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Logback could be groovy! But XML FTW

Posted by Dominic Cronin at Feb 09, 2014 02:37 PM |

Anyone who works with Tridion content delivery will be familiar with the fact that Logback is used as the logging framework. Recently I found myself looking into this more than I had previously, so here are a couple of observations that might be interesting. The first is that you can use the groovy scripting language instead of XML to write your configuration files. (I'll get to exactly how useful, or otherwise, this might be in a bit...) Anyway - the following is a machine translation of the logback.xml file that ships with Tridion, Now - proponents of the groovy approach will tell us that groovy can be much terser than the XML equivalent. At first sight it doesn't look much different, but I imagine you could factor out the creation of all those appenders to some sort of factory, and then it would look a lot shorter. Can I leave that as "an exercise for the student"? :-)

import ch.qos.logback.classic.encoder.PatternLayoutEncoder
import ch.qos.logback.core.rolling.RollingFileAppender
import ch.qos.logback.core.rolling.TimeBasedRollingPolicy
import java.nio.charset.Charset

import static ch.qos.logback.classic.Level.${LOG.LEVEL}
import static ch.qos.logback.classic.Level.OFF

def log.pattern = "%date %-5level %logger{0} - %message%n"
def log.history = "7"
def log.folder = "c:/tridion/log"
def log.level = "ERROR"
def log.encoding = "UTF-8"
appender("rollingTransportLog", RollingFileAppender) {
  rollingPolicy(TimeBasedRollingPolicy) {
    fileNamePattern = "${log.folder}/cd_transport.%d{yyyy-MM-dd}.log"
    maxHistory = "${log.history}"
  encoder(PatternLayoutEncoder) {
    charset = Charset.forName("${log.encoding}")
    pattern = "${log.pattern}"
  prudent = true
appender("rollingDeployerLog", RollingFileAppender) {
  rollingPolicy(TimeBasedRollingPolicy) {
    fileNamePattern = "${log.folder}/cd_deployer.%d{yyyy-MM-dd}.log"
    maxHistory = "${log.history}"
  encoder(PatternLayoutEncoder) {
    charset = Charset.forName("${log.encoding}")
    pattern = "${log.pattern}"
  prudent = true
appender("rollingMonitorLog", RollingFileAppender) {
  rollingPolicy(TimeBasedRollingPolicy) {
    fileNamePattern = "${log.folder}/cd_monitor.%d{yyyy-MM-dd}.log"
    maxHistory = "${log.history}"
  encoder(PatternLayoutEncoder) {
    charset = Charset.forName("${log.encoding}")
    pattern = "${log.pattern}"
  prudent = true
appender("rollingCoreLog", RollingFileAppender) {
  rollingPolicy(TimeBasedRollingPolicy) {
    fileNamePattern = "${log.folder}/cd_core.%d{yyyy-MM-dd}.log"
    maxHistory = "${log.history}"
  encoder(PatternLayoutEncoder) {
    charset = Charset.forName("${log.encoding}")
    pattern = "${log.pattern}"
  prudent = true
appender("rollingSessionPreviewLog", RollingFileAppender) {
  rollingPolicy(TimeBasedRollingPolicy) {
    fileNamePattern = "${log.folder}/cd_preview.%d{yyyy-MM-dd}.log"
    maxHistory = "${log.history}"
  encoder(PatternLayoutEncoder) {
    charset = Charset.forName("${log.encoding}")
    pattern = "${log.pattern}"
  prudent = true
logger("com.tridion", ${LOG.LEVEL})
logger("com.tridion.transport", ["rollingTransportLog"])
logger("com.tridion.transport.HTTPSReceiverServlet", ["rollingDeployerLog"])
logger("com.tridion.transport.transportpackage", ["rollingDeployerLog"])
logger("com.tridion.transformer", ["rollingDeployerLog"])
logger("com.tridion.deployer", ["rollingDeployerLog"])
logger("com.tridion.tcdl", ["rollingDeployerLog"])
logger("com.tridion.event", ["rollingDeployerLog"])
logger("com.tridion.monitor", ["rollingMonitorLog"])
logger("Tridion.ContentDelivery", ${LOG.LEVEL}, ["rollingCoreLog"])
logger("com.tridion.preview", ["rollingSessionPreviewLog"])
logger("", ["rollingSessionPreviewLog"])
root(OFF, ["rollingCoreLog"])

So why might this be interesting to Tridion infrastructure specialists? Well it isn't. Not at all. At least not right now - because doing it this way requires the groovy runtime to be available, and that isn't in a standard Tridion content delivery setup. I attempted a trivial hack by dropping a couple of the groovy jars in place, but no joy. Realistically, this would only be a practical approach if Tridion decided to build it into the product and support it. I imagine the dev team puts quite some effort into keeping their dependency tree as clean as possible, so this might come under the heading of stuff that would only get added if people really, really wanted it!

