src/main/java/pta/de/core/communication/RestServiceWrapper.java

package pta.de.core.communication;


import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
import org.apache.http.conn.ssl.TrustSelfSignedStrategy;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.ssl.SSLContextBuilder;
import org.apache.http.util.EntityUtils;
import org.apache.log4j.Logger;
import pta.de.core.common.Globals;
import pta.de.core.exceptions.HttpStatusException;

import java.io.IOException;
import java.nio.charset.StandardCharsets;

public class RestServiceWrapper {
    private static final Logger LOGGER = Logger.getLogger(RestServiceWrapper.class.getName());
    private boolean useHttps;

    public RestServiceWrapper(boolean https) {
        this.useHttps = https;
    }

    public String performGetRequest(String restFunctionWithParams) throws HttpStatusException {
        LOGGER.debug("CompleteUrl: " + restFunctionWithParams);
        // create HTTP Client
        CloseableHttpClient httpClient = createHttpsClient();

        // create new Request with given URL
        HttpGet getRequest = new HttpGet(restFunctionWithParams);
        getRequest.addHeader("accept", Globals.HEADER_JSON_UTF8);

        HttpResponse response;
        // Execute request an catch response
        try {
            response = httpClient.execute(getRequest);

        } catch (IOException e) {
            String errtext = "Communication to <" + restFunctionWithParams + "> failed!";
            LOGGER.warn(errtext, e);
            throw new HttpStatusException(HttpStatus.SC_SERVICE_UNAVAILABLE);
        }

        return createJson(response);
    }

    public String performPostRequest(String restFunctionWithParams, String data) throws HttpStatusException {

        // create HTTP Client
        CloseableHttpClient httpClient = createHttpsClient();

        // create new Post Request with given URL
        HttpPost postRequest = new HttpPost(restFunctionWithParams);

        // add additional header to getRequest which accepts application/JSON data
        postRequest.addHeader("accept", Globals.HEADER_JSON_UTF8);
        postRequest.addHeader("Content-Type", Globals.HEADER_JSON_UTF8);

        postRequest.setEntity(new StringEntity(data, StandardCharsets.UTF_8));

        HttpResponse response;
        // Execute request an catch response
        try {
            response = httpClient.execute(postRequest);
        } catch (IOException e) {
            String errtext = "Communication to <" + restFunctionWithParams + "> failed!";
            LOGGER.warn(errtext, e);
            throw new HttpStatusException(HttpStatus.SC_SERVICE_UNAVAILABLE);
        }
        return createJson(response);
    }

    private CloseableHttpClient createHttpsClient() throws HttpStatusException {
        if (useHttps) {
            try {
                SSLContextBuilder builder = new SSLContextBuilder();
                builder.loadTrustMaterial(null, new TrustSelfSignedStrategy());
                SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(builder.build());

                return HttpClients.custom().setSSLSocketFactory(sslsf).build();
            } catch (Exception e) {
                LOGGER.error(e);
                throw new HttpStatusException(HttpStatus.SC_INTERNAL_SERVER_ERROR);
            }
        } else {
            return HttpClientBuilder.create().build();
        }
    }

    private String createJson(HttpResponse response) throws HttpStatusException {
        String retJson;
        try {
            retJson = EntityUtils.toString(response.getEntity(), StandardCharsets.UTF_8);
        } catch (IOException e) {
            LOGGER.error(e);
            throw new HttpStatusException(HttpStatus.SC_INTERNAL_SERVER_ERROR);
        }

        return retJson;
    }

}