Scrapy Spider for JSON Response - json

Question

I am trying to write a spider which crawls through the following JSON response:
http://gdata.youtube.com/feeds/api/standardfeeds/UK/most_popular?v=2&alt=json
How would the spider look if I would want to crawl all the titles of the videos? All my Spiders dont work.
from scrapy.spider import BaseSpider
import json
from youtube.items import YoutubeItem
class MySpider(BaseSpider):
name = "youtubecrawler"
allowed_domains = ["gdata.youtube.com"]
start_urls = ['http://www.gdata.youtube.com/feeds/api/standardfeeds/DE/most_popular?v=2&alt=json']
def parse(self, response):
items []
jsonresponse = json.loads(response)
for video in jsonresponse["feed"]["entry"]:
item = YoutubeItem()
print jsonresponse
print video["media$group"]["yt$videoid"]["$t"]
print video["media$group"]["media$description"]["$t"]
item ["title"] = video["title"]["$t"]
print video["author"][0]["name"]["$t"]
print video["category"][1]["term"]
items.append(item)
return items
I always get following error:
2014-01-05 16:55:21+0100 [youtubecrawler] ERROR: Spider error processing <GET http://gdata.youtube.com/feeds/api/standardfeeds/DE/most_popular?v=2&alt=json>
Traceback (most recent call last):
File "/usr/local/lib/python2.7/dist-packages/twisted/internet/base.py", line 1201, in mainLoop
self.runUntilCurrent()
File "/usr/local/lib/python2.7/dist-packages/twisted/internet/base.py", line 824, in runUntilCurrent
call.func(*call.args, **call.kw)
File "/usr/local/lib/python2.7/dist-packages/twisted/internet/defer.py", line 382, in callback
self._startRunCallbacks(result)
File "/usr/local/lib/python2.7/dist-packages/twisted/internet/defer.py", line 490, in _startRunCallbacks
self._runCallbacks()
--- <exception caught here> ---
File "/usr/local/lib/python2.7/dist-packages/twisted/internet/defer.py", line 577, in _runCallbacks
current.result = callback(current.result, *args, **kw)
File "/home/bxxxx/svn/ba_txxxxx/scrapy/youtube/spiders/test.py", line 15, in parse
jsonresponse = json.loads(response)
File "/usr/lib/python2.7/json/__init__.py", line 326, in loads
return _default_decoder.decode(s)
File "/usr/lib/python2.7/json/decoder.py", line 365, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
exceptions.TypeError: expected string or buffer

Answer 1

found two issues in your code:
start url is not accessible, I took out the www from it
changed json.loads(response) to json.loads(response.body_as_unicode())
this works well for me:
class MySpider(BaseSpider):
name = "youtubecrawler"
allowed_domains = ["gdata.youtube.com"]
start_urls = ['http://gdata.youtube.com/feeds/api/standardfeeds/DE/most_popular?v=2&alt=json']
def parse(self, response):
items = []
jsonresponse = json.loads(response.body_as_unicode())
for video in jsonresponse["feed"]["entry"]:
item = YoutubeItem()
print video["media$group"]["yt$videoid"]["$t"]
print video["media$group"]["media$description"]["$t"]
item ["title"] = video["title"]["$t"]
print video["author"][0]["name"]["$t"]
print video["category"][1]["term"]
items.append(item)
return items