org.springframework.cloud.dataflow.shell.command.support.HttpClientUtils.java Source code

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Here is the source code for org.springframework.cloud.dataflow.shell.command.support.HttpClientUtils.java

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/*
 * Copyright 2017 the original author or authors.
 *
 * 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 org.springframework.cloud.dataflow.shell.command.support;

import java.net.URI;
import java.security.KeyManagementException;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;

import javax.net.ssl.SSLContext;

import org.apache.http.HttpHost;
import org.apache.http.auth.AuthScope;
import org.apache.http.auth.UsernamePasswordCredentials;
import org.apache.http.client.AuthCache;
import org.apache.http.client.HttpClient;
import org.apache.http.conn.ssl.NoopHostnameVerifier;
import org.apache.http.impl.auth.BasicScheme;
import org.apache.http.impl.client.BasicAuthCache;
import org.apache.http.impl.client.BasicCredentialsProvider;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.ssl.SSLContexts;
import org.apache.http.ssl.TrustStrategy;
import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;
import org.springframework.web.client.RestTemplate;

/**
 * Provides utilities for the Apache {@link HttpClient}, used to make REST calls by the Shell.
 *
 * @author Gunnar Hillert
 *
 */
public class HttpClientUtils {

    /**
     * Ensures that the passed-in {@link RestTemplate} is using the Apache HTTP Client. If the optional {@code username} AND
     * {@code password} are not empty, then a {@link BasicCredentialsProvider} will be added to the {@link CloseableHttpClient}.
     *
     * Furthermore, you can set the underlying {@link SSLContext} of the {@link HttpClient} allowing you to accept self-signed
     * certificates.
     *
     * @param restTemplate Must not be null
     * @param username Can be null
     * @param password Can be null
     * @param skipSslValidation Use with caution! If true certificate warnings will be ignored.
     */
    public static void prepareRestTemplate(RestTemplate restTemplate, URI host, String username, String password,
            boolean skipSslValidation) {

        Assert.notNull(restTemplate, "The provided RestTemplate must not be null.");

        final HttpClientBuilder httpClientBuilder = HttpClientBuilder.create();

        if (StringUtils.hasText(username) && StringUtils.hasText(password)) {
            final BasicCredentialsProvider credentialsProvider = new BasicCredentialsProvider();
            credentialsProvider.setCredentials(AuthScope.ANY, new UsernamePasswordCredentials(username, password));
            httpClientBuilder.setDefaultCredentialsProvider(credentialsProvider);
        }

        if (skipSslValidation) {
            httpClientBuilder.setSSLContext(HttpClientUtils.buildCertificateIgnoringSslContext());
            httpClientBuilder.setSSLHostnameVerifier(new NoopHostnameVerifier());
        }

        final CloseableHttpClient httpClient = httpClientBuilder.build();
        final HttpHost targetHost = new HttpHost(host.getHost(), host.getPort(), host.getScheme());

        final HttpComponentsClientHttpRequestFactory requestFactory = new PreemptiveBasicAuthHttpComponentsClientHttpRequestFactory(
                httpClient, targetHost);
        restTemplate.setRequestFactory(requestFactory);
    }

    /**
     * Will create a certificate-ignoring {@link SSLContext}. Please use with utmost caution as it undermines security,
     * but may be useful in certain testing or development scenarios.
     *
     * @return The SSLContext
     */
    public static SSLContext buildCertificateIgnoringSslContext() {
        try {
            return SSLContexts.custom().loadTrustMaterial(new TrustStrategy() {
                @Override
                public boolean isTrusted(X509Certificate[] arg0, String arg1) throws CertificateException {
                    return true;
                }
            }).build();
        } catch (KeyManagementException | NoSuchAlgorithmException | KeyStoreException e) {
            throw new IllegalStateException(
                    "Unexpected exception while building the certificate-ignoring SSLContext.", e);
        }
    }
}