/**
* Construct HttpResourceHandler. Reads all annotations from all the handler classes and methods
* passed in, constructs patternPathRouter which is routable by path to {@code HttpResourceModel}
* as destination of the route.
*
* @param handlers Iterable of HttpHandler.
* @param interceptors Iterable of interceptors.
* @param urlRewriter URL re-writer.
* @param exceptionHandler Exception handler
*/
public MicroserviceMetadata(
Iterable<? extends Object> handlers,
Iterable<? extends Interceptor> interceptors,
URLRewriter urlRewriter,
ExceptionHandler exceptionHandler) {
// Store the handlers to call init and destroy on all handlers.
this.handlers = ImmutableList.copyOf(handlers);
this.interceptors = ImmutableList.copyOf(interceptors);
this.urlRewriter = urlRewriter;
for (Object handler : handlers) {
String basePath = "";
if (handler.getClass().isAnnotationPresent(Path.class)) {
basePath = handler.getClass().getAnnotation(Path.class).value();
}
for (Method method : handler.getClass().getDeclaredMethods()) {
if (method.isAnnotationPresent(PostConstruct.class)
|| method.isAnnotationPresent(PreDestroy.class)) {
continue;
}
if (Modifier.isPublic(method.getModifiers()) && isHttpMethodAvailable(method)) {
String relativePath = "";
if (method.getAnnotation(Path.class) != null) {
relativePath = method.getAnnotation(Path.class).value();
}
String absolutePath = String.format("%s/%s", basePath, relativePath);
patternRouter.add(
absolutePath,
new HttpResourceModel(absolutePath, method, handler, new ExceptionHandler()));
} else {
log.trace(
"Not adding method {}({}) to path routing like. "
+ "HTTP calls will not be routed to this method",
method.getName(),
method.getParameterTypes());
}
}
}
}
/**
* MicroserviceMetadata handles the http request. HttpResourceHandler looks up all Jax-rs
* annotations in classes and dispatches to appropriate method on receiving requests.
*/
public final class MicroserviceMetadata {
private static final Logger log = LoggerFactory.getLogger(MicroserviceMetadata.class);
private final PatternPathRouterWithGroups<HttpResourceModel> patternRouter =
PatternPathRouterWithGroups.create();
private final Iterable<Object> handlers;
private final Iterable<Interceptor> interceptors;
private final URLRewriter urlRewriter;
/**
* Construct HttpResourceHandler. Reads all annotations from all the handler classes and methods
* passed in, constructs patternPathRouter which is routable by path to {@code HttpResourceModel}
* as destination of the route.
*
* @param handlers Iterable of HttpHandler.
* @param interceptors Iterable of interceptors.
* @param urlRewriter URL re-writer.
* @param exceptionHandler Exception handler
*/
public MicroserviceMetadata(
Iterable<? extends Object> handlers,
Iterable<? extends Interceptor> interceptors,
URLRewriter urlRewriter,
ExceptionHandler exceptionHandler) {
// Store the handlers to call init and destroy on all handlers.
this.handlers = ImmutableList.copyOf(handlers);
this.interceptors = ImmutableList.copyOf(interceptors);
this.urlRewriter = urlRewriter;
for (Object handler : handlers) {
String basePath = "";
if (handler.getClass().isAnnotationPresent(Path.class)) {
basePath = handler.getClass().getAnnotation(Path.class).value();
}
for (Method method : handler.getClass().getDeclaredMethods()) {
if (method.isAnnotationPresent(PostConstruct.class)
|| method.isAnnotationPresent(PreDestroy.class)) {
continue;
}
if (Modifier.isPublic(method.getModifiers()) && isHttpMethodAvailable(method)) {
String relativePath = "";
if (method.getAnnotation(Path.class) != null) {
relativePath = method.getAnnotation(Path.class).value();
}
String absolutePath = String.format("%s/%s", basePath, relativePath);
patternRouter.add(
absolutePath,
new HttpResourceModel(absolutePath, method, handler, new ExceptionHandler()));
} else {
log.trace(
"Not adding method {}({}) to path routing like. "
+ "HTTP calls will not be routed to this method",
method.getName(),
method.getParameterTypes());
}
}
}
}
private boolean isHttpMethodAvailable(Method method) {
return method.isAnnotationPresent(GET.class)
|| method.isAnnotationPresent(PUT.class)
|| method.isAnnotationPresent(POST.class)
|| method.isAnnotationPresent(DELETE.class);
}
/**
* Call the appropriate handler for handling the httprequest. 404 if path is not found. 405 if
* path is found but httpMethod does not match what's configured.