Anyway - I love the smell of XML in the morning, so it's all the same to me. So on with the useful part of this post. If you check out exactly how logback gets its configuration settings, you'll see that before it picks up logback.xml, it first looks for a file called logback-test.xml. I'm happy to say that this does work out-of-the-box. This means that when you come across a server where you need to debug a problem, and its standard logging settings need to be boosted up to DEBUG, you don't have to edit the existing config file. Just drop your insanely debuggy logback-test.xml file in next to logback.xml (and restart things) and Bob's your uncle. When you're done, just delete (and restart). Even the restarting might be optional - another feature of logback is that you can configure it to scan for configuration changes, although I have no clue whether it would then pick up the existence of logback-test.xml)

Ok - this is such a minor benefit over copying and renaming that it hardly justifies the deaths of all those IP packets that were bravely lost in transmission during the serving of this web page. Whatever.... that's the thing with research, eh? Negative results are also important to report. In short - logback.groovy looked cool, but won't work - and maybe carrying a customised logback-test.xml around in your toolkit might be handy, but then again, maybe not.

I'll sign off with one more public service announcement. I recently saw someone using a logback configuration that specified a logging level of ON. Apparently they had been advised to do so by someone who ought to have checked first. The possible values are OFF, ERROR, WARN, INFO, DEBUG and TRACE. Anything other than that will not be recognised, and you'll get DEBUG logging, which is the default if that happens.

What not to do when upgrading to Grub2

Posted by Dominic Cronin at Feb 08, 2014 04:10 PM |

I'd been following the Gentoo Wiki guidance on upgrading Grub, and had been taking it very carefully. I'd worried about getting this right, as getting it wrong would leave me with a brick, so I'd been very pleased to see the notes on using the old bootloader to chain load the new one. That way I could check that my configuration was correct before taking the plunge of installing the new version into the Master Boot Record. I didn't want to automatically generate the new config file, as I didn't trust it. (Rightly so as it turned out, because my initrd files didn't follow the strict naming requirements, so weren't picked up by the config generation script) Anyway - the hand-written config was half a dozen lines long, and the generated one was utterly incomprehensible.

So anyway - I managed to create the config file, and get everything set up for chain loading. I rebooted the server, and bingo - there was the chain loader entry in my "old" boot screen, and when I followed it, I got the new menu and could boot the server. Great stuff! Now it should have been a simple question of running grub2-install, and I'd be finished. So I did this, and then.... the computer wouldn't start. Fortunately I had a grub prompt, so grub was "working" - but it obviously couldn't find its config file. I already knew that with the right incantations it might be possible to get the thing to boot without a config file, and after a bit of googling, I got enough clues to attempt it. (For the record, what I think I'd done wrong was to fail to remount /boot after my chain test and before running grub2-install, with the result that grub then didn't know how to correctly find /boot.)

It took a few attempts, but the command line completion in grub helps a lot. This is what I eventually ended up typing at the grub prompt to get a working boot.

grub > set root=(hd0,1)
grub > linux /kernel-gen-newudev-3.3.8-gentoo root=/dev/sda3
grub > initrd /initramfs-gen-newudev-3.3.8-gentoo
grub > boot

Note that the root for the boot loader is different from the root of the operating system, so you have to specify them separately. Obviously YMMV for the names of the kernel and initrd files, not to mention device identifiers.

But the real advice here is to avoid missing out that crucial mount operation!!

Gentoo emerge dies with 'failed to open /dev/urandom' when wrong default python is configured.

Posted by Dominic Cronin at Jan 22, 2014 12:12 AM |

So there I was - just for fun building my new Gentoo system, when all of a sudden, I wasn't. Building, that is. I wasn't building anything. In fact, part of the motivation for a clean build had been that emerging new things was getting tiresomely fragile. Anyway - here's what happened when I tried an emerge. The interesting part is where it says: Fatal Python error: Failed to open /dev/urandom

