Most flies that find their way into our house end up in one particular window, which is the highest and brighest in the house, so it's not surprising that canny spiders tend to set up their snares there too. Some titanic battles take place, where the flies almost always come off worst - I posted one here a while ago. Here's another. The striking aspect of this one was the size difference between predator and prey.
Initially the fly was caught in only a few of the spider's loosely-woven threads and when the spider abseiled down it was a bit circumspect about engaging with the struggling fly, that might still have flown off with the spider attached to it.
Eventually it subdued the fly with enough threads, then spent some time cutting it free of the windowledge, before ....
... dragging it away into the corner of the window...
... and tucking into a meal that will last it quite a while..