On 12/22/08 8:28 AM, Brett Zamir wrote: > On 12/22/2008 10:37 PM, Dave Cridland wrote: >> On Mon Dec 22 13:24:25 2008, Brett Zamir wrote: >>> In the Data Forms spec XEP-0004, what is an implementation to do for >>> each type if there are empty fields? >>> >>> Send an empty<value/> or an empty<field/>? >>> >>> An empty field would seem to make sense for lists at least, but I >>> wasn't clear on what it should be for say, text-single. >> >> <value/> is semantically equivalent to <value></value>, and therefore >> suggests an actual value of a zero-length string, rather than no value >> at all. >> >> Which doesn't answer your question, of course, but it suggests that >> the answer might depend on what you mean by "empty fields". > Yeah. Or what the spec using Data Forms means (in whether to allow a > distinction between the two). I think perhaps the specs using Data Forms > should specify this. For example, in Pubsub, where it is used to send in > configuration items, perhaps it wouldn't be a bad idea to require > <value/> to indicate that the sender didn't mistakenly leave out the field.
As Dave said, <value></value> means the empty string (which in pubsub configuration forms might mean the root collection node). IMHO if the sender mistakenly leaves out a field, that is the sender's problem. The recipient's behavior should be to leave the existing values alone (if any). > Otherwise, it is possible one server-side implementation will reject > data that doesn't at least possess a <value/> child and spit out errors, > while another may treat an empty <field/> and <field><value/></field> as > the same, and yet another might spit out errors if there is a <value/> > child, so I really think this should be specified in the specs using > Data Forms, if not also mentioned in Data Forms. I admit that error handling related to data forms is less than perfect. However, for pubsub at least I will try to clarify this in the next revision of the spec. Peter -- Peter Saint-Andre https://stpeter.im/
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