[Feature/extensions] Pass REST params and content to extensions (#4633)

* Pass REST params and content to extensions 

Signed-off-by: Daniel Widdis <[email protected]>

CHANGELOG.md

@@ -104,6 +104,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
  - Adding create component extension point support for AD ([#4517](https:/opensearch-project/OpenSearch/pull/4517))
  - Add getSettings support for AD([#4519](https:/opensearch-project/OpenSearch/pull/4519))
  - Fixed javadoc warning for build failure([#4581](https:/opensearch-project/OpenSearch/pull/4581))
+ - Pass REST params and content to extensions ([#4633](https:/opensearch-project/OpenSearch/pull/4633))
 
 ## [2.x]
 ### Added

server/src/main/java/org/opensearch/extensions/rest/ExtensionRestRequest.java

@@ -0,0 +1,273 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.extensions.rest;
+
+import org.opensearch.common.bytes.BytesReference;
+import org.opensearch.common.io.stream.StreamInput;
+import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.common.xcontent.XContentType;
+import org.opensearch.identity.PrincipalIdentifierToken;
+import org.opensearch.rest.RestRequest;
+import org.opensearch.rest.RestRequest.Method;
+import org.opensearch.transport.TransportRequest;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+
+/**
+ * Request to execute REST actions on extension node.
+ * This contains necessary portions of a {@link RestRequest} object, but does not pass the full request for security concerns.
+ *
+ * @opensearch.api
+ */
+public class ExtensionRestRequest extends TransportRequest {
+
+ private Method method;
+ private String path;
+ private Map<String, String> params;
+ private XContentType xContentType = null;
+ private BytesReference content;
+ // The owner of this request object
+ private PrincipalIdentifierToken principalIdentifierToken;
+
+ // Tracks consumed parameters and content
+ private final Set<String> consumedParams = new HashSet<>();
+ private boolean contentConsumed = false;
+
+ /**
+ * This object can be instantiated given method, uri, params, content and identifier
+ *
+ * @param method of type {@link Method}
+ * @param path the REST path string (excluding the query)
+ * @param params the REST params
+ * @param xContentType the content type, or null for plain text or no content
+ * @param content the REST request content
+ * @param principalIdentifier the owner of this request
+ */
+ public ExtensionRestRequest(
+ Method method,
+ String path,
+ Map<String, String> params,
+ XContentType xContentType,
+ BytesReference content,
+ PrincipalIdentifierToken principalIdentifier
+ ) {
+ this.method = method;
+ this.path = path;
+ this.params = params;
+ this.xContentType = xContentType;
+ this.content = content;
+ this.principalIdentifierToken = principalIdentifier;
+ }
+
+ /**
+ * Instantiate this request from input stream
+ *
+ * @param in Input stream
+ * @throws IOException on failure to read the stream
+ */
+ public ExtensionRestRequest(StreamInput in) throws IOException {
+ super(in);
+ method = in.readEnum(RestRequest.Method.class);
+ path = in.readString();
+ params = in.readMap(StreamInput::readString, StreamInput::readString);
+ if (in.readBoolean()) {
+ xContentType = in.readEnum(XContentType.class);
+ }
+ content = in.readBytesReference();
+ principalIdentifierToken = in.readNamedWriteable(PrincipalIdentifierToken.class);
+ }
+
+ @Override
+ public void writeTo(StreamOutput out) throws IOException {
+ super.writeTo(out);
+ out.writeEnum(method);
+ out.writeString(path);
+ out.writeMap(params, StreamOutput::writeString, StreamOutput::writeString);
+ out.writeBoolean(xContentType != null);
+ if (xContentType != null) {
+ out.writeEnum(xContentType);
+ }
+ out.writeBytesReference(content);
+ out.writeNamedWriteable(principalIdentifierToken);
+ }
+
+ /**
+ * Gets the REST method
+ *
+ * @return This REST request {@link Method} type
+ */
+ public Method method() {
+ return method;
+ }
+
+ /**
+ * Gets the REST path
+ *
