|
| 1 | +package com.mageddo.dnsproxyserver.config.provider.dataformatv3.converter; |
| 2 | + |
| 3 | +import com.mageddo.dnsproxyserver.config.provider.dataformatv3.ConfigV3; |
| 4 | +import com.mageddo.json.JsonUtils; |
| 5 | +import org.apache.commons.lang3.StringUtils; |
| 6 | + |
| 7 | +import java.lang.reflect.Field; |
| 8 | +import java.lang.reflect.ParameterizedType; |
| 9 | +import java.util.ArrayList; |
| 10 | +import java.util.LinkedHashMap; |
| 11 | +import java.util.List; |
| 12 | +import java.util.Locale; |
| 13 | +import java.util.Map; |
| 14 | + |
| 15 | +public class EnvConverter implements Converter { |
| 16 | + |
| 17 | + static final String PREFIX = "DPS_"; |
| 18 | + |
| 19 | + @Override |
| 20 | + public ConfigV3 parse() { |
| 21 | + return parse(System.getenv()); |
| 22 | + } |
| 23 | + |
| 24 | + ConfigV3 parse(Map<String, String> envs) { |
| 25 | + final var tree = buildTree(envs); |
| 26 | + return JsonUtils.instance().convertValue(tree, ConfigV3.class); |
| 27 | + } |
| 28 | + |
| 29 | + @Override |
| 30 | + public String serialize(ConfigV3 config) { |
| 31 | + return ""; |
| 32 | + } |
| 33 | + |
| 34 | + @Override |
| 35 | + public int priority() { |
| 36 | + return 0; |
| 37 | + } |
| 38 | + |
| 39 | + Map<String, Object> buildTree(Map<String, String> envs) { |
| 40 | + final Map<String, Object> root = new LinkedHashMap<>(); |
| 41 | + envs.entrySet() |
| 42 | + .stream() |
| 43 | + .filter(entry -> entry.getKey().startsWith(PREFIX)) |
| 44 | + .forEach(entry -> insert(root, ConfigV3.class, entry.getKey().substring(PREFIX.length()), entry.getValue())); |
| 45 | + return root; |
| 46 | + } |
| 47 | + |
| 48 | + private void insert(Map<String, Object> current, Class<?> currentClass, String key, String value) { |
| 49 | + final var tokens = key.split("_"); |
| 50 | + assign(current, currentClass, tokens, 0, value); |
| 51 | + } |
| 52 | + |
| 53 | + private void assign(Map<String, Object> current, Class<?> currentClass, String[] tokens, int index, String value) { |
| 54 | + final var match = findField(currentClass, tokens, index); |
| 55 | + final var field = match.field(); |
| 56 | + final var nextIndex = index + match.consumedTokens(); |
| 57 | + |
| 58 | + if (List.class.isAssignableFrom(field.getType())) { |
| 59 | + final int listIndex = parseIndex(tokens, nextIndex); |
| 60 | + final var list = (List<Object>) current.computeIfAbsent(field.getName(), k -> new ArrayList<>()); |
| 61 | + ensureSize(list, listIndex + 1); |
| 62 | + |
| 63 | + final var elementType = match.elementType(); |
| 64 | + if (isSimple(elementType)) { |
| 65 | + list.set(listIndex, convert(value, elementType)); |
| 66 | + return; |
| 67 | + } |
| 68 | + |
| 69 | + Map<String, Object> nested = asMap(list.get(listIndex)); |
| 70 | + if (nested == null) { |
| 71 | + nested = new LinkedHashMap<>(); |
| 72 | + list.set(listIndex, nested); |
| 73 | + } |
| 74 | + assign(nested, elementType, tokens, nextIndex + 1, value); |
| 75 | + return; |
| 76 | + } |
| 77 | + |
| 78 | + if (isSimple(field.getType())) { |
| 79 | + current.put(field.getName(), convert(value, field.getType())); |
| 80 | + return; |
| 81 | + } |
| 82 | + |
| 83 | + final Map<String, Object> nested = (Map<String, Object>) current.computeIfAbsent(field.getName(), k -> new LinkedHashMap<>()); |
| 84 | + assign(nested, field.getType(), tokens, nextIndex, value); |
| 85 | + } |
| 86 | + |
| 87 | + private FieldMatch findField(Class<?> currentClass, String[] tokens, int startIndex) { |
| 88 | + for (int len = tokens.length - startIndex; len >= 1; len--) { |
| 89 | + final var property = toProperty(tokens, startIndex, len); |
| 90 | + final Field field = findField(currentClass, property); |
| 91 | + if (field != null) { |
