/** * @file HttpUtil.java * * @brief * HttpUtil is a single class containing methods to conveniently perform HTTP * requests. HttpUtil only uses regular java io and net functionality and does * not depend on external libraries. * The class contains methods to perform a get, post, put, and delete request, * and supports posting forms. Optionally, one can provide headers. * * Example usage: * * // get * String res = HttpUtil.get("http://www.google.com"); * * // post * String res = HttpUtil.post("http://sendmedata.com", "This is the data"); * * // post form * Map<String, String> params = new HashMap<String, String>(); * params.put("firstname", "Joe"); * params.put("lastname", "Smith"); * params.put("age", "28"); * String res = HttpUtil.postForm("http://site.com/newuser", params); * * // append query parameters to url * String url = "http://mydatabase.com/users"; * Map<String, String> params = new HashMap<String, String>(); * params.put("orderby", "name"); * params.put("limit", "10"); * String fullUrl = HttpUtil.appendQueryParams(url, params); * // fullUrl = "http://mydatabase.com/user?orderby=name&limit=10" * * @license * 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. * * Copyright (c) 2012 Almende B.V. * * @author Jos de Jong, <jos@almende.org> * @date 2012-05-14 */ package com.almende.util; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.net.HttpURLConnection; import java.net.URL; import java.net.URLDecoder; import java.net.URLEncoder; import java.util.HashMap; import java.util.Map; public class HttpUtil { /** * Send a get request * @param url * @return response * @throws IOException */ static public String get(String url) throws IOException { return get(url, null); } /** * Send a get request * @param url Url as string * @param headers Optional map with headers * @return response Response as string * @throws IOException */ static public String get(String url, Map<String, String> headers) throws IOException { return fetch("GET", url, null, headers); } /** * Send a post request * @param url Url as string * @param body Request body as string * @param headers Optional map with headers * @return response Response as string * @throws IOException */ static public String post(String url, String body, Map<String, String> headers) throws IOException { return fetch("POST", url, body, headers); } /** * Send a post request * @param url Url as string * @param body Request body as string * @return response Response as string * @throws IOException */ static public String post(String url, String body) throws IOException { return post(url, body, null); } /** * Post a form with parameters * @param url Url as string * @param params map with parameters/values * @return response Response as string * @throws IOException */ static public String postForm(String url, Map<String, String> params) throws IOException { return postForm(url, params, null); } /** * Post a form with parameters * @param url Url as string * @param params Map with parameters/values * @param headers Optional map with headers * @return response Response as string * @throws IOException */ static public String postForm(String url, Map<String, String> params, Map<String, String> headers) throws IOException { // set content type if (headers == null) { headers = new HashMap<String, String>(); } headers.put("Content-Type", "application/x-www-form-urlencoded"); // parse parameters String body = ""; if (params != null) { boolean first = true; for (String param : params.keySet()) { if (first) { first = false; } else { body += "&"; } String value = params.get(param); body += URLEncoder.encode(param, "UTF-8") + "="; body += URLEncoder.encode(value, "UTF-8"); } } return post(url, body, headers); } /** * Send a put request * @param url Url as string * @param body Request body as string * @param headers Optional map with headers * @return response Response as string * @throws IOException */ static public String put(String url, String body, Map<String, String> headers) throws IOException { return fetch("PUT", url, body, headers); } /** * Send a put request * @param url Url as string * @return response Response as string * @throws IOException */ static public String put(String url, String body) throws IOException { return put(url, body, null); } /** * Send a delete request * @param url Url as string * @param headers Optional map with headers * @return response Response as string * @throws IOException */ static public String delete(String url, Map<String, String> headers) throws IOException { return fetch("DELETE", url, null, headers); } /** * Send a delete request * @param url Url as string * @return response Response as string * @throws IOException */ static public String delete(String url) throws IOException { return delete(url, null); } /** * Append query parameters to given url * @param url Url as string * @param params Map with query parameters * @return url Url with query parameters appended * @throws IOException */ static public String appendQueryParams(String url, Map<String, String> params) throws IOException { String fullUrl = new String(url); if (params != null) { boolean first = (fullUrl.indexOf('?') == -1); for (String param : params.keySet()) { if (first) { fullUrl += '?'; first = false; } else { fullUrl += '&'; } String value = params.get(param); fullUrl += URLEncoder.encode(param, "UTF-8") + '='; fullUrl += URLEncoder.encode(value, "UTF-8"); } } return fullUrl; } /** * Retrieve the query parameters from given url * @param url Url containing query parameters * @return params Map with query parameters * @throws IOException */ static public Map<String, String> getQueryParams(String url) throws IOException { Map<String, String> params = new HashMap<String, String>(); int start = url.indexOf('?'); while (start != -1) { // read parameter name int equals = url.indexOf('=', start); String param = ""; if (equals != -1) { param = url.substring(start + 1, equals); } else { param = url.substring(start + 1); } // read parameter value String value = ""; if (equals != -1) { start = url.indexOf('&', equals); if (start != -1) { value = url.substring(equals + 1, start); } else { value = url.substring(equals + 1); } } params.put(URLDecoder.decode(param, "UTF-8"), URLDecoder.decode(value, "UTF-8")); } return params; } /** * Returns the url without query parameters * @param url Url containing query parameters * @return url Url without query parameters * @throws IOException */ static public String removeQueryParams(String url) throws IOException { int q = url.indexOf('?'); if (q != -1) { return url.substring(0, q); } else { return url; } } /** * Send a request * @param method HTTP method, for example "GET" or "POST" * @param url Url as string * @param body Request body as string * @param headers Optional map with headers * @return response Response as string * @throws IOException */ static public String fetch(String method, String url, String body, Map<String, String> headers) throws IOException { // connection URL u = new URL(url); HttpURLConnection conn = (HttpURLConnection)u.openConnection(); conn.setConnectTimeout(10000); conn.setReadTimeout(10000); // method if (method != null) { conn.setRequestMethod(method); } // headers if (headers != null) { for(String key : headers.keySet()) { conn.addRequestProperty(key, headers.get(key)); } } // body if (body != null) { conn.setDoOutput(true); OutputStream os = conn.getOutputStream(); os.write(body.getBytes()); os.flush(); os.close(); } // response InputStream is = conn.getInputStream(); String response = streamToString(is); is.close(); // handle redirects if (conn.getResponseCode() == 301) { String location = conn.getHeaderField("Location"); return fetch(method, location, body, headers); } return response; } /** * Read an input stream into a string * @param in * @return * @throws IOException */ static public String streamToString(InputStream in) throws IOException { StringBuffer out = new StringBuffer(); byte[] b = new byte[4096]; for (int n; (n = in.read(b)) != -1;) { out.append(new String(b, 0, n)); } return out.toString(); } }
