universe@184: /*
universe@184:  * Copyright 2021 Mike Becker. All rights reserved.
universe@184:  *
universe@184:  * Redistribution and use in source and binary forms, with or without
universe@184:  * modification, are permitted provided that the following conditions are met:
universe@184:  *
universe@184:  * 1. Redistributions of source code must retain the above copyright
universe@184:  * notice, this list of conditions and the following disclaimer.
universe@184:  *
universe@184:  * 2. Redistributions in binary form must reproduce the above copyright
universe@184:  * notice, this list of conditions and the following disclaimer in the
universe@184:  * documentation and/or other materials provided with the distribution.
universe@184:  *
universe@184:  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
universe@184:  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
universe@184:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
universe@184:  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
universe@184:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
universe@184:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
universe@184:  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
universe@184:  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
universe@184:  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
universe@184:  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
universe@184:  */
universe@184: 
universe@184: package de.uapcore.lightpit
universe@184: 
universe@184: import de.uapcore.lightpit.DataSourceProvider.Companion.SC_ATTR_NAME
universe@184: import de.uapcore.lightpit.dao.DataAccessObject
universe@184: import de.uapcore.lightpit.dao.createDataAccessObject
universe@184: import java.sql.SQLException
universe@184: import java.util.*
universe@184: import javax.servlet.http.HttpServlet
universe@184: import javax.servlet.http.HttpServletRequest
universe@184: import javax.servlet.http.HttpServletResponse
universe@184: 
universe@184: abstract class AbstractServlet : LoggingTrait, HttpServlet() {
universe@184: 
universe@184:     /**
universe@184:      * Contains the GET request mappings.
universe@184:      */
universe@184:     private val getMappings = mutableMapOf<PathPattern, MappingMethod>()
universe@184: 
universe@184:     /**
universe@184:      * Contains the POST request mappings.
universe@184:      */
universe@184:     private val postMappings = mutableMapOf<PathPattern, MappingMethod>()
universe@184: 
universe@184:     protected fun get(pattern: String, method: MappingMethod) {
universe@184:         getMappings[PathPattern(pattern)] = method
universe@184:     }
universe@184: 
universe@184:     protected fun post(pattern: String, method: MappingMethod) {
universe@184:         postMappings[PathPattern(pattern)] = method
universe@184:     }
universe@184: 
universe@184:     private fun notFound(http: HttpRequest, dao: DataAccessObject) {
universe@184:         http.response.sendError(HttpServletResponse.SC_NOT_FOUND)
universe@184:     }
universe@184: 
universe@184:     private fun findMapping(
universe@184:         mappings: Map<PathPattern, MappingMethod>,
universe@184:         req: HttpServletRequest
universe@184:     ): Pair<PathPattern, MappingMethod> {
universe@184:         val requestPath = sanitizedRequestPath(req)
universe@184:         val candidates = mappings.filter { it.key.matches(requestPath) }
universe@184:         return if (candidates.isEmpty()) {
universe@184:             Pair(PathPattern(requestPath), ::notFound)
universe@184:         } else {
universe@184:             if (candidates.size > 1) {
universe@184:                 logger().warn("Ambiguous mapping for request path '{}'", requestPath)
universe@184:             }
universe@184:             candidates.entries.first().toPair()
universe@184:         }
universe@184:     }
universe@184: 
universe@184:     private fun invokeMapping(
universe@184:         mapping: Pair<PathPattern, MappingMethod>,
universe@184:         req: HttpServletRequest,
universe@184:         resp: HttpServletResponse,
universe@184:         dao: DataAccessObject
universe@184:     ) {
universe@184:         val params = mapping.first.obtainPathParameters(sanitizedRequestPath(req))
universe@184:         val method = mapping.second
universe@184:         logger().trace("invoke {}", method)
universe@184:         method(HttpRequest(req, resp, params), dao)
universe@184:     }
universe@184: 
universe@184:     private fun sanitizedRequestPath(req: HttpServletRequest) = req.pathInfo ?: "/"
universe@184: 
universe@184:     private fun doProcess(
universe@184:         req: HttpServletRequest,
universe@184:         resp: HttpServletResponse,
universe@184:         mappings: Map<PathPattern, MappingMethod>
universe@184:     ) {
universe@184:         val session = req.session
universe@184: 
universe@184:         // the very first thing to do is to force UTF-8
universe@184:         req.characterEncoding = "UTF-8"
