/*
* Copyright 2002-2014 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.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.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Random;
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.util.Assert;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
import org.springframework.util.StreamUtils;
import org.springframework.util.StringUtils;
/**
* Implementation of {@link HttpMessageConverter} that can handle form data, including multipart form data (i.e. file
* uploads).
*
* <p>This converter can write the {@code application/x-www-form-urlencoded} and {@code multipart/form-data} media
* types, and read the {@code application/x-www-form-urlencoded}) media type (but not {@code multipart/form-data}).
*
* <p>In other words, this converter can read and write 'normal' HTML forms (as {@link MultiValueMap
* MultiValueMap<String, String>}), and it can write multipart form (as {@link MultiValueMap
* MultiValueMap<String, Object>}. When writing multipart, this converter uses other {@link HttpMessageConverter
* HttpMessageConverters} to write the respective MIME parts. By default, basic converters are registered (supporting
* {@code Strings} and {@code Resources}, for instance); these can be overridden by setting the {@link
* #setPartConverters(java.util.List) partConverters} property.
*
* <p>For example, the following snippet shows how to submit an HTML form: <pre class="code"> RestTemplate template =
* new RestTemplate(); // FormHttpMessageConverter is configured by default MultiValueMap<String, String> form =
* new LinkedMultiValueMap<String, String>(); form.add("field 1", "value 1"); form.add("field 2", "value 2");
* form.add("field 2", "value 3"); template.postForLocation("http://example.com/myForm", form); </pre> <p>The following
* snippet shows how to do a file upload: <pre class="code"> MultiValueMap<String, Object> parts = new
* LinkedMultiValueMap<String, Object>(); parts.add("field 1", "value 1"); parts.add("file", new
* ClassPathResource("myFile.jpg")); template.postForLocation("http://example.com/myFileUpload", parts); </pre>
*
* <p>Some methods in this class were inspired by {@code org.apache.commons.httpclient.methods.multipart.MultipartRequestEntity}.
*
* @author Arjen Poutsma
* @see MultiValueMap
* @since 1.0
*/
public class FormHttpMessageConverter implements HttpMessageConverter<MultiValueMap<String, ?>> {
private static final byte[] BOUNDARY_CHARS =
new byte[]{'-', '_', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', 'a', 'b', 'c', 'd', 'e', 'f', 'g',
'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'A',
'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U',
'V', 'W', 'X', 'Y', 'Z'};
private final Random rnd = new Random();
private Charset charset = Charset.forName("UTF-8");
private List<MediaType> supportedMediaTypes = new ArrayList<MediaType>();
private List<HttpMessageConverter<?>> partConverters = new ArrayList<HttpMessageConverter<?>>();
public FormHttpMessageConverter() {
this.supportedMediaTypes.add(MediaType.APPLICATION_FORM_URLENCODED);
this.supportedMediaTypes.add(MediaType.MULTIPART_FORM_DATA);
this.partConverters.add(new ByteArrayHttpMessageConverter());
StringHttpMessageConverter stringHttpMessageConverter = new StringHttpMessageConverter();
stringHttpMessageConverter.setWriteAcceptCharset(false);
this.partConverters.add(stringHttpMessageConverter);
this.partConverters.add(new ResourceHttpMessageConverter());
}
/**
* Set the message body converters to use. These converters are used to convert objects to MIME parts.
*/
public final void setPartConverters(List<HttpMessageConverter<?>> partConverters) {
Assert.notEmpty(partConverters, "'partConverters' must not be empty");
this.partConverters = partConverters;
}
/**
* Add a message body converter. Such a converters is used to convert objects to MIME parts.
*/
public final void addPartConverter(HttpMessageConverter<?> partConverter) {
Assert.notNull(partConverter, "'partConverter' must not be NULL");
this.partConverters.add(partConverter);
}
/**
* Sets the character set used for writing form data.
