[ http://issues.apache.org/jira/browse/NUTCH-139?page=comments#action_12363996 ]
Doug Cutting commented on NUTCH-139: ------------------------------------ I think this is all easily handled by naming, and that we don't need another map. We keep using "title" and "content-type" as examples, when these are actually not problematic, since nutch already has dedicated fields for them. Can someone please provide some examples of where multiple values are actually needed, besides the need to accurately represent multi-valued http and smtp headers? For title and content-type, the header in the metadata is what the parser and protocol found, respectively, and the field in the Parse and Content are what will be used. What are some cases where a value needs to be "overridden" where using an X-nutch value as the authoritative value will not suffice? > 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-139.060105.patch, 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
