An Alfresco Developer’s Challenge and Journey

The requirements posed were clear, so to come up with a technical implementation of the solution, we first scetched the new invitation page :

Easy so far, so lets continue tracing the process through the code. The Share part should boil down to some basic customizations of the Invitee list webscript, ending up with a JSON-/REST style call to the repo.

So far, so good. Continuing with the repository part, examining the data webscript implementation org/alfresco/repository/site/invitation/invitation.post.json.js, I found it reads:

invitation = site.inviteNominated(inviteeFirstName,
 inviteeLastName, inviteeEmail, inviteeRoleName,
 serverPath, acceptUrl, rejectUrl);

Ok, now :

• Where do I go with the additional header (Disposition-Notification-To) and the optional custom mail text ?
• Where is the freemarker template and how to I make the mail HTML instead of the default plain text ?
• How deep is the rabbit-hole ?

A stacktrace down to the Javamail API should give us some insight:

at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.read(SocketInputStream.java:129)
at com.sun.mail.util.TraceInputStream.read(TraceInputStream.java:97)
at java.io.BufferedInputStream.fill(BufferedInputStream.java:218)
at java.io.BufferedInputStream.read(BufferedInputStream.java:237)
- locked <0x00000000f44e8690> (a java.io.BufferedInputStream)
at com.sun.mail.util.LineInputStream.readLine(LineInputStream.java:75)
at com.sun.mail.smtp.SMTPTransport.readServerResponse(SMTPTransport.java:1440)
at com.sun.mail.smtp.SMTPTransport.issueSendCommand(SMTPTransport.java:1376)
at com.sun.mail.smtp.SMTPTransport.mailFrom(SMTPTransport.java:959)
at com.sun.mail.smtp.SMTPTransport.sendMessage(SMTPTransport.java:583)
- locked <0x00000000f44e5540> (a com.sun.mail.smtp.SMTPTransport)
at org.springframework.mail.javamail.JavaMailSenderImpl.doSend(JavaMailSenderImpl.java:402)
at org.springframework.mail.javamail.JavaMailSenderImpl.send(JavaMailSenderImpl.java:341)
at org.springframework.mail.javamail.JavaMailSenderImpl.send(JavaMailSenderImpl.java:356)
at org.springframework.mail.javamail.JavaMailSenderImpl.send(JavaMailSenderImpl.java:345)
at org.alfresco.repo.action.executer.MailActionExecuter.executeImpl(MailActionExecutor.java:439)
at org.alfresco.repo.action.executer.ActionExecuterAbstractBase.execute(ActionExecuterAbstractBase.java:133)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.alfresco.repo.management.subsystems.SubsystemProxyFactory$1.invoke(SubsystemProxyFactory.java:65)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
at $Proxy209.execute(Unknown Source)
at org.alfresco.repo.action.ActionServiceImpl.directActionExecution(ActionServiceImpl.java:749)
at org.alfresco.repo.action.ActionServiceImpl.executeActionImpl(ActionServiceImpl.java:675)
at org.alfresco.repo.action.ActionServiceImpl.executeAction(ActionServiceImpl.java:540)
at org.alfresco.repo.action.ActionServiceImpl.executeAction(ActionServiceImpl.java:526)
at org.alfresco.repo.action.ActionServiceImpl.executeAction(ActionServiceImpl.java:758)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:307)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
at org.alfresco.repo.security.permissions.impl.AlwaysProceedMethodInterceptor.invoke(AlwaysProceedMethodInterceptor.java:34)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.alfresco.repo.security.permissions.impl.ExceptionTranslatorMethodInterceptor.invoke(ExceptionTranslatorMethodInterceptor.java:44)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.alfresco.repo.audit.AuditMethodInterceptor.proceed(AuditMethodInterceptor.java:160)
at org.alfresco.repo.audit.AuditMethodInterceptor.invoke(AuditMethodInterceptor.java:137)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:107)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
at $Proxy34.executeAction(Unknown Source)
at org.alfresco.repo.invitation.site.InviteSender.sendMail(InviteSender.java:117)
at org.alfresco.repo.invitation.site.SendInviteAction.execute(SendInviteAction.java:82)
at org.jbpm.graph.def.Action.execute(Action.java:129)
at org.jbpm.graph.def.GraphElement.executeAction(GraphElement.java:284)
at org.jbpm.graph.def.GraphElement.executeActions(GraphElement.java:241)
at org.jbpm.graph.def.GraphElement.fireAndPropagateEvent(GraphElement.java:213)
at org.jbpm.graph.def.GraphElement.fireEvent(GraphElement.java:196)
at org.jbpm.graph.def.Transition.take(Transition.java:152)
at org.jbpm.graph.def.Node.leave(Node.java:479)
at org.jbpm.graph.node.StartState.leave(StartState.java:82)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.hibernate.proxy.pojo.cglib.CGLIBLazyInitializer.invoke(CGLIBLazyInitializer.java:157)
at org.jbpm.graph.def.Node$$EnhancerByCGLIB$$d588864a.leave()
at org.jbpm.graph.exe.Token.signal(Token.java:223)
at org.jbpm.graph.exe.Token.signal(Token.java:188)
at org.jbpm.taskmgmt.exe.TaskInstance.end(TaskInstance.java:495)
at org.alfresco.repo.workflow.jbpm.WorkflowTaskInstance.end(WorkflowTaskInstance.java:135)
at org.jbpm.taskmgmt.exe.TaskInstance.end(TaskInstance.java:436)
at org.alfresco.repo.workflow.jbpm.JBPMEngine$26.doInJbpm(JBPMEngine.java:1815)
at org.springmodules.workflow.jbpm31.JbpmTemplate$1.doInHibernate(JbpmTemplate.java:87)
at org.springframework.orm.hibernate3.HibernateTemplate.doExecute(HibernateTemplate.java:406)
at org.springframework.orm.hibernate3.HibernateTemplate.execute(HibernateTemplate.java:339)
at org.springmodules.workflow.jbpm31.JbpmTemplate.execute(JbpmTemplate.java:80)
at org.alfresco.repo.workflow.jbpm.JBPMEngine.endTask(JBPMEngine.java:1780)
at org.alfresco.repo.workflow.WorkflowServiceImpl.endTask(WorkflowServiceImpl.java:648)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:307)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
at org.alfresco.repo.security.permissions.impl.AlwaysProceedMethodInterceptor.invoke(AlwaysProceedMethodInterceptor.java:34)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.alfresco.repo.security.permissions.impl.ExceptionTranslatorMethodInterceptor.invoke(ExceptionTranslatorMethodInterceptor.java:44)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.alfresco.repo.audit.AuditMethodInterceptor.proceed(AuditMethodInterceptor.java:160)
at org.alfresco.repo.audit.AuditMethodInterceptor.invoke(AuditMethodInterceptor.java:137)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:107)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
at $Proxy68.endTask(Unknown Source)
at org.alfresco.repo.invitation.InvitationServiceImpl.startNominatedInvite(InvitationServiceImpl.java:1345)
at org.alfresco.repo.invitation.InvitationServiceImpl.inviteNominated(InvitationServiceImpl.java:228)
at org.alfresco.repo.invitation.InvitationServiceImpl.inviteNominated(InvitationServiceImpl.java:213)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:307)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
at org.alfresco.repo.security.permissions.impl.AlwaysProceedMethodInterceptor.invoke(AlwaysProceedMethodInterceptor.java:34)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.alfresco.repo.security.permissions.impl.ExceptionTranslatorMethodInterceptor.invoke(ExceptionTranslatorMethodInterceptor.java:44)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.alfresco.repo.audit.AuditMethodInterceptor.proceedWithAudit(AuditMethodInterceptor.java:217)
