TweetFollow Us on Twitter

Ship It! Distributing Your Software, Part 2

Volume Number: 20 (2004)
Issue Number: 2
Column Tag: Programming

Mac OS X Programming Secrets

by Scott Knaster

Ship It! Distributing Your Software, Part 2

In our last thrilling installment (or was it a thrilling installation?), we discussed the simplest method of distribution for your Mac OS X software: disk images. We talked about using Disk Copy or Disk Utility to make a disk image, and we described the relatively recent technology of Internet-enabling a disk image so that it cleans up after itself when users download it in Safari.

When you distribute software on a disk image, there is no actual installing taking place. Users simply drag and drop files onto their hard disks. That's the great strength and weakness of disk images: they're easy for you to make and easy for users to figure out, but you can quickly run into their limitations. For example, what if you need to make sure files end up in specific places on the disk? What about checking the progress of the installation and taking some action based on what's happening? Most commercial applications need to do things like this when they're installed. For more control of the installation process, Apple provides the PackageMaker and Installer tools.

Meet Your Maker

PackageMaker is an application that comes with Mac OS X. You use PackageMaker to create packages, which are documents with extension .pkg that contain files to be installed and related files used during the installation. An Apple application called Installer reads the information from a package and performs the installation.

The two biggest tricks PackageMaker installations can do that disk images can't are installing files anywhere in the system, and running scripts while the installation is happening. To install files where you want them, you'll create a directory structure in your package that shows how you want files installed in the system, and includes a few extra items used by the installation itself. In order to run scripts, Installer defines certain events in the installation process and looks for scripts with names corresponding to those events. If the scripts exist, Installer runs them.

Let's take a deeper look at setting up your files and scripts for installation. Please gaze directly into the magazine.

Everything in its right place

You'll make a set of directories and files that indicates where you want everything to end up after the installation. The basic pieces of the directory structure are as follows:

  • You'll create a directory that contains all the other directories and files in the package. This directory can have any name, such as "PackageContents" or "Fred". When you run PackageMaker, you locate this folder.

  • Within the all-enclosing directory, you'll have a directory that holds various files used for installation, such as install-time scripts, the license and readme docs, and so on. Again, this directory can have any name - you specify it in PackageMaker.

  • A second directory inside the outermost directory holds the files to be installed. They're arranged in directories according to the way you want them to be installed. When you run PackageMaker, you specify whether you the files can be installed anywhere or must be placed in absolute locations in the system.

Here's an example. Let's say we're going to install a package that consists of a music application, 3 system sounds, and a screen saver module. Our package directory structure would look like this:

PackageContents
   PackageRoot
      Applications
         Music2MyEars
      System
         Library
            Sounds
               sound1.aiff
               sound2.aiff
               sound3.aiff
            Screen Savers
               ears.saver
   PackageResources
      License.rtf
      ReadMe.rtf
      preflight
      preinstall
      postinstall 
      postflight

The files in the PackageRoot directory are the software itself. We want the files installed in specific locations. When we run PackageMaker to create the package, we can make sure that will happen.

The PackageResources directory is filled with files that will be used during the installation. These include the ReadMe and license documents, along with several scripts (preflight, preinstall, etc.) that Installer will run. In this example, our text files are RTF, but you can also use .txt or .html files.

Staying in Control

When the user runs Installer, usually by double-clicking a .pkg file, these are the steps that take place:

  • Installer looks in the package for an InstallationCheck script and runs it, if it's there. This script provides an opportunity to cancel the installation by returning a nonzero value.

  • If there's a Welcome file (such as Welcome.rtf or Welcome.html), Installer displays it. Otherwise, a default Welcome screen appears. If there's a background image (a file named "background" with extension .tiff, .jpg, .gif, .pdf, or .eps), it's displayed behind the Welcome.

  • If there's a ReadMe file (such as ReadMe.rtf or ReadMe.html), it's displayed next.

  • Next, the License file is displayed.

  • When the user gets to the Select a Destination screen, Installer runs the VolumeCheck script (if it exists) for each mounted volume. VolumeCheck can return a nonzero value to prevent a volume from being eligible for installation.

  • After the user clicks Install, the preflight script is run. Like the other scripts, preflight can cancel the installation by returning a nonzero value.

  • If the user is upgrading the package from a previous version, Installer runs the preupgrade script. Otherwise, preinstall is run.

  • The package contents are copied to the destination. Actual installing, wow!

  • If this was an upgrade, the postupgrade script is run. Otherwise, postinstall is run. There's still time to cancel the installation, which happens if these scripts return nonzero.

Installer runs the postflight script, if it's present.

As you can see from these steps, you have a chance to check the installation with many different scripts: InstallationCheck and VolumeCheck, preflight, preinstall or preupgrade, postinstall or postupgrade, and postflight. You should specify a shell in the first line of your script, using the !#/bin/sh convention. Installer provides a bunch of arguments and environment variables you can use in the scripts. For example, the first argument ($1) is the full path to the installation package, $2 is the path to the destination, and $3 is the mountpoint of the destination volume.

