Populus:DezInV/Notes

architecture

split between crawler/warc writer and processor

Having two separate processes for crawling and processing has advantages:

• The crawler is simple: Work a queue of URLs and write a warc file
• Processing can be redone as often as needed without network access

There should not be much overhead:

• The (compressed) data should still be in the Kernels page cache if processing starts immediately after the warc file has been written.
• Decompression is fast and the decompressed data can be piped directly into a HTML parser to minimize memory consumption.

relevant theory:

• page cache
  • https://biriukov.dev/docs/page-cache/3-page-cache-and-basic-file-operations/
  • https://programs.team/page-cache-why-is-my-container-memory-usage-always-at-the-critical-point.html

archive

• https://wiki.archiveteam.org
• The WARC format
• Discussion about compression with somebody working on Russian web archive

compression

• Book: 1999, Managing Gigabytes - Compressing and Indexing Documents and Images
• brotli
  • https://cran.r-project.org/web/packages/brotli/vignettes/brotli-2015-09-22.pdf

seekable (random access) compression

Spinning hard drives have sequential read speeds above 100 MB/s. Thus a record in e.g. a 64MB compressed warc file can be retrieved on average in less than 0.3s, even when the archive needs to be seeked from the start.

(64 MB once was the recommended size for Hadoop files.)

Still, these were the links I found:

• https://github.com/facebook/zstd/blob/dev/contrib/seekable_format/zstd_seekable_compression_format.md
• https://encode.su/threads/1766-Seekable-compression
• https://stackoverflow.com/questions/2046559/any-seekable-compression-library
• https://superuser.com/questions/1235351/what-makes-a-tar-archive-seekable
• https://serverfault.com/questions/59795/is-there-a-smarter-tar-or-cpio-out-there-for-efficiently-retrieving-a-file-store/546691#546691
• https://innovation.ebayinc.com/tech/engineering/gzinga-seekable-and-splittable-gzip/
• https://stackoverflow.com/questions/14225751/random-access-to-gzipped-files
• https://stackoverflow.com/questions/429987/compression-formats-with-good-support-for-random-access-within-archives
• https://stackoverflow.com/questions/236414/what-is-the-best-compression-algorithm-that-allows-random-reads-writes-in-a-file

crawling

• httparchive hat einen Almanach mit Statistiken über Webseiten
• https://www.commoncrawl.org

search

Search Engines

Terrier

• Terrier.org (Java) by the Information Retrieval Group within the School of Computing Science at the University of Glasgow

news archiving

• https://wiki.archiveteam.org/index.php?title=NewsGrabber

feeds

• https://hackage.haskell.org/package/feed-crawl

from org-mode/thk

dezentrale Suchmaschine

• https://yacy.net
  • RFP
  • https://www.youtube.com/c/YaCyTutorials/videos
• https://github.com/nvasilakis/yippee
  • Java
  • last commit 2012
• https://www.techdirt.com/articles/20140701/03143327738/distributed-search-engines-why-we-need-them-post-snowden-world.shtml
• https://metaphacts.com/diesel
  • non-free enterprise search engine
• https://fourweekmba.com/distributed-search-engines-vs-google/
• presearch.{io|org}
  • non-free, blockchain,bla bla
• https://github.com/kearch/kearch
  • letzter commit 2019
  • python
• https://hackernoon.com/is-the-concept-of-a-distributed-search-engine-potent-enough-to-challenge-googles-dominance-l1s44t2
• https://blog.florence.chat/a-distributed-search-engine-for-the-distributed-web-39c377dc700e
• https://wiki.p2pfoundation.net/Distributed_Search_Engines
• https://en.wikipedia.org/wiki/Distributed_search_engine
• https://searx.github.io/searx/
• https://www.astridmager.net Wissenschaftlerin, alternative, ethic search
• Warum man auch ein lokales Archiv haben sollte: https://www.medialens.org/2023/is-that-orwellian-or-kafkaesque-enough-for-you-the-guardian-removes-bin-ladens-letter-to-america

