Gal, Chris, Kauu,
So, if I understand correctly, you need a way to pass information along
the fetches, so that when Nutch fetches a feed entry, its <item> value
previously fetched is available.
This is how I tackled the issue:
- extend Outlinks.java and allow to create outlinks with more meta data.
So, in your feed parser, use this way to create outlinks
- pass on the metadata through ParseOutputFormat.java and Fetcher.java
- retrieve the metadata in HtmlParser.java and use it
This is very tedious, will blow the size of your outlinks db, makes
changes in the core code of Nutch, etc... But this is the only way I
came up with...
If someone sees a better way, please let me know :-)
Sample code, for Nutch 0.8.x :
Outlink.java
+ public Outlink(String toUrl, String anchor, String entryContents,
Configuration conf) throws MalformedURLException {
+ this.toUrl = new
UrlNormalizerFactory(conf).getNormalizer().normalize(toUrl);
+ this.anchor = anchor;
+
+ this.entryContents= entryContents;
+ }
and update the other methods
ParseOutputFormat.java, around lines 140
+ // set outlink info in metadata ME
+ String entryContents= links[i].getEntryContents();
+
+ if (entryContents.length() > 0) { // it's a feed entry
+ MapWritable meta = new MapWritable();
+ meta.put(new UTF8("entryContents"), new
UTF8(entryContents));//key/value
+ target = new CrawlDatum(CrawlDatum.STATUS_LINKED,
interval);
+ target.setMetaData(meta);
+ } else {
+ target = new CrawlDatum(CrawlDatum.STATUS_LINKED,
interval); // no meta
+ }
Fetcher.java, around l. 266
+ // add feed info to metadata
+ try {
+ String entryContents = datum.getMetaData().get(new
UTF8("entryContents")).toString();
+ metadata.set("entryContents", entryContents);
+ } catch (Exception e) { } //not found
HtmlParser.java
// get entry metadata
String entryContents = content.getMetadata().get("entryContents");
HTH,
Renaud
Gal Nitzan wrote:
Hi Chris,
I'm sorry I wasn't clear enough. What I mean is that in the current
implementation:
1. The RSS (channels, items) page ends up as one Lucene document in the index.
2. Indeed the links are extracted and each <item> link will be fetched in the
next fetch as a separate page and will end up as one Lucene document.
IMHO the data that is needed i.e. the data that will be fetched in the next fetch process
is already available in the <item> element. Each <item> element represents one
web resource. And there is no reason to go to the server and re-fetch that resource.
Another issue that arises from rss feeds is that once the feed page is fetched you can
not re-fetch it until its "time to fetch" expired. The feeds TTL is usually
very short. Since for now in Nutch, all pages created equal :) it is one more thing to
think about.
HTH,
Gal.
-----Original Message-----
From: Chris Mattmann [mailto:[EMAIL PROTECTED]
Sent: Thursday, February 01, 2007 7:01 PM
To: nutch-dev@lucene.apache.org
Subject: Re: RSS-fecter and index individul-how can i realize this function
Hi Gal, et al.,
I'd like to be explicit when we talk about what the issue with the RSS
parsing plugin is here; I think we have had conversations similar to this
before and it seems that we keep talking around each other. I'd like to get
to the heart of this matter so that the issue (if there is an actual one)
gets addressed ;)
Okay, so you mention below that the thing that you see missing from the
current RSS parsing plugin is the ability to store data in the CrawlDatum,
and parse "it" in the next fetch phase. Well, there are 2 options here for
what you refer to as "it":
1. If you're talking about the RSS file, then in fact, it is parsed, and
its data is stored in the CrawlDatum, akin to any other form of content that
is fetched, parsed and indexed.
2. If you're talking about the item links within the RSS file, in fact,
they are parsed (eventually), and their data stored in the CrawlDatum, akin
to any other form of content that is fetched, parsed, and indexed. This is
accomplished by adding the RSS items as Outlinks when the RSS file is
parsed: in this fashion, we go after all of the links in the RSS file, and
make sure that we index their content as well.
Thus, if you had an RSS file R that contained links in it to a PDF file A,
and another HTML page P, then not only would R get fetched, parsed, and
indexed, but so would A and P, because they are item links within R. Then
queries that would match R (the physical RSS file), would additionally match
things such as P and A, and all 3 would be capable of being returned in a
Nutch query. Does this make sense? Is this the issue that you're talking
about? Am I nuts? ;)
Cheers,
Chris
On 1/31/07 10:40 PM, "Gal Nitzan" <[EMAIL PROTECTED]> wrote:
Hi,
Many sites provide RSS feeds for several reasons, usually to save bandwidth,
to give the users concentrated data and so forth.
