001/* 002 * JGrapes Event Driven Framework 003 * Copyright (C) 2018 Michael N. Lipp 004 * 005 * This program is free software; you can redistribute it and/or modify it 006 * under the terms of the GNU Affero General Public License as published by 007 * the Free Software Foundation; either version 3 of the License, or 008 * (at your option) any later version. 009 * 010 * This program is distributed in the hope that it will be useful, but 011 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 012 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License 013 * for more details. 014 * 015 * You should have received a copy of the GNU Affero General Public License along 016 * with this program; if not, see <http://www.gnu.org/licenses/>. 017 */ 018 019package org.jgrapes.webconsole.base; 020 021import java.io.IOException; 022import java.io.OutputStream; 023import java.time.Instant; 024import org.jdrupes.httpcodec.protocols.http.HttpConstants.HttpStatus; 025import org.jdrupes.httpcodec.protocols.http.HttpField; 026import org.jdrupes.httpcodec.protocols.http.HttpResponse; 027import org.jdrupes.httpcodec.types.MediaType; 028import org.jgrapes.http.ResponseCreationSupport; 029import org.jgrapes.http.events.Response; 030import org.jgrapes.io.util.ByteBufferOutputStream; 031import org.jgrapes.webconsole.base.events.ResourceRequest; 032 033/** 034 * Returns a {@link Runnable} that writes to an {@link OutputStream} as result. 035 */ 036public class ResourceByGenerator extends ResourceResult { 037 038 private final Generator generator; 039 private final MediaType mediaType; 040 private final Instant lastModifiedAt; 041 private final int maxAge; 042 043 /** 044 * The interface that must be implemented by the content provider. 045 */ 046 public interface Generator { 047 048 /** 049 * Write the generated output to the given stream. 050 * 051 * @param stream the output stream 052 * @throws IOException Signals that an I/O exception has occurred. 053 */ 054 void write(OutputStream stream) throws IOException; 055 } 056 057 /** 058 * Instantiates a result that is provided by an {@link OutputStream}. 059 * 060 * @param request the request 061 * @param generator the generator 062 * @param mediaType the media type, may be `null` 063 * @param lastModifiedAt the last modified at 064 * @param maxAge the max age 065 */ 066 public ResourceByGenerator(ResourceRequest request, 067 Generator generator, MediaType mediaType, 068 Instant lastModifiedAt, int maxAge) { 069 super(request); 070 this.generator = generator; 071 this.mediaType = mediaType; 072 this.lastModifiedAt = lastModifiedAt; 073 this.maxAge = maxAge; 074 } 075 076 /* 077 * (non-Javadoc) 078 * 079 * @see org.jgrapes.webconsole.base.base.ResourceResult#process() 080 */ 081 @Override 082 @SuppressWarnings("PMD.ConfusingTernary") 083 public void process() throws IOException, InterruptedException { 084 if (generator == null) { 085 ResponseCreationSupport.sendResponse(request().httpRequest(), 086 request().httpChannel(), HttpStatus.NOT_FOUND); 087 return; 088 } 089 090 HttpResponse response = request().httpRequest().response().get(); 091 if (lastModifiedAt != null) { 092 response.setField(HttpField.LAST_MODIFIED, lastModifiedAt); 093 } 094 if (mediaType != null) { 095 response.setContentType(mediaType); 096 } else { 097 // Usually set by setContenType 098 response.setHasPayload(true); 099 } 100 ResponseCreationSupport.setMaxAge(response, maxAge); 101 response.setStatus(HttpStatus.OK); 102 request().httpChannel().respond(new Response(response)); 103 // Start sending content 104 try (@SuppressWarnings("resource") 105 OutputStream out = new ByteBufferOutputStream( 106 request().httpChannel()).suppressClose()) { 107 generator.write(out); 108 } 109 } 110 111}