Internet Archive

• https://netpreserve.org/about-us/
• https://github.com/iipc/awesome-web-archiving
• https://github.com/internetarchive
• https://github.com/iipc/openwayback
• http://timetravel.mementoweb.org/
  • http://timetravel.mementoweb.org/about/
• https://github.com/webrecorder

Crawling, Crawler

• https://en.wikipedia.org/wiki/WARC_(file_format)

1. ArchiveBox

   • https://github.com/ArchiveBox/ArchiveBox

   Python, aktiv

   Open source self-hosted web archiving. Takes URLs/browser history/bookmarks/Pocket/Pinboard/etc., saves HTML, JS, PDFs, media, and more…

   • https://archivebox.io

2. grab-site

   Python, aktiv https://github.com/ArchiveTeam/grab-site

3. WASP

   • Paper: WASP: Web Archiving and Search Personalized via https://github.com/webis-de/wasp
     • Java, inaktiv?
     • related Paper: Extending WASP: providing context to a personal web archive

4. StormCrawler

   • https://en.wikipedia.org/wiki/StormCrawler
   • Auf Basis von Apache Storm (distributed stream processing)

5. HTTrack

   • https://www.httrack.com
   • In C geschrieben, letztes Release 2017, aber aktives Forum und Github
   • https://github.com/xroche/httrack/tags

6. Grub.org

   dezentraler Crawler des Wikia Projektes In C#, Pyton

   • https://web.archive.org/web/20090207182028/http://grub.org/
   • https://en.wikipedia.org/wiki/Grub_(search_engine)

7. HCE – Hierarchical Cluster Engine

   • http://hierarchical-cluster-engine.com
   • https://en.wikipedia.org/wiki/Hierarchical_Cluster_Engine_Project
   • Ukraine, aktiv bis ca. 2014?

8. Heritrix

   • https://en.wikipedia.org/wiki/Heritrix
   • Crawler von archive.org

9. Haskell

   • https://shimweasel.com/2017/07/13/a-modest-scraping-proposal
     • https://www.reddit.com/r/haskell/comments/6nazqm/notes_on_design_of_webscrapers_in_haskell/
   • https://github.com/jordanspooner/haskell-web-crawler
     • dead since 2017, seems like student assignment
   • https://hackage.haskell.org/package/scalpel
     • A high level web scraping library for Haskell.
   • https://hackage.haskell.org/package/hScraper
     • eine Version 0.1.0.0 von 2015
   • https://hackage.haskell.org/package/hs-scrape
     • eine VErsion von 2014, aber git commit von 2020
   • https://hackage.haskell.org/package/http-conduit-downloader
     • HTTP/HTTPS downloader built on top of http-client and used in https://bazqux.com crawler.
   • https://github.com/hunt-framework/hunt
     • A flexible, lightweight search platform
     • Vorläufer https://github.com/fortytools/holumbus/
       • http://holumbus.fh-wedel.de/trac
   • lower level libs
     • https://github.com/haskell/wreq http://www.serpentine.com/wreq
     • https://github.com/snoyberg/http-client/blob/master/TUTORIAL.md

Search

1. openwebsearch.eu

   • https://openwebsearch.eu/the-project/research-results

2. lemurproject.org

   1. lucindri

      https://lemurproject.org/lucindri.php

      Lucindri is an open-source implementation of Indri search logic and structured query language using the Lucene Search Engine. Lucindri consists of two components: the indexer and the searcher.

   2. Galago

      toolkit for experimenting with text search

      • http://www.search-engines-book.com

Wikia

• https://en.wikipedia.org/wiki/Wikia_Search
• von Jimmy Wales
• Implementierung
  • Grub, dezentraler Crawler
  • Apache Nutch

Recherche 2023-11-26

• https://en.wikipedia.org/wiki/Category:Web_scraping
• https://en.wikipedia.org/wiki/Category:Web_archiving
• https://en.wikipedia.org/wiki/Category:Free_search_engine_software
• https://en.wikipedia.org/wiki/Category:Internet_search_engines
• https://en.wikipedia.org/wiki/Category:Free_web_crawlers

Scraping

• https://github.com/scrapy