Rumah > Soal Jawab > teks badan
仔细看了下scrapy的官方文档关于ImagesPipeline的介绍说明及使用例子：Downloading Item Images
感觉官方文档太过简单。
比如：通过在setting.py文件中通过给IMAGES_STORE赋值，就可以指定图片的保存路径。
并且默认情况下，文件名是通过对url使用SHA1 hash得来的。
现在我想以原来的图片名进行保存，不知道该如何做，希望有经验的朋友帮忙指点下~
另外求大家帮忙推荐下关于scrapy的相关书籍（中英文都行）
ringa_lee2017-04-17 12:04:50
查看下ImagePipeline的源码，发现可以重写file_path函数以修改图片名称，例如：
def file_path(self, request, response=None, info=None):
open("image_urls.txt","a").write(request.url + "\n")
image_guid = request.url.split('/')[-1]
return 'full/%s' % (image_guid)
ImagePipeline的源码如下：
class ImagesPipeline(FilesPipeline):
"""Abstract pipeline that implement the image thumbnail generation logic
"""
MEDIA_NAME = 'image'
MIN_WIDTH = 0
MIN_HEIGHT = 0
THUMBS = {}
DEFAULT_IMAGES_URLS_FIELD = 'image_urls'
DEFAULT_IMAGES_RESULT_FIELD = 'images'
@classmethod
def from_settings(cls, settings):
cls.MIN_WIDTH = settings.getint('IMAGES_MIN_WIDTH', 0)
cls.MIN_HEIGHT = settings.getint('IMAGES_MIN_HEIGHT', 0)
cls.EXPIRES = settings.getint('IMAGES_EXPIRES', 90)
cls.THUMBS = settings.get('IMAGES_THUMBS', {})
s3store = cls.STORE_SCHEMES['s3']
s3store.AWS_ACCESS_KEY_ID = settings['AWS_ACCESS_KEY_ID']
s3store.AWS_SECRET_ACCESS_KEY = settings['AWS_SECRET_ACCESS_KEY']
cls.IMAGES_URLS_FIELD = settings.get('IMAGES_URLS_FIELD', cls.DEFAULT_IMAGES_URLS_FIELD)
cls.IMAGES_RESULT_FIELD = settings.get('IMAGES_RESULT_FIELD', cls.DEFAULT_IMAGES_RESULT_FIELD)
store_uri = settings['IMAGES_STORE']
return cls(store_uri)
def file_downloaded(self, response, request, info):
return self.image_downloaded(response, request, info)
def image_downloaded(self, response, request, info):
checksum = None
for path, image, buf in self.get_images(response, request, info):
if checksum is None:
buf.seek(0)
checksum = md5sum(buf)
width, height = image.size
self.store.persist_file(
path, buf, info,
meta={'width': width, 'height': height},
headers={'Content-Type': 'image/jpeg'})
return checksum
def get_images(self, response, request, info):
path = self.file_path(request, response=response, info=info)
orig_image = Image.open(StringIO(response.body))
width, height = orig_image.size
if width < self.MIN_WIDTH or height < self.MIN_HEIGHT:
raise ImageException("Image too small (%dx%d < %dx%d)" %
(width, height, self.MIN_WIDTH, self.MIN_HEIGHT))
image, buf = self.convert_image(orig_image)
yield path, image, buf
for thumb_id, size in self.THUMBS.iteritems():
thumb_path = self.thumb_path(request, thumb_id, response=response, info=info)
thumb_image, thumb_buf = self.convert_image(image, size)
yield thumb_path, thumb_image, thumb_buf
def convert_image(self, image, size=None):
if image.format == 'PNG' and image.mode == 'RGBA':
background = Image.new('RGBA', image.size, (255, 255, 255))
background.paste(image, image)
image = background.convert('RGB')
elif image.mode != 'RGB':
image = image.convert('RGB')
if size:
image = image.copy()
image.thumbnail(size, Image.ANTIALIAS)
buf = StringIO()
image.save(buf, 'JPEG')
return image, buf
def get_media_requests(self, item, info):
return [Request(x) for x in item.get(self.IMAGES_URLS_FIELD, [])]
def item_completed(self, results, item, info):
if self.IMAGES_RESULT_FIELD in item.fields:
item[self.IMAGES_RESULT_FIELD] = [x for ok, x in results if ok]
return item
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(url).hexdigest() # change to request.url after deprecation
return 'full/%s.jpg' % (image_guid)
def thumb_path(self, request, thumb_id, 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.thumb_key(url) method is deprecated, please use '
'thumb_path(request, thumb_id, response=None, info=None) instead',
category=ScrapyDeprecationWarning, stacklevel=1)
# check if called from thumb_key with url as first argument
if not isinstance(request, Request):
_warn()
url = request
else:
url = request.url
# detect if thumb_key() method has been overridden
if not hasattr(self.thumb_key, '_base'):
_warn()
return self.thumb_key(url, thumb_id)
## end of deprecation warning block
thumb_guid = hashlib.sha1(url).hexdigest() # change to request.url after deprecation
return 'thumbs/%s/%s.jpg' % (thumb_id, thumb_guid)
# deprecated
def file_key(self, url):
return self.image_key(url)
file_key._base = True
# deprecated
def image_key(self, url):
return self.file_path(url)
image_key._base = True
# deprecated
def thumb_key(self, url, thumb_id):
return self.thumb_path(url, thumb_id)
thumb_key._base = True
PHPz2017-04-17 12:04:50
现在我想以原来的图片名进行保存
貌似这个没有直接的参数可以传，需要自己实现Images Pipeline
scrapy.contrib.pipeline.images.ImagesPipeline类的get_media_requests(item, info)会下载图片，并把结果喂给item_completed()方法，结果是一个tuple，(success, image_info_or_failure)，其中success是下载是否成功的bool，image_info_or_failure包括url、path和checksum三项。其中，path就是相对于IMAGES_STORE的路径（含文件名）。
[(True,
{'checksum': '2b00042f7481c7b056c4b410d28f33cf',
'path': 'full/7d97e98f8af710c7e7fe703abc8f639e0ee507c4.jpg',
'url': 'http://www.example.com/images/product1.jpg'}),
(True,
{'checksum': 'b9628c4ab9b595f72f280b90c4fd093d',
'path': 'full/1ca5879492b8fd606df1964ea3c1e2f4520f076f.jpg',
'url': 'http://www.example.com/images/product2.jpg'}),
(False,
Failure(...))]
上面是官网上的例子。
所以你需要做的是改写item_completed(results, items, info)方法，用原本的文件名替换掉item['image_paths']。
PHP中文网2017-04-17 12:04:50
修改file_path对原代码侵入太大，如果只是为了修改文件路径的话，可以在item_completed对文件进行重命名。
class NeteaseautoImagePipeline(ImagesPipeline):
def get_media_requests(self, item, info):
for image_url in item['image_urls']:
yield scrapy.Request(image_url.replace('120x90', '800x600'))
def item_completed(self, results, item, info):
image_paths = [x['path'] for ok, x in results if ok]
if not image_paths:
raise DropItem("Item contains no images")
if item['jk']:
newname = item['car'] + '-' + item['jk'] + '-' + item['model'] + '.jpg'
else:
newname = item['car'] + '-' + item['model'] + '.jpg'
os.rename("/neteaseauto/" + image_paths[0], "/neteaseauto/" + newname)
return item