scrapy custom name to download pictures

Recent data has to be fetched crawling with reptiles picture, a picture began to use the default pipeline, that is configured in settings.py

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

. But the picture name but can not be customized, find ImagesPipeline, find the default name of the picture code

def file_path(self, request, response=None, info=None):
    ## start of deprecation warning block (can be removed in the future)
    def _warn():
        from scrapy.exceptions import ScrapyDeprecationWarning
        import warnings
        warnings.warn('ImagesPipeline.image_key(url) and file_key(url) methods are deprecated, '
                      'please use file_path(request, response=None, info=None) instead',
                      category=ScrapyDeprecationWarning, stacklevel=1)

    # check if called from image_key or file_key with url as first argument
    if not isinstance(request, Request):
        _warn()
        url = request
    else:
        url = request.url

    # detect if file_key() or image_key() methods have been overridden
    if not hasattr(self.file_key, '_base'):
        _warn()
        return self.file_key(url)
    elif not hasattr(self.image_key, '_base'):
        _warn()
        return self.image_key(url)
    ## end of deprecation warning block

    image_guid = hashlib.sha1(to_bytes(url)).hexdigest()  # change to request.url after deprecation
    return 'full/%s.jpg' % (image_guid)

That is hashlib.sha1(to_bytes(url)).hexdigest(), the urlhash value. As the picture needs associated with some of the information, so there are three kinds of solutions.

• 1, recorded directly hash picture url in the message
• 2, custom ImagesPipeline, in scrapy picture pass in the name of custom.
• 3, custom ImagesPipeline, generate their own images in the name ImagesPipeline

Leaving aside scheme 1, scheme 3 can refer to this program two individuals feel more scalability. Which may be similar to the address for storing image IMAGES_URLS_FIELDprocessing method, a configuration in the settings IMAGES_NAME_FIELD, and then reads the items in the pipeline as the picture corresponding to the field name, so that the control picture name scrapy.
Specific code as follows:

• 1, scrapy add name attribute ImagenetItem

item = ImagenetItem()
url = imgs[i]
item['src'] = [url]
item['name'] = url[-35: -3]

• 2, the definition picture item in items.py in.

class ImagenetItem(scrapy.Item):
    # define the fields for your item here like:
    # name = scrapy.Field()
    src = scrapy.Field()
    name = scrapy.Field()
    pass

• 3, the definition of a pipeline inherit crapy.pipelines.images.ImagesPipeline in pipeline.py

class PicPipeline(ImagesPipeline):
    IMAGES_NAME_FIELD = ''

    def __init__(self, store_uri, download_func=None, settings=None):
        super(ImagesPipeline, self).__init__(store_uri, settings=settings,
                                             download_func=download_func)

        if isinstance(settings, dict) or settings is None:
            settings = Settings(settings)

        resolve = functools.partial(self._key_for_pipe,
                                    base_class_name="PicPipeline",
                                    settings=settings)
        self.expires = settings.getint(
            resolve("IMAGES_EXPIRES"), self.EXPIRES
        )

        if not hasattr(self, "IMAGES_RESULT_FIELD"):
            self.IMAGES_RESULT_FIELD = self.DEFAULT_IMAGES_RESULT_FIELD
        if not hasattr(self, "IMAGES_URLS_FIELD"):
            self.IMAGES_URLS_FIELD = self.DEFAULT_IMAGES_URLS_FIELD

        self.images_urls_field = settings.get(
            resolve('IMAGES_URLS_FIELD'),
            self.IMAGES_URLS_FIELD
        )
        self.images_result_field = settings.get(
            resolve('IMAGES_RESULT_FIELD'),
            self.IMAGES_RESULT_FIELD
        )
        self.min_width = settings.getint(
            resolve('IMAGES_MIN_WIDTH'), self.MIN_WIDTH
        )
        self.min_height = settings.getint(
            resolve('IMAGES_MIN_HEIGHT'), self.MIN_HEIGHT
        )
        self.thumbs = settings.get(
            resolve('IMAGES_THUMBS'), self.THUMBS
        )
        self.images_name_field = settings.get(
            resolve('IMAGES_NAME_FIELD'),
            self.IMAGES_NAME_FIELD
        )

    def get_media_requests(self, item, info):
        return [Request(x, meta={'file_name': item.get(self.images_name_field, '')}) for x in item.get(self.images_urls_field, [])]

    def file_path(self, request, response=None, info=None):
        ## start of deprecation warning block (can be removed in the future)
        def _warn():
            from scrapy.exceptions import ScrapyDeprecationWarning
            import warnings
            warnings.warn('ImagesPipeline.image_key(url) and file_key(url) methods are deprecated, '
                          'please use file_path(request, response=None, info=None) instead',
                          category=ScrapyDeprecationWarning, stacklevel=1)

        # check if called from image_key or file_key with url as first argument
        if not isinstance(request, Request):
            _warn()
            url = request
        else:
            url = request.url

        image_guid = request.meta['file_name']  # change to request.url after deprecation
        return 'full/%s.jpg' % (image_guid)

Substantially in the original code changes, focus images_name_field defined field, the initial value init in the name get_media_requests method will spread the meta attribute request, and then to get the value in file_path process.

• 4, configure the pipeline we have just defined in settings.py.

ITEM_PIPELINES = {
   'tutorial.pipelines.PicPipeline': 1,
}

IMAGES_STORE = 'imagesDownload'
IMAGES_URLS_FIELD = 'src'#定义url字段
IMAGES_NAME_FIELD = 'name'#定义图片名字字段与item对应

This will expand IMAGES_NAME_FIELD field as the name of the picture.