org.springframework.http.converter.FormHttpMessageConverter Maven / Gradle / Ivy
/*
* Copyright 2002-2022 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
*
* 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 org.springframework.http.converter;
import java.io.IOException;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import javax.mail.internet.MimeUtility;
import org.springframework.core.io.Resource;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpInputMessage;
import org.springframework.http.HttpOutputMessage;
import org.springframework.http.MediaType;
import org.springframework.http.StreamingHttpOutputMessage;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.CollectionUtils;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MimeTypeUtils;
import org.springframework.util.MultiValueMap;
import org.springframework.util.StreamUtils;
import org.springframework.util.StringUtils;
/**
* Implementation of {@link HttpMessageConverter} to read and write 'normal' HTML
* forms and also to write (but not read) multipart data (e.g. file uploads).
*
* In other words, this converter can read and write the
* {@code "application/x-www-form-urlencoded"} media type as
* {@link MultiValueMap MultiValueMap<String, String>}, and it can also
* write (but not read) the {@code "multipart/form-data"} and
* {@code "multipart/mixed"} media types as
* {@link MultiValueMap MultiValueMap<String, Object>}.
*
*
Multipart Data
*
* By default, {@code "multipart/form-data"} is used as the content type when
* {@linkplain #write writing} multipart data. As of Spring Framework 5.2 it is
* also possible to write multipart data using other multipart subtypes such as
* {@code "multipart/mixed"} and {@code "multipart/related"}, as long as the
* multipart subtype is registered as a {@linkplain #getSupportedMediaTypes
* supported media type} and the desired multipart subtype is specified
* as the content type when {@linkplain #write writing} the multipart data. Note
* that {@code "multipart/mixed"} is registered as a supported media type by
* default.
*
*
When writing multipart data, this converter uses other
* {@link HttpMessageConverter HttpMessageConverters} to write the respective
* MIME parts. By default, basic converters are registered for byte array,
* {@code String}, and {@code Resource}. These can be overridden via
* {@link #setPartConverters} or augmented via {@link #addPartConverter}.
*
*
Examples
*
* The following snippet shows how to submit an HTML form using the
* {@code "multipart/form-data"} content type.
*
*
* RestTemplate restTemplate = new RestTemplate();
* // AllEncompassingFormHttpMessageConverter is configured by default
*
* MultiValueMap<String, Object> form = new LinkedMultiValueMap<>();
* form.add("field 1", "value 1");
* form.add("field 2", "value 2");
* form.add("field 2", "value 3");
* form.add("field 3", 4); // non-String form values supported as of 5.1.4
*
* restTemplate.postForLocation("https://example.com/myForm", form);
*
* The following snippet shows how to do a file upload using the
* {@code "multipart/form-data"} content type.
*
*
* MultiValueMap<String, Object> parts = new LinkedMultiValueMap<>();
* parts.add("field 1", "value 1");
* parts.add("file", new ClassPathResource("myFile.jpg"));
*
* restTemplate.postForLocation("https://example.com/myFileUpload", parts);
*
* The following snippet shows how to do a file upload using the
* {@code "multipart/mixed"} content type.
*
*
* MultiValueMap<String, Object> parts = new LinkedMultiValueMap<>();
* parts.add("field 1", "value 1");
* parts.add("file", new ClassPathResource("myFile.jpg"));
*
* HttpHeaders requestHeaders = new HttpHeaders();
* requestHeaders.setContentType(MediaType.MULTIPART_MIXED);
*
* restTemplate.postForLocation("https://example.com/myFileUpload",
* new HttpEntity<>(parts, requestHeaders));
*
* The following snippet shows how to do a file upload using the
* {@code "multipart/related"} content type.
*
*
* MediaType multipartRelated = new MediaType("multipart", "related");
*
* restTemplate.getMessageConverters().stream()
* .filter(FormHttpMessageConverter.class::isInstance)
* .map(FormHttpMessageConverter.class::cast)
* .findFirst()
* .orElseThrow(() -> new IllegalStateException("Failed to find FormHttpMessageConverter"))
* .addSupportedMediaTypes(multipartRelated);
*
* MultiValueMap<String, Object> parts = new LinkedMultiValueMap<>();
* parts.add("field 1", "value 1");
* parts.add("file", new ClassPathResource("myFile.jpg"));
*
* HttpHeaders requestHeaders = new HttpHeaders();
* requestHeaders.setContentType(multipartRelated);
*
* restTemplate.postForLocation("https://example.com/myFileUpload",
* new HttpEntity<>(parts, requestHeaders));
*
* Miscellaneous
*
* Some methods in this class were inspired by
* {@code org.apache.commons.httpclient.methods.multipart.MultipartRequestEntity}.
