ORGANIZDR's SENT-BY not handled as per specification

If a participant is sending an update of a meeting invite, on behalf of the organizer, then that participant’s email needs to be put as shown below.

ORGANIZER;SENT-BY=“mailto:[e-mail]”:mailto:[e-mail] (from https://tools.ietf.org/html/rfc5545#section-3.1.18)

Unfortunately,

1. The double quotes and the mailto: are not getting added, if only email is set using Organizer.setSentBy().
2. If we add the escaped double quotes and mailto (like this -> “\“mailto:[e-mail]\””), then it would be rejected with the below IllegalArgumentException.

java.lang.IllegalArgumentException: Property "ORGANIZER" has a parameter named "SENT-BY" whose value contains one or more invalid characters.  The following characters are not permitted: [ \n \r " ]
	at com.github.mangstadt.vinnie.io.VObjectWriter.validate(VObjectWriter.java:617)
	at com.github.mangstadt.vinnie.io.VObjectWriter.writeProperty(VObjectWriter.java:465)
	at biweekly.io.text.ICalWriter.writeProperty(ICalWriter.java:327)
	at biweekly.io.text.ICalWriter.writeComponent(ICalWriter.java:250)
	at biweekly.io.text.ICalWriter.writeComponent(ICalWriter.java:266)
	at biweekly.io.text.ICalWriter._write(ICalWriter.java:212)
	at biweekly.io.StreamWriter.write(StreamWriter.java:83)
	at biweekly.io.chain.ChainingTextWriter.go(ChainingTextWriter.java:211)
	at biweekly.io.chain.ChainingTextWriter.go(ChainingTextWriter.java:187)
	at biweekly.io.chain.ChainingTextWriter.go(ChainingTextWriter.java:138)

[mangstadt]

The Javadocs for the setSentBy method do mention that it should be a mailto URI. I wonder why I didn’t make this required—the RFC states that it MUST be a mailto URI.

Javadocs:

@param uri a URI representing the person (typically, an email URI, e.g "mailto:[e-mail]") or null to remove

From RFC5545 p.27:

Description: This parameter can be specified on properties with a CAL-ADDRESS value type. The parameter specifies the calendar user that is acting on behalf of the calendar user specified by the property. The parameter value MUST be a mailto URI as defined in [RFC2368]. The individual calendar address parameter values MUST each be specified in a quoted-string.

[girishadat]

Adding this comment for reference by anyone who may face the same problem later.

The INCORRECT way of setting SENT-BY for Organizer:

Organizer organizer = new Organizer(null, "[e-mail]");
organizer.setSentBy("[e-mail]");
event.setOrganizer(organizer);

The result would be like this:

ORGANIZER;SENT-BY=[e-mail]:mailto:[e-mail]

The CORRECT way:

Organizer organizer = new Organizer(null, "[e-mail]");
organizer.setSentBy("mailto:[e-mail]");
event.setOrganizer(organizer);

The result would be like this:

ORGANIZER;SENT-BY=“mailto:[e-mail]”:mailto:[e-mail]

(Most probably this could be an issue for the DELEGATED-TO, DELEGATED-FROM, and MEMBER parameters of ATTENDEE as well)

Maybe it would be good to mention this somewhere in the right place in documentation. Though this may be a little less intuitive, it is unsafe to change or optimize this behavior as it may impact those who already have this in their code that uses biweekly library.