我想使用 zuul 来缓存一些请求。缓存作为 POJO 存储在 Redis 中，并包含纯文本（不是gzip压缩数据）。
对于正常测试和集成测试，一切都运行良好。使用jmeter负载测试时，某些请求失败并带有
java.util.zip.ZipException: Not in GZIP format (from jmeter)
我们发现，在这一点上，zuul正在返回一个空响应。
我的PreFilter：
public class CachePreFilter extends CacheBaseFilter {
private static DynamicIntProperty INITIAL_STREAM_BUFFER_SIZE = DynamicPropertyFactory.getInstance().getIntProperty(ZuulConstants.ZUUL_INITIAL_STREAM_BUFFER_SIZE, 8192);
@Autowired
CounterService counterService;
public CachePreFilter(RedisCacheManager redisCacheManager, Properties properties) {
super(redisCacheManager, properties);
}
@Override
public Object run() {
RequestContext ctx = RequestContext.getCurrentContext();
CachedResponse data = getFromCache(ctx);
if (null != data) {
counterService.increment("counter.cached");
HttpServletResponse response = ctx.getResponse();
response.addHeader("X-Cache", "HIT");
if (null != data.getContentType()) {
response.setContentType(data.getContentType());
}
if (null != data.getHeaders()) {
for (Entry<String, String> header : data.getHeaders().entrySet()) {
if (!response.containsHeader(header.getKey())) {
response.addHeader(header.getKey(), header.getValue());
}
}
}
OutputStream outStream = null;
try {
outStream = response.getOutputStream();
boolean isGzipRequested = ctx.isGzipRequested();
if (null != data.getBody()) {
final String requestEncoding = ctx.getRequest().getHeader(ZuulHeaders.ACCEPT_ENCODING);
if (requestEncoding != null && HTTPRequestUtils.getInstance().isGzipped(requestEncoding)) {
isGzipRequested = true;
}
ByteArrayOutputStream byteArrayOutputStream = null;
ByteArrayInputStream is = null;
try {
if (isGzipRequested) {
byteArrayOutputStream = new ByteArrayOutputStream();
GZIPOutputStream gzipOutputStream = new GZIPOutputStream(byteArrayOutputStream);
gzipOutputStream.write(data.getBody().getBytes(StandardCharsets.UTF_8));
gzipOutputStream.flush();
gzipOutputStream.close();
ctx.setResponseGZipped(true);
is = new ByteArrayInputStream(byteArrayOutputStream.toByteArray());
logger.debug(String.format("Send gzip content %s", data.getBody()));
response.setHeader(ZuulHeaders.CONTENT_ENCODING, "gzip");
} else {
logger.debug(String.format("Send content %s", data.getBody()));
is = new ByteArrayInputStream(data.getBody().getBytes(StandardCharsets.UTF_8));
}
writeResponse(is, outStream);
} catch (Exception e) {
logger.error("Error at sending response " + e.getMessage(), e);
throw new RuntimeException("Failed to send content", e);
} finally {
if (null != byteArrayOutputStream) {
byteArrayOutputStream.close();
}
if (null != is) {
is.close();
}
}
}
ctx.setSendZuulResponse(false);
} catch (IOException e) {
logger.error("Cannot read from Stream " + e.getMessage(), e.getMessage());
} finally {
// don't close the outputstream
}
ctx.set(CACHE_HIT, true);
return data;
} else {
counterService.increment("counter.notcached");
}
ctx.set(CACHE_HIT, false);
return null;
}
private ThreadLocal<byte[]> buffers = new ThreadLocal<byte[]>() {
@Override
protected byte[] initialValue() {
return new byte[INITIAL_STREAM_BUFFER_SIZE.get()];
}
};
private void writeResponse(InputStream zin, OutputStream out) throws Exception {
byte[] bytes = buffers.get();
int bytesRead = -1;
while ((bytesRead = zin.read(bytes)) != -1) {
out.write(bytes, 0, bytesRead);
}
}
@Override
public int filterOrder() {
return 99;
}
@Override
public String filterType() {
return "pre";
}
}
我的帖子过滤
public class CachePostFilter extends CacheBaseFilter {
public CachePostFilter(RedisCacheManager redisCacheManager, Properties properties) {
super(redisCacheManager, properties);
}
@Override
public boolean shouldFilter() {
RequestContext ctx = RequestContext.getCurrentContext();
return super.shouldFilter() && !ctx.getBoolean(CACHE_HIT);
}
@Override
public Object run() {
RequestContext ctx = RequestContext.getCurrentContext();
HttpServletRequest req = ctx.getRequest();
HttpServletResponse res = ctx.getResponse();
if (isSuccess(res, ctx.getOriginResponseHeaders())) {
// Store only successful responses
String cacheKey = cacheKey(req);
