Ignore:
Timestamp:
14/09/13 06:54:34 (8 years ago)
Author:
fielding@…
Message:

clarify that recipients MUST parse for empty list elements; addresses #475

File:
1 edited

Legend:

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  • draft-ietf-httpbis/latest/p1-messaging.xml

    r2391 r2392  
    32913291</t>
    32923292<figure><preamble>
    3293   Thus,
     3293  Thus, a sender &MUST; expand the list construct as follows:
    32943294</preamble><artwork type="example">
    32953295  1#element =&gt; element *( OWS "," OWS element )
     
    33063306</artwork></figure>
    33073307<t>
    3308   For compatibility with legacy list rules, recipients &SHOULD; accept empty
    3309   list elements. In other words, consumers would follow the list productions:
     3308  For compatibility with legacy list rules, recipients &MUST; parse and ignore
     3309  a reasonable number of empty list elements: enough to handle common mistakes
     3310  by senders that merge values, but not so much that they could be used as a
     3311  denial of service mechanism. In other words, recipients &MUST; expand the
     3312  list construct as follows:
    33103313</t>
    33113314<figure><artwork type="example">
     
    33153318</artwork></figure>
    33163319<t>
    3317   Note that empty elements do not contribute to the count of elements present,
    3318   though.
    3319 </t>
    3320 <t>
     3320  Empty elements do not contribute to the count of elements present.
    33213321  For example, given these ABNF productions:
    33223322</t>
     
    33263326</artwork></figure>
    33273327<t>
    3328   Then these are valid values for example-list (not including the double
    3329   quotes, which are present for delimitation only):
     3328  Then the following are valid values for example-list (not including the
     3329  double quotes, which are present for delimitation only):
    33303330</t>
    33313331<figure><artwork type="example">
     
    33353335</artwork></figure>
    33363336<t>
    3337   But these values would be invalid, as at least one non-empty element is
    3338   required:
     3337  In contrast, the following values would be invalid, since at least one
     3338  non-empty element is required by the example-list production:
    33393339</t>
    33403340<figure><artwork type="example">
     
    33443344</artwork></figure>
    33453345<t>
    3346   <xref target="collected.abnf"/> shows the collected ABNF, with the list rules
    3347   expanded as explained above.
     3346  <xref target="collected.abnf"/> shows the collected ABNF after the list
     3347  constructs have been expanded, as described above, for recipients.
    33483348</t>
    33493349</section>
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