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Re: Is pubdate element required?

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  • Randy Morin
    Although the pubDate and lastBuildDate are not required, often RSS readers/aggregators will use these as hints to determine if the feed or items within the
    Message 1 of 7 , Feb 1, 2005
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      Although the pubDate and lastBuildDate are not required, often RSS
      readers/aggregators will use these as hints to determine if the feed
      or items within the feed have changed. For instance, if the
      lastBuildDate remains the same, then the reader/aggregator may assume
      the feed has not changed and stop processing. I'm not familiar with
      the internals of either Firefox or Bloglines to tell you how they
      might be handling these elements.
      I hope this helps,

      Randy Charles Morin
      http://www.kbcafe.com

      --- In RSS2-Support@yahoogroups.com, yakovs <no_reply@y...> wrote:
      >
      > Hi,
      >
      > I am the author of the track2rss project (http://track2rss.sf.net)
      > which lets you track packages via RSS 2.0 feeds (Fedex, USPS and
      > UPS).
      > I have been having problems with my feeds not refreshing in
      Bloglines
      > but working fine in FireFox. The feed in question is here:
      >
      > http://www.shaftek.org/code/track2rss/track2rss.pl?
      > type=ups&tracking_number=1Z9R8A830327349416
      >
      > The feed validates through FeedValidator just fine. My suspicion
      now
      > centers around the pubdate and lastBuild elements of channel, and
      the
      > pubdate element of item. What I am wondering is whether any of
      these
      > elements are in fact required by aggregators in order to check
      feeds
      > more often (the RSS 2.0 spec they are not).
      >
      > Thanks,
      > Yakov
    • ecomputerd
      I can t vouch for other aggregators, but FeederReader parses all feeds that are downloaded. It does not look at lastBuildDate at all. It uses pubDate of
      Message 2 of 7 , Feb 1, 2005
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        I can't vouch for other aggregators, but FeederReader parses all
        feeds that are downloaded. It does not look at lastBuildDate at all.
        It uses pubDate of individual items to determine the relative age of
        the items and give a byline of "6 hours ago by Greg Smith on
        FeederReader Blog". It uses the relative age of items to optionally
        determine viewing order. This is not foolproof because of the clock
        difference between different producers' machines. I frequently see
        feeds that are published, according to pubDate, in the future. The
        New York Times feed is especially guilty of this; they seem to force
        pubDate to midnight, yet actually put the feed up an hour or two
        early. I would recommend against this practice.

        I find that the pubDate is very useful when reading posts, and I
        would strongly encourage its use within each item of your feed.

        For examples of what the byline looks like in FeederReader, see the
        screen shot on the front page of www.FeederReader.com with an
        additional screen shot of a byline on the "Enclosure Support" page.


        Greg Smith
        Author, FeederReader - The Pocket PC RSS reader and podcatcher
        www.FeederReader.com


        --- In RSS2-Support@yahoogroups.com, "Randy Morin" <randy@k...>
        wrote:
        >
        > Although the pubDate and lastBuildDate are not required, often RSS
        > readers/aggregators will use these as hints to determine if the
        feed
        > or items within the feed have changed. For instance, if the
        > lastBuildDate remains the same, then the reader/aggregator may
        assume
        > the feed has not changed and stop processing. I'm not familiar
        with
        > the internals of either Firefox or Bloglines to tell you how they
        > might be handling these elements.
        > I hope this helps,
        >
        > Randy Charles Morin
        > http://www.kbcafe.com
        >
        > --- In RSS2-Support@yahoogroups.com, yakovs <no_reply@y...> wrote:
        > >
        > > Hi,
        > >
        > > I am the author of the track2rss project
        (http://track2rss.sf.net)
        > > which lets you track packages via RSS 2.0 feeds (Fedex, USPS and
        > > UPS).
        > > I have been having problems with my feeds not refreshing in
        > Bloglines
        > > but working fine in FireFox. The feed in question is here:
        > >
        > > http://www.shaftek.org/code/track2rss/track2rss.pl?
        > > type=ups&tracking_number=1Z9R8A830327349416
        > >
        > > The feed validates through FeedValidator just fine. My suspicion
        > now
        > > centers around the pubdate and lastBuild elements of channel,
        and
        > the
        > > pubdate element of item. What I am wondering is whether any of
        > these
        > > elements are in fact required by aggregators in order to check
        > feeds
        > > more often (the RSS 2.0 spec they are not).
        > >
        > > Thanks,
        > > Yakov
      • yakovs
        Thank you. In my case it seems to be a BlogLines-specific problems since the other aggregators I tried out are working fine. ... assume
        Message 3 of 7 , Feb 1, 2005
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          Thank you.