Pack it Up

Once you have written the scripts you want, created the ReadMe and related files, and assembled everything in the right directories with your installation files, it's time to make the package itself. You do this by running PackageMaker, which is located in Developer/Applications/Utilities/. When you run PackageMaker, you see the lovely screen that appears in Figure 1. It's safe to say Jonathan Ive hasn't gotten hold of this one yet.


Figure 1. This is the screen that appears when you launch PackageMaker. It's not very pretty, but it works just fine.

To start assembling your package, fill out the fields on the Description tab. The Title and Description fields provide a place for information that's visible to users when the Installer is running. Click the Files tab to specify the source location of the files to be installed. In our example above, this is the PackageRoot directory. Just to be macho, note that the field for the directory is editable text, so if you're really geeky and you hate clicking through a file dialog, you can actually type the directory path yourself.

Next, use the Resources tab to specify where the scripts, ReadMe, and similar files are located. In our earlier example, this was the PackageResources directory.

The Info tab provides a few interesting options. For example, you can choose whether to recommend or require a restart here. Restarting is mean and should be avoided whenever possible. (In Panther, you can also specify that logout is required, but you can't do it here: you have to modify the Info.plist to do so. To make this happen, add an "IFPkgFlagRestartAction" key with a value of "RequiredLogout" to the package's Info.plist.) If your software doesn't have to be installed in a particular location, check the Relocatable box and users will get to pick where your software should go. The last tab, Version, lets you specify info that appears in the Finder.

When you have your package just the way you want, you should save in PackageMaker, then choose File * Create Package to make the package. When you double-click the package, Installer will launch and you'll get the exciting display you see in Figure 2.


Figure 2. The Installer opening screen can display custom text and background image.

There are a few more Installer features that aren't available in PackageMaker. Instead, you have to edit the package's Info.plist file to get them. For example, when you include a background image in your package, Installer stretches it out to fill the entire window, which is ugly if the image has the wrong proportions. You can gain more control over how the image is used by editing the Info.plist file with Property List Editor.

In the package shown in Figure 2, the Info.plist file has two new keys added to it: IFPkgFlagBackgroundScaling and IFPkgFlagBackgroundAlignment, to make sure that that bee and that guy don't take over the screen. The first key, which controls how the image is scaled, is set to "none". You can also use "tofit" (the default) and "proportional". The second key, for alignment, is set to "bottomleft". Other valid alignments are "left", "right", "top", "bottom", "center" (the default), "topleft", "topright", and "bottomright".

PackageMaker has a few more tricks, such as the ability to create metapackages, which are packages that contain and install other packages. Metapackages can present and sort through complex sets of dependencies for installing software. Another cool feature is the ability to install packages across a network, which you can do if you have Apple Remote Desktop.

Installermania

PackageMaker isn't the last word in installers. Lots of commercial software requires more control than you can get from PackageMaker and Installer. The best-known non-Apple installer packages are made by MindVision Software (InstallerVise, ViseX, and FileStorm), and Aladdin (StuffIt InstallerMaker). These applications let you do things that are beyond PackageMaker, such as creating installs that work on OS 9 or Windows, displaying multiple "tips" screens during install, and automatically adding items to the OS X dock. These products compete with free software from Apple, so they have to be feature-packed.

You can find out more, or even download whole manuals and applications, by visiting the web sites at www.mindvision.com and www.stuffit.com/mac/installermaker/. MindVision downloads are fully functional, with limits on the installers you build until you buy a registration key. The InstallerMaker download is fully functional, but produces installers that say you're using an unregistered copy.

Speaking of free stuff, Apple provides a pile of fine documentation on packages, PackageMaker, and related topics. For much more detail on the stuff we talked about in this article, check out the following URL:

http://developer.apple.com/documentation/DeveloperTools/Conceptual/SoftwareDistribution.

Have fun getting your installer together. Remember, no matter how hard you work on your application, nobody will be able to use it unless you produce an installer, disk image, or other trick to get it out into the world.


Scott Knaster has been playing with Apple computers, and occasionally working with them, since 1977. Wow, that's a long time! Scott has written books and articles for normal human beings as well as programmers. Photo of Scott and his friend Jollibee courtesy of John Vink Photography.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Latest Forum Discussions

