org.springframework.http.codec.FormHttpMessageWriter Maven / Gradle / Ivy
/*
* Copyright 2002-2018 the original author or 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
*
* http://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 org.springframework.http.codec;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import org.reactivestreams.Publisher;
import reactor.core.publisher.Mono;
import org.springframework.core.ResolvableType;
import org.springframework.core.codec.Hints;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.log.LogFormatUtils;
import org.springframework.http.MediaType;
import org.springframework.http.ReactiveHttpOutputMessage;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.MultiValueMap;
/**
* {@link HttpMessageWriter} for writing a {@code MultiValueMap}
* as HTML form data, i.e. {@code "application/x-www-form-urlencoded"}, to the
* body of a request.
*
* Note that unless the media type is explicitly set to
* {@link MediaType#APPLICATION_FORM_URLENCODED}, the {@link #canWrite} method
* will need generic type information to confirm the target map has String values.
* This is because a MultiValueMap with non-String values can be used to write
* multipart requests.
*
*
To support both form data and multipart requests, consider using
* {@link org.springframework.http.codec.multipart.MultipartHttpMessageWriter}
* configured with this writer as the fallback for writing plain form data.
*
* @author Sebastien Deleuze
* @author Rossen Stoyanchev
* @since 5.0
* @see org.springframework.http.codec.multipart.MultipartHttpMessageWriter
*/
public class FormHttpMessageWriter extends LoggingCodecSupport
implements HttpMessageWriter> {
/**
* The default charset used by the writer.
*/
public static final Charset DEFAULT_CHARSET = StandardCharsets.UTF_8;
private static final MediaType DEFAULT_FORM_DATA_MEDIA_TYPE =
new MediaType(MediaType.APPLICATION_FORM_URLENCODED, DEFAULT_CHARSET);
private static final List MEDIA_TYPES =
Collections.singletonList(MediaType.APPLICATION_FORM_URLENCODED);
private static final ResolvableType MULTIVALUE_TYPE =
ResolvableType.forClassWithGenerics(MultiValueMap.class, String.class, String.class);
private Charset defaultCharset = DEFAULT_CHARSET;
/**
* Set the default character set to use for writing form data when the response
* Content-Type header does not explicitly specify it.
* By default this is set to "UTF-8".
*/
public void setDefaultCharset(Charset charset) {
Assert.notNull(charset, "Charset must not be null");
this.defaultCharset = charset;
}
/**
* Return the configured default charset.
*/
public Charset getDefaultCharset() {
return this.defaultCharset;
}
@Override
public List getWritableMediaTypes() {
return MEDIA_TYPES;
}
@Override
public boolean canWrite(ResolvableType elementType, @Nullable MediaType mediaType) {
if (!MultiValueMap.class.isAssignableFrom(elementType.toClass())) {
return false;
}
if (MediaType.APPLICATION_FORM_URLENCODED.isCompatibleWith(mediaType)) {
// Optimistically, any MultiValueMap with or without generics
return true;
}
if (mediaType == null) {
// Only String-based MultiValueMap
return MULTIVALUE_TYPE.isAssignableFrom(elementType);
}
return false;
}
@Override
public Mono write(Publisher> inputStream,
ResolvableType elementType, @Nullable MediaType mediaType, ReactiveHttpOutputMessage message,
Map hints) {
mediaType = getMediaType(mediaType);
message.getHeaders().setContentType(mediaType);
Charset charset = mediaType.getCharset();
Assert.notNull(charset, "No charset"); // should never occur
return Mono.from(inputStream).flatMap(form -> {
logFormData(form, hints);
String value = serializeForm(form, charset);
ByteBuffer byteBuffer = charset.encode(value);
DataBuffer buffer = message.bufferFactory().wrap(byteBuffer);
message.getHeaders().setContentLength(byteBuffer.remaining());
return message.writeWith(Mono.just(buffer));
});
}
private MediaType getMediaType(@Nullable MediaType mediaType) {
if (mediaType == null) {
return DEFAULT_FORM_DATA_MEDIA_TYPE;
}
else if (mediaType.getCharset() == null) {
return new MediaType(mediaType, getDefaultCharset());
}
else {
return mediaType;
}
}
private void logFormData(MultiValueMap form, Map hints) {
LogFormatUtils.traceDebug(logger, traceOn -> Hints.getLogPrefix(hints) + "Writing " +
(isEnableLoggingRequestDetails() ?
LogFormatUtils.formatValue(form, !traceOn) :
"form fields " + form.keySet() + " (content masked)"));
}
protected String serializeForm(MultiValueMap formData, Charset charset) {
StringBuilder builder = new StringBuilder();
formData.forEach((name, values) ->
values.forEach(value -> {
try {
if (builder.length() != 0) {
builder.append('&');
}
builder.append(URLEncoder.encode(name, charset.name()));
if (value != null) {
builder.append('=');
builder.append(URLEncoder.encode(value, charset.name()));
}
}
catch (UnsupportedEncodingException ex) {
throw new IllegalStateException(ex);
}
}));
return builder.toString();
}
}