Java tutorial
// Copyright (C) 2009 The Android Open Source Project // // 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. package com.google.gerrit.server.mail; import com.google.common.collect.Sets; import com.google.gerrit.common.errors.EmailException; import com.google.gerrit.reviewdb.client.Account; import com.google.gerrit.reviewdb.client.UserIdentity; import com.google.gerrit.server.account.AccountState; import com.google.gerrit.server.mail.EmailHeader.AddressList; import com.google.gwtorm.server.OrmException; import org.apache.commons.lang.StringUtils; import org.apache.velocity.Template; import org.apache.velocity.VelocityContext; import org.apache.velocity.context.InternalContextAdapterImpl; import org.apache.velocity.runtime.RuntimeInstance; import org.apache.velocity.runtime.parser.node.SimpleNode; import org.eclipse.jgit.util.SystemReader; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.io.StringReader; import java.io.StringWriter; import java.net.MalformedURLException; import java.net.URL; import java.util.Collection; import java.util.Date; import java.util.HashSet; import java.util.Iterator; import java.util.LinkedHashMap; import java.util.Map; import java.util.Set; /** Sends an email to one or more interested parties. */ public abstract class OutgoingEmail { private static final Logger log = LoggerFactory.getLogger(OutgoingEmail.class); private static final String HDR_TO = "To"; private static final String HDR_CC = "CC"; protected String messageClass; private final HashSet<Account.Id> rcptTo = new HashSet<Account.Id>(); private final Map<String, EmailHeader> headers; private final Set<Address> smtpRcptTo = Sets.newHashSet(); private Address smtpFromAddress; private StringBuilder body; protected VelocityContext velocityContext; protected final EmailArguments args; protected Account.Id fromId; protected OutgoingEmail(EmailArguments ea, String mc) { args = ea; messageClass = mc; headers = new LinkedHashMap<String, EmailHeader>(); } public void setFrom(final Account.Id id) { fromId = id; } /** * Format and enqueue the message for delivery. * * @throws EmailException */ public void send() throws EmailException { if (!args.emailSender.isEnabled()) { // Server has explicitly disabled email sending. // return; } init(); format(); if (shouldSendMessage()) { if (fromId != null) { final Account fromUser = args.accountCache.get(fromId).getAccount(); if (fromUser.getGeneralPreferences().isCopySelfOnEmails()) { // If we are impersonating a user, make sure they receive a CC of // this message so they can always review and audit what we sent // on their behalf to others. // add(RecipientType.CC, fromId); } else if (rcptTo.remove(fromId)) { // If they don't want a copy, but we queued one up anyway, // drop them from the recipient lists. // final String fromEmail = fromUser.getPreferredEmail(); for (Iterator<Address> i = smtpRcptTo.iterator(); i.hasNext();) { if (i.next().email.equals(fromEmail)) { i.remove(); } } for (EmailHeader hdr : headers.values()) { if (hdr instanceof AddressList) { ((AddressList) hdr).remove(fromEmail); } } if (smtpRcptTo.isEmpty()) { return; } } } args.emailSender.send(smtpFromAddress, smtpRcptTo, headers, body.toString()); } } /** Format the message body by calling {@link #appendText(String)}. */ protected abstract void format() throws EmailException; /** Setup the message headers and envelope (TO, CC, BCC). */ protected void init() throws EmailException { setupVelocityContext(); smtpFromAddress = args.fromAddressGenerator.from(fromId); setHeader("Date", new Date()); headers.put("From", new EmailHeader.AddressList(smtpFromAddress)); headers.put(HDR_TO, new EmailHeader.AddressList()); headers.put(HDR_CC, new EmailHeader.AddressList()); setHeader("Message-ID", ""); if (fromId != null) { // If we have a user that this message is supposedly caused by // but the From header on the email does not match the user as // it is a generic header for this Gerrit server, include the // Reply-To header with the current user's email address. // final Address a = toAddress(fromId); if (a != null && !smtpFromAddress.email.equals(a.email)) { setHeader("Reply-To", a.email); } } setHeader("X-Gerrit-MessageType", messageClass); body = new StringBuilder(); if (fromId != null && args.fromAddressGenerator.isGenericAddress(fromId)) { appendText(getFromLine()); } } protected String getFromLine() { final Account account = args.accountCache.get(fromId).getAccount(); final String name = account.getFullName(); final String email = account.getPreferredEmail(); StringBuilder f = new StringBuilder(); if ((name != null && !name.isEmpty()) || (email != null && !email.isEmpty())) { f.append("From"); if (name != null && !name.isEmpty()) { f.append(" ").append(name); } if (email != null && !email.isEmpty()) { f.append(" <").append(email).append(">"); } f.append(":\n\n"); } return f.toString(); } public String getGerritHost() { if (getGerritUrl() != null) { try { return new URL(getGerritUrl()).getHost(); } catch (MalformedURLException e) { // Try something else. } } // Fall back onto whatever the local operating system thinks // this server is called. We hopefully didn't get here as a // good admin would have configured the canonical url. // return SystemReader.getInstance().getHostname(); } public String getSettingsUrl() { if (getGerritUrl() != null) { final StringBuilder r = new StringBuilder(); r.append(getGerritUrl()); r.append("settings"); return r.toString(); } return null; } public String getGerritUrl() { return args.urlProvider.get(); } /** Set a header in the outgoing message using a template. */ protected void setVHeader(final String name, final String value) throws EmailException { setHeader(name, velocify(value)); } /** Set a header in the outgoing message. */ protected void setHeader(final String name, final String value) { headers.put(name, new EmailHeader.String(value)); } protected void setHeader(final String name, final Date date) { headers.put(name, new EmailHeader.Date(date)); } /** Append text to the outgoing email body. */ protected void appendText(final String text) { if (text != null) { body.append(text); } } /** Lookup a human readable name for an account, usually the "full name". */ protected String getNameFor(final Account.Id accountId) { if (accountId == null) { return args.anonymousCowardName; } final Account userAccount = args.accountCache.get(accountId).getAccount(); String name = userAccount.getFullName(); if (name == null) { name = userAccount.getPreferredEmail(); } if (name == null) { name = args.anonymousCowardName + " #" + accountId; } return name; } public String getNameEmailFor(Account.Id accountId) { AccountState who = args.accountCache.get(accountId); String name = who.getAccount().getFullName(); String email = who.getAccount().getPreferredEmail(); if (name != null && email != null) { return name + " <" + email + ">"; } else if (name != null) { return name; } else if (email != null) { return email; } else /* (name == null && email == null) */ { return args.anonymousCowardName + " #" + accountId; } } protected boolean shouldSendMessage() { if (body.length() == 0) { // If we have no message body, don't send. log.warn("Skipping delivery of email with no body"); return false; } if (smtpRcptTo.isEmpty()) { // If we have nobody to send this message to, then all of our // selection filters previously for this type of message were // unable to match a destination. Don't bother sending it. log.info("Skipping delivery of email with no recipients"); return false; } if (smtpRcptTo.size() == 1 && rcptTo.size() == 1 && rcptTo.contains(fromId)) { // If the only recipient is also the sender, don't bother. // return false; } return true; } /** Schedule this message for delivery to the listed accounts. */ protected void add(final RecipientType rt, final Collection<Account.Id> list) { for (final Account.Id id : list) { add(rt, id); } } protected void add(final RecipientType rt, final UserIdentity who) { if (who != null && who.getAccount() != null) { add(rt, who.getAccount()); } } /** Schedule delivery of this message to the given account. */ protected void add(final RecipientType rt, final Account.Id to) { try { if (!rcptTo.contains(to) && isVisibleTo(to)) { rcptTo.add(to); add(rt, toAddress(to)); } } catch (OrmException e) { log.error("Error reading database for account: " + to, e); } } protected boolean isVisibleTo(final Account.Id to) throws OrmException { return true; } /** Schedule delivery of this message to the given account. */ protected void add(final RecipientType rt, final Address addr) { if (addr != null && addr.email != null && addr.email.length() > 0) { if (args.emailSender.canEmail(addr.email)) { if (smtpRcptTo.add(addr)) { switch (rt) { case TO: ((EmailHeader.AddressList) headers.get(HDR_TO)).add(addr); break; case CC: ((EmailHeader.AddressList) headers.get(HDR_CC)).add(addr); break; case BCC: break; } } } else { log.warn("Not emailing " + addr.email + " (prohibited by allowrcpt)"); } } } private Address toAddress(final Account.Id id) { final Account a = args.accountCache.get(id).getAccount(); final String e = a.getPreferredEmail(); if (!a.isActive() || e == null) { return null; } return new Address(a.getFullName(), e); } protected void setupVelocityContext() { velocityContext = new VelocityContext(); velocityContext.put("email", this); velocityContext.put("messageClass", messageClass); velocityContext.put("StringUtils", StringUtils.class); } protected String velocify(String template) throws EmailException { try { RuntimeInstance runtime = args.velocityRuntime; String templateName = "OutgoingEmail"; SimpleNode tree = runtime.parse(new StringReader(template), templateName); InternalContextAdapterImpl ica = new InternalContextAdapterImpl(velocityContext); ica.pushCurrentTemplateName(templateName); try { tree.init(ica, runtime); StringWriter w = new StringWriter(); tree.render(ica, w); return w.toString(); } finally { ica.popCurrentTemplateName(); } } catch (Exception e) { throw new EmailException("Cannot format velocity template: " + template, e); } } protected String velocifyFile(String name) throws EmailException { try { RuntimeInstance runtime = args.velocityRuntime; if (runtime.getLoaderNameForResource(name) == null) { name = "com/google/gerrit/server/mail/" + name; } Template template = runtime.getTemplate(name, "UTF-8"); StringWriter w = new StringWriter(); template.merge(velocityContext, w); return w.toString(); } catch (EmailException e) { throw e; } catch (Exception e) { throw new EmailException("Cannot format velocity template " + name, e); } } public String joinStrings(Iterable<Object> in, String joiner) { return joinStrings(in.iterator(), joiner); } public String joinStrings(Iterator<Object> in, String joiner) { if (!in.hasNext()) { return ""; } Object first = in.next(); if (!in.hasNext()) { return safeToString(first); } StringBuilder r = new StringBuilder(); r.append(safeToString(first)); while (in.hasNext()) { r.append(joiner).append(safeToString(in.next())); } return r.toString(); } private static String safeToString(Object obj) { return obj != null ? obj.toString() : ""; } }