See All

Can PokeMatch help you find love with Po...
The unofficial Pokemon GO companion app space has exploded almost as fast as the game itself over the last few weeks. Aspiring app developers, many of them working solo, have given us apps that locate Pokemon, keep track of the server status, and... | Read more »
How to get started with Prisma
If there's one thing people like to do more than taking pictures with their smartphones, it's tinkering with those photos in some way. Numerous apps have sprung up over the last several years that allow you to use filters and special effects to... | Read more »
6 Pokemon GO updates you can expect, acc...
Pokemon GO had a scheduled appearance at this year's San Diego Comic-Con for a while, but it was only relatively close to the show that it was upgraded to a spot in Hall H. That's the biggest venue at SDCC, one usually reserved for the largest... | Read more »
How to evolve Eevee in Pokemon GO
By now, almost everyone should be hip to how to evolve Pokemon in Pokemon GO (and if not, there's a guide for that). Just gather enough candy of the appropriate type, feed them all to the Pokemon, and evolution happens. It's a miracle that would... | Read more »
CSR Racing 2: Guide to all game modes
It might not seem like there are all that many ways to go fast in a straight line, but CSR Racing 2 begs to differ. [Read more] | Read more »
Bulb Boy (Games)
Bulb Boy 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Multi-award winning 2D point & click horror adventure about a boy with a glowing head. | Read more »
5 top free emoji keyboard apps
If we're not at peak emoji yet as a society, it feels like we definitely should be. The emoji concept has gone far beyond what anyone in Japan could have envisioned when the people there unleashed it on an unsuspecting world, but the West has... | Read more »
How to unlock more characters in Disney...
One of the big charms of Disney Emoji Blitz is seeing a wide variety of beloved Disney and Pixar characters transformed into smiling emojis. Even someone like the sneaky Randall from Monsters Inc., who probably never cracked a smile on film, is... | Read more »
Cubway (Games)
Cubway 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: Cubway is a journey with an abstract story of lifecycle of rebirth, called Samsara. Guide the cube through the long way full of dangers... | Read more »
Colorcube (Games)
Colorcube 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: Turn pieces and blend colours in this minimal yet visually stunning puzzler.Over 200 handcrafted and challenging levels. Features... | Read more »

Price Scanner via MacPrices.net

GSK Rheumatoid Arthritis Study Leverages iPho...
Global healthcare products company GlaxoSmithKline (GSK) says that since 2014 they have begun transforming the way they conduct research, by leveraging state-of-the-art digital technologies — a... Read more
Clearance 12-inch Retina MacBooks, Apple refu...
Apple has Certified Refurbished 2015 12″ Retina MacBooks available starting at $929. Apple will include a standard one-year warranty with each MacBook, and shipping is free. The following... Read more
13-inch Retina MacBook Pros on sale for up to...
B&H Photo has 13″ Retina MacBook Pros on sale for up to $150 off MSRP. Shipping is free, and B&H charges NY tax only: - 13″ 2.7GHz/128GB Retina MacBook Pro: $1199 $100 off MSRP - 13″ 2.7GHz/... Read more
13-inch 1.6GHz/128GB MacBook Air on sale for...
Amazon has the 13″ 1.6GHz/128GB MacBook Air on sale for $200 off MSRP for a limited time. Shipping is free: - 13″ 1.6GHz/128GB MacBook Air (sku MMGF2LL/A): $799.99 $200 off MSRP Their price is the... Read more
13-inch 1.6GHz/256GB MacBook Air on sale for...
Amazon has the 13″ 1.6GHz/256GB MacBook Air on sale for $200 off MSRP for a limited time. Shipping is free: - 13″ 1.6GHz/256GB MacBook Air (sku MMGG2LL/A): $999.99 $200 off MSRP Their price is the... Read more
Free iOS Business App notably* Helps Service...
PayStudio Inc. has introduced their new business app notably* 1.0, developed for iPhone and iPod touch. notably* was specifically developed to help service and trade professionals go digital and... Read more
27-inch iMacs on sale for $200 off MSRP
Amazon has 27″ iMacs on sale for $200 off MSRP including free shipping: - 27″ 3.3GHz iMac 5K: $2099 $200 off MSRP - 27″ 3.2GHz/1TB Fusion iMac 5K: $1799.99 $200 off MSRP - 27″ 3.2GHz/1TB HD iMac 5K... Read more
Mac Pros on sale for $200 off MSRP
B&H Photo has Mac Pros on sale for $200 off MSRP. Shipping is free, and B&H charges sales tax in NY only: - 3.7GHz 4-core Mac Pro: $2799, $200 off MSRP - 3.5GHz 6-core Mac Pro: $3799, $200... Read more
Save up to $600 with Apple refurbished Mac Pr...
Apple has Certified Refurbished Mac Pros available for up to $600 off the cost of new models. An Apple one-year warranty is included with each Mac Pro, and shipping is free. The following... Read more
Apple price trackers, updated continuously
Scan our Apple Price Trackers for the latest information on sales, bundles, and availability on systems from Apple’s authorized internet/catalog resellers. We update the trackers continuously: - 15″... Read more

Jobs Board

*Apple* Retail - Multiple Positions, Willow...
Job Description:SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Evangelist - JAMF Software (United S...
The Apple Evangelist is responsible for building and cultivating strategic relationships with Apple 's small and mid-market business development field teams. This Read more
*Apple* Solutions Consultant - APPLE (United...
Job Summary As an Apple Solutions Consultant, you'll be the link between our future customers and our products. You'll showcase your entrepreneurial spirit as you Read more
*Apple* Professional Learning Specialist - A...
Job Summary The Apple Professional Learning Specialist is a full-time position for one year with Apple in the Phoenix, AZ area. This position requires a high Read more
*Apple* Picker - Apple Hill Orchard (United...
Apple Hill Orchard, Co. Rte. 21,Whitehall, NY 9/7/16-10/228/16. Pick fresh market or processing apples Productivity of 60 boxes and 80 boxes processing fruit per Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.