At my current job, we have several external systems that interact with Salesforce, and they do so through web-services. This document will cover what I have learned in regards to web-services, caveats with them and common pitfalls.

Overview

The goal of our web-services is to provide a single point of entry for each major object represented in Salesforce.  A major object would be Account, Case, Case Comment etc.  The reason this is differentiated is that for instance, Case Groups would under the AccountAPI since they are a minor object.  Each web-service consists of two parts.  First the actual web-service class which holds the exterally facing methods and from which the WSDL is generated.  The second part is that of the util class which holds all of the logic and is reusable.

Web-service class

APIUtils

This class contains several static variables, exceptions and most importantly the classes that are returned from the web-service

Static Variables

The static variables listed here are used to set the returnCode in the resulting return class.  This helps to keep return codes consistent with what is expected by the calling app

Exceptions

There are two types of base exceptions in APIUtils

InvalidException

This is used for things that are passed into the web-service that are considered invalid.  For example an invalid username passed in, or if the account does not match the requesting contact.

UnknownException

This is used when the requested object cannot be found.  For example if the case 123456 was requested and was not found then this would be aUnknownCaseException

Generic Contexts

For most web-services, they will contain their own Context classes.  But there are some context classes that are common and reusable.  The primary one being the ContactContext.  The ContactContext is often passed into the method to determine access level.

Returned Classes

These are abstraction classes usually representative of a Salesforce object.

• Each field to be returned must be of type WebService
• Each class should have Integer returnCode and String message to be passed back to the caller.
• If the method is to return a List<Object> a wrapper class of APIObjects should contain returnCode, message and a List of Objects.  [Example below]
• Each class should have a constructor to aid in creation.  This will save time in the long run and will make writing tests 1000 times easier

Note: You could probably throw exceptions out to the calling service instead of setting a returnCode.  I think that setting the returnCode instead of throwing an exception makes it easier for integration since the integrator does not need to know the exceptions.

ObjectAPI

This class should be written primarily as a wrapper class for the Object’s util class

Specific Contexts

If contexts are needed and they will only be used by this API, then they should be included directly in the API file

• Each field must be of type WebService
• Each class should have a constructor to aid in creation
• Do not assume that variables in contexts will be set

Methods

Each method should be disparate function of work and contain minimal logic.  These methods should call the required Util methods, transform data, catch exceptions and set returnCode/messages

• Method must be of type WebService
• Method must be static
• Method should return an APIObject
• Method should set the returnCode and the message of the APIObject
• All calls should be in a try-catch block so that no exceptions are leaked

ObjectUtils

This class should have the majority of the logic.  The methods in this class should follow the idea of Samurai Programming.  Samurai Programming means the method should “return successful or not at all.”  This means instead of returning null if an error happens (if the method should return something ie getCase) then the method should throw an exception.

• Most methods will be static
• Methods should throw an exception if the parameters are set incorrectly
• SOQL queries that are single lines should have their exceptions caught, reported then throw the appropriate exception.  For example if we are selecting a single Case using Case c = [ select ... ] then we should catch the exception in case the query fails, and then thrown an UnknownCaseException.

Caveats

• Declaring a class as virtual and then implementing that class to try to have global variables that all classes get do not work.  The fields will not show up in the generated WSDL

What are supplemental wallpapers?

In addition to the standard wallpaper that the design team is working hard to design and finalize, we want to include some addition wallpapers for people to choose from.  We will still ship with the default GNOME upstream supplemental wallpapers but, we want to include some more from our community.

