io.github.kitarek.elasthttpd.server.producers.HttpConnectionCompliantResponseProducer.java Source code

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/*
 * Copyright 2015 Arek Kita
 *
 * 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 io.github.kitarek.elasthttpd.server.producers;

import io.github.kitarek.elasthttpd.commons.Optional;
import io.github.kitarek.elasthttpd.model.HttpMethod;
import org.apache.http.HttpException;
import org.apache.http.HttpRequest;
import org.apache.http.HttpResponse;
import org.apache.http.HttpServerConnection;
import org.apache.http.protocol.HttpContext;
import org.apache.http.protocol.HttpProcessor;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;

import static io.github.kitarek.elasthttpd.model.HttpMethod.HEAD;
import static org.apache.commons.lang3.Validate.notNull;
import static org.apache.http.HttpStatus.*;
import static org.apache.http.protocol.HttpCoreContext.HTTP_CONNECTION;
import static org.apache.http.protocol.HttpCoreContext.HTTP_REQUEST;

public class HttpConnectionCompliantResponseProducer implements HttpConnectionProducer {

    public static final Logger logger = LoggerFactory.getLogger(HttpConnectionCompliantResponseProducer.class);
    private final HttpProcessor httpProcessor;

    public HttpConnectionCompliantResponseProducer(HttpProcessor httpProcessor) {
        this.httpProcessor = notNull(httpProcessor, "HTTP procesorr needs to be specified");
    }

    public void sendResponse(HttpResponse responseToSend, HttpContext httpContext) {
        notNull(responseToSend, "HTTP response to send though connection cannot be null");
        notNull(httpContext, "HTTP context cannot be null");
        final HttpServerConnection connection = getConnectionFromContext(httpContext);
        try {
            httpProcessor.process(responseToSend, httpContext);
            sendResponseUnchecked(connection, responseToSend, getHttpMethodOptionalFromContext(httpContext));
        } catch (HttpException e) {
            logger.error("There was an HTTP application level exception when trying to send exception", e);
            closeConnectionIfPossible(connection);
        } catch (IOException e) {
            logger.error("I/O exception when trying to send response", e);
            closeConnectionIfPossible(connection);
        }
    }

    private Optional<HttpMethod> getHttpMethodOptionalFromContext(HttpContext httpContext) {
        final Object requestObject = notNull(httpContext.getAttribute(HTTP_REQUEST),
                "HTTP request must be defined in context");
        return (requestObject instanceof HttpRequest)
                ? getHttpMethodOptionalFromRequest((HttpRequest) requestObject)
                : Optional.<HttpMethod>empty();
    }

    private Optional<HttpMethod> getHttpMethodOptionalFromRequest(HttpRequest requestObject) {
        return HttpMethod.fromString(requestObject.getRequestLine().getMethod());
    }

    private HttpServerConnection getConnectionFromContext(HttpContext httpContext) {
        return (HttpServerConnection) notNull(httpContext.getAttribute(HTTP_CONNECTION),
                "HTTP connection needs to be defined in HTTP context");
    }

    private void closeConnectionIfPossible(HttpServerConnection serverConnection) {
        try {
            serverConnection.close();
        } catch (IOException e1) {
            logger.error("Cannot close connection for which HTTP response cannot be send", e1);
        }
    }

    private void sendResponseUnchecked(HttpServerConnection serverConnection, HttpResponse responseToSend,
            Optional<HttpMethod> optionalhttpRequestedMethod) throws HttpException, IOException {
        serverConnection.sendResponseHeader(responseToSend);
        if (canSendResponseBody(responseToSend, optionalhttpRequestedMethod)) {
            serverConnection.sendResponseEntity(responseToSend);
        }
        serverConnection.flush();
    }

    private boolean canSendResponseBody(HttpResponse responseToSend,
            Optional<HttpMethod> optionalhttpRequestedMethod) {
        return ((optionalhttpRequestedMethod.isNotPresent() || !isHeadRequestMethod(optionalhttpRequestedMethod))
                && getStatusCode(responseToSend) >= SC_OK && getStatusCode(responseToSend) != SC_NO_CONTENT
                && getStatusCode(responseToSend) != SC_RESET_CONTENT
                && getStatusCode(responseToSend) != SC_NOT_MODIFIED);
    }

    private boolean isHeadRequestMethod(Optional<HttpMethod> optionalhttpRequestedMethod) {
        return optionalhttpRequestedMethod.isPresent() && optionalhttpRequestedMethod.get() == HEAD;
    }

    private int getStatusCode(HttpResponse responseToSend) {
        return responseToSend.getStatusLine().getStatusCode();
    }
}