to support the new time parser and search functions in YaCy a high
precision detection of date and time on the day is necessary. That
requires that the time zone of the document content and the time zone of
the user, doing a search, is detected. The time zone of the search
request is done automatically using the browsers time zone offset which
is delivered to the search request automatically and invisible to the
user. The time zone for the content of web pages cannot be detected
automatically and must be an attribute of crawl starts. The advanced
crawl start now provides an input field to set the time zone in minutes
as an offset number. All parsers must get a time zone offset passed, so
this required the change of the parser java api. A lot of other changes
had been made which corrects the wrong handling of dates in YaCy which
was to add a correction based on the time zone of the server. Now no
correction is added and all dates in YaCy are UTC/GMT time zone, a
normalized time zone for all peers.
given css class and extends a given vocabulary with a term consisting
with the text content of the html class tag. Additionally, the term is
included into the semantic facet of the document. This allows the
creation of faceted search to documents without the pre-creation of
vocabularies; instead, the vocabulary is created on-the-fly, possibly
for use in other crawls. If any of the term scraping for a specific
vocabulary is successful on a document, this vocabulary is excluded for
auto-annotation on the page.
To use this feature, do the following:
- create a vocabulary on /Vocabulary_p.html (if not existent)
- in /CrawlStartExpert.html you will now see the vocabularies as column
in a table. The second column provides text fields where you can name
the class of html entities where the literal of the corresponding
vocabulary shall be scraped out
- when doing a search, you will see the content of the scraped fields in
a navigation facet for the given vocabulary
- snapshots can now also be xml files which are extracted from the solr
index and stored as individual xml files in the snapshot directory along
the pdf and jpg images
- a transaction layer was placed above of the snapshot directory to
distinguish snapshots into 'inventory' and 'archive'. This may be used
to do transactions of index fragments using archived solr search results
between peers. This is currently unfinished, we need a protocol to move
snapshots from inventory to archive
- the SNAPSHOT directory was renamed to snapshot and contains now two
snapshot subdirectories: inventory and archive
- snapshots may now be generated by everyone, not only such peers
running on a server with xkhtml2pdf installed. The expert crawl starts
provides the option for snapshots to everyone. PDF snapshots are now
optional and the option is only shown if xkhtml2pdf is installed.
- the snapshot api now provides the request for historised xml files,
i.e. call:
http://localhost:8090/api/snapshot.xml?urlhash=Q3dQopFh1hyQ
The result of such xml files is identical with solr search results with
only one hit.
The pdf generation has been moved from the http loading process to the
solr document storage process. This may slow down the process a lot and
a different version of the process may be needed.
be transcoded into jpg for image previews. To create such pdfs you must
do:
Add wkhtmltopdf and imagemagick to your OS, which you can do:
On a Mac download wkhtmltox-0.12.1_osx-cocoa-x86-64.pkg from
http://wkhtmltopdf.org/downloads.html and downloadh
ttp://cactuslab.com/imagemagick/assets/ImageMagick-6.8.9-9.pkg.zip
In Debian do "apt-get install wkhtmltopdf imagemagick"
Then check in /Settings_p.html?page=ProxyAccess: "Transparent Proxy" and
"Always Fresh" - this is used by wkhtmltopdf to fetch web pages using
the YaCy proxy. Using "Always Fresh" it is possible to get all pages
from the proxy cache.
Finally, you will see a new option when starting an expert web crawl.
You can set a maximum depth for crawling which should cause a pdf
generation. The resulting pdfs are then available in
DATA/HTCACHE/SNAPSHOTS/<host>.<port>/<depth>/<shard>/<urlhash>.<date>.pdf
filled with the date, when the url is recognized as to be outdated. That
field was partly misinterpreted and the time interval was filled in. In
case that all the urls which are in the index shall be treated as
outdated, the field is filled now with Long.MAX_VALUE because then all
crawl dates are before that date and therefore outdated.
attribute in the <a> tag for each crawl. This introduces a lot of
changes because it extends the usage of the AnchorURL Object type which
now also has a different toString method that the underlying
DigestURL.toString. It is therefore not advised to use .toString at all
for urls, just just toNormalform(false) instead.
may have contained multiple same expressions within the disjunction of
domain-restrictions. This fix removes the redundant restrictions and
makes the regex shorter.
webgraph index which is temporary filled with the crawl profile key.
This is used to select a set of documents for post-processing as soon as
a crawl is finished. Now the postprocessing for a specific crawl is
started when that specific crawl is finished and not at the end of all
post-processing steps.
all unique links! This made it necessary, that a large portion of the
parser and link processing classes must be adopted to carry a different
type of link collection which carry a property attribute which are
attached to web anchors.
- introduction of a new URL class, AnchorURL
- the other url classes, DigestURI and MultiProtocolURI had been renamed
and refactored to fit into a new document package schema, document.id
- cleanup of net.yacy.cora.document package and refactoring
regular expression on th url: the collection attribut for a crawl start
may be now either a token or a list of tokens, seperated by ',' where a
token is either a string or a pair <string,pattern> where the string is
separated to the pattern with a ':' and the string is assigned to the
document as collection only if the pattern matches with the url.
in intranets and the internet can now choose to appear as Googlebot.
This is an essential necessity to be able to compete in the field of
commercial search appliances, since most web pages are these days
optimized only for Google and no other search platform any more. All
commercial search engine providers have a built-in fake-Google User
Agent to be able to get the same search index as Google can do. Without
the resistance against obeying to robots.txt in this case, no
competition is possible any more. YaCy will always obey the robots.txt
when it is used for crawling the web in a peer-to-peer network, but to
establish a Search Appliance (like a Google Search Appliance, GSA) it is
necessary to be able to behave exactly like a Google crawler.
With this change, you will be able to switch the user agent when portal
or intranet mode is selected on per-crawl-start basis. Every crawl start
can have a different user agent.
jdk-based logger tend to block
at java.util.logging.Logger.log(Logger.java:476) in concurrent
environments. This makes logging a main performance issue. To overcome
this problem, this is a add-on to jdk logging to put log entries on a
concurrent message queue and log the messages one by one using a
separate process.
- FTPClient uses the concurrent logging instead of the log4j logger
- added the field in crawl profile
- adopted logging end error management
- adopted duplicate document detection
- added a new rule to the indexing process to reject non-matching
content
- full redesign of the expert crawl start servlet
The new filter field can now be seen in /CrawlStartExpert_p.html at
Section "Document Filter", subsection item "Filter on Content of
Document"
deleted which are selected by a crawl filter (host or subpath)
- site crawl used this option be default now
- made option to deleteDomain() concurrency
MultiProtocolURI during normalform computation because that should
always be done and also be done during initialization of the
MultiProtocolURI Object. The new normalform method takes only one
argument which should be 'true' unless you know exactly what you are
doing.
Michael Peter Christen