| 92 | + final Class<?> elementType; |
| 93 | + if (List.class.isAssignableFrom(field.getType())) { |
| 94 | + if (field.getGenericType() instanceof ParameterizedType parameterizedType) { |
| 95 | + elementType = (Class<?>) parameterizedType.getActualTypeArguments()[0]; |
| 96 | + } else { |
| 97 | + elementType = Object.class; |
| 98 | + } |
| 99 | + } else { |
| 100 | + elementType = null; |
| 101 | + } |
| 102 | + return new FieldMatch(field, len, elementType); |
| 103 | + } |
| 104 | + } |
| 105 | + throw new IllegalArgumentException("Unknown path for " + String.join("_", tokens)); |
| 106 | + } |
| 107 | + |
| 108 | + private Field findField(Class<?> clazz, String name) { |
| 109 | + try { |
| 110 | + return clazz.getField(name); |
| 111 | + } catch (NoSuchFieldException e) { |
| 112 | + return null; |
| 113 | + } |
| 114 | + } |
| 115 | + |
| 116 | + private String toProperty(String[] tokens, int startIndex, int len) { |
| 117 | + final StringBuilder sb = new StringBuilder(); |
| 118 | + for (int i = 0; i < len; i++) { |
| 119 | + if (i > 0) { |
| 120 | + sb.append('_'); |
| 121 | + } |
| 122 | + sb.append(tokens[startIndex + i]); |
| 123 | + } |
| 124 | + return toCamelCase(sb.toString()); |
| 125 | + } |
| 126 | + |
| 127 | + private String toCamelCase(String value) { |
| 128 | + final var parts = value.toLowerCase(Locale.US).split("_"); |
| 129 | + final var sb = new StringBuilder(parts[0]); |
| 130 | + for (int i = 1; i < parts.length; i++) { |
| 131 | + sb.append(StringUtils.capitalize(parts[i])); |
| 132 | + } |
| 133 | + return sb.toString(); |
| 134 | + } |
| 135 | + |
| 136 | + private boolean isSimple(Class<?> type) { |
| 137 | + if (type == null) { |
| 138 | + return false; |
| 139 | + } |
| 140 | + return type.isPrimitive() |
| 141 | + || Number.class.isAssignableFrom(type) |
| 142 | + || Boolean.class.isAssignableFrom(type) |
| 143 | + || CharSequence.class.isAssignableFrom(type); |
| 144 | + } |
| 145 | + |
| 146 | + private Object convert(String value, Class<?> type) { |
| 147 | + if (StringUtils.isBlank(value) && type != String.class) { |
| 148 | + return null; |
| 149 | + } |
| 150 | + if (type == String.class) { |
| 151 | + return value; |
| 152 | + } |
| 153 | + if (type == Integer.class || type == int.class) { |
| 154 | + return Integer.valueOf(value); |
| 155 | + } |
| 156 | + if (type == Boolean.class || type == boolean.class) { |
| 157 | + return Boolean.valueOf(value); |
| 158 | + } |
| 159 | + if (type == Long.class || type == long.class) { |
| 160 | + return Long.valueOf(value); |
| 161 | + } |
| 162 | + if (type == Double.class || type == double.class) { |
| 163 | + return Double.valueOf(value); |
| 164 | + } |
| 165 | + if (type == Float.class || type == float.class) { |
| 166 | + return Float.valueOf(value); |
| 167 | + } |
| 168 | + return value; |
| 169 | + } |
| 170 | + |
| 171 | + private int parseIndex(String[] tokens, int index) { |
| 172 | + if (index >= tokens.length) { |
| 173 | + throw new IllegalArgumentException("Missing list index for " + String.join("_", tokens)); |
| 174 | + } |
| 175 | + return Integer.parseInt(tokens[index]); |
| 176 | + } |
| 177 | + |
| 178 | + private void ensureSize(List<Object> list, int size) { |
| 179 | + while (list.size() < size) { |
| 180 | + list.add(null); |
| 181 | + } |
| 182 | + } |
| 183 | + |
| 184 | + @SuppressWarnings("unchecked") |
| 185 | + private Map<String, Object> asMap(Object value) { |
| 186 | + if (value instanceof Map<?, ?> map) { |
| 187 | + return (Map<String, Object>) map; |
| 188 | + } |
| 189 | + return null; |
| 190 | + } |
| 191 | + |
| 192 | + record FieldMatch(Field field, int consumedTokens, Class<?> elementType) { |
| 193 | + } |
| 194 | +} |
0 commit comments