*
* @param request instance of {@code HttpRequest}
* @param responder instance of {@code HttpResponder} to handle the request.
* @return HttpMethodInfo object, null if urlRewriter rewrite returns false, also when method
* cannot be invoked.
* @throws HandlerException If URL rewriting fails
*/
public HttpMethodInfoBuilder getDestinationMethod(HttpRequest request, HttpResponder responder)
throws HandlerException {
if (urlRewriter != null) {
try {
request.setUri(URI.create(request.getUri()).normalize().toString());
if (!urlRewriter.rewrite(request, responder)) {
return null;
}
} catch (Throwable t) {
log.error("Exception thrown during rewriting of uri {}", request.getUri(), t);
throw new HandlerException(
HttpResponseStatus.INTERNAL_SERVER_ERROR,
String.format("Caught exception processing request. Reason: %s", t.getMessage()));
}
}
String acceptHeaderStr = request.headers().get(HttpHeaders.Names.ACCEPT);
List<String> acceptHeader =
(acceptHeaderStr != null)
? Arrays.asList(acceptHeaderStr.split("\\s*,\\s*"))
.stream()
.map(mediaType -> mediaType.split("\\s*;\\s*")[0])
.collect(Collectors.toList())
: null;
String contentTypeHeaderStr = request.headers().get(HttpHeaders.Names.CONTENT_TYPE);
// Trim specified charset since UTF-8 is assumed
String contentTypeHeader =
(contentTypeHeaderStr != null) ? contentTypeHeaderStr.split("\\s*;\\s*")[0] : null;
try {
String path = URI.create(request.getUri()).normalize().getPath();
List<PatternPathRouterWithGroups.RoutableDestination<HttpResourceModel>>
routableDestinations = patternRouter.getDestinations(path);
List<PatternPathRouterWithGroups.RoutableDestination<HttpResourceModel>> matchedDestinations =
getMatchedDestination(routableDestinations, request.getMethod(), path);
if (!matchedDestinations.isEmpty()) {
PatternPathRouterWithGroups.RoutableDestination<HttpResourceModel> matchedDestination =
matchedDestinations
.stream()
.filter(
matchedDestination1 -> {
return matchedDestination1
.getDestination()
.matchConsumeMediaType(contentTypeHeader)
&& matchedDestination1
.getDestination()
.matchProduceMediaType(acceptHeader);
})
.findFirst()
.get();
HttpResourceModel httpResourceModel = matchedDestination.getDestination();
// Call preCall method of handler interceptors.
boolean terminated = false;
ServiceMethodInfo serviceMethodInfo =
new ServiceMethodInfo(
httpResourceModel.getMethod().getDeclaringClass().getName(),
httpResourceModel.getMethod());
for (Interceptor interceptor : interceptors) {
if (!interceptor.preCall(request, responder, serviceMethodInfo)) {
// Terminate further request processing if preCall returns false.
terminated = true;
break;
}
}
// Call httpresource handle method, return the HttpMethodInfo Object.
if (!terminated) {
// Wrap responder to make post hook calls.