+ * @return This REST request's path
+ */
+ public String path() {
+ return path;
+ }
+
+ /**
+ * Gets the full map of params without consuming them. Rest Handlers should use {@link #param(String)} or {@link #param(String, String)}
+ * to get parameter values.
+ *
+ * @return This REST request's params
+ */
+ public Map<String, String> params() {
+ return params;
+ }
+
+ /**
+ * Tests whether a parameter named {@code key} exists.
+ *
+ * @param key The parameter to test.
+ * @return True if there is a value for this parameter.
+ */
+ public boolean hasParam(String key) {
+ return params.containsKey(key);
+ }
+
+ /**
+ * Gets the value of a parameter, consuming it in the process.
+ *
+ * @param key The parameter key
+ * @return The parameter value if it exists, or null.
+ */
+ public String param(String key) {
+ consumedParams.add(key);
+ return params.get(key);
+ }
+
+ /**
+ * Gets the value of a parameter, consuming it in the process.
+ *
+ * @param key The parameter key
+ * @param defaultValue A value to return if the parameter value doesn't exist.
+ * @return The parameter value if it exists, or the default value.
+ */
+ public String param(String key, String defaultValue) {
+ consumedParams.add(key);
+ return params.getOrDefault(key, defaultValue);
+ }
+
+ /**
+ * Gets the value of a parameter as a long, consuming it in the process.
+ *
+ * @param key The parameter key
+ * @param defaultValue A value to return if the parameter value doesn't exist.
+ * @return The parameter value if it exists, or the default value.
+ */
+ public long paramAsLong(String key, long defaultValue) {
+ String value = param(key);
+ if (value == null) {
+ return defaultValue;
+ }
+ try {
+ return Long.parseLong(value);
+ } catch (NumberFormatException e) {
+ throw new IllegalArgumentException("Unable to parse param '" + key + "' value '" + value + "' to a long.", e);
+ }
+ }
+
+ /**
+ * Returns parameters consumed by {@link #param(String)} or {@link #param(String, String)}.
+ *
+ * @return a list of consumed parameters.
+ */
+ public List<String> consumedParams() {
+ return new ArrayList<>(consumedParams);
+ }
+
+ /**
+ * Gets the content type, if any.
+ *
+ * @return the content type of the {@link #content()}, or null if the context is plain text or if there is no content.
+ */
+ public XContentType getXContentType() {
+ return xContentType;
+ }
+
+ /**
+ * Gets the content.
+ *
+ * @return This REST request's content
+ */
+ public BytesReference content() {
+ contentConsumed = true;
+ return content;
+ }
+
+ /**
+ * Tests whether content exists.
+ *
+ * @return True if there is non-empty content.
+ */
+ public boolean hasContent() {
+ return content.length() > 0;
+ }
+
+ /**
+ * Tests whether content has been consumed.
+ *
+ * @return True if the content was consumed.
+ */
+ public boolean isContentConsumed() {
+ return contentConsumed;
+ }
+
+ /**
+ * @return This REST request issuer's identity token
+ */
+ public PrincipalIdentifierToken getRequestIssuerIdentity() {
+ return principalIdentifierToken;
+ }
+
+ @Override
+ public String toString() {
+ return "ExtensionRestRequest{method="
+ + method
+ + ", path="
+ + path
+ + ", params="
+ + params
+ + ", xContentType="
+ + xContentType
+ + ", contentLength="
+ + content.length()
+ + ", requester="
+ + principalIdentifierToken.getToken()
+ + "}";
+ }
+
+ @Override
+ public boolean equals(Object obj) {
+ if (this == obj) return true;
+ if (obj == null || getClass() != obj.getClass()) return false;
+ ExtensionRestRequest that = (ExtensionRestRequest) obj;
+ return Objects.equals(method, that.method)
+ && Objects.equals(path, that.path)
+ && Objects.equals(params, that.params)
+ && Objects.equals(xContentType, that.xContentType)
+ && Objects.equals(content, that.content)
+ && Objects.equals(principalIdentifierToken, that.principalIdentifierToken);
+ }
+
+ @Override
+ public int hashCode() {
+ return Objects.hash(method, path, params, xContentType, content, principalIdentifierToken);
+ }
+}