Associate cached content to the last redirection location, instead of
the first URL of a redirection(s) chain :
- for proper base URL processing in parsers (fixes mantis 636 -
http://mantis.tokeek.de/view.php?id=636)
- to prevent duplicated content in Solr index when recrawling a
redirected URL
- with only light constraint on known indexed documents load date, as it
can already been controlled by the selection query, and the goal of the
job is indeed to recrawl selected documents now
- using the iffresh cache strategy
Required for proper operation when the default system locale is Turkish,
as dottless and dotted i characters have specific case conversion rules
in this language.
When a crawl is started, a new field to exclude content from scraping is
available. The field can be identified with the class name of div tags.
All text contained in such a div tag where the configured class name(s)
match are not indexed, while the remaining page is indexed.
Previously, when checking for the first time the robots.txt policy on a
unknown host (not cached in the robots table), result was always empty
in the /getpageinfo_p.xml api and in the /CrawlCheck_p.html page. Next
calls returned however the correct information.
Some web servers provide both 'Content-Encoding : "gzip"' and
'Content-Type : "application/x-gzip"' HTTP headers on their ".gz" files.
This was annoying to fail on such resources which are not so uncommon,
while non conforming (see RFC 7231 section 3.1.2.2 for
"Content-Encoding" header specification
https://tools.ietf.org/html/rfc7231#section-3.1.2.2)
Thus enable getpageinfo_p API to return something in a reasonable amount
of time on resources over MegaBytes size range.
Support added first with the generic XML parser, for other formats
regular crawler limits apply as usual.
Especially for Turkish speaking users using "tr" as their system default
locale : strings for technical stuff (URLs, tag names, constants...)
must not be lower cased with the default locale, as 'I' doesn't becomes
'i' like in other locales such as "en", but becomes 'ı'.
Using a Reentrant lock instead of the intrinsic synchronization lock
permits limiting the blocking time to acquire a lock.
Useful on a very busy Cache concurrently accessed by many threads : when
the time to acquire a lock is too high, getting/storing content on the
cache becomes inefficient, and it is then better to fall back to loading
remote resources.
Illustrated by the CacheTest stress test and some traces reported in
mantis 751 ( http://mantis.tokeek.de/view.php?id=751 )
When using a public HTTP URL in /IndexImportMediawiki_p.html, the remote
file now is directly streamed and processed, allowing import of several
GB dumps even with a low memory remote peer, and without need to
manually download the dump file first.
following comment "use of properties as header values is discouraged"
in case where (proxy)HTTPClient overwrites values with supplied url.
Use defined request.referer procedure in response class.
This ensure consistent implementation of the url host hash generation
and easier usage finding in source code.
Also added a unit test for this function.
Applied rules :
- when the FTP URL denotes a file resource, stack it as any start URL :
eventually embedded links can be followed applying the usual depth rules
- when the FTP URL denotes a directory, list files under this directory
and stack them for crawl, and repeat the process on sub folders until
crawl depth is reached
When starting a crawl from a file containing thousands of links,
configuration setting "crawler.MaxActiveThreads" is effective to prevent
saturating the system with too many outgoing HTTP connections threads
launched by the crawler.
But robots.txt was not affected by this setting and was indefinitely
increasing the number of concurrently loading threads until most ot the
connections timed out.
To improve performance control, added a pool of threads for Robots.txt,
consistently used in its ensureExist() and massCrawlCheck() methods.
The Robots.txt threads pool max size can now be configured in the
/PerformanceQueus_p.html page, or with the new
"robots.txt.MaxActiveThreads" setting, initialized with the same default
value as the crawler.
Applied strategy : when there is no restriction on domains or
sub-path(s), stack anchor links once discovered by the content scraper
instead of waiting the complete parsing of the file.
This makes it possible to handle a crawling start file with thousands of
links in a reasonable amount of time.
Performance limitation : even if the crawl start faster with a large
file, the content of the parsed file still is fully loaded in memory.
Shutdown was hanging in CrawlQueues.close() at
this.workerQueue.put(POISON_REQUEST) when config value
crawler.MaxActiveThreads was greater than 200.