What we need

In order to us the image for the supplemental wallpapers we need some basic information

• URL of the image (ie. “where it’s at”)
• Title of the work in question
• Name of the author (their real name is preferable, but a nickname with a link to the profile on the page the image is from works as well)
• Contact information for the author, email if possible
• URL of the source page that the image was originally from
• The license of the photo (has to be compatible with the Fedora requirements)

In addition to this, what the image is of is important (see the wiki for the full requirements)

• Must not contain brand names or trademarks of any kind
• Must not contain material that is inappropriate, offensive, indecent, obscene, hateful, tortuous, defamatory, slanderous or libelous
• No religious, political, or nationalist imagery (including flags)
• No images of hats, particularly fedoras. (This is a matter of respect for our primary sponsor, Red Hat, Inc., and is not negotiable. Of course, passive appearance of hats, such as those upon heads in a crowd, may be allowed.)
• No version numbers. End users might prefer to continue to use an older theme, or use the latest theme in their older version of Fedora. To enable that choice, do not use any version numbers within the Fedora artwork.
• No text. Text should not be used in the backgrounds because the artwork is intended for a global audience and to be reused by derivative distributions.
• Should not contain images of people (contemporary, historical, or fictional)
• Should not contain images of pets, or captive or mistreated animals

How to submit

So, got that perfect image in mind for a supplemental wallpaper?  Great!  If the image meets all of the requirements then all you need to do is add it to the submissions section of the wiki and wait.  We will take submissions until 23:59 UTC on August 9th 2011 following that the design team will vote for the top 15 and they will be packaged up and included in the Fedora 16 release.

If you have any questions feel free to email me (pcon AT fedoraproject DOT org) or contact me (pcon) in #fedora-design on freenode

#!/bin/bash
meld “$2″ “$5″

Then make it executable with chmod.  Now add the following to your ~/.gitconfig file

[diff]
external = git-meld

This will now run meld whenever you do a git diff.  You can easily see diffs and apply diffs with it now.  If you click the arrow in the blue/green box it will move that chunk of code over.  If you diff multiple files, meld will run with each one of the files, so just quit out of meld and it will relaunch with the next file.

What is dropbox?
Dropbox is a cross-platform application / website that keeps files in sync and gives you 2Gb of storage space for free.  If you’re not a dropbox user already, you can sign up here.

Initial setup

The initial setup is the tricky part.  Fortunately you only need to install something (other than dropbox) on one system and only if you’re running Windows XP.

Windows XP

You’ll need to install junction to make the symlinks in Windows XP.  In Vista and later you can use mklink

Linux / OSX

You’ll use the ln command

After you have installed your game you will need to move your save game directory into your dropbox and then link to it.  For this example, I’ll be using Civ 4.  In the examples below, I’m assuming you’ve already moved your files into Dropbox/games/

Windows

junction “C:\Documents and Settings\User\My Documents\My Games\Sid Meier’s Civilization IV\replay” C:\Documents and Settings\User\My Documents\My Dropbox\games\civ4″

OSX / Linux

ln -s ~/Documents/Sid\ Meier\’s\ Civilzation\ IV/replay ~/My\ Dropbox/games/civ4

UDEV Rules

To start with, we need to set up static naming for the storage device that you want to make into backup disk.  Start by plugging in the disk.  (Now I’m not using Gnome or KDE so I’m not sure what their automounter will do.  So, you might have to find a way to exclude it from the automounter.  We need to find out the “model” of the drive.  My udev rules are pretty basic, and will work since most people don’t have more than one the same model of USB drive laying around that they would use.  You can always modify the udev rules to work for you.

udevadm info -a -p /sys/block/sdc | grep model

Here we are looking at the block device sdc (which is what the kernel named it since we don’t have any udev rules yet).  This could change depending on how many block devices you currently have.  Now we take this information, and feed it into a udev rule.  I created a file /etc/udev/rules.d/50-backup.rules The name isn’t really important, however, the number 50- is.  That is the order in which it runs.  We want that number to be less than 90 so that hal doesn’t run first.  Inside that file, we have the following:

KERNEL==”sd?1″, SUBSYSTEM==”block”, ATTRS{model}==”MODEL GOES HERE”, SYMLINK+=”backup”, RUN+=”/usr/local/bin/backup.sh”

