com.google.testing.security.firingrange.utils.Templates.java Source code

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Here is the source code for com.google.testing.security.firingrange.utils.Templates.java

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/*
 * Copyright 2014 Google Inc. All rights reserved.
 *
 * 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.google.testing.security.firingrange.utils;

import static java.nio.charset.StandardCharsets.UTF_8;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
import com.google.common.base.Splitter;
import com.google.common.io.Resources;

import java.io.IOException;
import java.net.URL;
import java.util.logging.Logger;

import javax.annotation.concurrent.Immutable;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;

/**
 * A helper class to manipulate templates.
 */
@Immutable
public final class Templates {
    private static final String ERROR_TEMPLATE = "data/error.tmpl";
    @VisibleForTesting
    static final String PAYLOAD_PLACEHOLDER = "%%PAYLOAD%%";
    private static final Logger logger = Logger.getLogger(Templates.class.getCanonicalName());

    private Templates() {
    }

    /**
     * Extract a template given an HTTP request. The last path component is the template.
     * @throws IOException if it cannot find the template.
     */
    public static String getTemplate(HttpServletRequest request, Class<? extends HttpServlet> clazz)
            throws IOException {
        String firstPathPart = Splitter.on('/').splitToList(request.getPathInfo()).get(1);
        String templateName = firstPathPart + ".tmpl";
        return getTemplate(templateName, clazz);
    }

    /**
     * Extracts a template given the path relative to a {@code clazz}.
     * @throws IOException if it cannot find the template.
     */
    public static String getTemplate(String relativePath, Class<? extends HttpServlet> clazz) throws IOException {
        Preconditions.checkArgument(!relativePath.contains(".."));
        try {
            URL resource = Resources.getResource(clazz, "data/" + relativePath);
            return templateToString(resource);
        } catch (IllegalArgumentException e) {
            logger.info("Cannot find template for " + relativePath);
            throw new IOException(errorTemplate());
        }
    }

    @VisibleForTesting
    static String errorTemplate() {
        // Unable to find this template. Return error template.
        try {
            return templateToString(Resources.getResource(Templates.class, ERROR_TEMPLATE));
        } catch (IllegalArgumentException e2) {
            // Unable to find the error template!
            logger.severe("Cannot find error template");
            return "";
        }
    }

    private static String templateToString(URL resource) {
        try {
            return Resources.toString(resource, UTF_8);
        } catch (IOException e) {
            logger.severe("Cannot open template: " + resource);
            return "ERROR, cannot open template";
        }
    }

    /**
     * Sets the payload in a given template.
     */
    public static String replacePayload(String template, String payload) {
        return template.replace(PAYLOAD_PLACEHOLDER, payload);
    }
}