ASWI - Pokročilé softwarové inženýrství » ASWI 2020 » Aplikace nad otevřenými daty (KIV) – BHVS

h1. DatasetCrawler

Složka obsahuje implementace crawleru pro jednotlivé datasety. Crawlery jsou dynamicky importovány je tedy proto nutné dodržet pojemnování *"dataset-name"_crawler.py*.

Je velmi žádoucí aby crawler pro stažení souboru používal funkci *basic_crawler_functions.download_file_from_url("url_souboru", "jmeno_datasetu")*.

Ta totiž ukládá do databáze zmínku o tom, které soubory byly již staženy aby nedocházelo k duplicitám nebo zbytečnému stahování.

h2. Generovaný crawler

Při použití skriptu *PrepareNewDataset.py* vznikne následující kostra pro doplnění funkčnosti.

<pre>

# Path to crawled data

CRAWLED_DATA_PATH = "CrawledData/"

def crawl(config):

    """

    Implement crawl method that downloads new data to path_for_files

    For keeping the project structure

    url , regex, and dataset_name from config

    You can use already implemented functions from Utilities/Crawler/BasicCrawlerFunctions.py

    Args:

        config: loaded configuration file of dataset

    """

    dataset_name = config["dataset-name"]

    url = config['url']

    regex = config['regex']

    path_for_files = CRAWLED_DATA_PATH + dataset_name + '/'

    print("You must implements Crawl method first!")

</pre>

h2. Vzorově implementovaný crawler

Pro ukázku byl zvonel crawler pro dataset koloběžek. Je zde využito hlavně funkcí z *Utilities.Crawler.basic_crawler_functions*.

<pre>

from Utilities import folder_processor

from Utilities.Crawler import basic_crawler_functions

# Path to crawled data

CRAWLED_DATA_PATH = "CrawledData/"

def crawl(config):

    """

    Implement crawl method that downloads new data to path_for_files

    For keeping the project structure

    url , regex, and dataset_name from config

    You can use already implemented functions from Utilities/Crawler/basic_crawler_functions.py

    Args:

        config: loaded configuration file of dataset

    """

    dataset_name = config["dataset-name"]

    url = config['url']

    regex = config['regex']

    path_for_files = CRAWLED_DATA_PATH + dataset_name + '/'

    first_level_links = basic_crawler_functions.get_all_links(url)

    filtered_first_level_links = basic_crawler_functions.filter_links(first_level_links, "^OD_ZCU")

    absolute_first_level_links = basic_crawler_functions.create_absolute_links(filtered_first_level_links, url)

    files = []

    for link in absolute_first_level_links:

        second_level_links = basic_crawler_functions.get_all_links(link)

        filtered_second_level_links = basic_crawler_functions.filter_links(second_level_links, regex)

        absolute_second_level_links = basic_crawler_functions.create_absolute_links(filtered_second_level_links, link)

        final_links = basic_crawler_functions.remove_downloaded_links(absolute_second_level_links, dataset_name)

        for file_link in final_links:

            files.append(file_link)

    for file in files:

        basic_crawler_functions.download_file_from_url(file, dataset_name)

    folder_processor.unzip_all_csv_zip_files_in_folder(path_for_files)

</pre>