          In my case it seems to be a BlogLines-specific problems since the
          other aggregators I tried out are working fine.

          --- In RSS2-Support@yahoogroups.com, "Randy Morin" <randy@k...> wrote:
          >
          > Although the pubDate and lastBuildDate are not required, often RSS
          > readers/aggregators will use these as hints to determine if the feed
          > or items within the feed have changed. For instance, if the
          > lastBuildDate remains the same, then the reader/aggregator may
          assume
          > the feed has not changed and stop processing. I'm not familiar with
          > the internals of either Firefox or Bloglines to tell you how they
          > might be handling these elements.
          > I hope this helps,
          >
          > Randy Charles Morin
          > http://www.kbcafe.com
          >
          > --- In RSS2-Support@yahoogroups.com, yakovs <no_reply@y...> wrote:
          > >
          > > Hi,
          > >
          > > I am the author of the track2rss project (http://track2rss.sf.net)
          > > which lets you track packages via RSS 2.0 feeds (Fedex, USPS and
          > > UPS).
          > > I have been having problems with my feeds not refreshing in
          > Bloglines
          > > but working fine in FireFox. The feed in question is here:
          > >
          > > http://www.shaftek.org/code/track2rss/track2rss.pl?
          > > type=ups&tracking_number=1Z9R8A830327349416
          > >
          > > The feed validates through FeedValidator just fine. My suspicion
          > now
          > > centers around the pubdate and lastBuild elements of channel, and
          > the
          > > pubdate element of item. What I am wondering is whether any of
          > these
          > > elements are in fact required by aggregators in order to check
          > feeds
          > > more often (the RSS 2.0 spec they are not).
          > >
          > > Thanks,
          > > Yakov
        • yakovs
          A question: what happens if there is not pubData OR lastBuiltDate? According to the RSS 2.0 spec it seems that they are not required elements. In my case,
          Message 4 of 7 , Feb 1, 2005
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            A question: what happens if there is not pubData OR lastBuiltDate?
            According to the RSS 2.0 spec it seems that they are not required
            elements.

            In my case, since this data is coming out of UPS/Fedex/USPS systems I
            cannot put a normal lastBuildDate in (unless I set it to the current
            date). As for pubData, I can probably convert the date/time given to
            me by UPS/Fedex/etc. but they are often in local time depending on
            where the package was. In those cases, the times may vary greatly.