*/
public void setCharset(Charset charset) {
this.charset = charset;
}
public boolean canRead(Class<?> clazz, MediaType mediaType) {
if (!MultiValueMap.class.isAssignableFrom(clazz)) {
return false;
}
if (mediaType == null) {
return true;
}
for (MediaType supportedMediaType : getSupportedMediaTypes()) {
// we can't read multipart
if (!supportedMediaType.equals(MediaType.MULTIPART_FORM_DATA) &&
supportedMediaType.includes(mediaType)) {
return true;
}
}
return false;
}
public boolean canWrite(Class<?> clazz, 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;
}
/**
* Set the list of {@link MediaType} objects supported by this converter.
*/
public void setSupportedMediaTypes(List<MediaType> supportedMediaTypes) {
this.supportedMediaTypes = supportedMediaTypes;
}
public List<MediaType> getSupportedMediaTypes() {
return Collections.unmodifiableList(this.supportedMediaTypes);
}
public MultiValueMap<String, String> read(Class<? extends MultiValueMap<String, ?>> clazz,
HttpInputMessage inputMessage) throws IOException, HttpMessageNotReadableException {
MediaType contentType = inputMessage.getHeaders().getContentType();
Charset charset = contentType.getCharSet() != null ? contentType.getCharSet() : this.charset;
String body = StreamUtils.copyToString(inputMessage.getBody(), charset);
String[] pairs = StringUtils.tokenizeToStringArray(body, "&");
MultiValueMap<String, String> result = new LinkedMultiValueMap<String, String>(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;
}
@SuppressWarnings("unchecked")
public void write(MultiValueMap<String, ?> map, MediaType contentType, HttpOutputMessage outputMessage)
throws IOException, HttpMessageNotWritableException {
if (!isMultipart(map, contentType)) {
writeForm((MultiValueMap<String, String>) map, contentType, outputMessage);
}
else {
writeMultipart((MultiValueMap<String, Object>) map, outputMessage);
}
}
private boolean isMultipart(MultiValueMap<String, ?> map, MediaType contentType) {
if (contentType != null) {
return MediaType.MULTIPART_FORM_DATA.includes(contentType);
}
for (String name : map.keySet()) {
for (Object value : map.get(name)) {
if (value != null && !(value instanceof String)) {
return true;
}
}
}
return false;
}
private void writeForm(MultiValueMap<String, String> form, MediaType contentType, HttpOutputMessage outputMessage)
throws IOException {
Charset charset;
if (contentType != null) {
outputMessage.getHeaders().setContentType(contentType);
charset = contentType.getCharSet() != null ? contentType.getCharSet() : this.charset;
}
else {
outputMessage.getHeaders().setContentType(MediaType.APPLICATION_FORM_URLENCODED);
charset = this.charset;
}
StringBuilder builder = new StringBuilder();
for (Iterator<String> nameIterator = form.keySet().iterator(); nameIterator.hasNext();) {
String name = nameIterator.next();
for (Iterator<String> valueIterator = form.get(name).iterator(); valueIterator.hasNext();) {
String value = valueIterator.next();
builder.append(URLEncoder.encode(name, charset.name()));
if (value != null) {
builder.append('=');
builder.append(URLEncoder.encode(value, charset.name()));
if (valueIterator.hasNext()) {
builder.append('&');
}
}
}
if (nameIterator.hasNext()) {
builder.append('&');
}
}
byte[] bytes = builder.toString().getBytes(charset.name());
outputMessage.getHeaders().setContentLength(bytes.length);
StreamUtils.copy(bytes, outputMessage.getBody());
}
private void writeMultipart(MultiValueMap<String, Object> parts, HttpOutputMessage outputMessage)
throws IOException {
byte[] boundary = generateMultipartBoundary();
Map<String, String> parameters = Collections.singletonMap("boundary", new String(boundary, "US-ASCII"));
MediaType contentType = new MediaType(MediaType.MULTIPART_FORM_DATA, parameters);
outputMessage.getHeaders().setContentType(contentType);
writeParts(outputMessage.getBody(), parts, boundary);
writeEnd(boundary, outputMessage.getBody());
}
private void writeParts(OutputStream os, MultiValueMap<String, Object> parts, byte[] boundary) throws IOException {
