Java tutorial
/** * Licensed to The Apereo Foundation under one or more contributor license * agreements. See the NOTICE file distributed with this work for additional * information regarding copyright ownership. * * * The Apereo Foundation licenses this file to you under the Educational * Community 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://opensource.org/licenses/ecl2.txt * * 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.opencastproject.util; import static org.opencastproject.util.EqualsUtil.eq; import static org.opencastproject.util.data.Collections.list; import static org.opencastproject.util.data.Either.left; import static org.opencastproject.util.data.Either.right; import static org.opencastproject.util.data.Monadics.mlist; import static org.opencastproject.util.data.Prelude.sleep; import static org.opencastproject.util.data.functions.Misc.chuck; import org.opencastproject.security.api.TrustedHttpClient; import org.opencastproject.security.api.TrustedHttpClient.RequestRunner; import org.opencastproject.util.data.Collections; import org.opencastproject.util.data.Either; import org.opencastproject.util.data.Function; import org.opencastproject.util.data.Tuple; import org.apache.commons.io.IOUtils; import org.apache.http.Header; import org.apache.http.HttpEntityEnclosingRequest; import org.apache.http.HttpResponse; import org.apache.http.HttpStatus; import org.apache.http.NameValuePair; import org.apache.http.client.entity.UrlEncodedFormEntity; import org.apache.http.client.methods.HttpGet; import org.apache.http.client.methods.HttpHead; import org.apache.http.client.methods.HttpPost; import org.apache.http.message.BasicNameValuePair; import java.io.IOException; import java.io.UnsupportedEncodingException; import java.net.URI; import java.net.URLEncoder; import java.util.List; /** Functions to support Apache httpcomponents and HTTP related operations in general. */ /** Functions to support Apache httpcomponents. */ public final class HttpUtil { private HttpUtil() { } public static HttpPost post(NameValuePair... formParams) { final HttpPost post = new HttpPost(); setFormParams(post, formParams); return post; } public static HttpPost post(String uri, NameValuePair... formParams) { final HttpPost post = new HttpPost(uri); setFormParams(post, formParams); return post; } public static HttpPost post(String uri, List<NameValuePair> formParams) { final HttpPost post = new HttpPost(uri); setFormParams(post, Collections.toArray(NameValuePair.class, formParams)); return post; } public static HttpGet get(String path, Tuple<String, String>... queryParams) { final String url = mlist(path, mlist(queryParams).map(new Function<Tuple<String, String>, String>() { @Override public String apply(Tuple<String, String> a) { try { return a.getA() + "=" + URLEncoder.encode(a.getB(), "UTF-8"); } catch (UnsupportedEncodingException e) { return chuck(e); } } }).mkString("&")).mkString("?"); return new HttpGet(url); } public static String path(String... path) { return UrlSupport.concat(path); } private static void setFormParams(HttpEntityEnclosingRequest r, NameValuePair[] formParams) { final List<NameValuePair> params = list(formParams); try { r.setEntity(new UrlEncodedFormEntity(params, "UTF-8")); } catch (UnsupportedEncodingException e) { chuck(e); } } public static NameValuePair param(String name, String value) { return new BasicNameValuePair(name, value); } public static NameValuePair param(Tuple<String, String> p) { return new BasicNameValuePair(p.getA(), p.getB()); } public static final Function<Tuple<String, String>, NameValuePair> param_ = new Function<Tuple<String, String>, NameValuePair>() { @Override public NameValuePair apply(Tuple<String, String> p) { return param(p); } }; public static final Function<HttpResponse, Integer> getStatusCode = new Function<HttpResponse, Integer>() { @Override public Integer apply(HttpResponse response) { return response.getStatusLine().getStatusCode(); } }; /** * Return the content of the response as a string if its status code equals one of the given statuses. Throw an * exception on an unexpected status. * <p/> * Function composition of {@link #getContentFn} and {@link #expect(int...)}. */ public static Function<HttpResponse, String> getContentOn(final int... status) { return getContentFn.o(expect(status)); } public static String getContentOn(final RequestRunner<String> runner, final int... status) { final Either<Exception, String> res = runner.run(getContentOn(status)); if (res.isRight()) { return res.right().value(); } else { return chuck(res.left().value()); } } /** Return the content of the response as a string. */ public static final Function<HttpResponse, String> getContentFn = new Function.X<HttpResponse, String>() { @Override public String xapply(HttpResponse httpResponse) throws Exception { final Header h = httpResponse.getEntity().getContentEncoding(); if (h != null) { return IOUtils.toString(httpResponse.getEntity().getContent(), h.getValue()); } else { return IOUtils.toString(httpResponse.getEntity().getContent()); } } }; /** Return the response if its status code equals one of the given statuses or throw an exception. */ public static Function<HttpResponse, HttpResponse> expect(final int... status) { return new Function.X<HttpResponse, HttpResponse>() { @Override public HttpResponse xapply(HttpResponse response) { final int sc = response.getStatusLine().getStatusCode(); for (int s : status) { if (sc == s) return response; } String responseBody; try { responseBody = IOUtils.toString(response.getEntity().getContent()); } catch (IOException e) { responseBody = ""; } throw new RuntimeException( "Returned status " + sc + " does not match any of the expected codes. " + responseBody); } }; } /** Get the value or throw the exception. */ public static <A> A getOrError(Either<Exception, A> response) { if (response.isRight()) { return response.right().value(); } else { return chuck(response.left().value()); } } public static boolean isOk(HttpResponse res) { return res.getStatusLine().getStatusCode() == HttpStatus.SC_OK; } /** * Wait for a certain status of a resource. * * @return either an exception or the status code of the last http response */ public static Either<Exception, Integer> waitForResource(final TrustedHttpClient http, final URI resourceUri, final int expectedStatus, final long timeout, final long pollingInterval) { long now = 0L; while (true) { final HttpHead head = new HttpHead(resourceUri); final Either<Exception, Integer> result = http.<Integer>run(head).apply(getStatusCode); for (final Integer status : result.right()) { if (eq(status, expectedStatus) || now >= timeout) { return right(status); } else if (now < timeout) { if (!sleep(pollingInterval)) { return left(new Exception("Interrupted")); } else { now = now + pollingInterval; } } } for (Exception e : result.left()) { return left(e); } } } }