            Yakov

            --- In RSS2-Support@yahoogroups.com, "ecomputerd" <ecomputerd@y...>
            wrote:
            >
            > I can't vouch for other aggregators, but FeederReader parses all
            > feeds that are downloaded. It does not look at lastBuildDate at all.
            > It uses pubDate of individual items to determine the relative age of
            > the items and give a byline of "6 hours ago by Greg Smith on
            > FeederReader Blog". It uses the relative age of items to optionally
            > determine viewing order. This is not foolproof because of the clock
            > difference between different producers' machines. I frequently see
            > feeds that are published, according to pubDate, in the future. The
            > New York Times feed is especially guilty of this; they seem to force
            > pubDate to midnight, yet actually put the feed up an hour or two
            > early. I would recommend against this practice.
            >
            > I find that the pubDate is very useful when reading posts, and I
            > would strongly encourage its use within each item of your feed.
            >
            > For examples of what the byline looks like in FeederReader, see the
            > screen shot on the front page of www.FeederReader.com with an
            > additional screen shot of a byline on the "Enclosure Support" page.
            >
            >
            > Greg Smith
            > Author, FeederReader - The Pocket PC RSS reader and podcatcher
            > www.FeederReader.com
            >
            >
            > --- In RSS2-Support@yahoogroups.com, "Randy Morin" <randy@k...>
            > wrote:
            > >
            > > Although the pubDate and lastBuildDate are not required, often RSS
            > > readers/aggregators will use these as hints to determine if the
            > feed
            > > or items within the feed have changed. For instance, if the
            > > lastBuildDate remains the same, then the reader/aggregator may
            > assume
            > > the feed has not changed and stop processing. I'm not familiar
            > with
            > > the internals of either Firefox or Bloglines to tell you how they
            > > might be handling these elements.
            > > I hope this helps,
            > >
            > > Randy Charles Morin
            > > http://www.kbcafe.com
            > >
            > > --- In RSS2-Support@yahoogroups.com, yakovs <no_reply@y...> wrote:
            > > >
            > > > Hi,
            > > >
            > > > I am the author of the track2rss project
            > (http://track2rss.sf.net)
            > > > which lets you track packages via RSS 2.0 feeds (Fedex, USPS and
            > > > UPS).
            > > > I have been having problems with my feeds not refreshing in
            > > Bloglines
            > > > but working fine in FireFox. The feed in question is here:
            > > >
            > > > http://www.shaftek.org/code/track2rss/track2rss.pl?
            > > > type=ups&tracking_number=1Z9R8A830327349416
            > > >
            > > > The feed validates through FeedValidator just fine. My suspicion
            > > now
            > > > centers around the pubdate and lastBuild elements of channel,
            > and
            > > the
            > > > pubdate element of item. What I am wondering is whether any of
            > > these
            > > > elements are in fact required by aggregators in order to check
            > > feeds
            > > > more often (the RSS 2.0 spec they are not).
            > > >
            > > > Thanks,
            > > > Yakov
          • ecomputerd
            I think the lastBuildDate is very appropriate for the current time when the RSS file is created. I would hope that any aggregator developer would design their
            Message 5 of 7 , Feb 1, 2005
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              I think the lastBuildDate is very appropriate for the current time
              when the RSS file is created. I would hope that any aggregator
              developer would design their program to be independent of the
              difference in time between the producer's and consumer's machine. In
              the case of lastBuildDate, this would mean (the aggregator)
              comparing the lastBuildDate to the previous lastBuildDate obtained
              and not to any date/time derived from the consumer's machine. That
              is, if the lastBuildDate is used at all.

              The pubDate (in RSS 2.0) is in the format of RFC882
              http://asg.web.cmu.edu/rfc/rfc822.html with a preferred 4-digit
              year, and includes a timezone. FeederReader correctly parses the
              timezone of a feed and converts it to local time (the timezone
              indicated by the device) upon display. If you could get the proper
              timezone in there, FeederReader would make the display really nice
              for those not in the timezone of the destination. 1) I don't know if
              this is useful for you, 2) I don't know what other aggregators
              display.

              If pubDate is not included in an item, FeederReader uses the
              date/time of download, which is usually much less useful. (I also
              include display "DL" before the age to specify that this was based
              on the "DownLoad" date/time and not a pubDate.)

              For your application, I would consider making the title of each item
              display very useful information as some aggregators might make it
              easy to see the titles as a group, but split the individual items on
              separate pages.

              Greg Smith
              Author, FeederReader - The Pocket PC RSS reader and podcatcher
              Catches video, too!
              www.FeederReader.com