*
* @author Arjen Poutsma
* @author Rossen Stoyanchev
* @author Juergen Hoeller
* @author Sam Brannen
* @since 3.0
* @see org.springframework.http.converter.support.AllEncompassingFormHttpMessageConverter
* @see org.springframework.util.MultiValueMap
*/
public class FormHttpMessageConverter implements HttpMessageConverter> {
/**
* The default charset used by the converter.
*/
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 List supportedMediaTypes = new ArrayList<>();
private List> partConverters = new ArrayList<>();
private Charset charset = DEFAULT_CHARSET;
@Nullable
private Charset multipartCharset;
public FormHttpMessageConverter() {
this.supportedMediaTypes.add(MediaType.APPLICATION_FORM_URLENCODED);
this.supportedMediaTypes.add(MediaType.MULTIPART_FORM_DATA);
this.supportedMediaTypes.add(MediaType.MULTIPART_MIXED);
this.partConverters.add(new ByteArrayHttpMessageConverter());
this.partConverters.add(new StringHttpMessageConverter());
this.partConverters.add(new ResourceHttpMessageConverter());
applyDefaultCharset();
}
/**
* Set the list of {@link MediaType} objects supported by this converter.
* @see #addSupportedMediaTypes(MediaType...)
* @see #getSupportedMediaTypes()
*/
public void setSupportedMediaTypes(List supportedMediaTypes) {
Assert.notNull(supportedMediaTypes, "'supportedMediaTypes' must not be null");
// Ensure internal list is mutable.
this.supportedMediaTypes = new ArrayList<>(supportedMediaTypes);
}
/**
* Add {@link MediaType} objects to be supported by this converter.
* The supplied {@code MediaType} objects will be appended to the list
* of {@linkplain #getSupportedMediaTypes() supported MediaType objects}.
* @param supportedMediaTypes a var-args list of {@code MediaType} objects to add
* @since 5.2
* @see #setSupportedMediaTypes(List)
*/
public void addSupportedMediaTypes(MediaType... supportedMediaTypes) {
Assert.notNull(supportedMediaTypes, "'supportedMediaTypes' must not be null");
Assert.noNullElements(supportedMediaTypes, "'supportedMediaTypes' must not contain null elements");
Collections.addAll(this.supportedMediaTypes, supportedMediaTypes);
}
/**
* {@inheritDoc}
* @see #setSupportedMediaTypes(List)
* @see #addSupportedMediaTypes(MediaType...)
*/
@Override
public List getSupportedMediaTypes() {
return Collections.unmodifiableList(this.supportedMediaTypes);
}
/**
* Set the message body converters to use. These converters are used to
* convert objects to MIME parts.
*/
public void setPartConverters(List> partConverters) {
Assert.notEmpty(partConverters, "'partConverters' must not be empty");
this.partConverters = partConverters;
}
/**
* Return the {@linkplain #setPartConverters configured converters} for MIME
* parts.
* @since 5.3
*/
public List> getPartConverters() {
return Collections.unmodifiableList(this.partConverters);
}
/**
* Add a message body converter. Such a converter is used to convert objects
* to MIME parts.
*/
public void addPartConverter(HttpMessageConverter partConverter) {
Assert.notNull(partConverter, "'partConverter' must not be null");
this.partConverters.add(partConverter);
}
/**
* Set the default character set to use for reading and writing form data when
* the request or response {@code Content-Type} header does not explicitly
* specify it.
* As of 4.3, this is also used as the default charset for the conversion
* of text bodies in a multipart request.
*
As of 5.0, this is also used for part headers including
* {@code Content-Disposition} (and its filename parameter) unless (the mutually
* exclusive) {@link #setMultipartCharset multipartCharset} is also set, in
* which case part headers are encoded as ASCII and filename is encoded
* with the {@code encoded-word} syntax from RFC 2047.
*
By default this is set to "UTF-8".
*/
public void setCharset(@Nullable Charset charset) {
if (charset != this.charset) {
this.charset = (charset != null ? charset : DEFAULT_CHARSET);
applyDefaultCharset();
}
}
/**
* Apply the configured charset as a default to registered part converters.
