b74a3ebd85
At this stage, the crawler will use the WARCs to resume a crawl if it terminates incorrectly. This is a WIP commit, since the warc files are not fully incorporated into the work flow, they are deleted after the domain is crawled. The commit also includes fairly invasive refactoring of the crawler classes, to accomplish better separation of concerns. |
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|---|---|---|
| .. | ||
| converting-process | ||
| crawling-process | ||
| index-constructor-process | ||
| loading-process | ||
| test-data | ||
| website-adjacencies-calculator | ||
| readme.md | ||
Processes
1. Crawl Process
The crawling-process fetches website contents and saves them as compressed JSON models described in crawling-model.
The operation is specified by a crawl specification, which can be created in the control GUI.
2. Converting Process
The converting-process reads crawl data from the crawling step and processes them, extracting keywords and metadata and saves them as parquet files described in processed-data.
3. Loading Process
The loading-process reads the processed data.
It has creates an index journal, a link database, and loads domains and domain-links into the MariaDB database.
4. Index Construction Process
The index-construction-process constructs indices from the data generated by the loader.
Overview
Schematically the crawling and loading process looks like this:
//====================\\
|| Compressed JSON: || Specifications
|| ID, Domain, Urls[] || File
|| ID, Domain, Urls[] ||
|| ID, Domain, Urls[] ||
|| ... ||
\\====================//
|
+-----------+
| CRAWLING | Fetch each URL and
| STEP | output to file
+-----------+
|
//========================\\
|| Compressed JSON: || Crawl
|| Status, HTML[], ... || Files
|| Status, HTML[], ... ||
|| Status, HTML[], ... ||
|| ... ||
\\========================//
|
+------------+
| CONVERTING | Analyze HTML and
| STEP | extract keywords
+------------+ features, links, URLs
|
//==================\\
|| Parquet: || Processed
|| Documents[] || Files
|| Domains[] ||
|| Links[] ||
\\==================//
|
+------------+ Insert domains into mariadb
| LOADING | Insert URLs, titles in link DB
| STEP | Insert keywords in Index
+------------+
|
+------------+
| CONSTRUCT | Make the data searchable
| INDEX |
+------------+