Is there a way to slow down the internet connection to the iPhone Simulator, so as to mimic how the App might react when you are in a slow spot on the cellular network?
It also worth mentioning that Xcode also has a built in way for devices, not simulator.
cmmd+shift+2
)To have this working you need to install 'Network Link Conditioner' on your Mac. See steps mention in Alan's answer
There isn't a direct way to emulate a slow connection, unlike, say, the nice network connection emulator that blackberry developers enjoy. However, since your simulator's connection goes through your computer - you can simply focus on slowing down your computer's connection.
You'll want to achieve two things (depending upon your circumstances):
Maybe this will point you in right direction:
http://www.macosxhints.com/article.php?story=20080119112509736
There are some good open source solutions, too, but I so can't remember their names.
This question might help: How to throttle network traffic for environment simulation?
"There's an app for that!" ;) Apple provides "Network Link Conditioner" preference pane that does the job quite well.
Developer
folder, e.g. "/Developer/Applications/Utilities/Network Link Conditioner"
, after installation, if daemon fails to start and you don't want to reboot your machine, just use sudo launchctl load /system/library/launchdaemons/com.apple.networklinkconditioner.plist
Developer
folder, you can install the pane as a part of "Hardware IO Tools for Xcode" package available via Mac Dev Center additional downloads section.Link to download page (you must log in with your Apple ID): https://developer.apple.com/downloads/index.action
(credits to @nverinaud)
These instructions current as of October 2019.
Warning: If you just upgraded to new version of macOS, make sure you install the very latest Network Conditioner (in Additional Tools for Xcode) or it may silently fail; that is, you will turn it on but it won’t throttle anything or drop any packets.
Update: As of Xcode 11, there may be an even simpler way to simulate network conditions on tethered devices; see this blog post. For how to affect simulated devices, continue below, as before.
Install Xcode if you don’t have it.
Open Xcode and go to Xcode › Open Developer Tool › More Developer Tools…
Download Additional Tools for Xcode (matching your current Xcode version)
Open the downloaded disk image and double-click the Network Link Conditioner .prefpane under “Hardware” to install it.
There we go!
Be sure to turn it on. You need to select a profile and enable the network conditioner with the big toggle that should be familiar from the Time Machine prefpane.
This won't affect localhost, so be sure to use a staging server or co-worker's computer to simulate slow network connections to an API you’re running yourself. You may find https://ngrok.com/ helpful in this regard.
I would argue that a slow connection isn't enough to simulate real-work mobile data network behaviour - since there is also much more packet loss, higher latencies and more dropped connections too.
Here is a handy script to configure the firewall to emulate these parameters:
http://pmilosev-notes.blogspot.com/2011/02/ios-simulator-testing-over-different.html
An app called SpeedLimit
https://github.com/mschrag/speedlimit
Works great.
chris.