001/* 002 * (C) Copyright 2006-2012 Nuxeo SA (http://nuxeo.com/) and others. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * http://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 * 016 * Contributors: 017 * Nuxeo - initial API and implementation 018 * 019 */ 020 021package org.nuxeo.template.fm; 022 023import java.util.ArrayList; 024import java.util.List; 025import java.util.ListIterator; 026import java.util.regex.Matcher; 027import java.util.regex.Pattern; 028 029import org.nuxeo.runtime.api.Framework; 030import org.nuxeo.template.api.TemplateInput; 031import org.nuxeo.template.api.TemplateProcessorService; 032 033/** 034 * Helper class used to extract variable names from a FreeMarker template. This is used to initialize the 035 * {@link TemplateInput} parameters. Extraction is for now simple and system may not detect all the cases, but user is 036 * able to add parameters from the UI. 037 * 038 * @author Tiry (tdelprat@nuxeo.com) 039 */ 040public class FreeMarkerVariableExtractor { 041 042 protected final static Pattern simpleVariableMatcher = Pattern.compile("\\$\\{([^\\}]*)\\}"); 043 044 protected final static String[] spliters = new String[] { ".", "?", "=", ">", "<", "!", " ", "[" }; 045 046 protected final static Pattern[] directiveMatchers = new Pattern[] { Pattern.compile("\\[\\#if\\s([^\\]]*)\\]"), 047 Pattern.compile("\\[\\#list\\s[\\d\\.\\.]*(.+)\\sas\\s([^\\]]*)\\]") }; 048 049 protected final static Pattern[] assignMatchers = new Pattern[] { Pattern.compile("\\[\\#assign\\s(.+)=.*\\]") }; 050 051 protected static final List<String> reservedContextKeywords = new ArrayList<>(); 052 053 protected static final String[] freeMarkerVariableSuffix = { "_index", "_has_next" }; 054 055 protected static String extractVariableName(String match) { 056 057 String varName = match.trim(); 058 059 if (varName.startsWith("!")) { 060 varName = varName.substring(1); 061 } 062 063 while (varName.startsWith("(")) { 064 varName = varName.substring(1); 065 } 066 067 int idx = varName.indexOf("."); 068 if (idx > 1) { 069 varName = varName.substring(0, idx); 070 } 071 072 for (String spliter : spliters) { 073 idx = varName.indexOf(spliter); 074 if (idx > 1) { 075 varName = varName.substring(0, idx); 076 } 077 } 078 return varName; 079 } 080 081 public static void resetReservedContextKeywords() { 082 synchronized (reservedContextKeywords) { 083 reservedContextKeywords.clear(); 084 } 085 } 086 087 protected static List<String> getreservedContextKeywords() { 088 synchronized (reservedContextKeywords) { 089 if (reservedContextKeywords.size() == 0) { 090 TemplateProcessorService tps = Framework.getService(TemplateProcessorService.class); 091 if (tps != null) { 092 reservedContextKeywords.addAll(tps.getReservedContextKeywords()); 093 } 094 } 095 } 096 return reservedContextKeywords; 097 } 098 099 public static List<String> extractVariables(String content) { 100 101 List<String> variables = new ArrayList<>(); 102 103 List<String> blackListedVariables = new ArrayList<>(); 104 105 if (content.length() > 10000) { 106 // split content in multilines 107 // otherwise some regexp won't capture everything 108 content = content.replaceAll("</", "\n</"); 109 } 110 111 Matcher matcher = simpleVariableMatcher.matcher(content); 112 113 matcher.matches(); 114 while (matcher.find()) { 115 if (matcher.groupCount() > 0) { 116 String v = extractVariableName(matcher.group(1)); 117 if (!variables.contains(v)) { 118 variables.add(v); 119 } 120 } 121 } 122 123 for (Pattern dPattern : directiveMatchers) { 124 Matcher dmatcher = dPattern.matcher(content); 125 dmatcher.matches(); 126 while (dmatcher.find()) { 127 if (dmatcher.groupCount() > 0) { 128 String v = extractVariableName(dmatcher.group(1)); 129 if (!variables.contains(v)) { 130 variables.add(v); 131 } 132 if (dmatcher.groupCount() > 1) { 133 String localVariable = extractVariableName(dmatcher.group(2)); 134 blackListedVariables.add(localVariable); 135 for (String suffix : freeMarkerVariableSuffix) { 136 blackListedVariables.add(localVariable + suffix); 137 } 138 } 139 } 140 } 141 } 142 143 for (Pattern dPattern : assignMatchers) { 144 Matcher dmatcher = dPattern.matcher(content); 145 dmatcher.matches(); 146 while (dmatcher.find()) { 147 if (dmatcher.groupCount() > 0) { 148 String v = extractVariableName(dmatcher.group(1)); 149 blackListedVariables.add(extractVariableName(v)); 150 } 151 } 152 } 153 154 // remove internal variables 155 for (String bVar : blackListedVariables) { 156 variables.remove(bVar); 157 } 158 159 // remove reserved variables that don't need specific bindings 160 for (String bVar : getreservedContextKeywords()) { 161 variables.remove(bVar); 162 } 163 164 // remove any non valid variable names 165 ListIterator<String> varIter = variables.listIterator(); 166 while (varIter.hasNext()) { 167 String var = varIter.next(); 168 if (var.contains("<") || var.contains(">")) { 169 varIter.remove(); 170 } else if (var.contains("\n")) { 171 varIter.set(var.replaceAll("\n", "").trim()); 172 } else if (var.startsWith(".")) { 173 // remove FM "Special Variables" 174 varIter.remove(); 175 } 176 } 177 178 return variables; 179 } 180 181}