io.micronaut.http.uri.UriTemplateExpander Maven / Gradle / Ivy
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/*
* Copyright 2017-2024 original 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
*
* https://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 io.micronaut.http.uri;
import io.micronaut.core.annotation.Internal;
import io.micronaut.core.beans.BeanMap;
import io.micronaut.core.reflect.ClassUtils;
import io.micronaut.core.util.CollectionUtils;
import io.micronaut.core.util.StringUtils;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.stream.Stream;
/**
* Implementation of expanding for rfc6570.
*
* @author Denis Stepanov
* @since 4.6.0
*/
@Internal
final class UriTemplateExpander implements UriTemplateParser.PartVisitor {
private final Map parameters;
private final StringBuilder builder = new StringBuilder();
private boolean queryStarted;
private boolean hashStarted;
private boolean needsSeparator;
UriTemplateExpander(Map parameters) {
this.parameters = parameters;
}
@Override
public void visitLiteral(String literal) {
builder.append(literal);
}
@Override
public void visitExpression(UriTemplateParser.ExpressionType type, List variables) {
for (UriTemplateParser.Variable variable : variables) {
appendValue(type, variable);
}
needsSeparator = false;
}
@Override
public String toString() {
return builder.toString();
}
private void appendValue(UriTemplateParser.ExpressionType type, UriTemplateParser.Variable variable) {
Object value = parameters.get(variable.name());
value = value instanceof Optional optional ? optional.orElse(null) : value;
if (value == null) {
return;
}
if (value.getClass().isArray()) {
value = Arrays.asList((Object[]) value);
}
if (variable.explode()) {
value = expandPOJO(value);
}
if (value instanceof Iterable iterable) {
List values = asListOfString(iterable);
if (!values.isEmpty()) {
appendListValues(type, variable, values);
}
} else if (value instanceof Map map) {
if (map.isEmpty()) {
return;
}
List>> mapOfStrings = map.entrySet()
.stream()
.filter(e -> e.getValue() != null)
.map(e -> Map.entry(e.getKey().toString(), asListOfString(e.getValue())))
.filter(e -> !e.getValue().isEmpty())
.toList();
appendMapValues(type, variable, mapOfStrings);
} else {
appendValue(type, variable, value.toString());
}
}
private List asListOfString(Object some) {
return some instanceof Iterable i
? CollectionUtils.iterableToList(i).stream().filter(Objects::nonNull).map(String::valueOf).toList()
: List.of(some.toString());
}
private void appendMapValues(UriTemplateParser.ExpressionType type, UriTemplateParser.Variable variable, List>> entries) {
if (variable.explode()) {
for (Map.Entry> entry : entries) {
appendKeyValues(type, variable, entry.getKey(), entry.getValue());
}
return;
}
if (type.isQueryPart()) {
appendKeyValues(type, variable, variable.name(), aggregate(entries));
} else {
appendOperator(type);
appendValues(type, variable, aggregate(entries));
}
}
private List aggregate(List>> entries) {
return entries
.stream()
.flatMap(e -> Stream.concat(Stream.of(e.getKey()), e.getValue().stream()))
.toList();
}
private void appendListValues(UriTemplateParser.ExpressionType type, UriTemplateParser.Variable variable, List values) {
if (variable.explode()) {
for (String value : values) {
appendValue(type, variable, value);
}
return;
}
if (type.isQueryPart()) {
appendKeyValues(type, variable, variable.name(), values);
} else {
appendOperator(type);
appendValues(type, variable, values);
}
}
private void appendKeyValues(UriTemplateParser.ExpressionType type, UriTemplateParser.Variable variable, String key, List values) {
appendOperator(type);
builder.append(key)
.append('=');
appendValues(type, variable, values);
}
private void appendValues(UriTemplateParser.ExpressionType type, UriTemplateParser.Variable variable, List values) {
for (Iterator iterator = values.iterator(); iterator.hasNext(); ) {
String value = iterator.next();
value = applyModifier(value, variable.modifier());
builder.append(type.isEncode() ? encode(value, type.isQueryPart()) : escape(value));
if (iterator.hasNext()) {
builder.append(',');
}
}
}
private void appendValue(UriTemplateParser.ExpressionType type, UriTemplateParser.Variable variable, String value) {
value = applyModifier(value, variable.modifier());
appendOperator(type);
if (type.isQueryPart()) {
builder.append(variable.name());
if (StringUtils.isNotEmpty(value) || type != UriTemplateParser.ExpressionType.PATH_STYLE_PARAMETER_EXPANSION) {
builder.append('=')
.append(encode(value, true));
}
} else {
builder.append(type.isEncode() ? encode(value, false) : escape(value));
}
}
private void appendOperator(UriTemplateParser.ExpressionType type) {
char separator = type.getSeparator();
if (type == UriTemplateParser.ExpressionType.NONE) {
appendSeparator(type, separator);
} else if (type == UriTemplateParser.ExpressionType.FORM_STYLE_PARAMETER_EXPANSION) {
builder.append(queryParamSeparator());
} else {
appendSeparator(type, separator);
if (type == UriTemplateParser.ExpressionType.FRAGMENT_EXPANSION) {
if (!hashStarted) {
hashStarted = true;
builder.append(type.getOperator());
}
} else if (type != UriTemplateParser.ExpressionType.RESERVED_EXPANSION) {
builder.append(type.getOperator());
}
}
}
private void appendSeparator(UriTemplateParser.ExpressionType type, char separator) {
// Append separator for previous value
if (!needsSeparator) {
needsSeparator = true;
} else if (separator != type.getOperator()) {
builder.append(separator);
}
}
private char queryParamSeparator() {
if (queryStarted) {
return '&';
}
queryStarted = true;
return '?';
}
private String applyModifier(String value, String modifier) {
if (modifier == null) {
return value;
}
try {
int limit = Integer.parseInt(modifier.trim(), 10);
if (limit < value.length()) {
return value.substring(0, limit);
}
} catch (NumberFormatException e) {
// Ignore
}
return value;
}
private String encode(String str, boolean query) {
String encoded = URLEncoder.encode(str, StandardCharsets.UTF_8);
return query ? encoded : encoded.replace("+", "%20");
}
private String escape(String v) {
return v.replace("%", "%25").replaceAll("\\s", "%20");
}
private Object expandPOJO(Object found) {
// Check for common expanded types, such as list or Map
if (found instanceof Iterable || found instanceof Map) {
return found;
}
// If a simple value, just use that
if (found == null || ClassUtils.isJavaLangType(found.getClass())) {
return found;
}
// Otherwise, expand the object into properties (after all, the user asked for an expanded parameter)
return BeanMap.of(found);
}
}
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