>>> Emerging (1 of 18) sys-libs/glibc-2.17
 * Fetching files in the background. To view fetch progress, run
 * `tail -f /var/log/emerge-fetch.log` in another terminal.
 * glibc-2.17.tar.xz SHA256 SHA512 WHIRLPOOL size ;-) ...                                                                            [ ok ]
 * glibc-2.17-patches-8.tar.bz2 SHA256 SHA512 WHIRLPOOL size ;-) ...                                                                 [ ok ]
make -j2 -s glibc-test
make -j2 -s glibc-test
>>> Unpacking source...
 * Checking gcc for __thread support ...                                                                                             [ ok ]
 * Checking kernel version (3.3.8 >= 2.6.16) ...                                                                                     [ ok ]
 * Checking linux-headers version (3.9.0 >= 2.6.16) ...                                                                              [ ok ]
>>> Unpacking glibc-2.17.tar.xz to /var/tmp/portage/sys-libs/glibc-2.17/work
>>> Unpacking glibc-2.17-patches-8.tar.bz2 to /var/tmp/portage/sys-libs/glibc-2.17/work
 * Applying Gentoo Glibc Patchset 2.17-8 ...
 *   0035_all_glibc-2.16-i386-math-feraiseexcept-overhead.patch ...                                                                  [ ok ]
 *   0059_all_glibc-2.19-make-4.0.patch ...                                                                                          [ ok ]
 *   0065_all_glibc-2.18-qecvt-guards.patch ...                                                                                      [ ok ]
 *   0070_all_glibc-2.18-localedef-page-align-1.patch ...                                                                            [ ok ]
 *   0071_all_glibc-2.18-localedef-page-align-2.patch ...                                                                            [ ok ]
 *   0072_all_glibc-2.18-localedef-page-align-3.patch ...                                                                            [ ok ]
 *   0085_all_glibc-disable-ldconfig.patch ...                                                                                       [ ok ]
 *   0090_all_glibc-2.17-arm-ldso.cache.patch ...                                                                                    [ ok ]
 *   1005_all_glibc-sigaction.patch ...                                                                                              [ ok ]
 *   1008_all_glibc-2.16-fortify.patch ...                                                                                           [ ok ]
 *   1040_all_2.3.3-localedef-fix-trampoline.patch ...                                                                               [ ok ]
 *   1055_all_glibc-resolv-dynamic.patch ...                                                                                         [ ok ]
 *   1505_all_glibc-nptl-stack-grows-up.patch ...                                                                                    [ ok ]
 *   1506_all_glibc-2.17-hppa-fpu.patch ...                                                                                          [ ok ]
 *   1507_all_glibc-2.17-hppa-ldso-flag.patch ...                                                                                    [ ok ]
 *   1507_all_hppa-ia64-DL_AUTO_FUNCTION_ADDRESS.patch ...                                                                           [ ok ]
 *   1508_all_glibc-2.17-hppa-futex.patch ...                                                                                        [ ok ]
 *   1508_all_hppa-fanotify_mark.patch ...                                                                                           [ ok ]
 *   3020_all_glibc-tests-sandbox-libdl-paths.patch ...                                                                              [ ok ]
 *   5063_all_glibc-dont-build-timezone.patch ...                                                                                    [ ok ]
 *   6024_all_alpha-fix-signal-thunk-unwind-info.patch ...                                                                           [ ok ]
 *   6230_all_arm-glibc-hardened.patch ...                                                                                           [ ok ]
 * Done with patching
 * Using GNU config files from /usr/share/gnuconfig
 *   Updating scripts/config.sub                                                                                                     [ ok ]
 *   Updating scripts/config.guess                                                                                                   [ ok ]
>>> Source unpacked in /var/tmp/portage/sys-libs/glibc-2.17/work
Fatal Python error: Failed to open /dev/urandom
/usr/lib/portage/bin/ line 87:  4204 Aborted                 "${PORTAGE_PYTHON:-/usr/bin/python}" "${PORTAGE_BIN_PATH}"/ "${filtered_vars}"
 * ERROR: sys-libs/glibc-2.17::gentoo failed (unpack phase):
 * failed
 * Call stack:
 *  , line 714:  Called __ebuild_main 'unpack'
 *, line 993:  Called __filter_readonly_variables '--filter-features'
 *, line 137:  Called die
 * The specific snippet of code:
 *      "${PORTAGE_PYTHON:-/usr/bin/python}" "${PORTAGE_BIN_PATH}"/ "${filtered_vars}" || die " failed"

So what was going on here? Well as it turned out, my system has three versions of python loaded, and Gentoo's portage system (of which emerge is part) seems to rely on you not using python 3. After a short bit of fiddling with "eselect python list" and "eselect python set", to get the default python back to 2.7, the build ran like a charm.

So anyway - this has got to count as the most bizarrely mis-reported error in my most recent years. "/dev/urandom" was working fine. I could start it and stop it ("/etc/init.d/urandom stop" and so forth) and I could use it to access randomness. Why then did I get the "failed to open" message with one version of python, and not with another. Answers on a postcard? Whatever - this was a public service announcement.

The Razor Mediator for Tridion - in practice

Most of my blog output is to be found right here, but this week I published an article on the Indivirtual web site.

The article goes into the background of the Razor Mediator for Tridion, and our thinking behind using it on a customer project. I hope you find it interesting.

Straightforward Powershell scripting with the Tridion core service

Posted by Dominic Cronin at Apr 04, 2013 11:30 PM |

Almost exactly a year ago, I blogged about Getting to grips with the Tridion core service in Powershell. The core service had been around for a while even then, and the point was to actually start using it for some of the scripting tasks I had habitually done via the TOM. In many ways the TOM was much more script-friendly. Of course, that might have had something to do with the fact that it was created expressly for use from scripting languages. The Tridion core service API wasn't. I don't know exactly what they had in mind, but I'd imagine the thinking was that most mainstream users would use C#. Yeah, sure - any compliant .NET language would do, but F#? Nah!

