Creating a web scraper out of nowhere Part.2

Rebeca Sarai · September 2, 2017

Originally published on medium

Please write the part 2. Please write the
part 2.

Attending the many requests I receive this week (wrong, it was only one), I brought the second part of creating a web scraper out of nowhere. If you don’t read the first part, you check here.

As I say in part 1, the job was to retrieve data from a website. One big part of this data where images, totalizing almost 600 items, each image was on your own page and should be downloaded with the name of the page.

For this, we use Scrapy a Python library. With scrapy, you can easily download images from websites with the ImagesPipeline.

Download Pillow

Pillow is imaging library that scrapy uses it for thumbnailing and normalizing images to JPEG/RGB format.

pip install Pillow

Enable ImagesPipeline.

In your include:

ITEM_PIPELINES = {'scrapy.pipelines.images.ImagesPipeline': 1}

and configure the target storage setting to a valid value that will be used for storing the downloaded images. Otherwise the pipeline will remain disabled, even if you include it in the ITEM_PIPELINES setting.

IMAGES_STORE = '/path/to/valid/dir'

Create a item

In your main directory, if not exists create a file

class ProductsItem(scrapy.Item):
    image_urls = scrapy.Field()
    images = scrapy.Field()
    #other fields...

Scrape an item and add URLs.

In your Spider, scrape an item and put the URLs of the desired into a image_urls field (must be a list).

The item is returned from the spider and goes to the ImagePipeline. The URLs in the image_urls field are scheduled for download using the standard Scrapy scheduler and downloader (which means the scheduler and downloader middlewares are reused), but with a higher priority, processing them before other pages are scraped. The item remains “locked” at that particular pipeline stage until the files have finish downloading (or fail for some reason).

Create custom filenames

The files are stored using a SHA1 hash of their URLs for the file names. e.g.:

  • For this URL:
  • The filename would be: 3afec3b4765f8f0a07b78f98c07b83f013567a0a

As cool as I think that SHA1 hash is, this nomenclature couldn’t be used in a real system.

For overriding the images name you have create a new Pipeline and extend the ImagesPipeline.

To finish don’t forget to update the ITEM_PIPELINES to use the new file that we just write.

ITEM_PIPELINES = {'scrapy.pipelines.images.ScrapymercadoPipeline': 1}

And that’s all. See you soon and buy bitcoin!

Did I make a mistake? Please consider sending a pull request.