Revealed by "Collision" Threads dumps in mantis 689
(http://mantis.tokeek.de/view.php?id=689#c1312)
Fixed consistency between this.worker.length and this.workerQueue
capacity, and made the process more reliable using non-blocking offer()
function.
Even after network switch, ErroCache was still holding a reference to
the previous Solr cores, thus becoming useless until next YaCy restart.
Initial error cache filling with recent errors from the index was also
missing after the swtich.
after restart, put hosthash in queue's filename (which is used as primary
key for crawl queue. Hint: initial hosthash from url and recalculated hosthash
from just hostname:port are not the same.
fixes http://mantis.tokeek.de/view.php?id=668 (partially)
This is the 1st rudimentary approach to support the translatio utilities.
It allows currently to edit untranslated text and save it in a local translation file
in the DATA/LOCALE directory.
+ refactor Translator (less static's) to leverage on class overrides and support garbage collection for this 1 time routine
+ adjust TranslatorXliff to check for local translations in DATA/LOCALE,
this includes storing manually downloaded translation files in DATA as well
(to keep default untouched)
+ on 1st call of Translator_p a master tanslation file is generated, checking
the supported languages for missing translation text (later this masterfile is planned to part of the distribution, to harmonize translation key text between the languages)
Outlook: the local modifications (possibly as translation fragments instead of complete file) to be shared with maintainer using xlif features.
- Above brought up that parser start url parameter, declared as AnchorURL uses only methodes of parent object DigestURL (changed parameter declaration accordingly).
In rare cases hostname may not be a valid filesystem directory name,
which can't be created (e.g. containing '*' char). To prevent crawl queue
looping on this invalid entry by throwing a malformedurlexception.
and allow injection of recrawl urls before queue is empty
During recrawl the balancer hangs on the very last urls often on hosts with huge delay time,
by allowing injection earlier progress is more balanced. Max number of injected crawl urls by recrawl job is 2 * max loader.
This is a workaround for existing index (not fully reindexed) since intro of schema with docvalues
to prevent solr exception causing recrawljob to fail with
org.apache.solr.core.SolrCore java.lang.IllegalStateException: unexpected docvalues type NONE for field 'load_date_dt' (expected=NUMERIC). Use UninvertingReader or index with docvalues.
If remote crawl option is not activated, skip init of remoteCrawlJob to save the resources of queue and ideling thread.
Deploy of the remoteCrawlJob deferred on activation of the option.
added to IndexReIndexMonitor_p.html
Selects existing documents from index and feeds it to the crawler.
currently only the field fresh_date_dt is used determine documents for recrawl (fresh_date_dt:[* TO NOW-1DAY]
Documents are added in small chunks (200) to the crawler, only if no other crawl is running.
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.
- date navigation
The date is taken from the CONTENT of the documents / web pages, NOT
from a date submitted in the context of metadata (i.e. http header or
html head form). This makes it possible to search for documents in the
future, i.e. when documents contain event descriptions for future
events.
The date is written to an index field which is now enabled by default.
All documents are scanned for contained date mentions.
To visualize the dates for a specific search results, a histogram
showing the number of documents for each day is displayed. To render
these histograms the morris.js library is used. Morris.js requires also
raphael.js which is now also integrated in YaCy.
The histogram is now also displayed in the index browser by default.
To select a specific range from a search result, the following modifiers
had been introduced:
from:<date>
to:<date>
These modifiers can be used separately (i.e. only 'from' or only 'to')
to describe an open interval or combined to have a closed interval. Both
dates are inclusive. To select a specific single date only, use the
'to:' - modifier.
The histogram shows blue and green lines; the green lines denot weekend
days (saturday and sunday).
Clicking on bars in the histogram has the following reaction:
1st click: add a from:<date> modifier for the date of the bar
2nd click: add a to:<date> modifier for the date of the bar
3rd click: remove from and date modifier and set a on:<date> for the bar
When the on:<date> modifier is used, the histogram shows an unlimited
time period. This makes it possible to click again (4th click) which is
then interpreted as a 1st click again (sets a from modifier).
The display feature is NOT switched on by default; to switch it on use
the /ConfigSearchPage_p.html servlet.
luccioman