responder = new WrappedHttpResponder(responder, interceptors, request, serviceMethodInfo);
return HttpMethodInfoBuilder.getInstance()
.httpResourceModel(httpResourceModel)
.httpRequest(request)
.httpResponder(responder)
.requestInfo(
matchedDestination.getGroupNameValues(), contentTypeHeader, acceptHeader);
}
} else if (!routableDestinations.isEmpty()) {
// Found a matching resource but could not find the right HttpMethod so return 405
throw new HandlerException(HttpResponseStatus.METHOD_NOT_ALLOWED, request.getUri());
} else {
throw new HandlerException(
HttpResponseStatus.NOT_FOUND,
String.format("Problem accessing: %s. Reason: Not Found", request.getUri()));
}
} catch (NoSuchElementException ex) {
throw new HandlerException(
HttpResponseStatus.UNSUPPORTED_MEDIA_TYPE,
String.format("Problem accessing: %s. Reason: Unsupported Media Type", request.getUri()),
ex);
}
return null;
}
/**
* Get HttpResourceModel which matches the HttpMethod of the request.
*
* @param routableDestinations List of ResourceModels.
* @param targetHttpMethod HttpMethod.
* @param requestUri request URI.
* @return RoutableDestination that matches httpMethod that needs to be handled. null if there are
* no matches.
*/
private List<PatternPathRouterWithGroups.RoutableDestination<HttpResourceModel>>
getMatchedDestination(
List<PatternPathRouterWithGroups.RoutableDestination<HttpResourceModel>>
routableDestinations,
HttpMethod targetHttpMethod,
String requestUri) {
Iterable<String> requestUriParts = Splitter.on('/').omitEmptyStrings().split(requestUri);
List<PatternPathRouterWithGroups.RoutableDestination<HttpResourceModel>> matchedDestinations =
Lists.newArrayListWithExpectedSize(routableDestinations.size());
int maxExactMatch = 0;
int maxGroupMatch = 0;
int maxPatternLength = 0;
for (PatternPathRouterWithGroups.RoutableDestination<HttpResourceModel> destination :
routableDestinations) {
HttpResourceModel resourceModel = destination.getDestination();
int groupMatch = destination.getGroupNameValues().size();
for (HttpMethod httpMethod : resourceModel.getHttpMethod()) {
if (targetHttpMethod.equals(httpMethod)) {
int exactMatch =
getExactPrefixMatchCount(
requestUriParts,
Splitter.on('/').omitEmptyStrings().split(resourceModel.getPath()));
// When there are multiple matches present, the following precedence order is used -
// 1. template path that has highest exact prefix match with the url is chosen.
// 2. template path has the maximum groups is chosen.
// 3. finally, template path that has the longest length is chosen.
if (exactMatch > maxExactMatch) {
maxExactMatch = exactMatch;
maxGroupMatch = groupMatch;
maxPatternLength = resourceModel.getPath().length();
matchedDestinations.clear();
matchedDestinations.add(destination);
} else if (exactMatch == maxExactMatch && groupMatch >= maxGroupMatch) {
if (groupMatch > maxGroupMatch || resourceModel.getPath().length() > maxPatternLength) {
maxGroupMatch = groupMatch;
maxPatternLength = resourceModel.getPath().length();
matchedDestinations.clear();
}
matchedDestinations.add(destination);
}
}
}
}
return matchedDestinations;
}
/** @return the number of path components that match from left to right. */
private int getExactPrefixMatchCount(Iterable<String> first, Iterable<String> second) {
int count = 0;
for (Iterator<String> fit = first.iterator(), sit = second.iterator();
fit.hasNext() && sit.hasNext(); ) {
if (fit.next().equals(sit.next())) {
++count;
} else {
break;
}
}
return count;
}
}
/**
* Call the appropriate handler for handling the httprequest. 404 if path is not found. 405 if
* path is found but httpMethod does not match what's configured.
*
* @param request instance of {@code HttpRequest}
* @param responder instance of {@code HttpResponder} to handle the request.
