| Andrew Cooke | Contents | Latest | RSS | Twitter | Previous | Next


Welcome to my blog, which was once a mailing list of the same name and is still generated by mail. Please reply via the "comment" links.

Always interested in offers/projects/new ideas. Eclectic experience in fields like: numerical computing; Python web; Java enterprise; functional languages; GPGPU; SQL databases; etc. Based in Santiago, Chile; telecommute worldwide. CV; email.

Personal Projects

Lepl parser for Python.

Colorless Green.

Photography around Santiago.

SVG experiment.

Professional Portfolio

Calibration of seismometers.

Data access via web services.

Cache rewrite.

Extending OpenSSH.

C-ORM: docs, API.

Last 100 entries

Have to add...; Culturally Liberal and Nothing More; Weird Finite / Infinite Result; Your diamond is a beaten up mess; Maths Books; Good Bike Route from Providencia / Las Condes to Panul\; Iain Pears (Author of Complex Plots); Plum Jam; Excellent; More Recently; For a moment I forgot StackOverflow sucked; A Few Weeks On...; Chilean Book Recommendations; How To Write Shared Libraries; Jenny Erpenbeck (Author); Dijkstra, Coins, Tables; Python libraries error on OpenSuse; Deserving Trump; And Smugness; McCloskey Economics Trilogy; cmocka - Mocks for C; Concept Creep (Americans); Futhark - OpenCL Language; Moved / Gone; Fan and USB issues; Burgers in Santiago; The Origin of Icosahedral Symmetry in Viruses; autoenum on PyPI; Jars Explains; Tomato Chutney v3; REST; US Elections and Gender: 24 Point Swing; PPPoE on OpenSuse Leap 42.1; SuperMicro X10SDV-TLN4F/F with Opensuse Leap 42.1; Big Data AI Could Be Very Bad Indeed....; Cornering; Postcapitalism (Paul Mason); Black Science Fiction; Git is not a CDN; Mining of Massive Data Sets; Rachel Kaadzi Ghansah; How great republics meet their end; Raspberry, Strawberry and Banana Jam; Interesting Dead Areas of Math; Later Taste; For Sale; Death By Bean; It's Good!; Tomato Chutney v2; Time ATAC MX 2 Pedals - First Impressions; Online Chilean Crafts; Intellectual Variety; Taste + Texture; Time Invariance and Gauge Symmetry; Jodorowsky; Tomato Chutney; Analysis of Support for Trump; Indian SF; TP-Link TL-WR841N DNS TCP Bug; TP-Link TL-WR841N as Wireless Bridge; Sending Email On Time; Maybe run a command; Sterile Neutrinos; Strawberry and Banana Jam; The Best Of All Possible Worlds; Kenzaburo Oe: The Changeling; Peach Jam; Taste Test; Strawberry and Raspberry Jam; flac to mp3 on OpenSuse 42.1; Also, Sebald; Kenzaburo Oe Interview; Otake (Kitani Minoru) move Black 121; Is free speech in British universities under threat?; I am actually good at computers; Was This Mansplaining?; WebFaction / LetsEncrypt / General Disappointment; Sensible Philosophy of Science; George Ellis; Misplaced Intuition and Online Communities; More Reading About Japan; Visibilty / Public Comments / Domestic Violence; Ferias de Santiago; More (Clearly Deliberate); Deleted Obit Post; And then a 50 yo male posts this...; We Have Both Kinds Of Contributors; Free Springer Books; Books on Religion; Books on Linguistics; Palestinan Electronica; Books In Anthropology; Taylor Expansions of Spacetime; Info on Juniper; Efficient Stream Processing; The Moral Character of Crypto; Hearing Aid Info; Small Success With Go!; Re: Quick message - This link is broken; Adding Reverb To The Echo Chamber; Sox Audio Tools

© 2006-2015 Andrew Cooke (site) / post authors (content).

Session Limitation with Acegi

From: "andrew cooke" <andrew@...>

Date: Mon, 27 Feb 2006 14:44:16 -0300 (CLST)

Sometimes it's useful to restrict a user a single session.  This
simplifies the logic needed to guarantee certain restrictions.

For example, I always want a user to have a minimum of one valid email
address.  With two parallel sessions and two valid emails a user could
delete one email in each session and I would need to verify consistency in
the database.  Restrictig to one session lets me implement the restriction
in the business logic.

However, the exact configuration was not obvious.  After some
experimentation the following seemed to work.

First, you need some way of detectig when sessions expire.  This is
largely automatic as long as you register the following in web.xml:

  <!-- used to track session events (single user session) -->

I have all my authentication-related xml in web-authentication.xml (and
referenced via context-param in web.xml).  It includes:

  <bean id="authenticationManager"
    <property name="sessionController" ref="singleSession"/>
    <property name="providers">

  <bean id="sessionRegistry"

  <bean id="singleSession"
    <property name="maximumSessions" value="1"/>
    <property name="exceptionIfMaximumExceeded" value="true"/>
    <property name="sessionRegistry" ref="sessionRegistry"/>

Which is all that is needed (I suspect sessionRegistry is supplied by
default anyway).

The way it seems to work is as follows:
- authenticationManager calls the appropriate provider
- if that succeeds, it calls sessionController
- sessionController applies the appropriate logic, using the information
  in sessionRegistry
- sessionRegistry is correct because of the event system (which includes
  the listener you registered).


Session Limitation with Acegi blog post

From: "andrew cooke" <andrew@...>

Date: Fri, 10 Oct 2008 07:07:52 -0400 (CLT)

---------------------------- Original Message ----------------------------
From:    "m zyzy" <myzyzy@...>
Date:    Thu, October 9, 2008 10:40 pm

First of all, I am new in spring and acegi , and I know the post is a bit
old, but I am stuck with acegi v1.0.4 - Spring security V2.0.4 -wait for
me-We'll meet in my next project..

why you dont use this filter below ? is there an explanation as why you
didnt use it?
<bean id="concurrentSessionFilter"
      <property name="sessionRegistry"> <ref bean="sessionRegistry"/>
      <property name="expiredUrl" value="/login.jsp"/>

I also use the same config xml code as you wrote in the blog post but with
the addition of above code and it's work fine for me (of course, with the
above code , I need to add the concurrentSessionFilter in the
filterChainProxy's filter sequence).

-Second as we both use the way that to prevent second login attempt at a
time in different machine/browser , how to show a text message in a jsp
page to indicate that the unsuccessful second logger of user he/she is
trying to log in to is in used already currently? How this can be done?

Thanks .

No Idea!

From: "andrew cooke" <andrew@...>

Date: Fri, 10 Oct 2008 07:14:33 -0400 (CLT)


No idea why I didn't use that - perhaps it wasn't around when I wrote the
code?  Perhaps I missed it?

Curiously, it's not mentioned at

I haven't used Acegi since this post, so I'm afraid I can't help more (but
thanks for posting - people do sometimes read this page, according to my
logs, so it will help them).


Comment on this post