at org.alfresco.repo.audit.AuditMethodInterceptor.proceed(AuditMethodInterceptor.java:184)
at org.alfresco.repo.audit.AuditMethodInterceptor.invoke(AuditMethodInterceptor.java:137)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:107)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
at $Proxy96.inviteNominated(Unknown Source)
at org.alfresco.repo.site.script.Site.inviteNominated(Site.java:643)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.mozilla.javascript.MemberBox.invoke(MemberBox.java:155)
at org.mozilla.javascript.NativeJavaMethod.call(NativeJavaMethod.java:243)
at org.mozilla.javascript.optimizer.OptRuntime.callN(OptRuntime.java:86)
at org.mozilla.javascript.gen.c6._c1(file:.../webscripts/org/alfresco/repository/site/invitation/invitation.post.json.js:130)
at org.mozilla.javascript.gen.c6.call(file:.../webscripts/org/alfresco/repository/site/invitation/invitation.post.json.js)
at org.mozilla.javascript.optimizer.OptRuntime.callName0(OptRuntime.java:108)
at org.mozilla.javascript.gen.c6._c0(file:.../webscripts/org/alfresco/repository/site/invitation/invitation.post.json.js:141)
at org.mozilla.javascript.gen.c6.call(file:.../webscripts/org/alfresco/repository/site/invitation/invitation.post.json.js)
at org.mozilla.javascript.ContextFactory.doTopCall(ContextFactory.java:393)
at org.mozilla.javascript.ScriptRuntime.doTopCall(ScriptRuntime.java:2834)
at org.mozilla.javascript.gen.c6.call(file:.../webscripts/org/alfresco/repository/site/invitation/invitation.post.json.js)
at org.mozilla.javascript.gen.c6.exec(file:.../webscripts/org/alfresco/repository/site/invitation/invitation.post.json.js)
at org.alfresco.repo.jscript.RhinoScriptProcessor.executeScriptImpl(RhinoScriptProcessor.java:472)
at org.alfresco.repo.jscript.RhinoScriptProcessor.execute(RhinoScriptProcessor.java:190)
at org.alfresco.repo.processor.ScriptServiceImpl.executeScript(ScriptServiceImpl.java:282)
at org.alfresco.repo.web.scripts.RepositoryScriptProcessor.executeScript(RepositoryScriptProcessor.java:102)
at org.springframework.extensions.webscripts.AbstractWebScript.executeScript(AbstractWebScript.java:981)
at org.springframework.extensions.webscripts.DeclarativeWebScript.execute(DeclarativeWebScript.java:86)
at org.alfresco.repo.web.scripts.RepositoryContainer$2.execute(RepositoryContainer.java:383)
at org.alfresco.repo.transaction.RetryingTransactionHelper.doInTransaction(RetryingTransactionHelper.java:381)
at org.alfresco.repo.web.scripts.RepositoryContainer.transactionedExecute(RepositoryContainer.java:436)
at org.alfresco.repo.web.scripts.RepositoryContainer.transactionedExecuteAs(RepositoryContainer.java:466)
at org.alfresco.repo.web.scripts.RepositoryContainer.executeScript(RepositoryContainer.java:304)
at org.springframework.extensions.webscripts.AbstractRuntime.executeScript(AbstractRuntime.java:333)
at org.springframework.extensions.webscripts.AbstractRuntime.executeScript(AbstractRuntime.java:189)
at org.springframework.extensions.webscripts.servlet.WebScriptServlet.service(WebScriptServlet.java:118)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.alfresco.web.app.servlet.GlobalLocalizationFilter.doFilter(GlobalLocalizationFilter.java:58)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:555)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:852)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Thread.java:662)

