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Add checkNotModified support in ServerWebExchange

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Issue: SPR-14522
This commit is contained in:
Rossen Stoyanchev
2016-08-30 14:36:19 -04:00
parent 638e6cc7f8
commit 6071e01168
3 changed files with 508 additions and 0 deletions
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39
spring-web/src/main/java/org/springframework/web/server/ServerWebExchange.java
View File

@@ -16,6 +16,7 @@
package org.springframework.web.server;
import java.time.Instant;
import java.util.Map;
import java.util.Optional;
@@ -67,4 +68,42 @@ public interface ServerWebExchange {
*/
Mono<WebSession> getSession();
/**
* An overloaded variant of {@link #checkNotModified(String, Instant)} with
* a last-modified timestamp only.
* @param lastModified the last-modified time
* @return whether the request qualifies as not modified
*/
boolean checkNotModified(Instant lastModified);
/**
* An overloaded variant of {@link #checkNotModified(String, Instant)} with
* an {@code ETag} (entity tag) value only.
* @param etag the entity tag for the underlying resource.
* @return true if the request does not require further processing.
*/
boolean checkNotModified(String etag);
/**
* Check whether the requested resource has been modified given the supplied
* {@code ETag} (entity tag) and last-modified timestamp as determined by
* the application. Also transparently prepares the response, setting HTTP
* status, and adding "ETag" and "Last-Modified" headers when applicable.
* This method works with conditional GET/HEAD requests as well as with
* conditional POST/PUT/DELETE requests.
*
* <p><strong>Note:</strong> The HTTP specification recommends setting both
* ETag and Last-Modified values, but you can also use
* {@code #checkNotModified(String)} or
* {@link #checkNotModified(Instant)}.
*
* @param etag the entity tag that the application determined for the
* underlying resource. This parameter will be padded with quotes (")
* if necessary.
* @param lastModified the last-modified timestamp that the application
* determined for the underlying resource
* @return true if the request does not require further processing.
*/
boolean checkNotModified(String etag, Instant lastModified);
}

137
spring-web/src/main/java/org/springframework/web/server/adapter/DefaultServerWebExchange.java
View File

@@ -16,15 +16,23 @@
package org.springframework.web.server.adapter;
import java.time.Instant;
import java.time.temporal.ChronoUnit;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.concurrent.ConcurrentHashMap;
import reactor.core.publisher.Mono;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.server.WebSession;
import org.springframework.web.server.session.WebSessionManager;
@@ -37,6 +45,9 @@ import org.springframework.web.server.session.WebSessionManager;
*/
public class DefaultServerWebExchange implements ServerWebExchange {
private static final List<HttpMethod> SAFE_METHODS = Arrays.asList(HttpMethod.GET, HttpMethod.HEAD);
private final ServerHttpRequest request;
private final ServerHttpResponse response;
@@ -45,6 +56,8 @@ public class DefaultServerWebExchange implements ServerWebExchange {
private final Mono<WebSession> sessionMono;
private volatile boolean notModified;
public DefaultServerWebExchange(ServerHttpRequest request, ServerHttpResponse response,
WebSessionManager sessionManager) {
@@ -63,11 +76,19 @@ public class DefaultServerWebExchange implements ServerWebExchange {
return this.request;
}
private HttpHeaders getRequestHeaders() {
return getRequest().getHeaders();
}
@Override
public ServerHttpResponse getResponse() {
return this.response;
}
private HttpHeaders getResponseHeaders() {
return getResponse().getHeaders();
}
@Override
public Map<String, Object> getAttributes() {
return this.attributes;
@@ -83,4 +104,120 @@ public class DefaultServerWebExchange implements ServerWebExchange {
return this.sessionMono;
}
@Override
public boolean checkNotModified(Instant lastModified) {
return checkNotModified(null, lastModified);
}
@Override
public boolean checkNotModified(String etag) {
return checkNotModified(etag, Instant.MIN);
}
@Override
public boolean checkNotModified(String etag, Instant lastModified) {
HttpStatus status = getResponse().getStatusCode();
if (this.notModified || (status != null && !HttpStatus.OK.equals(status))) {
return this.notModified;
}
// Evaluate conditions in order of precedence.
// See https://tools.ietf.org/html/rfc7232#section-6
if (validateIfUnmodifiedSince(lastModified)) {
if (this.notModified) {
getResponse().setStatusCode(HttpStatus.PRECONDITION_FAILED);
}
return this.notModified;
}
boolean validated = validateIfNoneMatch(etag);
if (!validated) {
validateIfModifiedSince(lastModified);
}
// Update response
boolean isHttpGetOrHead = SAFE_METHODS.contains(getRequest().getMethod());
if (this.notModified) {
getResponse().setStatusCode(isHttpGetOrHead ?
HttpStatus.NOT_MODIFIED : HttpStatus.PRECONDITION_FAILED);
}
if (isHttpGetOrHead) {
if (lastModified.isAfter(Instant.EPOCH) && getResponseHeaders().getLastModified() == -1) {
getResponseHeaders().setLastModified(lastModified.toEpochMilli());
}
if (StringUtils.hasLength(etag) && getResponseHeaders().getETag() == null) {
getResponseHeaders().setETag(padEtagIfNecessary(etag));
}
}
return this.notModified;
}
private boolean validateIfUnmodifiedSince(Instant lastModified) {
if (lastModified.isBefore(Instant.EPOCH)) {
return false;
}
long ifUnmodifiedSince = getRequestHeaders().getIfUnmodifiedSince();
if (ifUnmodifiedSince == -1) {
return false;
}
// We will perform this validation...
Instant sinceInstant = Instant.ofEpochMilli(ifUnmodifiedSince);
this.notModified = sinceInstant.isBefore(lastModified.truncatedTo(ChronoUnit.SECONDS));
return true;
}
private boolean validateIfNoneMatch(String etag) {
if (!StringUtils.hasLength(etag)) {
return false;
}
List<String> ifNoneMatch;
try {
ifNoneMatch = getRequestHeaders().getIfNoneMatch();
}
catch (IllegalArgumentException ex) {
return false;
}
if (ifNoneMatch.isEmpty()) {
return false;
}
// We will perform this validation...
etag = padEtagIfNecessary(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/", ""))) {
this.notModified = true;
break;
}
}
return true;
}
private String padEtagIfNecessary(String etag) {
if (!StringUtils.hasLength(etag)) {
return etag;
}
if ((etag.startsWith("\"") || etag.startsWith("W/\"")) && etag.endsWith("\"")) {
return etag;
}
return "\"" + etag + "\"";
}
private boolean validateIfModifiedSince(Instant lastModified) {
if (lastModified.isBefore(Instant.EPOCH)) {
return false;
}
long ifModifiedSince = getRequestHeaders().getIfModifiedSince();
if (ifModifiedSince == -1) {
return false;
}
// We will perform this validation...
this.notModified = ChronoUnit.SECONDS.between(lastModified, Instant.ofEpochMilli(ifModifiedSince)) >= 0;
return true;
}
}