But a year further on, and where are all those scripts I was going to write? I have to say, the comfort zone for scripting is quite different than for writing "proper" programmes. There's huge usefulness in being able to hack out something quickly, and very much a sense that stuff will be intermingled ina-code-is-data-stylee. So when I started actually trying to use the core service for scripting tasks, it sucked pretty hard. There were two main areas of difficulty:

  1. Getting the core service wired up in the first place
  2. Powershell doesn't natively have the equivalent of C#'s using directive to allow you to avoid typing the full namespace of your type.


I covered the first point last year. Suffice it to say that currently, I'm still using Peter Kjaer's Tridion powershell module, although at the moment I'm running a local copy, modified to cope with the Tridion 2013 client, and also to allow me to specify which protocol I want to use. (Obviously I don't want to have a permanent fork, so with a bit of luck, Peter will be able to integrate some of this work into the next release of the module.) On a related subject, my experience has been that working with the core service client has some fundamental differences with using the TOM. You could keep a TDSE lying around for minutes at a time, and it would still be usable, even after a method call had failed. The core service, even when you're on the same server, is most definitely a web service. Failed calls tend to leave your connection in a "faulted" state (i.e. unusable), and the timeouts are generally shorter. Once you are aware of this, you can adjust your coding style accordingly, but it adds somewhat to the ritual.

The namespace issue is on the face of it more trivial. OK - so it's a PITA to have to type something like:

$folder = new-object Tridion.ContentManager.CoreService.Client.FolderData

when all you wanted was a folder. You could argue: "well it works, doesn't it? Get over it!". However, I found all this extra verbiage too much of a distraction, not only when reading and editing longer scripts, but also when "knocking off a quick one". After all, what's the point of having a great scripting environment if your one-liners aren't?

So what to do? Well I scoured the Internet, and discovered that Powershell has something called a Type Accelerator. You've seen these often enough, as there are several available by default. For example, you can (and should) type "[string]" when what you really mean is "[System.String]". Unfortunately, creating type accelerators isn't completely straightforward, but No Worries, the Powershell community is vibrant and there are implementations available that take care of it for you. (OK, at the time of writing I know of one that works, but that's enough, eh? My first Googling had taken me to the Type Accelerators module (PSTX) at codeplex. At first this seemed to be useful, but as soon as I moved to Tridion 2013, support for Powershell 3 became a hard requirement. This project is not actively maintained, and it doesn't work in Powershell 3. As I said, it's not straightforward to wire up type accelerators, and the code uses an undocumented API, which changed. Not Microsoft's fault.)

At this point, I went to the Powershell IRC channel (#powershell on freenode) and asked there if anyone knew about fixes or updates. I was steered in the direction of Jaykul's reflection module, available on Poshcode. (Make sure you get the latest version, and beware of the script getting truncated.) Installing modules is a fairly straightforward task: often as simple as dropping the files into a suitably named directory in your WindowsPowerShell modules directory (sometimes you need to "unblock" them) . Here's a shot of what mine looks like: (What you can see is C:\Users\Administrator\Documents\WindowsPowerShell\Modules)

My Modules folder

In there you can see the Reflection module and AutoLoad (which is another module it depends on). Apart from that you can see the Tridion core service module (and Pscx).

With all this in place, you are set to start writing your "straightforward" Tridion scripts. I've chosen to demonstrate this by hacking out a script that will create a default publication layout for you. It will be a handy tool to have on my research image, but mostly it's to show some real-world scripting.

param ($publicationPrefix = "")

$core = Get-TridionCoreServiceClient -protocol nettcp
import-module reflection
import-namespace Tridion.ContentManager.CoreService.Client

function createPublication {
	write-host "Creating publication $title"
	$newPublication = $core.GetDefaultData([ItemType]::Publication,"",$null)
	$newPublication.Title = $title
	if ($key -eq [string]::Empty){
		$newPublication.Key = $title
	else {
		$newPublication.Key = $key
	foreach ($parent in $parents){
		$link = new-object LinkToRepositoryData
		if ($parent -match "^tcm:"){
			$link.IdRef = $parent
		} elseif ($parent -match "^/webdav"){
			$link.WebDavUrl = $parent
		} else {
		$newPublication.Parents += $link
	if ($Passthru){
		$core.Create($newPublication, (new-object ReadOptions))
	else {

function createFolder([SessionAwareCoreServiceClient]$core, [string]$parentId, [string]$title, [switch]$Passthru){
	write-Host "Creating folder $title"
	$newFolder = $core.GetDefaultData([ItemType]::Folder, $parentId, $null)
	$newFolder.Title = $title
	if ($Passthru){
		$core.Create($newFolder, (new-object ReadOptions))
	else {
		$core.Create($newFolder, $null)

function createStructureGroup([SessionAwareCoreServiceClient]$core, [string]$parentId, [string]$title, [string]$directory, [switch]$Passthru){
	write-Host "Creating Structure Group $title"
	$newStructureGroup = $core.GetDefaultData([ItemType]::StructureGroup, $parentId, $null)
	$newStructureGroup.Title = $title
	$newStructureGroup.Directory = $directory
	if ($Passthru){
		$core.Create($newStructureGroup, (new-object ReadOptions))
	else {
		$core.Create($newStructureGroup, $null)