* @return HttpMethodInfo object, null if urlRewriter rewrite returns false, also when method
* cannot be invoked.
* @throws HandlerException If URL rewriting fails
*/
public HttpMethodInfoBuilder getDestinationMethod(HttpRequest request, HttpResponder responder)
throws HandlerException {
if (urlRewriter != null) {
try {
request.setUri(URI.create(request.getUri()).normalize().toString());
if (!urlRewriter.rewrite(request, responder)) {
return null;
}
} catch (Throwable t) {
log.error("Exception thrown during rewriting of uri {}", request.getUri(), t);
throw new HandlerException(
HttpResponseStatus.INTERNAL_SERVER_ERROR,
String.format("Caught exception processing request. Reason: %s", t.getMessage()));
}
}
String acceptHeaderStr = request.headers().get(HttpHeaders.Names.ACCEPT);
List<String> acceptHeader =
(acceptHeaderStr != null)
? Arrays.asList(acceptHeaderStr.split("\\s*,\\s*"))
.stream()
.map(mediaType -> mediaType.split("\\s*;\\s*")[0])
.collect(Collectors.toList())
: null;
String contentTypeHeaderStr = request.headers().get(HttpHeaders.Names.CONTENT_TYPE);
// Trim specified charset since UTF-8 is assumed
String contentTypeHeader =
(contentTypeHeaderStr != null) ? contentTypeHeaderStr.split("\\s*;\\s*")[0] : null;
try {
String path = URI.create(request.getUri()).normalize().getPath();
List<PatternPathRouterWithGroups.RoutableDestination<HttpResourceModel>>
routableDestinations = patternRouter.getDestinations(path);
List<PatternPathRouterWithGroups.RoutableDestination<HttpResourceModel>> matchedDestinations =
getMatchedDestination(routableDestinations, request.getMethod(), path);
if (!matchedDestinations.isEmpty()) {
PatternPathRouterWithGroups.RoutableDestination<HttpResourceModel> matchedDestination =
matchedDestinations
.stream()
.filter(
matchedDestination1 -> {
return matchedDestination1
.getDestination()
.matchConsumeMediaType(contentTypeHeader)
&& matchedDestination1
.getDestination()
.matchProduceMediaType(acceptHeader);
})
.findFirst()
.get();
HttpResourceModel httpResourceModel = matchedDestination.getDestination();
// Call preCall method of handler interceptors.
boolean terminated = false;
ServiceMethodInfo serviceMethodInfo =
new ServiceMethodInfo(
httpResourceModel.getMethod().getDeclaringClass().getName(),
httpResourceModel.getMethod());
for (Interceptor interceptor : interceptors) {
if (!interceptor.preCall(request, responder, serviceMethodInfo)) {
// Terminate further request processing if preCall returns false.
terminated = true;
break;
}
}
// Call httpresource handle method, return the HttpMethodInfo Object.
if (!terminated) {
// Wrap responder to make post hook calls.
responder = new WrappedHttpResponder(responder, interceptors, request, serviceMethodInfo);
return HttpMethodInfoBuilder.getInstance()
.httpResourceModel(httpResourceModel)
.httpRequest(request)
.httpResponder(responder)
.requestInfo(
matchedDestination.getGroupNameValues(), contentTypeHeader, acceptHeader);
}
} else if (!routableDestinations.isEmpty()) {
// Found a matching resource but could not find the right HttpMethod so return 405
throw new HandlerException(HttpResponseStatus.METHOD_NOT_ALLOWED, request.getUri());
} else {
throw new HandlerException(
HttpResponseStatus.NOT_FOUND,
String.format("Problem accessing: %s. Reason: Not Found", request.getUri()));
}
} catch (NoSuchElementException ex) {
throw new HandlerException(
HttpResponseStatus.UNSUPPORTED_MEDIA_TYPE,
String.format("Problem accessing: %s. Reason: Unsupported Media Type", request.getUri()),
ex);
}
return null;
}