Replace “MODEL GOES HERE” with the output from the udevadm command

The backup script

Now we udev running our script /usr/local/bin/backup.sh we need to make that script

#!/bin/bash

NOTIFYUSER="pcon"
MAINDIR="/home/pcon/"
BACKUPDIR="/mnt/backup"

su $NOTIFYUSER alt-notify-send backup "Waiting for things to settle" 0
sleep 5

su $NOTIFYUSER alt-notify-send backup "Starting backup" 0
echo "$(date) - Mounting /dev/backup to $BACKUPDIR" > /tmp/backup.log
mount /dev/backup $BACKUPDIR >> /tmp/backup.log 2>&1
echo "$(date) - Staring rsync of $MAINDIR to $BACKUPDIR" >> /tmp/backup.log
rsync -arvuz --inplace --delete $MAINDIR $BACKUPDIR >> /tmp/backup.log 2>&1
echo "$(date) - Mounting /dev/backup to $BACKUPDIR" >> /tmp/backup.log
umount $BACKUPDIR >> /tmp/backup.log 2>&1
su $NOTIFYUSER alt-notify-send backup "Backup completed" 0

We have a couple of things to setup here.  First we need to create /mnt/backup as root, and fill out the other variables in the top of the script.  Aslo, if we want notification in gnome, we need to make a notify-send work around.  Put the following in /usr/local/bin/alt-notify-send

#!/bin/sh
user=`whoami`
pids=`pgrep -u $user gnome-panel`
title=$1
text=$2
timeout=$3

if [ -z "$title" ]; then
    echo You need to give me a title >&2
    exit 1
fi
if [ -z "$text" ]; then
     text=$title
fi
if [ -z "$timeout" ]; then
     timeout=60000
fi

for pid in $pids; do
    # find DBUS session bus for this session
    DBUS_SESSION_BUS_ADDRESS=`grep -z DBUS_SESSION_BUS_ADDRESS \
    /proc/$pid/environ | sed -e 's/DBUS_SESSION_BUS_ADDRESS=//'`
    # use it
    DBUS_SESSION_BUS_ADDRESS=$DBUS_SESSION_BUS_ADDRESS \
    notify-send -u low -t $timeout "$title" "$text"
done

Now chmod +x the two scripts, and everything should be good to go.  You can download the scripts used in this post below:

• 50-backup.rules
• backup.sh
• alt-notify-send (Taken from here)

In your .screenrc, make sure you have a place that will show messages.  If you start up screen and you see “New screen…” then you’ve got this.  Next add your script to your .screenrc

bind -k k5 exec /home/pcon/bin/build_script.sh

Now everything in your screen is ready to go.  Now, on to build_script.sh

#!/bin/bash

echo -n -e “\033^Starting Build\033\\”

# Do something here

echo -n -e “\033^Ending Build\033\\”

That’s it.  Now your screen will display “Starting Build” and “Ending Build” on your display.  If the stuff in between happens too fast, you may only see your last message.  The key thing is that your message has to start with “\033^”  and end with “\033\\” otherwise you’ll loose your cursor.  And you have to have the -e on the echo so that it will interpret the octal codes correctly.

• Generic user with a generic password to hand to the person in charge
• Ability to play dvd stored locally.  (Called presentation_dvd)
• Ability to play any dvd inserted.
• Require no user input except to choose presentation_dvd or dvd

Preperation

To get ready, we need to do a couple of things

• Create a presenter user
• Install xine and xine-lib-extras-freeworld
• Copy our presentation_dvd to an iso
  

  dd if=/dev/dvd of=/home/presenter/presentation_dvd.iso

Xesssions

Xsessions are what defines your window manager.  It’s what tells X11 what to run when you say Session->Gnome or Session->fluxbox.  These files are stored in /usr/share/xsessions.

