co.cask.http.internal.HttpResourceModel Maven / Gradle / Ivy
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/*
* Copyright © 2017 Cask Data, Inc.
*
* 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 co.cask.http.internal;
import co.cask.http.ExceptionHandler;
import co.cask.http.HttpHandler;
import co.cask.http.HttpResponder;
import io.netty.handler.codec.http.HttpMethod;
import io.netty.handler.codec.http.HttpRequest;
import io.netty.handler.codec.http.HttpResponseStatus;
import io.netty.handler.codec.http.QueryStringDecoder;
import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.IdentityHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import javax.annotation.Nullable;
import javax.ws.rs.DefaultValue;
import javax.ws.rs.HeaderParam;
import javax.ws.rs.PathParam;
import javax.ws.rs.QueryParam;
/**
* HttpResourceModel contains information needed to handle Http call for a given path. Used as a destination in
* {@code PatternPathRouterWithGroups} to route URI paths to right Http end points.
*/
public final class HttpResourceModel {
private static final Set> SUPPORTED_PARAM_ANNOTATIONS =
Collections.unmodifiableSet(new HashSet<>(Arrays.asList(PathParam.class, QueryParam.class, HeaderParam.class)));
private final Set httpMethods;
private final String path;
private final Method method;
private final HttpHandler handler;
private final List, ParameterInfo>> paramsInfo;
private final ExceptionHandler exceptionHandler;
/**
* Construct a resource model with HttpMethod, method that handles httprequest, Object that contains the method.
*
* @param httpMethods Set of http methods that is handled by the resource.
* @param path path associated with this model.
* @param method handler that handles the http request.
* @param handler instance {@code HttpHandler}.
*/
public HttpResourceModel(Set httpMethods, String path, Method method, HttpHandler handler,
ExceptionHandler exceptionHandler) {
this.httpMethods = httpMethods;
this.path = path;
this.method = method;
this.handler = handler;
this.paramsInfo = createParametersInfos(method);
this.exceptionHandler = exceptionHandler;
}
/**
* @return httpMethods.
*/
public Set getHttpMethod() {
return httpMethods;
}
/**
* @return path associated with this model.
*/
public String getPath() {
return path;
}
/**
* @return handler method that handles an http end-point.
*/
public Method getMethod() {
return method;
}
/**
* @return instance of {@code HttpHandler}.
*/
public HttpHandler getHttpHandler() {
return handler;
}
/**
* Handle http Request.
*
* @param request HttpRequest to be handled.
* @param responder HttpResponder to write the response.
* @param groupValues Values needed for the invocation.
*/
@SuppressWarnings("unchecked")
public HttpMethodInfo handle(HttpRequest request,
HttpResponder responder, Map groupValues) throws Exception {
//TODO: Refactor group values.
try {
if (httpMethods.contains(request.method())) {
//Setup args for reflection call
Object [] args = new Object[paramsInfo.size()];
int idx = 0;
for (Map, ParameterInfo> info : paramsInfo) {
if (info.containsKey(PathParam.class)) {
args[idx] = getPathParamValue(info, groupValues);
}
if (info.containsKey(QueryParam.class)) {
args[idx] = getQueryParamValue(info, request.uri());
}
if (info.containsKey(HeaderParam.class)) {
args[idx] = getHeaderParamValue(info, request);
}
idx++;
}
return new HttpMethodInfo(method, handler, responder, args, exceptionHandler);
} else {
//Found a matching resource but could not find the right HttpMethod so return 405
throw new HandlerException(HttpResponseStatus.METHOD_NOT_ALLOWED, String.format
("Problem accessing: %s. Reason: Method Not Allowed", request.uri()));
}
} catch (Throwable e) {
throw new HandlerException(HttpResponseStatus.INTERNAL_SERVER_ERROR,
String.format("Error in executing request: %s %s", request.method(),
request.uri()), e);
}
}
@Override
public String toString() {
return "HttpResourceModel{" +
"httpMethods=" + httpMethods +
", path='" + path + '\'' +
", method=" + method +
", handler=" + handler +
'}';
}
@SuppressWarnings("unchecked")
private Object getPathParamValue(Map, ParameterInfo> annotations,
Map groupValues) throws Exception {
ParameterInfo info = (ParameterInfo) annotations.get(PathParam.class);
PathParam pathParam = info.getAnnotation();
String value = groupValues.get(pathParam.value());
if (value == null) {
throw new IllegalArgumentException("Could not resolve value for path parameter " + pathParam.value());
}
return info.convert(value);
}
@SuppressWarnings("unchecked")
private Object getQueryParamValue(Map, ParameterInfo> annotations,
String uri) throws Exception {
ParameterInfo> info = (ParameterInfo>) annotations.get(QueryParam.class);
QueryParam queryParam = info.getAnnotation();
List values = new QueryStringDecoder(uri).parameters().get(queryParam.value());
return (values == null) ? info.convert(defaultValue(annotations)) : info.convert(values);
}
@SuppressWarnings("unchecked")
private Object getHeaderParamValue(Map, ParameterInfo> annotations,
HttpRequest request) throws Exception {
ParameterInfo> info = (ParameterInfo>) annotations.get(HeaderParam.class);
HeaderParam headerParam = info.getAnnotation();
String headerName = headerParam.value();
boolean hasHeader = request.headers().contains(headerName);
return hasHeader ? info.convert(request.headers().getAll(headerName)) : info.convert(defaultValue(annotations));
}
/**
* Returns a List of String created based on the {@link DefaultValue} if it is presented in the annotations Map.
