![]() ![]() url ) # Get all the tags a_selectors = response. Spider ): name = 'link_checker' allowed_domains = start_urls = def parse ( self, response ): """ Main function that parses downloaded pages """ # Print what the spider is doing print ( response. Import scrapy class LinkCheckerSpider ( scrapy. Return the link URL with the yield keyword to add it to the download queue: This method returns an iterable of new URLs that will be added to the downloading queue for future crawling and parsing.Įdit your linkChecker/spiders/link_checker.py file to extract all the tags and get the href link text. The Spider parses the downloaded pages with the parse(self,response) method. Test some selectors until you get what you want: more information about Selectors, refer to the Scrapy selector documentation. Run the Scrapy shell on your web page: scrapy shell "" To retrieve the URLs of all images that are inside a link, use: can try your selectors with the interactive Scrapy shell: The response.xpath() method gets tags from a XPath query. To retrieve all links in a btn CSS class: response.css("a.btn::attr(href)") The response.css() method get tags with a CSS selector. Scrapy provides two easy ways for extracting content from HTML: The newly created spider does nothing more than downloads the page We will now create the crawling logic. Start the link_checker Spider: cd ~/scrapy/linkChecker The Spider registers itself in Scrapy with its name that is defined in the name attribute of your Spider class. Scrapy genspider link_checker This will create a file ~/scrapy/linkChecker/linkChecker/spiders/link_checker.py with a base spider.Īll path and commands in the below section are relative to the new scrapy project directory ~/scrapy/linkChecker. ![]() Adjust it to the web site you want to scrape. This guide uses a starting URL for scraping. Go to your new Scrapy project and create a spider. If you restart your session, don’t forget to reactivate scrapyenv.Ĭreate a directory to hold your Scrapy project: mkdir ~/scrapy Note that you don’t need sudo anymore, the library will be installed only in your newly created virtual environment: pip3 install scrapyĪll the following commands are done inside the virtual environment. Install Scrapy in the virtual environment. Your shell prompt will then change to indicate which environment you are using. However, on a Debian 9 it require a few more steps: sudo apt install python3-venvĬreate your virtual environment: python -m venv ~/scrapyenvĪctivate your virtual environment: source ~/scrapyenv/bin/activate On a CentOS system, virtualenv for Python 3 is installed with Python. Scrapy will be installed in a virtualenv environment to prevent any conflicts with system wide library. This is the recommended installation method. Install Scrapy Inside a Virtual Environment Use this method only if your system is dedicated to Scrapy: sudo pip3 install scrapy System-wide installation is the easiest method, but may conflict with other Python scripts that require different library versions. Install Scrapy System-wide Installation (Not recommended) Sudo ln -s /usr/bin/python3 /usr/bin/pythonĬheck you use the proper version with: python -version ![]() Replace the symbolic link /usr/bin/python that link by default to a Python 2 installation to the newly installed Python 3: sudo rm -f /usr/bin/python Sudo yum install python34 python34-pip gcc python34-devel On a CentOS system, install Python, PIP and some dependencies from EPEL repositories: sudo yum install epel-release Install pip, the Python package installer: sudo apt install python3-pip Update-alternatives -install /usr/bin/python python /usr/bin/python3.5 2Ĭheck you are using a Python 3 version: python -version Change it with: update-alternatives -install /usr/bin/python python /usr/bin/python2.7 1 On Debian 9 Systemĭebian 9 is shipped is both Python 3.5 and 2.7, but 2.7 is the default. On most systems, including Debian 9 and CentOS 7, the default Python version is 2.7, and the pip installer need to be installed manually. If you’re not familiar with the sudo command, see the Users and Groups guide. Commands that require elevated privileges are prefixed with sudo. This guide is written for a non-root user.
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