
+  test(
+    'authenticated fragment is replaced only after a complete page is fetched',
+    () async {
+      expect(await restore(), FullPageRecoveryResult.restored);
+      expect(gateway.requests, 1);
+      expect(gateway.renders, 1);
+      expect(gateway.discards, 1);
+    },
+  );
+  test(
+    'incomplete head or password form preserves current page and does not loop',
+    () async {
+      for (final html in [
+        _fragment,
+        _complete.replaceFirst(
+          'PRIVATE_PAGE_CONTENT',
+          '<input type="password">',
+        ),
+        _complete.replaceFirst(
+          '</head>',
+          '<base href="https://other.test/"></head>',
+        ),
+        _complete.replaceFirst(
+          '</head>',
+          '<meta http-equiv="refresh" content="0;url=/login"></head>',
+        ),
+      ]) {
+        gateway.html = html;
+        recovery.reset();
+        expect(await restore(), FullPageRecoveryResult.failed);
+        expect(await restore(), FullPageRecoveryResult.unchanged);
+      }
+      expect(gateway.renders, 0);
+      expect(gateway.requests, 4);
+      expect(gateway.discards, 4);
+    },
+  );
+  for (final started in [false, true]) {
+    test(
+      'session recovers once and completes after render, started=$started',
+      () async {
+        final session = UndergraduateSession(pageRecovery: recovery);
+        addTearDown(session.dispose);
+        await session.openTimetable();
+        var rendered = false;
+        platform.web.javascript = (script) async {
+          if (script == undergraduateStatusProbeScript) {
+            return jsonEncode({
+              'topUrl': platform.web.url!,
+              'authenticated': true,
+              'pages': [],
+            });
+          }
+          return jsonEncode({
+            'scripts': rendered ? 20 : 2,
+            'styles': 0,
+            'links': rendered ? 3 : 0,
+            'jquery': rendered,
+            'documentToken': 'fixture-document-token',
+          });
+        };
+        gateway.onRender = () {
+          rendered = true;
+          if (started) platform.delegate.started(platform.web.url!);
+          platform.delegate.finished(platform.web.url!);
+        };
+        platform.web.url = url.toString();
+        platform.delegate.started(url.toString());
+        platform.delegate.finished(url.toString());
+        await flushSchoolEvents();
+        await Future<void>.delayed(const Duration(milliseconds: 550));
+        await flushSchoolEvents();
+        expect(session.statusLabel, '已连接');
+        expect(session.busy, false);
+        expect(session.message, UndergraduateSession.manualMessage);
+        expect(gateway.requests, 1);
+        expect(gateway.renders, 1);
+        expect(session.pendingDraft, isNull);
+      },
+    );
+  }
+  test(
+    'same URL document replacement or closing during fetch cancels rendering',
+    () async {
+      gateway.pending = Completer<SchoolPageCandidate>();
+      var current = true;
+      final task = restore(current: () => current);
+      await flushSchoolEvents();
+      expect(gateway.requests, 1);
+      current = false;
+      gateway.pending!.complete(
+        const SchoolPageCandidate('opaque-token', _complete),
+      );
+      expect(await task, FullPageRecoveryResult.cancelled);
+      expect(gateway.renders, 0);
+      expect(gateway.discards, 1);
+    },
+  );
+  test(
+    'reset invalidates a native render awaiting document verification',
+    () async {
+      gateway.pendingRender = Completer<bool>();
+      final task = restore();
+      await flushSchoolEvents();
+      expect(gateway.renders, 1);
+      recovery.reset();
+      gateway.pendingRender!.complete(true);
+      expect(await task, FullPageRecoveryResult.cancelled);
+      expect(gateway.live, false);
+      expect(gateway.discards, 1);
+    },
+  );
+  test(
+    'authentication pages and complete documents are not refetched',
+    () async {
+      expect(
+        await restore(authenticated: false),
+        FullPageRecoveryResult.unchanged,
+      );
+      platform.web.javascript = (_) async => jsonEncode({
+        'scripts': 20,
+        'styles': 4,
+        'links': 4,
+        'loaded': 4,
+        'jquery': true,
+        'beangle': true,
+        'require': true,
+        'script202': 0,
+        'style202': 0,
+      });
+      expect(await restore(), FullPageRecoveryResult.unchanged);
+      expect(gateway.requests, 0);
+    },
+  );
+  test(
+    'logout and external or credential-bearing addresses never use the gateway',
+    () async {
+      for (final address in [
+        'https://eams.uestc.edu.cn/eams/logout.action',
+        'https://other.test/eams/home.action',
+        'https://eams.uestc.edu.cn/eams/home.action?ticket=PRIVATE_TICKET',
+        'http://eams.uestc.edu.cn/eams/home.action',
+      ]) {
+        platform.web.url = address;
+        expect(
+          await recovery.tryRestore(
+            web,
+            Uri.parse(address),
+            authenticated: true,
+            documentKey: address,
+            isCurrent: () => true,
+          ),
+          FullPageRecoveryResult.unchanged,
+        );
+      }
+      expect(gateway.requests, 0);
+    },
+  );
+}