if (cacheKey != null) {
String body = null;
if (null != ctx.getResponseBody()) {
body = ctx.getResponseBody();
} else if (null != ctx.getResponseDataStream()) {
InputStream is = null;
try {
is = ctx.getResponseDataStream();
final Long len = ctx.getOriginContentLength();
if (len == null || len > 0) {
if (ctx.getResponseGZipped()) {
is = new GZIPInputStream(is);
}
StringWriter writer = new StringWriter();
IOUtils.copy(is, writer, "UTF-8");
body = writer.toString();
if (null != body && !body.isEmpty()) {
ctx.setResponseDataStream(new ByteArrayInputStream(body.getBytes()));
ctx.setResponseGZipped(false);
ctx.setOriginContentLength(String.valueOf(body.getBytes().length));
} else {
ctx.setResponseBody("{}");
}
}
} catch (IOException e) {
logger.error("Cannot read body " + e.getMessage(), e);
} finally {
if (null != is) {
try {
is.close();
} catch (IOException e) {
}
}
}
saveToCache(ctx, cacheKey, body);
}
}
}
return null;
}
@Override
public int filterOrder() {
return 1;
}
@Override
public String filterType() {
return "post";
}
private boolean isSuccess(HttpServletResponse res, List<Pair<String, String>> originHeaders) {
if (res != null && res.getStatus() < 300) {
if (null != originHeaders) {
for (Pair<String, String> header : originHeaders) {
if (header.first().equals("X-CACHEABLE") && header.second().equals("1")) {
return true;
}
}
}
}
return false;
}
我们在没有 Redis 的情况下测试它（只是将它存储到局部变量中），这仍然是相同的。我们总是记录来自缓存的响应（在gzip之前）并且一切看起来都很好。
答案 0 :(得分：1)
（代表作者提问）。
<强>解决方案
我们重构了PostFilter，并且在针对zuul的响应中没有做太多改变。在此更改后，我们再也看不到任何问题：
工作过滤后
public class CachePostFilter extends CacheBaseFilter {
public CachePostFilter(RedisCacheManager redisCacheManager, Properties properties) {
super(redisCacheManager, properties);
}
@Override
public boolean shouldFilter() {
RequestContext ctx = RequestContext.getCurrentContext();
return super.shouldFilter() && !ctx.getBoolean(CACHE_HIT);
}
@Override
public Object run() {
RequestContext ctx = RequestContext.getCurrentContext();
HttpServletRequest req = ctx.getRequest();
HttpServletResponse res = ctx.getResponse();
if (isSuccess(res, ctx.getOriginResponseHeaders())) {
// Store only successful responses
String cacheKey = cacheKey(req);
if (cacheKey != null) {
String body = null;
if (null != ctx.getResponseBody()) {
body = ctx.getResponseBody();
} else if (null != ctx.getResponseDataStream()) {
InputStream rawInputStream = null;
InputStream gzipByteArrayInputStream = null;
try {
rawInputStream = ctx.getResponseDataStream();
gzipByteArrayInputStream = null;
// If origin tell it's GZipped but the content is ZERO
// bytes,
// don't try to uncompress
final Long len = ctx.getOriginContentLength();
if (len == null || len > 0) {
byte[] rawData = IOUtils.toByteArray(rawInputStream);
ctx.setResponseDataStream(new ByteArrayInputStream(rawData));
if (ctx.getResponseGZipped()) {
gzipByteArrayInputStream = new GZIPInputStream(new ByteArrayInputStream(rawData));
} else {
gzipByteArrayInputStream = new ByteArrayInputStream(rawData);
}
StringWriter writer = new StringWriter();
IOUtils.copy(gzipByteArrayInputStream, writer, "UTF-8");
body = writer.toString();
}
} catch (IOException e) {
logger.error("Cannot read body " + e.getMessage(), e);
} finally {
if (null != rawInputStream) {
try {
rawInputStream.close();
} catch (IOException e) {
}
}
if (null != gzipByteArrayInputStream) {
try {
gzipByteArrayInputStream.close();
} catch (IOException e) {
}
}
}
// if we read from the stream, the other filter cannot read
// and they dont' deliver any response
// ctx.setResponseBody(body);
// ctx.setResponseGZipped(false);
saveToCache(ctx, cacheKey, body);
}
}
}
return null;
}
@Override
public int filterOrder() {
return 1;
}
@Override
public String filterType() {
return "post";
}
private boolean isSuccess(HttpServletResponse res, List<Pair<String, String>> originHeaders) {
if (res != null && res.getStatus() == 200) {
if (null != originHeaders) {
for (Pair<String, String> header : originHeaders) {
if (header.first().equals("X-CACHEABLE") && header.second().equals("1")) {
return true;
}
}
}
}
return false;
}
}