$chainMasterPub = createPublication $core "$($publicationPrefix)ChainMaster" -Passthru
$rsg = createStructureGroup $core $chainMasterPub.Id "root" "root" -Passthru

$definitionsPub = createPublication $core "$($publicationPrefix)Definitions" -parents @($chainMasterPub.Id) -Passthru
$systemFolder = createFolder $core  $definitionsPub.RootFolder.IdRef "System" -Passthru
createFolder $core $systemFolder.Id "Schemas"

$contentPub = createPublication $core "$($publicationPrefix)Content" -parents @($definitionsPub.Id) -Passthru
$contentFolder = createFolder $core $contentPub.RootFolder.IdRef "Content" -Passthru

$layoutPub = createPublication $core "$($publicationPrefix)Layout" -parents @($definitionsPub.Id) -Passthru
createFolder $core $core.GetTcmUri($systemFolder.Id, $layoutPub.Id, $null) "Templates"

createPublication $core "$($publicationPrefix)Web" -parents @($contentPub.Id,$layoutPub.Id)

The script accepts a parameter which lets me prefix the publications with some name relevant to whatever I'm doing, so if you invoke it like this:

PS C:\code\dominic\tridion> .\CreateDefaultStructure.ps1 "Apple"
Connecting to the Core Service at localhost...
Creating publication Apple 00 ChainMaster
Creating Structure Group root
Creating publication Apple 01 Definitions
Creating folder System
Creating folder Schemas
Creating publication Apple 02 Content
Creating folder Content
Creating publication Apple 03 Layout
Creating folder Templates
Creating publication Apple 04 Web
PS C:\code\dominic\tridion> .\CreateDefaultStructure.ps1 "Banana"
Connecting to the Core Service at localhost...
Creating publication Banana 00 ChainMaster
Creating Structure Group root
Creating publication Banana 01 Definitions
Creating folder System
Creating folder Schemas
Creating publication Banana 02 Content
Creating folder Content
Creating publication Banana 03 Layout
Creating folder Templates
Creating publication Banana 04 Web
PS C:\code\dominic\tridion>

... you end up with publications like this:

The resulting publications


I import the Tridion-CoreService module in my Powershell profile, so it's not needed in the script. (As noted earlier, my copy is a bit hacked, as you can see from the fact that I'm passing a protocol parameter to Get-TridionCoreServiceClient). I don't import the reflection module by default, so this is done in the script, followed immediately by "import-namespace Tridion.ContentManager.CoreService.Client", which is the magic from the Reflection module that wires up all the type accelerators. Once this is done, you can see that I can simply type [ReadOptions] instead of [Tridion.ContentManager.CoreService.Client.ReadOptions], and so on. Much better, I think! :-)

If you're wondering about the -Passthru switch on my functions, this is a powershell idiom that lets you indicate whether or not you are interested in the return value. In Tridion, this is controlled by whether or not you pass a ReadOptions argument. Perhaps obviously, the Read() method wouldn't make any sense if it didn't return anything, so a $null works fine - I'm still agonizing over whether it would be more stylish to pass a ReadOptions anyway. What do you think?)

Actually that's a good question. What do you think? I'm still trying to find my feet in terms of the correct idioms for this kind of work. Let's get the debate out in the open. Feel free to say mean things about my code (not obligatory). I've got a thick skin, and I'd genuinely value your feedback, especially if you think I'm doing it wrong.

Enabling XML syntax-highlighting for .config files in gVim

Posted by Dominic Cronin at Nov 23, 2012 10:15 PM |

I've used the vi text editor for many years; (at least long enough to know that it's pronounced vie and not vee-eye!). Over those years my level of expertise has varied somewhat - I'm fairly sure I've learned some commands and forgotten them several times over. Anyway - recently (i.e. in the last year or so), I've put some more effort in to reacquainting myself with some of its many joys. In practice, of course, I really mean vim: I'd be hard-pressed to remember the last time I saw vi in its "good-old-fashioned" form (does one say Plain-old-vi?) As most of my work is on Windows systems, this means using gVim.