*/
private void applyDefaultCharset() {
for (HttpMessageConverter candidate : this.partConverters) {
if (candidate instanceof AbstractHttpMessageConverter) {
AbstractHttpMessageConverter converter = (AbstractHttpMessageConverter) candidate;
// Only override default charset if the converter operates with a charset to begin with...
if (converter.getDefaultCharset() != null) {
converter.setDefaultCharset(this.charset);
}
}
}
}
/**
* Set the character set to use when writing multipart data to encode file
* names. Encoding is based on the {@code encoded-word} syntax defined in
* RFC 2047 and relies on {@code MimeUtility} from {@code javax.mail}.
*
As of 5.0 by default part headers, including {@code Content-Disposition}
* (and its filename parameter) will be encoded based on the setting of
* {@link #setCharset(Charset)} or {@code UTF-8} by default.
* @since 4.1.1
* @see Encoded-Word
*/
public void setMultipartCharset(Charset charset) {
this.multipartCharset = charset;
}
@Override
public boolean canRead(Class clazz, @Nullable MediaType mediaType) {
if (!MultiValueMap.class.isAssignableFrom(clazz)) {
return false;
}
if (mediaType == null) {
return true;
}
for (MediaType supportedMediaType : getSupportedMediaTypes()) {
if (supportedMediaType.getType().equalsIgnoreCase("multipart")) {
// We can't read multipart, so skip this supported media type.
continue;
}
if (supportedMediaType.includes(mediaType)) {
return true;
}
}
return false;
}
@Override
public boolean canWrite(Class clazz, @Nullable MediaType mediaType) {
if (!MultiValueMap.class.isAssignableFrom(clazz)) {
return false;
}
if (mediaType == null || MediaType.ALL.equals(mediaType)) {
return true;
}
for (MediaType supportedMediaType : getSupportedMediaTypes()) {
if (supportedMediaType.isCompatibleWith(mediaType)) {
return true;
}
}
return false;
}
@Override
public MultiValueMap read(@Nullable Class> clazz,
HttpInputMessage inputMessage) throws IOException, HttpMessageNotReadableException {
MediaType contentType = inputMessage.getHeaders().getContentType();
Charset charset = (contentType != null && contentType.getCharset() != null ?
contentType.getCharset() : this.charset);
String body = StreamUtils.copyToString(inputMessage.getBody(), charset);
String[] pairs = StringUtils.tokenizeToStringArray(body, "&");
MultiValueMap result = new LinkedMultiValueMap<>(pairs.length);
for (String pair : pairs) {
int idx = pair.indexOf('=');
if (idx == -1) {
result.add(URLDecoder.decode(pair, charset.name()), null);
}
else {
String name = URLDecoder.decode(pair.substring(0, idx), charset.name());
String value = URLDecoder.decode(pair.substring(idx + 1), charset.name());
result.add(name, value);
}
}
return result;
}
@Override
@SuppressWarnings("unchecked")
public void write(MultiValueMap map, @Nullable MediaType contentType, HttpOutputMessage outputMessage)
throws IOException, HttpMessageNotWritableException {
if (isMultipart(map, contentType)) {
writeMultipart((MultiValueMap) map, contentType, outputMessage);
}
else {
writeForm((MultiValueMap) map, contentType, outputMessage);
}
}
private boolean isMultipart(MultiValueMap map, @Nullable MediaType contentType) {
if (contentType != null) {
return contentType.getType().equalsIgnoreCase("multipart");
}
for (List values : map.values()) {
for (Object value : values) {
if (value != null && !(value instanceof String)) {
return true;
}
}
}
return false;
}
private void writeForm(MultiValueMap formData, @Nullable MediaType contentType,
HttpOutputMessage outputMessage) throws IOException {
contentType = getFormContentType(contentType);
outputMessage.getHeaders().setContentType(contentType);
Charset charset = contentType.getCharset();
Assert.notNull(charset, "No charset"); // should never occur
byte[] bytes = serializeForm(formData, charset).getBytes(charset);
outputMessage.getHeaders().setContentLength(bytes.length);
if (outputMessage instanceof StreamingHttpOutputMessage) {
StreamingHttpOutputMessage streamingOutputMessage = (StreamingHttpOutputMessage) outputMessage;
streamingOutputMessage.setBody(outputStream -> StreamUtils.copy(bytes, outputStream));
}
else {
StreamUtils.copy(bytes, outputMessage.getBody());
}
}
/**
* Return the content type used to write forms, given the preferred content type.
