scrapy: exceptions.AttributeError: 'unicode' object has no attribute 'dont_filter'

Question

In scrapy, I am getting the error exceptions.AttributeError: 'unicode' object has no attribute 'dont_filter'. After searching around, I found this answer (which made sense as it was the only bit of code I modified before getting the error) according to which I modified my code. I changed start_request to yield values in the list instead of retruning it whole but I'm still getting it. Any ideas?

def start_requests(self):
    connection = pymongo.Connection(settings['MONGODB_SERVER'],
                                    settings['MONGODB_PORT'])
    db = connection[settings['MONGODB_DB']]
    collection = db[settings['MONGODB_COLLECTION']]
    for el in [i['url'] for i in collection.find({}, {'_id':0, 'url':1})]:
        yield el

I have checked the other parts of the code to affirm that everything else is fine.

Traceback:

[-] Unhandled Error
    Traceback (most recent call last):
      File "/home/myName/scrapy-test/venv/local/lib/python2.7/site-packages/scrapy/crawler.py", line 93, in start
        self.start_reactor()
      File "/home/myName/scrapy-test/venv/local/lib/python2.7/site-packages/scrapy/crawler.py", line 130, in start_reactor
        reactor.run(installSignalHandlers=False)  # blocking call
      File "/home/myName/scrapy-test/venv/local/lib/python2.7/site-packages/twisted/internet/base.py", line 1192, in run
        self.mainLoop()
      File "/home/myName/scrapy-test/venv/local/lib/python2.7/site-packages/twisted/internet/base.py", line 1201, in mainLoop
        self.runUntilCurrent()
    --- <exception caught here> ---
      File "/home/myName/scrapy-test/venv/local/lib/python2.7/site-packages/twisted/internet/base.py", line 824, in runUntilCurrent
        call.func(*call.args, **call.kw)
      File "/home/myName/scrapy-test/venv/local/lib/python2.7/site-packages/scrapy/utils/reactor.py", line 41, in __call__
        return self._func(*self._a, **self._kw)
      File "/home/myName/scrapy-test/venv/local/lib/python2.7/site-packages/scrapy/core/engine.py", line 120, in _next_request
        self.crawl(request, spider)
      File "/home/myName/scrapy-test/venv/local/lib/python2.7/site-packages/scrapy/core/engine.py", line 176, in crawl
        self.schedule(request, spider)
      File "/home/myName/scrapy-test/venv/local/lib/python2.7/site-packages/scrapy/core/engine.py", line 182, in schedule
        return self.slot.scheduler.enqueue_request(request)
      File "/home/myName/scrapy-test/venv/local/lib/python2.7/site-packages/scrapy/core/scheduler.py", line 48, in enqueue_request
        if not request.dont_filter and self.df.request_seen(request):
    exceptions.AttributeError: 'unicode' object has no attribute 'dont_filter'

Answer 1

start_requests is supposed to yield individual Request objects, not just individual URLs. But each el in your code is apparently a URL. Try changing

yield el

to

yield self.make_requests_from_url(el)

(see the question you link to for an example of this)