We use the Domino redirect [url] to direct to users to different web pages.

One of our systems handles the Athens devolved authentication used many by UK Universities to provide access to journal subscriptions to students off-campus.

Athens basically works by a set of redirects and can be used by users either pre journal search or post. If they choose not to pre-authenticate. When a user accesses a journal they’re directed to Athen’s login page. They can then identify their host institution. At this point a series of redirects takes place.

Basically Athens sends a long URL to a Java agent on Domino. This url has a long MD5 session hash and information to pass back to Athens so that it can then direct the user to the correct page on publisher’s website.

We process the hash, validate it and then using a private key create a new hash that includes information about the user such as a unique id number and any permission sets that apply to them.

Today, it stopped working.

A publisher recently restructured their website and this created much longer url hashes. (2200 characters long)

Every time the agent was called from the Athens, Domino generated a http error – ‘Buffer Overflow’.

After some debugging. We identified that the error was generated by the in-built Domino redirect. It appears that there is a 2048 character limit on Java redirects.

The solution is simple to implement. You just need to return url string as part of the header via the http ‘Location’. But it’s odd that Domino will accept 4kb’s long URLs but less for redirects.

Technote: ‘Buffer Overflow Exception’ error using URL redirection with a string longer than 2048

Sorry, for posting a job advert. But it might be useful to any out of work Domino developers.

2 x Applications and Development Consultant (with a focus on Learning Technology)

We are looking for experienced web-based software development professionals with substantial programming experience (preferably with expertise in Lotus Domino, Lotuscript, Java but additional languages such as .NET would be of interest) to join our web and learning applications team; developing and supporting the University’s intranet and on-line learning and business support environments.

More details can be found on The University of Hertfordshire’s website

]]> http://blog.pahudson.net/archives/217/feed 0 http://blog.pahudson.net/archives/200 http://blog.pahudson.net/archives/200#comments Tue, 16 Jun 2009 20:40:38 +0000 Paul http://blog.pahudson.net/?p=200

Our Domino servers (7.03) run on Solaris and we’ve recently moved them onto new hardware. As part of the move, they have been moved in Solaris zones. Unfortunately since the changes we’ve experienced a serious issue that appears to be related to server permissions. Users are loosing the ability to upload files as it appears that the server is rewriting the permissions to the ID file so root access is required. Effectively the server is loosing access to it’s own ID file. So far we’ve been unable to identify why this happens.

We all experience issues with all software and Domino / Notes is not immune but it’s really infuriating when two issues strike at once.

We’ve been moving server’s around and my Design (8.02) client stopped replicating. Not in the normal way, an invalid connection document, but one where any replication event caused an immediate NSD. After much hair pulling – and at my age that’s something you want to avoid in case it doesn’t grow back – the only solution appears to be a complete reinstall.

The second more serious issue was that one of our servers lost permissions to it’s own ID file. Although HTTP continued to serve files anything requiring the ID file stopped functioning. A quick chmod solved the problem and all functionality returned. But this is the first live server we’ve run in a Solaris zone and the how zones function is beyond my basic unix skills. Hopefully this is a simple unix configuration issue and not some fundamental problem with domino on solaris (it wouldn’t be the first time we’ve run into solaris issues). One for our Domino admin to sort out tomorrow.

We have a facility for staff that allows them to download an Excel marking scheme, enter student marks and then to upload it as a tab delimited file (or xml file) back into the system. Last night a member of staff using the facility crashed both servers in our cluster.

On further inspection (and a lot of development server crashes!) I finally narrowed the problem down to a single line of code

Line Input #fileID, strLine

On further investigation it appears that the user exported their marking scheme from Excel using the ‘Unicode (.txt)’ rather than ‘ Text (.txt)’ and it’s the import of Unicode that was causing Domino to crash. My quick solution to stop the server crash is to use ‘Dos2Unix’ convert the file before importing. Although it seems to alter the format so that it no long imports correctly, it’s stopped the server from crashing.

A word of warning if you use a Google Search Appliance to index your Domino content. The latest version of the appliance software (5.2.0.G32) has a bug which means it is now case sensitive when checking for Domino rewrite and ignore rules. For example it will only exclude agents if they are correctly capitalised. i.e OpenAgent. If you have agents which might cause you some problems (say agents that delete content or send emails), make sure you add ignore statements to the exception lists before starting the index. Luckily our Google box runs with ‘student’ access so couldn’t do any damage!