universe@184: 
universe@184:         // choose the requested language as session language (if available) or fall back to english, otherwise
universe@184:         if (session.getAttribute(Constants.SESSION_ATTR_LANGUAGE) == null) {
universe@184:             val availableLanguages = availableLanguages()
universe@184:             val reqLocale = req.locale
universe@184:             val sessionLocale = if (availableLanguages.contains(reqLocale)) reqLocale else availableLanguages.first()
universe@184:             session.setAttribute(Constants.SESSION_ATTR_LANGUAGE, sessionLocale)
universe@184:             logger().debug(
universe@184:                 "Setting language for new session {}: {}", session.id, sessionLocale.displayLanguage
universe@184:             )
universe@184:         } else {
universe@184:             val sessionLocale = session.getAttribute(Constants.SESSION_ATTR_LANGUAGE) as Locale
universe@184:             resp.locale = sessionLocale
universe@184:             logger().trace("Continuing session {} with language {}", session.id, sessionLocale)
universe@184:         }
universe@184: 
universe@184:         // set some internal request attributes
universe@184:         val http = HttpRequest(req, resp)
universe@184:         val fullPath = req.servletPath + Optional.ofNullable(req.pathInfo).orElse("")
universe@184:         req.setAttribute(Constants.REQ_ATTR_BASE_HREF, http.baseHref)
universe@184:         req.setAttribute(Constants.REQ_ATTR_PATH, fullPath)
universe@184:         req.getHeader("Referer")?.let {
universe@184:             // TODO: add a sanity check to avoid link injection
universe@184:             req.setAttribute(Constants.REQ_ATTR_REFERER, it)
universe@184:         }
universe@184: 
universe@184:         // if this is an error path, bypass the normal flow
universe@184:         if (fullPath.startsWith("/error/")) {
universe@184:             http.styleSheets = listOf("error")
universe@184:             http.render("error")
universe@184:             return
universe@184:         }
universe@184: 
universe@184:         // obtain a connection and create the data access objects
universe@184:         val dsp = req.servletContext.getAttribute(SC_ATTR_NAME) as DataSourceProvider
universe@184:         val dialect = dsp.dialect
universe@184:         val ds = dsp.dataSource
universe@184:         if (ds == null) {
universe@184:             resp.sendError(
universe@184:                 HttpServletResponse.SC_SERVICE_UNAVAILABLE,
universe@184:                 "JNDI DataSource lookup failed. See log for details."
universe@184:             )
universe@184:             return
universe@184:         }
universe@184:         try {
universe@184:             ds.connection.use { connection ->
universe@184:                 val dao = createDataAccessObject(dialect, connection)
universe@184:                 try {
universe@184:                     connection.autoCommit = false
universe@184:                     invokeMapping(findMapping(mappings, req), req, resp, dao)
universe@184:                     connection.commit()
universe@184:                 } catch (ex: SQLException) {
universe@184:                     logger().warn("Database transaction failed (Code {}): {}", ex.errorCode, ex.message)
universe@184:                     logger().debug("Details: ", ex)
universe@184:                     resp.sendError(
universe@184:                         HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
universe@184:                         "Unhandled Transaction Error - Code: " + ex.errorCode
universe@184:                     )
universe@184:                     connection.rollback()
universe@184:                 }
universe@184:             }
universe@184:         } catch (ex: SQLException) {
universe@184:             logger().error("Severe Database Exception (Code {}): {}", ex.errorCode, ex.message)
universe@184:             logger().debug("Details: ", ex)
universe@184:             resp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, "Database Error - Code: " + ex.errorCode)
universe@184:         }
universe@184:     }
universe@184: 
universe@184:     override fun doGet(req: HttpServletRequest, resp: HttpServletResponse) {
universe@184:         doProcess(req, resp, getMappings)
universe@184:     }
universe@184: 
universe@184:     override fun doPost(req: HttpServletRequest, resp: HttpServletResponse) {
universe@184:         doProcess(req, resp, postMappings)
universe@184:     }
universe@184: 
universe@184:     protected fun availableLanguages(): List<Locale> {
universe@184:         val langTags = servletContext.getInitParameter(Constants.CTX_ATTR_LANGUAGES)?.split(",")?.map(String::trim) ?: emptyList()
universe@184:         val locales = langTags.map(Locale::forLanguageTag).filter { it.language.isNotEmpty() }
universe@184:         return if (locales.isEmpty()) listOf(Locale.ENGLISH) else locales
universe@184:     }
universe@184: 
universe@184: }