com.facebook.buck.httpserver.TraceDataHandler.java Source code

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Here is the source code for com.facebook.buck.httpserver.TraceDataHandler.java

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/*
 * Copyright 2013-present Facebook, 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 com.facebook.buck.httpserver;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
import com.google.common.io.CharStreams;
import com.google.common.io.InputSupplier;
import com.google.common.net.MediaType;

import org.eclipse.jetty.server.Request;
import org.eclipse.jetty.server.handler.AbstractHandler;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Writer;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * HTTP handler for requests to the {@code /tracedata} path.
 */
class TraceDataHandler extends AbstractHandler {

    static final Pattern ID_PATTERN = Pattern.compile("/([0-9a-zA-Z]+)");

    @VisibleForTesting
    static final Pattern CALLBACK_PATTERN = Pattern.compile("[\\w\\.]+");

    private final TracesHelper tracesHelper;

    TraceDataHandler(TracesHelper tracesHelper) {
        this.tracesHelper = Preconditions.checkNotNull(tracesHelper);
    }

    @Override
    public void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response)
            throws IOException, ServletException {
        if ("GET".equals(baseRequest.getMethod())) {
            doGet(baseRequest, response);
        } else {
            Responses.writeFailedResponse(baseRequest, response);
        }
    }

    private void doGet(Request baseRequest, HttpServletResponse response) throws ServletException, IOException {
        String path = baseRequest.getPathInfo();
        Matcher matcher = ID_PATTERN.matcher(path);

        if (!matcher.matches()) {
            Responses.writeFailedResponse(baseRequest, response);
            return;
        }

        String id = matcher.group(1);

        response.setContentType(MediaType.JAVASCRIPT_UTF_8.toString());
        response.setStatus(HttpServletResponse.SC_OK);

        boolean hasValidCallbackParam = false;
        Writer responseWriter = response.getWriter();
        String callback = baseRequest.getParameter("callback");
        if (callback != null) {
            Matcher callbackMatcher = CALLBACK_PATTERN.matcher(callback);
            if (callbackMatcher.matches()) {
                hasValidCallbackParam = true;
                responseWriter.write(callback);
                responseWriter.write("(");
            }
        }

        InputSupplier<? extends InputStream> inputSupplier = tracesHelper.getInputForTrace(id);
        try (InputStreamReader inputStreamReader = new InputStreamReader(inputSupplier.getInput())) {
            CharStreams.copy(inputStreamReader, responseWriter);
        }

        if (hasValidCallbackParam) {
            responseWriter.write(");\n");
        }

        response.flushBuffer();
        baseRequest.setHandled(true);
    }
}