Of the many improvements that vim has over vi, syntax highlighting is one of my favourites. The trouble is, one of my commonest use-cases for editing text files on Windows systems is .NET configuration files. Because these have a file extension of .config, they aren't recognised by default as XML files, and I end up going through the rigmarole of selecting one menu option to get a choice of file types added to the menus, and then locating XML among those newly added options to get highlighting to come on. Well there had to be a better way, and of course there was. What you have to do is this:

  • Locate your vi directory (on the system I was working on this evening, it's "C:\Program Files (x86)\Vim\"
  • Having found this directory, locate or create C:\Program Files (x86)\Vim\vimfiles\ftdetect
  • In ftdetect, create a file called config.vim with the following contents:
au BufRead,BufNewFile *.config     set filetype=xml

I have Windows configured to use vi as the default editor for .config files, so now with this in place, all I have to do is double-click on the file and it opens with XML syntax-highlighting enabled. Great stuff!

A thing of beauty is a joy for ever

Posted by Dominic Cronin at Jul 09, 2012 09:30 PM |

So - I've been using the Windows Powershell for the odd bit of Tridion work. You knew that.

And you probably also knew that very often the Tridion API hands you back a string representing an XML document, and that it's very convenient to "cast" this to a .NET XmlDocument using the [xml] operator. Just search on this blog for "powershell" and you'll find enough examples. But still - there's a missing piece in the puzzle. So today I wanted to look at the output from the .GetTridionWebSchemaXMl() method on a Tridion Object Model Schema object. (Don't worry - I am weaning myself off the TOM; I wanted to compare this API with the ReadSchemaFields() method on the core service client API.)

Anyway - for what it's worth, here's what the raw string looks like:

> $tdse.GetObject("tcm:21-509-8",1).GetTridionWebSchemaXML(1919,$true)
<tcm:TridionWebSchema ID="tcm:21-509-8" IsEditable="false" xmlns:tcm=""><tcm:C
ontext xmlns:xlink="" xmlns:i="" xmlns:transform-e
xt="urn:tridion:transform-ext"><tcm:Publication xlink:type="simple" xlink:title="Synchroniser tests" xlink:href="tcm:0-
21-1" /><tcm:OrganizationalItem xlink:type="simple" xlink:title="TestSchemaOne" xlink:href="tcm:21-50-2" /></tcm:Contex
t><tcm:Info xmlns:xlink="" xmlns:i="" xmlns:transf
tSchemaOne/TestSchemaCategories.xsd</tcm:WebDAVURL><tcm:Path>\Synchroniser tests\Building Blocks\TestSchemaOne</tcm:Pat
h></tcm:LocationInfo><tcm:BluePrintInfo><tcm:OwningPublication xlink:type="simple" xlink:title="Synchroniser tests" xli
nk:href="tcm:0-21-1" /><tcm:IsShared>false</tcm:IsShared><tcm:IsLocalized>false</tcm:IsLocalized></tcm:BluePrintInfo><t
ationDate><tcm:RevisionDate>2012-07-09T20:18:21</tcm:RevisionDate><tcm:Creator xlink:type="simple" xlink:title="TRIDION
DEV\Administrator" xlink:href="tcm:0-11-65552" /><tcm:Revisor xlink:type="simple" xlink:title="TRIDIONDEV\Administrator
" xlink:href="tcm:0-11-65552" /><tcm:ItemLock Title="No lock" Type="0" /><tcm:IsNew>false</tcm:IsNew></tcm:VersionInfo>
<tcm:AllowedActions><tcm:Actions Allow="1173513" Deny="102" Managed="0" /></tcm:AllowedActions></tcm:Info><tcm:Data xml
ns:xlink="" xmlns:i="" xmlns:transform-ext="urn:tr
ion>ColoursOne</tcm:Description><tcm:MinOccurs>1</tcm:MinOccurs><tcm:MaxOccurs>unbounded</tcm:MaxOccurs><tcm:Category x
link:type="simple" xlink:title="Colours" xlink:href="tcm:21-59-512" /><tcm:Size>1</tcm:Size><tcm:List Type="tree" /><tc
m:ExtensionXml xmlns="" /></tcm:KeywordField><tcm:SingleLineTextField><tcm:N
ame>Animals</tcm:Name><tcm:Description>Test field with locally declared list</tcm:Description><tcm:MinOccurs>1</tcm:Min
Occurs><tcm:MaxOccurs>1</tcm:MaxOccurs><tcm:Size>1</tcm:Size><tcm:List Type="select"><tcm:Entry>Horse</tcm:Entry><tcm:E
ntry>Haddock</tcm:Entry><tcm:Entry>Weasel</tcm:Entry></tcm:List><tcm:ExtensionXml xmlns="
entManager/R6" /></tcm:SingleLineTextField></tcm:Fields><tcm:MetadataFields /><tcm:AllowedMultimediaTypes /><tcm:Compon
entProcess xlink:type="simple" xlink:title="" xlink:href="tcm:0-0-0" /></tcm:Data></tcm:TridionWebSchema>

Yeah - erm ... Okaayyyy. Great.