              --- In RSS2-Support@yahoogroups.com, yakovs <no_reply@y...> wrote:
              >
              > A question: what happens if there is not pubData OR lastBuiltDate?
              > According to the RSS 2.0 spec it seems that they are not required
              > elements.
              >
              > In my case, since this data is coming out of UPS/Fedex/USPS
              systems I
              > cannot put a normal lastBuildDate in (unless I set it to the
              current
              > date). As for pubData, I can probably convert the date/time given
              to
              > me by UPS/Fedex/etc. but they are often in local time depending on
              > where the package was. In those cases, the times may vary greatly.
              >
              > Yakov
              >
              > --- In RSS2-Support@yahoogroups.com, "ecomputerd"
              <ecomputerd@y...>
              > wrote:
              > >
              > > I can't vouch for other aggregators, but FeederReader parses all
              > > feeds that are downloaded. It does not look at lastBuildDate at
              all.
              > > It uses pubDate of individual items to determine the relative
              age of
              > > the items and give a byline of "6 hours ago by Greg Smith on
              > > FeederReader Blog". It uses the relative age of items to
              optionally
              > > determine viewing order. This is not foolproof because of the
              clock
              > > difference between different producers' machines. I frequently
              see
              > > feeds that are published, according to pubDate, in the future.
              The
              > > New York Times feed is especially guilty of this; they seem to
              force
              > > pubDate to midnight, yet actually put the feed up an hour or two
              > > early. I would recommend against this practice.
              > >
              > > I find that the pubDate is very useful when reading posts, and I
              > > would strongly encourage its use within each item of your feed.
              > >
              > > For examples of what the byline looks like in FeederReader, see
              the
              > > screen shot on the front page of www.FeederReader.com with an
              > > additional screen shot of a byline on the "Enclosure Support"
              page.
              > >
              > >
              > > Greg Smith
              > > Author, FeederReader - The Pocket PC RSS reader and podcatcher
              > > www.FeederReader.com
              > >
              > >
              > > --- In RSS2-Support@yahoogroups.com, "Randy Morin" <randy@k...>
              > > wrote:
              > > >
              > > > Although the pubDate and lastBuildDate are not required, often
              RSS
              > > > readers/aggregators will use these as hints to determine if
              the
              > > feed
              > > > or items within the feed have changed. For instance, if the
              > > > lastBuildDate remains the same, then the reader/aggregator may
              > > assume
              > > > the feed has not changed and stop processing. I'm not familiar
              > > with
              > > > the internals of either Firefox or Bloglines to tell you how
              they
              > > > might be handling these elements.
              > > > I hope this helps,
              > > >
              > > > Randy Charles Morin
              > > > http://www.kbcafe.com
              > > >
              > > > --- In RSS2-Support@yahoogroups.com, yakovs <no_reply@y...>
              wrote:
              > > > >
              > > > > Hi,
              > > > >
              > > > > I am the author of the track2rss project
              > > (http://track2rss.sf.net)
              > > > > which lets you track packages via RSS 2.0 feeds (Fedex, USPS
              and
              > > > > UPS).
              > > > > I have been having problems with my feeds not refreshing in
              > > > Bloglines
              > > > > but working fine in FireFox. The feed in question is here:
              > > > >
              > > > > http://www.shaftek.org/code/track2rss/track2rss.pl?
              > > > > type=ups&tracking_number=1Z9R8A830327349416
              > > > >
              > > > > The feed validates through FeedValidator just fine. My
              suspicion
              > > > now
              > > > > centers around the pubdate and lastBuild elements of
              channel,
              > > and
              > > > the
              > > > > pubdate element of item. What I am wondering is whether any
              of
              > > > these
              > > > > elements are in fact required by aggregators in order to
              check
              > > > feeds
              > > > > more often (the RSS 2.0 spec they are not).
              > > > >
              > > > > Thanks,
              > > > > Yakov
            • Bill Kearney
              From: yakovs ... The spec is widely considered less than ideal . If you need to use a more refined spec you d do well to look at
              Message 6 of 7 , Feb 1, 2005
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                From: "yakovs" <no_reply@yahoogroups.com>
                > A question: what happens if there is not pubData OR lastBuiltDate?
                > According to the RSS 2.0 spec it seems that they are not required
                > elements.

                The spec is widely considered "less than ideal". If you need to use a more
                refined spec you'd do well to look at RSS-1.0.

                > In my case, since this data is coming out of UPS/Fedex/USPS systems I
                > cannot put a normal lastBuildDate in (unless I set it to the current
                > date). As for pubData, I can probably convert the date/time given to
                > me by UPS/Fedex/etc. but they are often in local time depending on
                > where the package was. In those cases, the times may vary greatly.

                If you're pulling the data at a given interval and caching the data it might
                be worth considering use of that timestamp for a build date. It's critical
                to get as good a set of data as possible. If you're talking about making
                something useful for folks don't fall short on handling date info.

                =Bill Kearney
                Syndic8.com
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