org.elasticsearch.rest.RestHandler Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of elasticsearch Show documentation
Show all versions of elasticsearch Show documentation
Elasticsearch subproject :server
/*
* Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
* or more contributor license agreements. Licensed under the Elastic License
* 2.0 and the Server Side Public License, v 1; you may not use this file except
* in compliance with, at your election, the Elastic License 2.0 or the Server
* Side Public License, v 1.
*/
package org.elasticsearch.rest;
import org.apache.logging.log4j.Level;
import org.elasticsearch.client.node.NodeClient;
import org.elasticsearch.core.Nullable;
import org.elasticsearch.core.RestApiVersion;
import org.elasticsearch.rest.RestRequest.Method;
import org.elasticsearch.xcontent.XContent;
import java.util.Collections;
import java.util.List;
import java.util.Objects;
/**
* Handler for REST requests
*/
@FunctionalInterface
public interface RestHandler {
/**
* Handles a rest request.
* @param request The request to handle
* @param channel The channel to write the request response to
* @param client A client to use to make internal requests on behalf of the original request
*/
void handleRequest(RestRequest request, RestChannel channel, NodeClient client) throws Exception;
default boolean canTripCircuitBreaker() {
return true;
}
/**
* Indicates if the RestHandler supports content as a stream. A stream would be multiple objects delineated by
* {@link XContent#streamSeparator()}. If a handler returns true this will affect the types of content that can be sent to
* this endpoint.
*/
default boolean supportsContentStream() {
return false;
}
/**
* Indicates if the RestHandler supports working with pooled buffers. If the request handler will not escape the return
* {@link RestRequest#content()} or any buffers extracted from it then there is no need to make a copies of any pooled buffers in the
* {@link RestRequest} instance before passing a request to this handler. If this instance does not support pooled/unsafe buffers
* {@link RestRequest#ensureSafeBuffers()} should be called on any request before passing it to {@link #handleRequest}.
*
* @return true iff the handler supports requests that make use of pooled buffers
*/
default boolean allowsUnsafeBuffers() {
return false;
}
/**
* The list of {@link Route}s that this RestHandler is responsible for handling.
*/
default List routes() {
return Collections.emptyList();
}
/**
* Controls whether requests handled by this class are allowed to to access system indices by default.
* @return {@code true} if requests handled by this class should be allowed to access system indices.
*/
default boolean allowSystemIndexAccessByDefault() {
return false;
}
class Route {
private final Method method;
private final String path;
private final RestApiVersion restApiVersion;
private final String deprecationMessage;
@Nullable
private final Level deprecationLevel;
private final Route replacedRoute;
private Route(
Method method,
String path,
RestApiVersion restApiVersion,
String deprecationMessage,
Level deprecationLevel,
Route replacedRoute
) {
this.method = Objects.requireNonNull(method);
this.path = Objects.requireNonNull(path);
this.restApiVersion = Objects.requireNonNull(restApiVersion);
// a deprecated route will have a deprecation message, and the restApiVersion
// will represent the version when the route was deprecated
this.deprecationMessage = deprecationMessage;
this.deprecationLevel = deprecationLevel;
// a route that replaces another route will have a reference to the route that was replaced
this.replacedRoute = replacedRoute;
}
/**
* Constructs a Route that pairs an HTTP method with an associated path.
*
* This is sufficient for most routes in Elasticsearch, like "GET /", "PUT /_cluster/settings", or "POST my_index/_close".
*
* @param method the method, e.g. GET
* @param path the path, e.g. "/"
*/
public Route(Method method, String path) {
this(method, path, RestApiVersion.current(), null, null, null);
}
public static class RouteBuilder {
private final Method method;
private final String path;
private RestApiVersion restApiVersion;
private String deprecationMessage;
@Nullable
private Level deprecationLevel;
private Route replacedRoute;
private RouteBuilder(Method method, String path) {
this.method = Objects.requireNonNull(method);
this.path = Objects.requireNonNull(path);
this.restApiVersion = RestApiVersion.current();
}
/**
* Marks that the route being built has been deprecated (for some reason -- the deprecationMessage), and notes the major
* version in which that deprecation occurred.
*
* For example:
*
{@code
* Route.builder(GET, "_upgrade")
* .deprecated("The _upgrade API is no longer useful and will be removed.", RestApiVersion.V_7)
* .build()}
*
* @param deprecationMessage the user-visible explanation of this deprecation
* @param deprecatedInVersion the major version in which the deprecation occurred
* @return a reference to this object.
*/
public RouteBuilder deprecated(String deprecationMessage, RestApiVersion deprecatedInVersion) {
assert this.replacedRoute == null;
this.restApiVersion = Objects.requireNonNull(deprecatedInVersion);
this.deprecationMessage = Objects.requireNonNull(deprecationMessage);
return this;
}
/**
* Marks that the route being built has been deprecated (for some reason -- the deprecationMessage), and notes the major
* version in which that deprecation occurred.
*
* For example:
*
{@code
* Route.builder(GET, "_upgrade")
* .deprecated("The _upgrade API is no longer useful and will be removed.", RestApiVersion.V_7)
* .build()}
*
* @param deprecationMessage the user-visible explanation of this deprecation
* @param deprecationLevel the level at which to log the deprecation
* @param deprecatedInVersion the major version in which the deprecation occurred
* @return a reference to this object.
*/
public RouteBuilder deprecated(String deprecationMessage, Level deprecationLevel, RestApiVersion deprecatedInVersion) {
assert this.replacedRoute == null;
this.restApiVersion = Objects.requireNonNull(deprecatedInVersion);
this.deprecationMessage = Objects.requireNonNull(deprecationMessage);
this.deprecationLevel = deprecationLevel;
return this;
}
/**
* Marks that the route being built replaces another route, and notes the major version in which that replacement occurred.
*
* For example:
*
{@code
* Route.builder(GET, "/_security/user/")
* .replaces(GET, "/_xpack/security/user/", RestApiVersion.V_7).build()}
*
* @param method the method being replaced
* @param path the path being replaced
* @param replacedInVersion the major version in which the replacement occurred
* @return a reference to this object.
*/
public RouteBuilder replaces(Method method, String path, RestApiVersion replacedInVersion) {
assert this.deprecationMessage == null;
this.replacedRoute = new Route(method, path, replacedInVersion, null, null, null);
return this;
}
public Route build() {
if (replacedRoute != null) {
return new Route(method, path, restApiVersion, null, null, replacedRoute);
} else if (deprecationMessage != null) {
return new Route(method, path, restApiVersion, deprecationMessage, deprecationLevel, null);
} else {
// this is a little silly, but perfectly legal
return new Route(method, path, restApiVersion, null, null, null);
}
}
}
public static RouteBuilder builder(Method method, String path) {
return new RouteBuilder(method, path);
}
public String getPath() {
return path;
}
public Method getMethod() {
return method;
}
public RestApiVersion getRestApiVersion() {
return restApiVersion;
}
public String getDeprecationMessage() {
return deprecationMessage;
}
@Nullable
public Level getDeprecationLevel() {
return deprecationLevel;
}
public boolean isDeprecated() {
return deprecationMessage != null;
}
public Route getReplacedRoute() {
return replacedRoute;
}
public boolean isReplacement() {
return replacedRoute != null;
}
}
}