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Appendix A. Presentation Issues

This appendix is provided for informational purposes only; it is not a normative part of this specification.

The string representation described in this document is not intended to be presented to humans without translation. However, at times it may be desirable to present non-translated DN strings to users. This section discusses presentation issues associated with non-translated DN strings. Issues with presentation of translated DN strings are not discussed in this appendix. Transcoding issues are also not discussed in this appendix.

This appendix provides guidance for applications presenting DN strings to users. This section is not comprehensive; it does not discuss all presentation issues that implementers may face.

Not all user interfaces are capable of displaying the full set of Unicode characters. Some Unicode characters are not displayable.

It is recommended that human interfaces use the optional hex pair escaping mechanism (Section 2.3) to produce a string representation suitable for display to the user. For example, an application can generate a DN string for display that escapes all non-printable characters appearing in the AttributeValue's string representation (as demonstrated in the final example of Section 4).

When a DN string is displayed in free-form text, it is often necessary to distinguish the DN string from surrounding text. While this is often done with whitespace (as demonstrated in Section 4), it is noted that DN strings may end with whitespace. Careful readers of Section 3 will note that the characters '<' (U+003C) and '>' (U+003E) may only appear in the DN string if escaped. These characters are intended to be used in free-form text to distinguish a DN string from surrounding text. For example, <CN=Sam\ > distinguishes the string representation of the DN composed of one RDN consisting of the AVA (the commonName (CN) value 'Sam ') from the surrounding text. It should be noted to the user that the wrapping '<' and '>' characters are not part of the DN string.

DN strings can be quite long. It is often desirable to line-wrap overly long DN strings in presentations. Line wrapping should be done by inserting whitespace after the RDN separator character or, if necessary, after the AVA separator character. It should be noted to the user that the inserted whitespace is not part of the DN string and is to be removed before use in LDAP. For example, the following DN string is long:

     CN=Kurt D.  Zeilenga,OU=Engineering,L=Redwood Shores,
     O=OpenLDAP Foundation,ST=California,C=US

So it has been line-wrapped for readability. The extra whitespace is to be removed before the DN string is used in LDAP.

Inserting whitespace is not advised because it may not be obvious to the user which whitespace is part of the DN string and which whitespace was added for readability.

Another alternative is to use the LDAP Data Interchange Format (LDIF) [RFC2849]. For example:

     # This entry has a long DN...
     dn: CN=Kurt D.  Zeilenga,OU=Engineering,L=Redwood Shores,
      O=OpenLDAP Foundation,ST=California,C=US
     CN: Kurt D.  Zeilenga
     SN: Zeilenga
     objectClass: person