*
* @return a List of String or an empty List if {@link DefaultValue} is not presented
*/
private List defaultValue(Map, ParameterInfo> annotations) {
ParameterInfo defaultInfo = annotations.get(DefaultValue.class);
if (defaultInfo == null) {
return Collections.emptyList();
}
DefaultValue defaultValue = defaultInfo.getAnnotation();
return Collections.singletonList(defaultValue.value());
}
/**
* Gathers all parameters' annotations for the given method, starting from the third parameter.
*/
private List, ParameterInfo>> createParametersInfos(Method method) {
if (method.getParameterTypes().length <= 2) {
return Collections.emptyList();
}
List, ParameterInfo>> result = new ArrayList<>();
Type[] parameterTypes = method.getGenericParameterTypes();
Annotation[][] parameterAnnotations = method.getParameterAnnotations();
for (int i = 2; i < parameterAnnotations.length; i++) {
Annotation[] annotations = parameterAnnotations[i];
Map, ParameterInfo> paramAnnotations = new IdentityHashMap<>();
for (Annotation annotation : annotations) {
Class annotationType = annotation.annotationType();
ParameterInfo parameterInfo;
if (PathParam.class.isAssignableFrom(annotationType)) {
parameterInfo = ParameterInfo.create(annotation,
ParamConvertUtils.createPathParamConverter(parameterTypes[i]));
} else if (QueryParam.class.isAssignableFrom(annotationType)) {
parameterInfo = ParameterInfo.create(annotation,
ParamConvertUtils.createQueryParamConverter(parameterTypes[i]));
} else if (HeaderParam.class.isAssignableFrom(annotationType)) {
parameterInfo = ParameterInfo.create(annotation,
ParamConvertUtils.createHeaderParamConverter(parameterTypes[i]));
} else {
parameterInfo = ParameterInfo.create(annotation, null);
}
paramAnnotations.put(annotationType, parameterInfo);
}
// Must have either @PathParam, @QueryParam or @HeaderParam, but not two or more.
int presence = 0;
for (Class annotationClass : paramAnnotations.keySet()) {
if (SUPPORTED_PARAM_ANNOTATIONS.contains(annotationClass)) {
presence++;
}
}
if (presence != 1) {
throw new IllegalArgumentException(
String.format("Must have exactly one annotation from %s for parameter %d in method %s",
SUPPORTED_PARAM_ANNOTATIONS, i, method));
}
result.add(Collections.unmodifiableMap(paramAnnotations));
}
return Collections.unmodifiableList(result);
}
/**
* A container class to hold information about a handler method parameters.
*/
private static final class ParameterInfo {
private final Annotation annotation;
private final Converter converter;
static ParameterInfo create(Annotation annotation, @Nullable Converter converter) {
return new ParameterInfo<>(annotation, converter);
}
private ParameterInfo(Annotation annotation, @Nullable Converter converter) {
this.annotation = annotation;
this.converter = converter;
}
@SuppressWarnings("unchecked")
V getAnnotation() {
return (V) annotation;
}
Object convert(T input) throws Exception {
return (converter == null) ? null : converter.convert(input);
}
}
}
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