[ http://issues.apache.org/jira/browse/NUTCH-139?page=comments#action_12360909 ]
Andrzej Bialecki commented on NUTCH-139: ----------------------------------------- Yes, that was again the reason for prefixing - we want to keep as much of the original metadata as we can, to facilitate various processing in plugins that know how to handle unreliable data. But at the same we need a place to keep the metadata that we believe in. So, first of all the protocol plugins collect any metadata "as is" from the wire, and put the original values in properties. Then, those plugins that know what they are doing should put the reliable metadata under the "X-nutch-" namespace. If some metadata is required (e.g. content type), then the code that is responsible for handling this metadata should ensure that we have a reliable value under the "X-nutch-" namespace, even if the original value is missing. > Standard metadata property names in the ParseData metadata > ---------------------------------------------------------- > > Key: NUTCH-139 > URL: http://issues.apache.org/jira/browse/NUTCH-139 > Project: Nutch > Type: Improvement > Components: fetcher > Versions: 0.7.1, 0.7, 0.6, 0.7.2-dev, 0.8-dev > Environment: Power Mac OS X 10.4, Dual Processor G5 2.0 Ghz, 1.5 GB RAM, > although bug is independent of environment > Reporter: Chris A. Mattmann > Assignee: Chris A. Mattmann > Priority: Minor > Fix For: 0.7.2-dev, 0.8-dev, 0.7.1, 0.7, 0.6 > Attachments: NUTCH-139.Mattmann.patch.txt, NUTCH-139.jc.review.patch.txt > > Currently, people are free to name their string-based properties anything > that they want, such as having names of "Content-type", "content-TyPe", > "CONTENT_TYPE" all having the same meaning. Stefan G. I believe proposed a > solution in which all property names be converted to lower case, but in > essence this really only fixes half the problem right (the case of > identifying that "CONTENT_TYPE" > and "conTeNT_TyPE" and all the permutations are really the same). What about > if I named it "Content Type", or "ContentType"? > I propose that a way to correct this would be to create a standard set of > named Strings in the ParseData class that the protocol framework and the > parsing framework could use to identify common properties such as > "Content-type", "Creator", "Language", etc. > The properties would be defined at the top of the ParseData class, something > like: > public class ParseData{ > ..... > public static final String CONTENT_TYPE = "content-type"; > public static final String CREATOR = "creator"; > .... > } > In this fashion, users could at least know what the name of the standard > properties that they can obtain from the ParseData are, for example by making > a call to ParseData.getMetadata().get(ParseData.CONTENT_TYPE) to get the > content type or a call to ParseData.getMetadata().set(ParseData.CONTENT_TYPE, > "text/xml"); Of course, this wouldn't preclude users from doing what they are > currently doing, it would just provide a standard method of obtaining some of > the more common, critical metadata without pouring over the code base to > figure out what they are named. > I'll contribute a patch near the end of the this week, or beg. of next week > that addresses this issue. -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira
