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Fix conditional requests support for HttpEntity

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Prior to this commit, `HttpEntityMethodProcessor` would rely on
`ServletWebRequest` to process conditional requests and with incoming
`"If-Modified-Since"` / `"If-None-Match"` request headers.

This approach is problematic since in that class:

* response is wrapped in a `ServletServerHttpResponse`
* this wrapped response does not write response headers right away
* `ServletWebRequest.checkNotModified` methods can't apply their
logic with incomplete response headers

This solution adds some minimal code duplication and applies
the conditional request logic within the Processor.

A possible alternative would be to improve the
`ServletServerHttpResponse$ServletResponseHttpHeaders` implementation
with write methods - but this solution would only work for Servlet 3.x
applications.

Issue: SPR-13090
This commit is contained in:
Brian Clozel
2015-06-26 15:28:59 +02:00
parent 338a18ef99
commit 39d689da0c
4 changed files with 88 additions and 48 deletions
Download Patch File Download Diff File Expand all files Collapse all files

65
spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/HttpEntityMethodProcessor.java
View File

@@ -27,6 +27,7 @@ import org.springframework.core.ResolvableType;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.HttpStatus;
import org.springframework.http.RequestEntity;
import org.springframework.http.ResponseEntity;
import org.springframework.http.converter.HttpMessageConverter;
@@ -163,32 +164,22 @@ public class HttpEntityMethodProcessor extends AbstractMessageConverterMethodPro
Assert.isInstanceOf(HttpEntity.class, returnValue);
HttpEntity<?> responseEntity = (HttpEntity<?>) returnValue;
if (responseEntity instanceof ResponseEntity) {
outputMessage.setStatusCode(((ResponseEntity<?>) responseEntity).getStatusCode());
}
HttpHeaders entityHeaders = responseEntity.getHeaders();
if (!entityHeaders.isEmpty()) {
outputMessage.getHeaders().putAll(entityHeaders);
}
Object body = responseEntity.getBody();
if (responseEntity instanceof ResponseEntity) {
for (String headerName : entityHeaders.keySet()) {
if(!HttpHeaders.LAST_MODIFIED.equals(headerName)
&& !HttpHeaders.ETAG.equals(headerName)) {
outputMessage.getHeaders().put(headerName, entityHeaders.get(headerName));
}
}
if (isResourceNotModified(webRequest, (ResponseEntity<?>) responseEntity)) {
outputMessage.setStatusCode(((ResponseEntity<?>) responseEntity).getStatusCode());
if (isResourceNotModified(inputMessage, outputMessage)) {
outputMessage.setStatusCode(HttpStatus.NOT_MODIFIED);
// Ensure headers are flushed, no body should be written.
outputMessage.flush();
// Skip call to converters, as they may update the body.
return;
}
}
else {
if (!entityHeaders.isEmpty()) {
outputMessage.getHeaders().putAll(entityHeaders);
}
}
// Try even with null body. ResponseBodyAdvice could get involved.
writeWithMessageConverters(body, returnType, inputMessage, outputMessage);
@@ -197,22 +188,52 @@ public class HttpEntityMethodProcessor extends AbstractMessageConverterMethodPro
outputMessage.flush();
}
private boolean isResourceNotModified(NativeWebRequest webRequest, ResponseEntity<?> responseEntity) {
String eTag = responseEntity.getHeaders().getETag();
long lastModified = responseEntity.getHeaders().getLastModified();
private boolean isResourceNotModified(ServletServerHttpRequest inputMessage, ServletServerHttpResponse outputMessage) {
List<String> ifNoneMatch = inputMessage.getHeaders().getIfNoneMatch();
long ifModifiedSince = inputMessage.getHeaders().getIfModifiedSince();
String eTag = addEtagPadding(outputMessage.getHeaders().getETag());
long lastModified = outputMessage.getHeaders().getLastModified();
boolean notModified = false;
if (lastModified != -1 && StringUtils.hasLength(eTag)) {
notModified = webRequest.checkNotModified(eTag, lastModified);
notModified = isETagNotModified(ifNoneMatch, eTag) && isTimeStampNotModified(ifModifiedSince, lastModified);
}
else if (lastModified != -1) {
notModified = webRequest.checkNotModified(lastModified);
notModified = isTimeStampNotModified(ifModifiedSince, lastModified);
}
else if (StringUtils.hasLength(eTag)) {
notModified = webRequest.checkNotModified(eTag);
notModified = isETagNotModified(ifNoneMatch, eTag);
}
return notModified;
}
private boolean isETagNotModified(List<String> ifNoneMatch, String etag) {
if (StringUtils.hasLength(etag)) {
for (String clientETag : ifNoneMatch) {
// compare weak/strong ETags as per https://tools.ietf.org/html/rfc7232#section-2.3
if (StringUtils.hasLength(clientETag) &&
(clientETag.replaceFirst("^W/", "").equals(etag.replaceFirst("^W/", ""))
|| clientETag.equals("*"))) {
return true;
}
}
}
return false;
}
private boolean isTimeStampNotModified(long ifModifiedSince, long lastModifiedTimestamp) {
return (ifModifiedSince >= (lastModifiedTimestamp / 1000 * 1000));
}
private String addEtagPadding(String etag) {
if (StringUtils.hasLength(etag) &&
(!(etag.startsWith("\"") || etag.startsWith("W/\"")) || !etag.endsWith("\"")) ) {
etag = "\"" + etag + "\"";
}
return etag;
}
@Override
protected Class<?> getReturnValueType(Object returnValue, MethodParameter returnType) {
if (returnValue != null) {