A survey by WebAIM on how users of screen readers interact with web pages is worth a read. It gives a small insight into how screen reader users navigate around pages and some of the problems they face. The survey failed to clarify the term Web 2.0 so the survey hasn’t helped to understand if AJAX based sites disenfranchise partially sighted users but it does confirm some of the advice accessibility experts make. It also reinforces some of the point I tried to make to the Domino developers at Lotusphere about where the new XPage technology fails to meet basic accessibility criteria, namely that screen reader users use the page’s semantics to navigate around the page. A good practice that XPage authoring using the visual interface fails to support.

When html was originally specified it was intended to be a docuument markup language and the tags selected define the page’s content – headings, paragraphs, lists, etc. As web developers we all know this, it’s really basic stuff.

Since headings are more important than paragraphs, a significant percentage of screen reader users use headings to quickly navigate around sections of the page and this confirms the advice accessibility experts have been giving for years. Define a readable document and then style it to look like an application. XPages gets this fundamentally wrong and provides no visual tools to generate standard page markup, a glaring omission that no other editor that I’m aware off fails to include.

All’s not lost. If you want to develop a semantic page it’s just a case of switching to code view and you can add normal markup and it wouldn’t take much for Lotus to add some simple page editing tools.

Hopefully surveys like this help developers see how some simple changes to their pages can make page browsing easier for a small forgotten number of web users

Ok, I’ve been using Domino long enough to know that templates don’t do what you think they should do so I shouldn’t really be surprised.

I had a problem with document locking. Some documents couldn’t be edited because there were some temporary locks being set and my code didn’t unlock them. Okay, my code was at fault, I’d accidentally allowed temporary locks when the administration server was unavailable, but since our servers only get rebooted once a week about 2 in the morning and the documents in question were created during the day, I shouldn’t have been seeing temporary locks.

On further investigation it appears that reason temporary locks were being set was because there was no administration server set in the ACL. This was despite the fact I had set one in the template the database was created from.

I’ve never understood why some features are inherited at creation and others aren’t. If the tick option for document locking is inherited and designed to use the administration server to ensure locking in a cluster, is it wrong of me to think that this should also be inherited from the template?

From my personal perspective the big feature in 8.5 is XPages, but 8.5 is not a one trick pony. There have been a number of other improvements, such as the ID Vault (something not applicable in our institution) and Domino Attachment and Object Service (DAOS).

DAOS

DAOS is described elsewhere. But basically, DAOS allows you to store the attachments in your Domino databases outside of the database, reducing the size of the nsf. 

Big figures are being thrown around; reducing storage size by 40-60%, removal of duplicate attachments and DAOS invisible to Domino apps

DAOS can be enabled per-database or across the entire server and it’s possible to undo the change at a later stage, which is excellent news. Also since it’s implemented at the API level, it’s invisible to the end user or developer.

Reflecting on our system, DAOS  offers:

• Quicker backups. DAOS are stored as files on the file system so can be incrementally backed up.
• NSF are smaller. Since these are loaded into the server’s cache for web delivery, this means more apps can stay resident in memory and so less disk IO.
• We create 4000 modules (databases) per year and carry across teaching resources from previous years. Often resources are uploaded as attachments, and don’t change year on year, so we should see another significant space saving

Other 8.5 features and benefits

• 8.5 contains 400 bug fixes to the nsf
• 50% reduction in CPU for transaction logging
• ID Vault (easier password change)
• Domino configuration tuner for identifying performance issues with your Domino setup. This will be updated as and when, rather than being tied to a Domino release, another positive step from Lotus. 

Developments post 8.5

There will finally be a new Eclipse based lotuscript editor release with 8.5.1

Further ahead the team are investigating how XPages can consume SOAP, REST, and XML (data sources). New controls for XPages such as menu bar, toolbar, outline and general performance improvements.

They are also working on directory independence such as using user info from ldap or active directory to improve single sign-on

…. confusing! I’m sure it will make sense once I start to use it. 

Had a brief look at the 8.5 discussion template and it appears all that all link properties are blank so no effort has been made to generate alternative views when Javascript is unavailable. Bad design. 

I’m not sure when I’ll be able to use XPages in anger. Our learning environment has 22,000 users with 14,000 individuals logging in daily. It’s completely web based – no Notes clients, and with the environment heavily used in teaching, we have to ensure the software is reliable before upgrading. We’ve experienced reliability issues with Domino on Solaris pre X.02/X.52 release so we tend to wait for these releases. We’re also are limited to making big system upgrades to the month of August. So it may even be 2010 before I see 8.5 live on our systems. Let’s hope 8.5 proves to be reliable and we can go sooner.