Copyright (c) John Holdsworth 2012
Injection is a plugin for Xcode that allows you to "inject" Objective-C code changes into a running application without having to restart it during development and testing. After making a couple of minor changes to your application's "main.m" and pre-compilation header it will connect to a server running inside Xcode during testing to receive commands to load bundles containing the code changes.
Stop Press: Injection has been refactored and no longer has to convert your classes into categories in order for it to work so no changes are made to your class source. It works for OS X and iOS projects in the simulator and on the device (if you add an extra "run script" build phase as instructed.)
A quick demonstration video/tutorial of Injection in action is available here:
Announcements of major commits to the repo will be made on twitter @Injection4Xcode.
To use Injection, open the InjectionPluginLite project, build it and restart Xcode. Alternatively you can download a small installer app "Injection Plugin.app" from http://injectionforxcode.com (this will also install the AppCode plugin when you "File/Install Plugin") This should add a submenu and an "Inject Source" item to Xcode's "Product" menu. If at first it doesn't appear, try restarting Xcode again.
Open a simple example project such as UICatalog or GLEssentials from Apple and use the "Product/Injection Plugin/Patch Project for Injection" menu item to prepare the project and rebuild it (Be sure to #define DEBUG.) When you run the project it should connect to Xcode which will display a red badge on it's dock icon showing the application is prepared to load patch bundles. Select text in a class source file and use menu item "Product/Inject Source" to inject any changes you may have made into the app.
On OS X remember to have your entitlements include "Allow outgoing connections".
JetBrains AppCode IDE Support
The InjectionPluginAppCode project provides basic support for code injection in the AppCode IDE. To use, install the file Injection.jar into directory "~/Library/Application Support/appCode10". The new menu options should appear at the end of the "Run" menu when you restart AppCode. For it to work you must also have the most recent version of the Xcode plugin installed as they share some of the same scripts.
For some reason there is a very long delay when the client first connects to the plugin. This seems to be Java specific. If anyone has any ideas how to fix this, get in touch!
All the code to perform injection direct to a device is included but this is always a "challenge" to get going. It requires an extra build phase to run a script and the client app has to find it's way over Wi-Fi to connect back to the plugin. Start small by injecting to the simulator then injecting to a device using the Xcode plugin. Then try injecting to the device from AppCode. Don't forget to re-patch the project for injection in AppCode as it uses a different port than the Xcode plugin.
Injection will now inject UIViewController layouts in a storyboarded application. To do this you need to select the "Inject Storybds" option in the Tunable Parameters and add the following as a "Build Phase" of type "Run Script" to your project (quotes included.)
When you next run the application, if you edit the storyboard and build the project, layout changes will be injected onto the UIViewControllers currently visible while the application is still running. This is achieved by reloading their "nib" onto the existing view controller and sending -viewDidLoad, -viewWillAppear:YES and -viewDidAppear:YES to the view controller for it to redraw. This only works for applications with a single active Storyboard. See class method +reloadNibs in the file "BundleInjection.h".
This source code is provided on github on the understanding it will not be redistributed. License is granted to use this software during development for any purpose indefinitely (it should never be included in a released application!) After two weeks you will be prompted to register and have the opportunity to make a donation $10 (or $25 in a commercial environment) as suggested by code included in the software.
If you find (m)any issues in the code, get in contact using the email: support (at) injectionforxcode.com
How it works
A project patched for injection #imports the file "BundleInjection.h" from the resources of the plugin into it's "main.m" source file. Code in this header uses a +load method to connect back through a socket to a server running inside Xcode and waits in a thread for commands to load bundles.
When you inject a source, it is #imported into "BundleContents.m" in a bundle project which is then built and the application messaged by Xcode through the socket connection to load the bundle. When the bundle loads, it too has a +load method which calls the method [BundleInjection loadClass:theNewClass notify:flags]. This method aligns the instance variables of the newly loaded class to the original (as @properties can be reordered) and then swizzles the new implementations onto the original class.
Support for injecting projects using "CocoaPods" and "workspaces" has been added since version 2.7. Classes in the project or Pods can be injected as well as categories or extensions. The only limitation is that the class being injected must not itself have a +load method. Other options are on the "Project..Tunable Parameters" page such as the "Silent" option for turning off the message dialogue each time classes are injected.
The projects in the source tree are related as follows:
InjectionPluginLite is a standalone, complete rewrite of the Injection plugin removing dead code from the long and winding road injection has taken to get to this point. This is now the only project you need to build. After building, restart Xcode and check for the new items at the end of the "Product" menu.
InjectionPluginAppCode Java plugin for JetBrains AppCode IDE support.
I've removed the InjectionInstallerIII project as it needs you to have built the plugin anyway which will have already put it in the right place to load when you restart Xcode.
Responsible for coordinating the injection menu and running up TCP server process on port 31442 receiving connections from applications with their main.m patched for injection. When an incoming connection arrives it sets the current connection on the associated "client" controller instance.
A (currently) singleton instance to shadow a client connection from an application. It runs unix scripts to prepare the project and bundles used as part of injection and monitors for successful loading of the bundle.
Patches all main.m and ".pch" files to include headers for use with injection.
The script called when you inject a source file to create/build the injection bundle project and signal the client application to load the resulting bundle to apply the code changes.
Opens the Xcode project used by injection to build a loadable bundle to track down build problems.
Un-patches main.m and the project's .pch file when you have finished using injection.
Code shared across the above scripts including the code that patches classes into categories.
Script output line-prefix conventions from -[INPluginClientController monitorScript]:
> open local file for write
< read from local file (and send to local file or to application)
!> open file on device/simulator for write
!< open file on device/simulator for read (can be directory)
!/ load bundle at remote path into client application
? display alert to user with message
Otherwise the line is appended as rich text to the console NSTextView.
Command line arguments to all scripts (in order)
$resources Path to "Resources" directory of plugin for headers etc.
$workspace Path to Xcode workspace document currently open.
$mainFile Path to main.m of application currently connected.
$executable Path to application binary connected to plugin for this project
$patchNumber Incrementing counter for sequentially naming bundles
$flags As defined below...
$unlockCommand Command to be used to make files writable from "app parameters" panel
$addresses IP addresses injection server is running on for connecting from device.
$selectedFile Last source file selected in Xcode editor
Bitfields of $flags argument passed to scripts
1<<2 Display UIAlert on load of changes (disabled with the "Silent" tunable parameter)
1<<3 Activate application/simulator on load.
1<<4 Plugin is running in AppCode.
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