[Add] Pixiv 添加一组与 Pixiv 登录会话相关的类;

[Add] PixivLogin, PixivLoginException 初版的登录器接口;
[Add] PixivSession, BasicPixivSession Pixiv 帐号登录会话抽象类和一个默认基本实现;
[Add] ObjectInputStreamLogin 通过反序列化 CacheStore 进行登录的登录器;

ContentGrabbingJi-pixiv/src/main/java/net/lamgc/pixiv/BasicPixivSession.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2020  LamGC
+ *
+ * ContentGrabbingJi is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * ContentGrabbingJi is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package net.lamgc.pixiv;
+
+import com.google.common.net.HttpHeaders;
+import org.apache.http.HttpResponse;
+import org.apache.http.client.CookieStore;
+import org.apache.http.client.HttpClient;
+import org.apache.http.client.methods.HttpGet;
+
+import java.io.IOException;
+
+/**
+ * 基本的 Pixiv 会话对象.
+ * @author LamGC
+ */
+public class BasicPixivSession extends PixivSession {
+
+    private final static String PIXIV_LOGOUT_URL = "https://www.pixiv.net/logout.php";
+    private final HttpClient httpClient;
+    private boolean login = true;
+
+    /**
+     * 构造一个会话对象.
+     * @param cookieStore 会话 Cookies.
+     * @param httpClient 用于请求登出的 HttpClient 对象.
+     */
+    public BasicPixivSession(CookieStore cookieStore, HttpClient httpClient) {
+        super(cookieStore);
+        this.httpClient = httpClient;
+    }
+
+    @Override
+    public boolean logOut() throws IOException {
+        HttpGet request = new HttpGet(PIXIV_LOGOUT_URL);
+        StringBuilder builder = new StringBuilder();
+        getCookies().getCookies().forEach(cookie ->
+                builder.append(cookie.getName()).append("=").append(cookie.getValue()).append("; "));
+        request.addHeader(HttpHeaders.COOKIE, builder.toString());
+
+        HttpResponse response = httpClient.execute(request);
+        final int httpRedirectCode = 302;
+        if (response.getStatusLine().getStatusCode() == httpRedirectCode) {
+            login = false;
+            return true;
+        }
+        return false;
+    }
+
+    @Override
+    public boolean isLogin() {
+        return login;
+    }
+
+}

ContentGrabbingJi-pixiv/src/main/java/net/lamgc/pixiv/PixivLogin.java

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+package net.lamgc.pixiv;
+
+/**
+ * @author LamGC
+ */
+public interface PixivLogin {
+
+    /**
+     * 执行登录操作.
+     * @return 返回登录后的会话对象
+     * @see PixivSession
+     * @throws PixivLoginException 当无法完成登录时抛出.
+     */
+    PixivSession login() throws PixivLoginException;
+
+}

ContentGrabbingJi-pixiv/src/main/java/net/lamgc/pixiv/PixivLoginException.java

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+package net.lamgc.pixiv;
+
+/**
+ * Pixiv 登录异常.
+ * @author LamGC
+ */
+public class PixivLoginException extends Exception {
+
+    public PixivLoginException(String message) {
+        super(message);
+    }
+
+    public PixivLoginException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+}

ContentGrabbingJi-pixiv/src/main/java/net/lamgc/pixiv/PixivSession.java

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+package net.lamgc.pixiv;
+
+import org.apache.http.client.CookieStore;
+
+import java.io.IOException;
+import java.util.Objects;
+
+/**
+ * Pixiv 会话.
+ * @author LamGC
+ */
+public abstract class PixivSession {
+
+    private final CookieStore cookieStore;
+
+    protected PixivSession(CookieStore cookieStore) {
+        this.cookieStore = Objects.requireNonNull(cookieStore);
+    }
+
+    /**
+     * 登出当前会话.
+     *
+     * <p>登出后该会话 Cookies 将会失效.
+     * @return 如果登出成功, 返回 true.
+     * @throws IOException 当尝试登出发生异常时抛出.
+     */
+    public abstract boolean logOut() throws IOException;
+
+    /**
+     * 检查是否已登录, 或者说会话是否有效.
+     * @return 如果会话已登出(失效), 返回 false.
+     */
+    public abstract boolean isLogin();
+
+    /**
+     * 获取 CookieStore 对象.
+     * @return 返回 CookieStore.
+     */
+    public CookieStore getCookies() {
+        return cookieStore;
+    }
+
+}

ContentGrabbingJi-pixiv/src/main/java/net/lamgc/pixiv/login/ObjectInputStreamLogin.java

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+/*
+ * Copyright (C) 2020  LamGC
+ *
+ * ContentGrabbingJi is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * ContentGrabbingJi is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package net.lamgc.pixiv.login;
+
+import net.lamgc.pixiv.*;
+import org.apache.http.client.CookieStore;
+import org.apache.http.client.HttpClient;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.ObjectInputStream;
+import java.util.concurrent.atomic.AtomicReference;
+
+/**
+ * 读入对象进行登录.
+ * @author LamGC
+ */
+public class ObjectInputStreamLogin implements PixivLogin {
+
+    private final HttpClient httpClient;
+    private final ObjectInputStream inputStream;
+    private final AtomicReference<PixivSession> sessionCache = new AtomicReference<>();
+
+    public ObjectInputStreamLogin(HttpClient httpClient, InputStream cookieInput) throws IOException {
+        this.httpClient = httpClient;
+        this.inputStream = new ObjectInputStream(cookieInput);
+    }
+
+
+    @Override
+    public synchronized PixivSession login() throws PixivLoginException {
+        if (sessionCache.get() == null) {
+            CookieStore cookieStore;
+            try {
+                cookieStore = (CookieStore) inputStream.readObject();
+            } catch (Exception e) {
+                throw new PixivLoginException("An exception occurred while trying to read in a Java serialized object", e);
+            }
+            PixivSession session = new BasicPixivSession(cookieStore, this.httpClient);
+            sessionCache.set(session);
+            return session;
+        } else {
+            return sessionCache.get();
+        }
+
+    }
+}