Wecr - simple web crawler

Overview

Just a simple HTML web spider with minimal dependencies. It is possible to search for pages with a text on them or for the text itself, extract images and save pages that satisfy the criteria along the way.

Configuration

The flow of work fully depends on the configuration file. By default conf.json is used as a configuration file, but the name can be changed via -conf flag. The default configuration is embedded in the program so on the first launch or by simply deleting the file, a new conf.json will be created in the same directory as the executable itself unless the wDir (working directory) flag is set to some other value.

The configuration is split into different branches like requests (how requests are made, ie: request timeout, wait time, user agent), logging (use logs, output to a file), save (output file|directory, save pages or not) or search (use regexp, query string) each of which contain tweakable parameters. There are global ones as well such as workers (working threads that make requests in parallel) and depth (literally, how deep the recursive search should go). The names are simple and self-explanatory so no attribute-by-attribute explanation needed for most of them.

The parsing starts from initial_pages and goes deeper while ignoring the pages on domains that are in blacklisted_domains or are NOT in allowed_domains. If all initial pages are happen to be on blacklisted domains or are not in the allowed list - the program will get stuck. It is important to note that *_domains should be specified with an existing scheme (ie: https://en.wikipedia.org). Subdomains and ports matter: https://unbewohnte.su:3000/ and https://unbewohnte.su/ are different.

Search query

if is_regexp is false, then query is the text to be searched for, but there are some special values:

• links - tells wecr to search for all links there are on the page
• images - find all image links and output to the output_dir (IMPORTANT: set wait_timeout_ms to 0 so the images load fully)

When is_regexp is enabled, the query is treated as a regexp string and pages will be scanned for matches that satisfy it.

Output

By default, if the query is not images all the matches and other data will be outputted to output.json file as separate continuous JSON objects, but if save_pages is set to true and|or query is set to images - the additional contents will be put in the output_dir directory neatly created by the executable's side.

TODO

• PARSE HTML WITH REGEXP (EVIL LAUGH)

License

AGPLv3