Some of the RSS files supplied by sites are created specially for search
engines where each RSS "item" represent a web page in the site.
IMHO the only thing "missing" in the parse-rss plugin is storing the data in
the CrawlDatum and "parsing" it in the next fetch phase. Maybe adding a new
flag to CrawlDatum, that would flag the URL as "parsable" not "fetchable"?
Just my two cents...
Gal.
-----Original Message-----
From: Chris Mattmann [mailto:[EMAIL PROTECTED]
Sent: Wednesday, January 31, 2007 8:44 AM
To: nutch-dev@lucene.apache.org
Subject: Re: RSS-fecter and index individul-how can i realize this function
Hi there,
With the explanation that you give below, it seems like parse-rss as it
exists would address what you are trying to do. parse-rss parses an RSS
channel as a set of items, and indexes overall metadata about the RSS file,
including parse text, and index data, but it also adds each item (in the
channel)'s URL as an Outlink, so that Nutch will process those pieces of
content as well. The only thing that you suggest below that parse-rss
currently doesn't do, is to allow you to associate the metadata fields
category:, and author: with the item Outlink...
Cheers,
Chris
On 1/30/07 7:30 PM, "kauu" <[EMAIL PROTECTED]> wrote:
thx for ur reply .
mybe i didn't tell clearly .
I want to index the item as a
individual page .then when i search the some
thing for example "nutch-open
source", the nutch return a hit which contain
title : nutch-open source
description : nutch nutch nutch ....nutch nutch
url :
http://lucene.apache.org/nutch
category : news
author : kauu
so , is
the plugin parse-rss can satisfy what i need?
<item>
<title>nutch--open
source</title>
<description>
nutch nutch nutch ....nutch
nutch
</description>
<link>http://lucene.apache.org/nutch</link>
<category>news
</category>
<author>kauu</author>
On 1/31/07, Chris
Mattmann <[EMAIL PROTECTED]> wrote:
Hi there,
I could most
likely be of assistance, if you gave me some more
information.
For
instance: I'm wondering if the use case you describe below is already
supported by the current RSS parse plugin?
The current RSS parser,
parse-rss, does in fact index individual items
that
are pointed to by an
RSS document. The items are added as Nutch Outlinks,
and added to the
overall queue of URLs to fetch. Doesn't this satisfy what
you mention below?
Or am I missing something?
Cheers,
Chris
On 1/30/07 6:01 PM,
"kauu" <[EMAIL PROTECTED]> wrote:
Hi folks :
What's I want to
do is to separate a rss file into several pages .
Just as what has
been discussed before. I want fetch a rss page and
index
it as different
documents in the index. So the searcher can search the
Item's info as a
individual hit.
What's my opinion create a protocol for fetch the rss
page and store it
as
several one which just contain one ITEM tag .but
the unique key is the
url ,
so how can I store them with the ITEM's link
tag as the unique key for a
document.
So my question is how to
realize this function in nutch-.0.8.x.
I've check the code of the
plug-in protocol-http's code ,but I can't
find the code where to store a
page to a document. I want to separate
the
rss page to several ones
before storing it as a document but several
ones.
So any one can
give me some hints?
Any reply will be appreciated !
ITEM's structure
<item>
<title>欧洲暴风雪后发制人 致航班
延误交通混乱(组图)</title>
<description>暴风雪横扫欧洲，导致多次航班延误 1
月24日，几架民航客机在德
国斯图加特机场内等待去除机身上冰雪。1月24日，工作人员在德国南部
的慕尼黑机场
清扫飞机跑道上的积雪。 据报道，迟来的暴风雪连续两天横扫中...
</description>
<link>http://news.sohu.com/20070125
<http://news.sohu.com/20070125/n247833568.shtml> /n247833568.shtml</
link>
<category>搜狐焦点图新闻</category>
<author>[EMAIL PROTECTED]
</author>
<pubDate>Thu, 25 Jan 2007
11:29:11 +0800</pubDate>
<comments
http://comment.news.sohu.com
<http://comment.news.sohu.com/comment/topic.jsp?id=247833847>
/comment/topic.jsp?id=247833847</comments>
</item
______________________________________________
Chris A. Mattmann
[EMAIL PROTECTED]
Staff Member
Modeling and Data Management Systems Section (387)
Data Management Systems and Technologies Group
_________________________________________________
Jet Propulsion Laboratory Pasadena, CA
Office: 171-266B Mailstop: 171-246
_______________________________________________________
Disclaimer: The opinions presented within are my own and do not reflect
those of either NASA, JPL, or the California Institute of Technology.
--
renaud richardet +1 617 230 9112
renaud <at> oslutions.com http://www.oslutions.com
