Java tutorial
/** * OLAT - Online Learning and Training<br> * http://www.olat.org * <p> * Licensed under the Apache License, Version 2.0 (the "License"); <br> * you may not use this file except in compliance with the License.<br> * You may obtain a copy of the License at * <p> * http://www.apache.org/licenses/LICENSE-2.0 * <p> * Unless required by applicable law or agreed to in writing,<br> * software distributed under the License is distributed on an "AS IS" BASIS, <br> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. <br> * See the License for the specific language governing permissions and <br> * limitations under the License. * <p> * Copyright (c) 2009 frentix GmbH, Switzerland<br> * <p> */ package org.olat.user.propertyhandlers; import java.util.Locale; import java.util.Map; import org.apache.commons.httpclient.HttpClient; import org.apache.commons.httpclient.HttpMethod; import org.apache.commons.httpclient.HttpStatus; import org.apache.commons.httpclient.NameValuePair; import org.apache.commons.httpclient.methods.GetMethod; import org.apache.commons.httpclient.params.HttpClientParams; import org.olat.core.gui.components.form.ValidationError; import org.olat.core.gui.components.form.flexible.FormItem; import org.olat.core.gui.components.form.flexible.FormItemContainer; import org.olat.core.gui.components.form.flexible.elements.TextElement; import org.olat.core.id.User; import org.olat.core.logging.OLog; import org.olat.core.logging.Tracing; import org.olat.core.util.StringHelper; import org.olat.core.util.httpclient.HttpClientFactory; import org.olat.user.UserManager; /** * Implements a user property handler for MSN screen names. * <P> * Initial Date: Jul 28, 2009 <br> * * @author twuersch */ public class MSNPropertyHandler extends Generic127CharTextPropertyHandler { public static final int MSN_NAME_MAX_LENGTH = 64; public static final String MSN_NAME_VALIDATION_URL = "http://spaces.live.com/profile.aspx"; public static final String MSN_NAME_URL_PARAMETER = "mem"; /** * @see org.olat.user.AbstractUserPropertyHandler#getUserPropertyAsHTML(org.olat.core.id.User, java.util.Locale) */ @Override public String getUserPropertyAsHTML(final User user, final Locale locale) { final String msnname = getUserProperty(user, locale); if (StringHelper.containsNonWhitespace(msnname)) { final StringBuffer stringBuffer = new StringBuffer(); stringBuffer.append("<a href=\"" + MSN_NAME_VALIDATION_URL + "?" + MSN_NAME_URL_PARAMETER + "=" + msnname + "\" target=\"_blank\">" + msnname + "</a>"); return stringBuffer.toString(); } else { return null; } } /** * @see org.olat.user.propertyhandlers.Generic127CharTextPropertyHandler#isValidValue(java.lang.String, org.olat.core.gui.components.form.ValidationError, * java.util.Locale) */ @Override public boolean isValidValue(final String value, final ValidationError validationError, final Locale locale) { if (!super.isValidValue(value, validationError, locale)) { return false; } if (StringHelper.containsNonWhitespace(value)) { return value.length() <= MSN_NAME_MAX_LENGTH; } return true; } /** * @see org.olat.user.propertyhandlers.Generic127CharTextPropertyHandler#addFormItem(java.util.Locale, org.olat.core.id.User, java.lang.String, boolean, * org.olat.core.gui.components.form.flexible.FormItemContainer) */ @Override public FormItem addFormItem(final Locale locale, final User user, final String usageIdentifyer, final boolean isAdministrativeUser, final FormItemContainer formItemContainer) { final TextElement textElement = (TextElement) super.addFormItem(locale, user, usageIdentifyer, isAdministrativeUser, formItemContainer); textElement.setMaxLength(MSN_NAME_MAX_LENGTH); if (!UserManager.getInstance().isUserViewReadOnly(usageIdentifyer, this) || isAdministrativeUser) { textElement.setExampleKey("form.example.msnname", null); } return textElement; } /** * @see org.olat.user.propertyhandlers.Generic127CharTextPropertyHandler#isValid(org.olat.core.gui.components.form.flexible.FormItem, java.util.Map) */ @SuppressWarnings({ "unchecked" }) @Override public boolean isValid(final FormItem formItem, final Map formContext) { boolean result; final TextElement textElement = (TextElement) formItem; OLog log = Tracing.createLoggerFor(this.getClass()); if (StringHelper.containsNonWhitespace(textElement.getValue())) { // Use an HttpClient to fetch a profile information page from MSN. final HttpClient httpClient = HttpClientFactory.getHttpClientInstance(); final HttpClientParams httpClientParams = httpClient.getParams(); httpClientParams.setConnectionManagerTimeout(2500); httpClient.setParams(httpClientParams); final HttpMethod httpMethod = new GetMethod(MSN_NAME_VALIDATION_URL); final NameValuePair idParam = new NameValuePair(MSN_NAME_URL_PARAMETER, textElement.getValue()); httpMethod.setQueryString(new NameValuePair[] { idParam }); // Don't allow redirects since otherwise, we won't be able to get the correct status httpMethod.setFollowRedirects(false); try { // Get the user profile page httpClient.executeMethod(httpMethod); final int httpStatusCode = httpMethod.getStatusCode(); // Looking at the HTTP status code tells us whether a user with the given MSN name exists. if (httpStatusCode == HttpStatus.SC_MOVED_PERMANENTLY) { // If the user exists, we get a 301... result = true; } else if (httpStatusCode == HttpStatus.SC_INTERNAL_SERVER_ERROR) { // ...and if the user doesn't exist, MSN sends a 500. textElement.setErrorKey("form.name.msn.error", null); result = false; } else { // For HTTP status codes other than 301 and 500 we will assume that the given MSN name is valid, but inform the user about this. textElement.setExampleKey("form.example.msnname.notvalidated", null); log.warn("MSN name validation: Expected HTTP status 301 or 500, but got " + httpStatusCode); result = true; } } catch (final Exception e) { // In case of any exception, assume that the given MSN name is valid (The opposite would block easily upon network problems), and inform the user about // this. textElement.setExampleKey("form.example.msnname.notvalidated", null); log.warn("MSN name validation: Exception: " + e.getMessage()); result = true; } } else { result = true; } log = null; return result; } }