* By default, this method returns the given content type, but adds the
* {@linkplain #setCharset(Charset) charset} if it does not have one.
* If {@code contentType} is {@code null},
* {@code application/x-www-form-urlencoded; charset=UTF-8} is returned.
* Subclasses can override this method to change this behavior.
* @param contentType the preferred content type (can be {@code null})
* @return the content type to be used
* @since 5.2.2
*/
protected MediaType getFormContentType(@Nullable MediaType contentType) {
if (contentType == null) {
return DEFAULT_FORM_DATA_MEDIA_TYPE;
}
else if (contentType.getCharset() == null) {
return new MediaType(contentType, this.charset);
}
else {
return contentType;
}
}
protected String serializeForm(MultiValueMap formData, Charset charset) {
StringBuilder builder = new StringBuilder();
formData.forEach((name, values) -> {
if (name == null) {
Assert.isTrue(CollectionUtils.isEmpty(values), () -> "Null name in form data: " + formData);
return;
}
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(String.valueOf(value), charset.name()));
}
}
catch (UnsupportedEncodingException ex) {
throw new IllegalStateException(ex);
}
});
});
return builder.toString();
}
private void writeMultipart(
MultiValueMap parts, @Nullable MediaType contentType, HttpOutputMessage outputMessage)
throws IOException {
// If the supplied content type is null, fall back to multipart/form-data.
// Otherwise rely on the fact that isMultipart() already verified the
// supplied content type is multipart.
if (contentType == null) {
contentType = MediaType.MULTIPART_FORM_DATA;
}
Map parameters = new LinkedHashMap<>(contentType.getParameters().size() + 2);
parameters.putAll(contentType.getParameters());
byte[] boundary = generateMultipartBoundary();
if (!isFilenameCharsetSet()) {
if (!this.charset.equals(StandardCharsets.UTF_8) &&
!this.charset.equals(StandardCharsets.US_ASCII)) {
parameters.put("charset", this.charset.name());
}
}
parameters.put("boundary", new String(boundary, StandardCharsets.US_ASCII));
// Add parameters to output content type
contentType = new MediaType(contentType, parameters);
outputMessage.getHeaders().setContentType(contentType);
if (outputMessage instanceof StreamingHttpOutputMessage) {
StreamingHttpOutputMessage streamingOutputMessage = (StreamingHttpOutputMessage) outputMessage;
streamingOutputMessage.setBody(outputStream -> {
writeParts(outputStream, parts, boundary);
writeEnd(outputStream, boundary);
});
}
else {
writeParts(outputMessage.getBody(), parts, boundary);
writeEnd(outputMessage.getBody(), boundary);
}
}
/**
* When {@link #setMultipartCharset(Charset)} is configured (i.e. RFC 2047,
* {@code encoded-word} syntax) we need to use ASCII for part headers, or
* otherwise we encode directly using the configured {@link #setCharset(Charset)}.
*/
private boolean isFilenameCharsetSet() {
return (this.multipartCharset != null);
}
private void writeParts(OutputStream os, MultiValueMap parts, byte[] boundary) throws IOException {
for (Map.Entry> entry : parts.entrySet()) {
String name = entry.getKey();
for (Object part : entry.getValue()) {
if (part != null) {
writeBoundary(os, boundary);
writePart(name, getHttpEntity(part), os);
writeNewLine(os);
}
}
}
}
@SuppressWarnings("unchecked")
private void writePart(String name, HttpEntity partEntity, OutputStream os) throws IOException {
Object partBody = partEntity.getBody();
if (partBody == null) {
throw new IllegalStateException("Empty body for part '" + name + "': " + partEntity);
}
Class partType = partBody.getClass();
HttpHeaders partHeaders = partEntity.getHeaders();
MediaType partContentType = partHeaders.getContentType();
for (HttpMessageConverter messageConverter : this.partConverters) {
if (messageConverter.canWrite(partType, partContentType)) {
Charset charset = isFilenameCharsetSet() ? StandardCharsets.US_ASCII : this.charset;
HttpOutputMessage multipartMessage = new MultipartHttpOutputMessage(os, charset);
multipartMessage.getHeaders().setContentDispositionFormData(name, getFilename(partBody));
if (!partHeaders.isEmpty()) {
multipartMessage.getHeaders().putAll(partHeaders);
}
((HttpMessageConverter