edu.cwru.apo.RestClient.java Source code

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Here is the source code for edu.cwru.apo.RestClient.java

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/*
 * Copyright 2011 Devin Schwab, Umang Banugaria
 *
 * This file is part of the APO Theta Upsilon App for Case Western Reserve University's Alpha Phi Omega Theta Upsilon Chapter.
 *
 * The APO Theta Upsilon program is free software: you can redistribute it and/or modify
 * it under the terms of the Lesser GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * Lesser GNU General Public License for more details.
 *
 * You should have received a copy of the Lesser GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package edu.cwru.apo;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.List;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.methods.HttpUriRequest;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.protocol.HTTP;

public class RestClient {

    private ArrayList<NameValuePair> params;
    private ArrayList<NameValuePair> headers;

    private String url;
    private HttpClient httpClient;

    private int responseCode;
    private String message;

    private String response;

    // sets the clients request type
    // defaults to POST
    private RequestMethod requestType = RequestMethod.POST;

    protected static enum RequestMethod {
        GET, POST, PUT, DELETE
    };

    public String getResponse() {
        return response;
    }

    public String getErrorMessage() {
        return message;
    }

    public int getResponseCode() {
        return responseCode;
    }

    public List<NameValuePair> getParams() {
        return params;
    }

    public RestClient(String url, HttpClient httpClient, RequestMethod requestType) {
        this.url = url;
        this.httpClient = httpClient;
        this.requestType = requestType;
        params = new ArrayList<NameValuePair>();
        headers = new ArrayList<NameValuePair>();
    }

    public void AddParam(String name, String value) {
        params.add(new BasicNameValuePair(name, value));
    }

    public void AddHeader(String name, String value) {
        headers.add(new BasicNameValuePair(name, value));
    }

    public void Execute() throws Exception {
        switch (requestType) {
        case GET: {
            //add parameters
            String combinedParams = "";
            if (!params.isEmpty()) {
                combinedParams += "?";
                for (NameValuePair p : params) {
                    String paramString = p.getName() + "=" + URLEncoder.encode(p.getValue(), "UTF-8");
                    if (combinedParams.length() > 1) {
                        combinedParams += "&" + paramString;
                    } else {
                        combinedParams += paramString;
                    }
                }
            }

            HttpGet request = new HttpGet(url + combinedParams);

            //add headers
            for (NameValuePair h : headers) {
                request.addHeader(h.getName(), h.getValue());
            }

            executeRequest(request, url);
            break;
        }
        case POST: {
            HttpPost request = new HttpPost(url);

            //add headers
            for (NameValuePair h : headers) {
                request.addHeader(h.getName(), h.getValue());
            }

            if (!params.isEmpty()) {
                request.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8));
            }

            executeRequest(request, url);
            break;
        }
        }
    }

    private void executeRequest(HttpUriRequest request, String url) {
        HttpResponse httpResponse;

        try {
            httpResponse = httpClient.execute(request);
            responseCode = httpResponse.getStatusLine().getStatusCode();
            message = httpResponse.getStatusLine().getReasonPhrase();

            HttpEntity entity = httpResponse.getEntity();

            if (entity != null) {

                InputStream instream = entity.getContent();
                response = convertStreamToString(instream);

                // Closing the input stream will trigger connection release
                instream.close();
            }

        } catch (ClientProtocolException e) {
            httpClient.getConnectionManager().shutdown();
            e.printStackTrace();
        } catch (IOException e) {
            httpClient.getConnectionManager().shutdown();
            e.printStackTrace();
        }
    }

    private static String convertStreamToString(InputStream is) {

        BufferedReader reader = new BufferedReader(new InputStreamReader(is));
        StringBuilder sb = new StringBuilder();

        String line = null;
        try {
            while ((line = reader.readLine()) != null) {
                sb.append(line + "\n");
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return sb.toString();
    }
}