[Desktop Entry]
Encoding=UTF-8
Name=Presentation_DVD
Comment=Start the presentation DVD
Exec=/usr/local/bin/presentation_dvd
Terminal=False

[Window Manager]
SessionManaged=true

This is our file in /usr/share/xesssions/presentation_dvd.desktop We then create one in /usr/share/xesssions/dvd.desktop and replace presentation_dvd with dvd.

The Scripts

Our /usr/local/bin/presentation_dvd looks like this:

#!bin/bash
amixer set Master playback 100%
xine -f -g --no-splash dvd:/home/presenter/presentation_dvd.iso

This will turn the volume up to 100% and then start xine on the iso.  To exit, just right click and say exit.  This will take you back to the login screen.

Now to handle any dvd with the /usr/local/bin/dvd

#!/bin/bash
amixer set Master playback 100%
xine -f -g --no-splash dvd://

And the final touch, make them both executable

chmod a+x /usr/local/bin/dvd /usr/local/bin/presentation_dvd

NOTE:  The xine parameter is dash dash no dash splash.  The font I’m using doesn’t render two dashes well

Usage

From the login menu, choose your presenter user, and then choose the appropriate session at the bottom.  Then type in the password.  Like magic, everything should work.

Potential problems

If you don’t see your session in the list, you might have a typo in your xsession file

If one of the xine scripts don’t work, try logging into gnome and running the script from the command-line to see why.

1. Install Eclipse for your platform (it’s eclipse-platform if you are using Fedora)
2. Install both the Force.com and Subclipse plugin (eclipse-subclipse)
3. Add your Force.com project to Eclipse (Howto)
4. Add your SVN repo to Eclipse.  (Howto)
5. Share your Force.com project (Right-click on Project name -> Team -> Share Project -> SVN -> Choose repo)
6. Then after updating a file in the Force.com project, commit the update to SVN before deploying to the server ()

Now if you want to use this in another Eclipse instance then, you’ll want to do the first two steps to prepare your Eclipse environment.  Then:

1. Add the existing SVN repo to Eclipse (Howto)
2. Right click on the Project Force.com -> Project Properties   and update the username / password

When using this in a collaborative setting, the following workflow should be followed whenever possible.

1. Team -> Update
2. Make changes to code
3. Team -> Update
4. Make changes to resolve collisions if needed
5. Team -> Commit
6. Force.com -> Deploy to Server

In Fedora, you need to do the following as root before running any of the commands from the article

ln -s /usr/bin/gunzip /usr/bin/uncompress

Now.  To figure out how the server.cfg

1. Prior to starting up the AppleTV or even unboxing it, get your patchstick ready by following these instructions
2. Unbox and setup the AppleTV to your LAN.
3. Then, navigate to the setup->general->updates and make sure you STOP the update if you can.  The update won’t technically break anything, but there are some problems with the newest firmware.  If you can stop it it’s better
4. Insert your patchstick, and reboot the AppleTV
   
5. Once it’s done open up your favorite terminal, and get ready to ssh to make sure that AppleTV can run any updates.  The password is ‘frontrow‘
   

   ssh frontrow@appletv
   sudo bash -c ‘echo “127.0.0.1 mesu.apple.com” >> /etc/hosts’

6. From the menu select ‘XBMC/Boxee’->Updates and select the non-alpha boxee
7. Wait and wait some more
8. Download the darwinx86 iso from here you can get a free login for this by following the links
9. Mount it up on the loop back and scp the /usr/bin/vim and /sbin/mount_nfs to the AppleTV
10. You will need to make sure you nfs export has the option insecure or the AppleTV won’t be able to mount it
11. Reboot one last time.  You can do this with ‘sudo /sbin/reboot now’
12. Choose boxee from the menu and launch it.  There are a couple of known bugs with the latest firmware and boxee version.

• Boxee starts with a black screen.  The only real ‘fix’ for that is to restart it a bunch until it starts up right.
• Boxee freezes on the menu.  Remove the ‘/Users/frontrow/Library/Application Support/BOXEE/UserData/’ folder.
• For more information, go here