SessionAspect.java

/*
 * Copyright 2011-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.glowroot.agent.plugin.servlet;

import java.util.Map;
import java.util.Map.Entry;

import javax.annotation.Nullable;

import org.glowroot.agent.plugin.api.ThreadContext;
import org.glowroot.agent.plugin.api.ThreadContext.Priority;
import org.glowroot.agent.plugin.api.weaving.BindParameter;
import org.glowroot.agent.plugin.api.weaving.BindReceiver;
import org.glowroot.agent.plugin.api.weaving.OnAfter;
import org.glowroot.agent.plugin.api.weaving.Pointcut;
import org.glowroot.agent.plugin.servlet.ServletAspect.HttpSession;

public class SessionAspect {

    @Pointcut(className = "javax.servlet.http.HttpSession", methodName = "setAttribute|putValue",
            methodParameterTypes = {"java.lang.String", "java.lang.Object"},
            nestingGroup = "servlet-inner-call")
    public static class SetAttributeAdvice {

        @OnAfter
        public static void onAfter(ThreadContext context, @BindReceiver HttpSession session,
                @BindParameter @Nullable String name, @BindParameter @Nullable Object value) {
            if (name == null) {
                // theoretically possible, so just ignore
                return;
            }
            // name is non-null per HttpSession.setAttribute() javadoc, but value may be null
            // (which per the javadoc is the same as calling removeAttribute())
            ServletMessageSupplier messageSupplier =
                    (ServletMessageSupplier) context.getServletMessageSupplier();
            if (messageSupplier != null) {
                updateUserIfApplicable(context, name, value, session);
                updateSessionAttributesIfApplicable(messageSupplier, name, value, session);
            }
        }

        private static void updateUserIfApplicable(ThreadContext context, String name,
                @Nullable Object value, HttpSession session) {
            if (value == null) {
                // if user value is set to null, don't clear it
                return;
            }
            String sessionUserAttributePath = ServletPluginProperties.sessionUserAttributePath();
            if (!sessionUserAttributePath.isEmpty()) {
                // capture user now, don't use a lazy supplier
                if (sessionUserAttributePath.equals(name)) {
                    context.setTransactionUser(value.toString(), Priority.CORE_PLUGIN);
                } else if (sessionUserAttributePath.startsWith(name + ".")) {
                    String user = HttpSessions.getSessionAttributeTextValue(session,
                            sessionUserAttributePath);
                    if (user != null) {
                        // if user is null, don't clear it by setting Suppliers.ofInstance(null)
                        context.setTransactionUser(user, Priority.CORE_PLUGIN);
                    }
                }
            }
        }

        private static void updateSessionAttributesIfApplicable(
                ServletMessageSupplier messageSupplier,
                String name, @Nullable Object value, HttpSession session) {
            if (ServletPluginProperties.captureSessionAttributeNames().contains(name)
                    || ServletPluginProperties.captureSessionAttributeNames().contains("*")) {
                // update all session attributes (possibly nested) at or under the set attribute
                for (String capturePath : ServletPluginProperties.captureSessionAttributePaths()) {
                    if (capturePath.equals(name) || capturePath.equals("*")) {
                        updateSessionAttribute(messageSupplier, name, value);
                    } else if (capturePath.startsWith(name + ".")) {
                        updateNestedSessionAttributes(messageSupplier, capturePath, value, session);
                    }
                }
            }
        }

        private static void updateSessionAttribute(ServletMessageSupplier messageSupplier,
                String name,
                @Nullable Object value) {
            if (value == null) {
                messageSupplier.putSessionAttributeChangedValue(name, null);
            } else {
                messageSupplier.putSessionAttributeChangedValue(name, value.toString());
            }
        }

        private static void updateNestedSessionAttributes(ServletMessageSupplier messageSupplier,
                String capturePath, @Nullable Object value, HttpSession session) {
            if (capturePath.endsWith(".*")) {
                String capturePathBase = capturePath.substring(0, capturePath.length() - 2);
                Object val = HttpSessions.getSessionAttribute(session, capturePathBase);
                if (val == null) {
                    messageSupplier.putSessionAttributeChangedValue(capturePathBase, null);
                } else if (val instanceof Map<?, ?>) {
                    for (Entry<?, ?> entry : ((Map<?, ?>) val).entrySet()) {
                        Object v = entry.getValue();
                        messageSupplier.putSessionAttributeChangedValue(
                                capturePathBase + "." + entry.getKey(),
                                v == null ? null : v.toString());
                    }
                } else {
                    for (Entry<String, String> entry : Beans.propertiesAsText(val).entrySet()) {
                        messageSupplier.putSessionAttributeChangedValue(
                                capturePathBase + "." + entry.getKey(), entry.getValue());
                    }
                }
            } else if (value == null) {
                // no need to navigate path since it will always be null
                messageSupplier.putSessionAttributeChangedValue(capturePath, null);
            } else {
                String val = HttpSessions.getSessionAttributeTextValue(session, capturePath);
                messageSupplier.putSessionAttributeChangedValue(capturePath, val);
            }
        }
    }

    @Pointcut(className = "javax.servlet.http.HttpSession", methodName = "removeAttribute",
            methodParameterTypes = {"java.lang.String"}, nestingGroup = "servlet-inner-call")
    public static class RemoveAttributeAdvice {
        @OnAfter
        public static void onAfter(ThreadContext context, @BindReceiver HttpSession session,
                @BindParameter @Nullable String name) {
            // calling HttpSession.setAttribute() with null value is the same as calling
            // removeAttribute(), per the setAttribute() javadoc
            SetAttributeAdvice.onAfter(context, session, name, null);
        }
    }
}