This works great for keeping spam off your devices -- off your local network at any rate. Not possible to modify iOS hosts file without jailbreaking it.
On an iPhone without jailbreak you can use 1blocker[1]. Since every browser on the iPhone is basically a UIWebView/SFSafariViewController controlled by iOS, Safari Content Blockers[2] apply globally preventing web visits. Safari Content Blockers also prevent Messages from rendering Facebook content inline.
My 1blocker rule called "Bye Facebook" is:
https?://([a-z\.]*)?facebook\.com.*
I should probably update it to factor in a lot of these other TLD URLs now that I think about it.
> Since every browser on the iPhone is basically a UIWebView/SFSafariViewController controlled by iOS
Most browsers rely on WKWebView, which uses the Safari Nitro JavaScript engine but allows customization of the user interface as well. UIWebView is pretty much legacy at this point, and SFSafariViewController does not allow any customization beyond basic theming.
> Safari Content Blockers apply globally preventing web visits
Unfortunately, this is not true. They only work in Safari and Safari view controllers.
> Safari Content Blockers also prevent Messages from rendering Facebook content inline
Are you sure about this? As far as I know, Messages uses a web view.
Actually I just double checked and I was incorrect. I just remembered that I have another app on my phone called AdBlock[1] which is responsible for blocking requests at the network layer. They run their own DNS server and create a custom list to black hole network requests that match certain formats. If you add Facebook as a custom rule to AdBlock, that will prevent Messages from pre-rendering content and also block any messages to facebook from any service on your phone as long as you're connected to their VPN.
Sorry about the confusion... I'm really doing a lot to keep myself off of Facebooks radar.
I do not believe this is true. In messages the previews need an approval the first time some domain should load a preview and then this setting is stored. AFAIK there is no way to recall the permission though.
