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Steve Kemp: Putting the finishing touches to a nodejs library

Fri, 11/04/2014 - 15:14

For the past few years I've been running a simple service to block blog/comment-spam, which is (currently) implemented as a simple JSON API over HTTP, with a minimal core and all the logic in a series of plugins.

One obvious thing I wasn't doing until today was paying attention to the anchor-text used in hyperlinks, for example:

<a href="http://fdsf.example.com/">buy viagra</a>

Blocking on the anchor-text is less prone to false positives than blocking on keywords in the comment/message bodies.

Unfortunately there seem to exist no simple nodejs modules for extracting all the links, and associated anchors, from a random Javascript string. So I had to write such a module, but .. given how small it is there seems little point in sharing it. So I guess this is one of the reasons why there often large gaps in the module ecosystem.

(Equally some modules are essentially applications; great that the authors shared, but virtually unusable, unless you 100% match their problem domain.)

I've written about this before when I had to construct, and publish, my own cidr-matching module.

Anyway expect an upload soon, currently I "parse" HTML and BBCode. Possibly markdown to follow, since I have an interest in markdown.

Categories: LUG Community Blogs

Steve Kemp: A small assortment of content

Thu, 10/04/2014 - 16:34

Today I took down my KVM-host machine, rebooting it and restarting all of my guests. It has been a while since I'd done so and I was a little nerveous, as it turned out this nerveousness was prophetic.

I'd forgotten to hardwire the use of proxy_arp so my guests were all broken when the systems came back online.

If you're curious this is what my incoming graph of email SPAM looks like:

I think it is obvious where the downtime occurred, right?

In other news I'm awaiting news from the system administration job I applied for here in Edinburgh, if that doesn't work out I'll need to hunt for another position..

Finally I've started hacking on my console based mail-client some more. It is a modal client which means you're always in one of three states/modes:

  • maildir - Viewing a list of maildir folders.
  • index - Viewing a list of messages.
  • message - Viewing a single message.

As a result of a lot of hacking there is now a fourth mode/state "text-mode". Which allows you to view arbitrary text, for example scrolling up and down a file on-disk, to read the manual, or viewing messages in interesting ways.

Support is still basic at the moment, but both of these work:

-- -- Show a single file -- show_file_contents( "/etc/passwd" ) global_mode( "text" )

Or:

function x() txt = { "${colour:red}Steve", "${colour:blue}Kemp", "${bold}Has", "${underline}Definitely", "Made this work" } show_text( txt ) global_mode( "text") end x()

There will be a new release within the week, I guess, I just need to wire up a few more primitives, write more of a manual, and close some more bugs.

Happy Thursday, or as we say in this house, Hyvää torstai!

Categories: LUG Community Blogs

Steve Kemp: So that distribution I'm not-building?

Sun, 06/04/2014 - 15:35

The other week I was toying with using GNU stow to build an NFS-share, which would allow remote machines to boot from it.

It worked. It worked well. (Standard stuff, PXE booting with an NFS-root.)

Then I started wondering about distributions, since in one sense what I'd built was a minimal distribution.

On that basis yesterday I started hacking something more minimal:

  • I compiled a monolithic GNU/Linux kernel.
  • I created a minimal initrd image, using busybox.
  • I built a static version of the tcc compiler.
  • I got the thing booting, via KVM.

Unfortunately here is where I ran out of patience. Using tcc and the static C library I can compile code. But I can't link it.

$ cat > t.c <>EOF int main ( int argc, char *argv[] ) { printf("OK\n" ); return 1; } EOF $ /opt/tcc/bin/tcc t.c tcc: error: file 'crt1.o' not found tcc: error: file 'crti.o' not found ..

Attempting to fix this up resulted in nothing much better:

$ /opt/tcc/bin/tcc t.c -I/opt/musl/include -L/opt/musl/lib/

And because I don't have a full system I cannot compile t.c to t.o and use ld to link (because I have no ld.)

I had a brief flirt with the portable c-compiler, pcc, but didn't get any further with that.

I suspect the real solution here is to install gcc onto my host system, with something like --prefix=/opt/gcc, and then rsync that into my (suddenly huge) intramfs image. Then I have all the toys.

Categories: LUG Community Blogs