OK - so how about we do the cast?


> [xml]$tdse.GetObject("tcm:21-509-8",1).GetTridionWebSchemaXML(1919,$true)


Well - at least you can read it.. but seriously - also not super helpful if you just want to scan the XML with good-old-fashioned human eyeballs.

So what can we do? Well I got to the point where I actually typed the following into Google:

powershell pretty print xml

and the first hit was on Keith Hill's blog.  Keith had written a nice little function that looks like this:

function XmlPrettyPrint([string]$xml) {
    $tr = new-object System.IO.StringReader($xml)
    $settings = new-object System.Xml.XmlReaderSettings
    $settings.CloseInput = $true
    $settings.IgnoreWhitespace = $true
    $reader = [System.Xml.XmlReader]::Create($tr, $settings)
    $sw = new-object System.IO.StringWriter
    $settings = new-object System.Xml.XmlWriterSettings
    $settings.CloseOutput = $true
    $settings.Indent = $true
    $writer = [System.Xml.XmlWriter]::Create($sw, $settings)
    while (!$reader.EOF) {
        $writer.WriteNode($reader, $false)
    $result = $sw.ToString()

A minute later, this function was in my Powershell profile (and I slightly altered the name and added an alias) so now I can do the following:

> ppx ([xml]$tdse.GetObject("tcm:21-509-8",1).GetTridionWebSchemaXML(1919,$true)).OuterXml
<?xml version="1.0" encoding="utf-16"?>
<tcm:TridionWebSchema ID="tcm:21-509-8" IsEditable="false" xmlns:tcm="">
  <tcm:Context xmlns:xlink="" xmlns:i="" xmlns:transform-ext="urn:tridion:transform-ext">
    <tcm:Publication xlink:type="simple" xlink:title="Synchroniser tests" xlink:href="tcm:0-21-1" />
    <tcm:OrganizationalItem xlink:type="simple" xlink:title="TestSchemaOne" xlink:href="tcm:21-50-2" />
  <tcm:Info xmlns:xlink="" xmlns:i="" xmlns:transform-ext="urn:tridion:transform-ext">
      <tcm:Path>\Synchroniser tests\Building Blocks\TestSchemaOne</tcm:Path>
      <tcm:OwningPublication xlink:type="simple" xlink:title="Synchroniser tests" xlink:href="tcm:0-21-1" />
      <tcm:Creator xlink:type="simple" xlink:title="TRIDIONDEV\Administrator" xlink:href="tcm:0-11-65552" />
      <tcm:Revisor xlink:type="simple" xlink:title="TRIDIONDEV\Administrator" xlink:href="tcm:0-11-65552" />
      <tcm:ItemLock Title="No lock" Type="0" />
      <tcm:Actions Allow="1173513" Deny="102" Managed="0" />
  <tcm:Data xmlns:xlink="" xmlns:i="" xmlns:transform-ext="urn:tridion:transform-ext">    <tcm:Title>TestSchemaCategories</tcm:Title>
        <tcm:Category xlink:type="simple" xlink:title="Colours" xlink:href="tcm:21-59-512" />
        <tcm:List Type="tree" />
        <tcm:ExtensionXml xmlns="" />
        <tcm:Description>Test field with locally declared list</tcm:Description>
        <tcm:List Type="select">
        <tcm:ExtensionXml xmlns="" />
    <tcm:MetadataFields />
    <tcm:AllowedMultimediaTypes />
    <tcm:ComponentProcess xlink:type="simple" xlink:title="" xlink:href="tcm:0-0-0" />

So what's my point? Well I have a couple:

  1. The Internet is great (by which I mean, the people of the Internet are great.). I could have written that function myself in about half an hour. But in practice I might not have had the energy to do so at 10pm on a working Monday. Thanks to Keith's willingness to share, I had my solution inside a minute - working and tested. How cool is that?
  2. Somehow, this has just taken a little bit of the friction out of my working day, not to mention my so-called free time. I can now pull data straight out of a method that returns string, and get human-readable XML. This stuff makes a difference.


Thanks Keith - and all the other Keith's out there.

P.S. Maybe even nicely formatted XML will never be a thing of beauty, so apologies to Keats.

Getting to grips with the Tridion core service in Powershell

Posted by Dominic Cronin at Apr 01, 2012 05:05 PM |

As regular readers of this blog will know, I've been a long-standing fan of the Windows Powershell as a tool for interacting with Tridion. On more than one project, the flexibility of the Powershell has allowed me to process Tridion data in ad-hoc ways that would be unthinkable if you had to bring with you all the overhead of, say, C# and Visual Studio. All of that is, of course, positive, but the downside of it has been that I don't seem to be making the jump over to the core service, which, after all, I should expect to be one of my primary APIs for some time to come. So time to make a change.