The essence here is :

• The Javascript based webscript implementation calls a method org.alfresco.repo.site.script.Site.inviteNominated
• A BPM task-transition triggers the execution of a custom (BPM) Action org.alfresco.repo.invitation.site.SendInviteAction
• The ActionService then invokes an (Alfresco) Action org.alfresco.repo.action.executer.MailActionExecuter which finally gets down to the Javamail API sending out the email

Somewhere in between, the TemplateService (Freemarker) is used to generate the mail body.

Solution

Disclaimer: The solution introduced here surely does not qualify as Alfresco Best Practice from an academical perspective. Speaking from experience, this is a real exception and not the common case. Its contrary to my engineering desire creating elegant, long-lived solutions with high educational value. I really tried hard to do it in a more clean fashion. But in the end – I think given boundary conditions justify the approach.

That said, the Alfresco Share part indeed proved to be as simple as expected, so I’ll skip it here and start right away with the repository.

The first thing implemented was a small repository script extension scriptableUtils basically wrapping org.springframework.extensions.webscripts.ScriptableUtils to get URL-encoding functionality in Javascript, and some slight tweaks to invitation.post.json.js shipped:

var inviteeEmail = json.get("inviteeEmail");
var allInOne;
if (json.has("inviteeMsg")) {
  allInOne = acceptUrl + "\n" +
    scriptableUtils.urlEncode(json.get("inviteeMsg"));
} else {
  allInOne = acceptUrl;
}
invitation = site.inviteNominated(inviteeFirstName,
 inviteeLastName, inviteeEmail, inviteeRoleName,
 serverPath, allInOne, rejectUrl);

Yes, I’m routing multiple (logical) strings through allInOne (formerly known as acceptUrl) to get the data down the hole (The alternative I considered was using a ThreadLocal).

The abused string comes back into play in InviteSender.buildArgs where the freemarker model is set up. To handle it accordingly, I had to provide custom implementations of InviteSender and SendInviteAction. The main purpose of the latter being to invoke the former. The significant changes to InviteSender where

private Map buildArgs(Map properties, NodeRef inviter, NodeRef invitee)
{
    // unchanged before
    String[] hack = properties.get(wfVarAcceptUrl).split("\n");

    String acceptLink = serverPath + hack[0] + params; 
    String inviterMsg = null;
    if (hack.length > 1 && hack[1].trim().length() > 0) {
    	inviterMsg = URLDecoder.decode(hack[1]);
    }
    // unimportant stuff not shown
    args.put("acceptLink", acceptLink);
    if (inviterMsg != null) {
    	args.put("inviterMsg", inviterMsg);       	
    }
    // unimportant stuff not shown
    return args;
}

along with an adjustment of the path to the template (to address the HTML template requirement), and the introduction of a hint about the disposition-notification header:

public void sendMail(Map properties)
{
    // unimportant stuff not shown
    mail.setParameterValue(MailActionExecutor.PARAM_DISP_TO,
                           getEmail(inviter));

Thanks to Alfresco being Open Source and 4.0 shipping with an HTML version of the invitation, I had some code to peek at.

Further down, the email had to be made aware of the new text/html content-type and Javamail had somehow had to apply the new SMTP Header. My Implementation went into a custom MailActionExecutor derived from the one provided by Alfresco.

public void sendMail(Map properties)
{
// unimportant stuff not shown
boolean isHTML = false;
String htmlPrefix = "= htmlPrefix.length() &&
text.substring(0, htmlPrefix.length()).equalsIgnoreCase(htmlPrefix))
{
    isHTML = true;
}
// unimportant stuff not shown
message.setText(text, isHTML);
// unimportant stuff not shown
String dispTo = (String) ruleAction.getParameterValue(PARAM_DISP_TO);
if (dispTo != null) {
    mimeMessage.setHeader("Disposition-Notification-To"
                , dispTo);
}

The final pieces of the puzzle where minor customizations to Spring-Context XML and the jBPM process definition, to get the custom code executed:

  
  jbpm
  alfresco/module/de_cu_alfresco/workflow/cu-invitation-nominated_processdefinition.xml
  text/xml
  true

The last hurdle was figuring out how to override the default MailActionExecutor, as this Spring bean lives in a child-application context. In this case (the email subsystem), the classpath location had to match classpath*:alfresco/extension/subsystems/email/OutboundSMTP/outbound/*-context.xml

Thats it :

Trust Me, I’m an “Engineer”

Thanks for reading – I hope you had a pleasant flight !

PS : Flames or alternative ideas are welcome.

References:

• Trust Me, I’m an “Engineer”
• Heisenberg uncertainty principle
• Image Credits

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