for (Map.Entry<String, List<Object>> entry : parts.entrySet()) {
String name = entry.getKey();
for (Object part : entry.getValue()) {
if (part != null) {
writeBoundary(boundary, os);
HttpEntity entity = getEntity(part);
writePart(name, entity, os);
writeNewLine(os);
}
}
}
}
private void writeBoundary(byte[] boundary, OutputStream os) throws IOException {
os.write('-');
os.write('-');
os.write(boundary);
writeNewLine(os);
}
@SuppressWarnings("unchecked")
private HttpEntity getEntity(Object part) {
if (part instanceof HttpEntity) {
return (HttpEntity) part;
}
else {
return new HttpEntity(part);
}
}
@SuppressWarnings("unchecked")
private void writePart(String name, HttpEntity partEntity, OutputStream os) throws IOException {
Object partBody = partEntity.getBody();
Class<?> partType = partBody.getClass();
HttpHeaders partHeaders = partEntity.getHeaders();
MediaType partContentType = partHeaders.getContentType();
for (HttpMessageConverter messageConverter : partConverters) {
if (messageConverter.canWrite(partType, partContentType)) {
HttpOutputMessage multipartOutputMessage = new MultipartHttpOutputMessage(os);
multipartOutputMessage.getHeaders().setContentDispositionFormData(name, getFilename(partBody));
if (!partHeaders.isEmpty()) {
multipartOutputMessage.getHeaders().putAll(partHeaders);
}
messageConverter.write(partBody, partContentType, multipartOutputMessage);
return;
}
}
throw new HttpMessageNotWritableException(
"Could not write request: no suitable HttpMessageConverter found for request type [" +
partType.getName() + "]");
}
private void writeEnd(byte[] boundary, OutputStream os) throws IOException {
os.write('-');
os.write('-');
os.write(boundary);
os.write('-');
os.write('-');
writeNewLine(os);
}
private void writeNewLine(OutputStream os) throws IOException {
os.write('\r');
os.write('\n');
}
/**
* Generate a multipart boundary.
* <p>The default implementation returns a random boundary.
* Can be overridden in subclasses.
*/
protected byte[] generateMultipartBoundary() {
byte[] boundary = new byte[rnd.nextInt(11) + 30];
for (int i = 0; i < boundary.length; i++) {
boundary[i] = BOUNDARY_CHARS[rnd.nextInt(BOUNDARY_CHARS.length)];
}
return boundary;
}
/**
* Return the filename of the given multipart part. This value will be used for the
* {@code Content-Disposition} header.
* <p>The default implementation returns {@link Resource#getFilename()} if the part is a
* {@code Resource}, and {@code null} in other cases. Can be overridden in subclasses.
* @param part the part to determine the file name for
* @return the filename, or {@code null} if not known
*/
protected String getFilename(Object part) {
if (part instanceof Resource) {
Resource resource = (Resource) part;
return resource.getFilename();
}
else {
return null;
}
}
/**
* Implementation of {@link org.springframework.http.HttpOutputMessage} used for writing multipart data.
*/
private class MultipartHttpOutputMessage implements HttpOutputMessage {
private final HttpHeaders headers = new HttpHeaders();
private final OutputStream os;
private boolean headersWritten = false;
public MultipartHttpOutputMessage(OutputStream os) {
this.os = os;
}
public HttpHeaders getHeaders() {
return headersWritten ? HttpHeaders.readOnlyHttpHeaders(headers) : this.headers;
}
public OutputStream getBody() throws IOException {
writeHeaders();
return this.os;
}
private void writeHeaders() throws IOException {
if (!this.headersWritten) {
for (Map.Entry<String, List<String>> entry : this.headers.entrySet()) {
byte[] headerName = getAsciiBytes(entry.getKey());
for (String headerValueString : entry.getValue()) {
byte[] headerValue = getAsciiBytes(headerValueString);
os.write(headerName);
os.write(':');
os.write(' ');
os.write(headerValue);
writeNewLine(os);
}
}
writeNewLine(os);
this.headersWritten = true;
}
}
protected byte[] getAsciiBytes(String name) {
try {
return name.getBytes("US-ASCII");
}
catch (UnsupportedEncodingException ex) {
// should not happen, US-ASCII is always supported
throw new IllegalStateException(ex);
}
}
}
}