A while ago, I had tinkered with using the TOM.NET API from the Powershell, but I stopped putting effort into that once I got the basics working. The advice from SDL is clearly to use the core service for the kind of scenarios that the Powershell covers. Just for the record, though - getting a TOM.NET session in the Powershell is considerably more difficult than the equivalent activity using the core service. To be fair, neither technique even remotely approaches the simplicity of "$tdse = new-object -com TDS.TDSE", but like I said, it's time to move on.

So once I started looking at this, I had a quick look at Frank van Puffelen's GetCoreServiceClientWithoutConfigFile recipe in the Tridion Cookbook, and then I spent some time snuffling around in Peter Kjaer's Tridion Powershell Modules. Both of these are great resources, but I suffer quite badly from Not Invented Here syndrome, so at the very least, I had to poke around a bit and see what's going on. After some blatant stealing: mostly from Peter's code, I ended up with this:

Add-Type -assemblyName System.ServiceModel
$binding = new-object System.ServiceModel.WsHttpBinding
$binding.MaxBufferPoolSize = [int]::MaxValue
$binding.MaxReceivedMessageSize = [int]::MaxValue
$binding.ReaderQuotas.MaxArrayLength = [int]::MaxValue
$binding.ReaderQuotas.MaxBytesPerRead = [int]::MaxValue
$binding.ReaderQuotas.MaxNameTableCharCount = [int]::MaxValue
$binding.ReaderQuotas.MaxStringContentLength = [int]::MaxValue
$endpoint = new-object System.ServiceModel.EndpointAddress http://localhost/webservices/CoreService2011.svc/wsHttp
Add-Type -Path 'C:\Program Files (x86)\Tridion\bin\client\Tridion.ContentManager.CoreService.Client.dll'
$core = new-object Tridion.ContentManager.CoreService.Client.SessionAwareCoreServiceClient $binding,$endpoint

So what's going on here? What I've extracted is pretty close to the barest minimum implementation I could get to. Maybe you could get it smaller if you weren't bothered by running up against the fairly low default quota values offered by the Windows Communication Framework. In fact, I'm quite unsure about my approach to the quotas. What I've done is effectively to say that quotas aren't helpful for my scenario, and set them all to the maximum possible. Does this make sense? Let me know what you think. (Edit: I asked a question about this on stackoverflow, and got some good answers.)

So - to use the service you need three things:

  1. The core service client assembly. (It's great that SDL are now shipping this with the product. This means I can mail you a script, and say "use the 'official' client", and expect it to work.)
  2. A System.ServiceModel.WsHttpBinding object
  3. A System.ServiceModel.EndpointAddress object

So we load the System.ServiceModel assembly using Powershell's Add-Type cmdlet. This assembly is part of the .NET framework so we can just ask for it by name. Later in the script we use the same cmdlet to load the client dll, but then we have to specify its location. Once we have System.ServiceModel loaded, we can instantiate a binding and an endpoint, and pass those to the constructor of the client. Even though we end up with a few lines of code, it's not really hard, eh?

From here on we can just use the $core object to talk to the service. To be honest, having had a bit of a dig into how it works, you're probably better off just using Peter's module, which takes care of more than my hard-coded version does, and also offers some utility methods, for example, to create a new user. In fact, assuming you have installed the module, getting started is even easier than instantiating a TDSE: just "$core = Get-TridionCoreServiceClient". Nice job, Peter. Thanks.

Edit: If you prefer a NetTcp binding, this is pretty simple too: Just instantiate the correct binding type:

$binding = new-object System.ServiceModel.NetTcpBinding

And use a different endpoint

$endpoint = new-object System.ServiceModel.EndpointAddress net.tcp://localhost:2660/CoreService/2011/netTcp

Using Ghostscript to reduce the size of a PDF

Posted by Dominic Cronin at Dec 18, 2011 12:10 PM |
Filed under: , ,

I had scanned in a document with the intention of emailing it. (For this I usually use PDFCreator which allows you to aggregate the results of several scans into a single PDF.) On this occasion, I had scanned all four pages of the document before realising that with, my current scanner settings, the resulting document would be about 12MB. So I was faced with the choice of either scanning them all again, or finding a way to reduce the size of the PDF. A quick Google turned up this link, which gave the following command line to use with Ghostscript:

gswin32c -sDEVICE=pdfwrite -dNOPAUSE -dBATCH 
-dPDFSETTINGS=/ebook -sOutputFile=C:newFile.pdf C:originalFile.pdf

The reason I had Googled for a Ghostscript solution was that I already knew I had it installed as part of Cygwin. (I always install Cygwin on any Windows machine I need to use regularly - mostly for the SSH client, but I usually do a full install just so that all those useful utilities are just there. After a bit of poking, I realised that instead of typing "gswin32c" I just needed "gs". The rest of the command worked just fine, and I ended up with a PDF of somewhat less than 2MB.

So here's a hat tip to the Ghostscript contributers over the years. Thanks. Isn't free software great?