Ben McGraw’s Egometry

…or Part 2 of “Could not open the requested SVN filesystem”

Two years ago I ran into a problem with my SVN filesystem and got “Could not open the requested SVN filesystem” as the front-end error.

This appears to be an annoying catch-all error for “shit is broken with your SVN, dawg.”

Last time, it was because I had SVNPath defined in my apache’s httpd.conf file instead of SVNParentPath (when I had many repos in the same root directory.) This time I did not have that problem, but I did have the same error message.

That is annoying.

After several dead-ends, the vital kernel of information came from Mr. Mike Rooney’s suggestion to go to the host server itself and run:

sudo svn ls file:///path/to/local/repo

The two important parts here are that I’m trying to access the bjorked repo from the local filesystem, so the webdav layer isn’t being retarded at me and giving me the same enigmatic error message. The second important part here is that I’m running sudo to get past possible permission problems.

That command produced the following output:

$ sudo svn ls file:///path/to/local/repo/
svn: Unable to open an ra_local session to URL
svn: Unable to open repository 'file:///path/to/local/repo/'
svn: Berkeley DB error for filesystem '/path/to/local/repo/db' while opening environment:

svn: DB_VERSION_MISMATCH: Database environment version mismatch
svn: bdb: Program version 4.6 doesn't match environment version 4.4

At this point, I used the tried and true google-the-unique-error-message technique. After googling “svn: DB_VERSION_MISMATCH: Database environment version mismatch” (including the quotation marks for an exact search), I found this blog post that solved my problem.

Here’s the punchline:

$ cd /path/to/myrepo/db
$ db4.4_checkpoint -1
$ db4.4_recover
$ db4.4_archive
$ svnlook youngest ..
$ db4.6_archive -d

BUT…

The double-punchline that screwed me for a while was the fact that the berekley db utils for 4.4 were unavailable via apt-get in modern times. Thankfully, long-time systems-administration bad-ass Ted Reed was here to suggest the following set of commands:

$ wget http://mirrors.kernel.org/ubuntu/pool/universe/d/db4.4/libdb4.4_4.4.20-12_i386.deb
$ wget http://mirrors.kernel.org/ubuntu/pool/universe/d/db4.4/db4.4-util_4.4.20-12_i386.deb
$ dpkg -i libdb4.4_4.4.20-12_i386.deb
$ dpkg -i db4.4-util_4.4.20-12_i386.deb

All of these commands (run as root or through sudo) grab the neccesary files from arcane places and got them installed. After that, the previous blog post’s wisdom could be applied. From there, I was a chmod, a chgrp, and a chown away from actually being able to access my old repository again.

Of course, this was about 10 hours after where I expected to grab my old repo’s contents…

Ask http://packages.debian.org/

Specifically the searchbox partway down the page under “Search package directories”.

Yeah, hat’s about it.

<Hyptosis> Nice, there was a copper head asleep ontop of the turnoff to our 
           main water vein.
<Hyptosis> And, ontop of the snake
<Hyptosis> I shit you not
<Hyptosis> A fucking Brown Recluse
<Hyptosis> It was like a poison cocktail
<gru> Did you kill them both?
<gru> Or did you decide "Nah, no need to turn off the water."
<Hyptosis> I flick the spider out of the way and tossed the snake into the grass
<Hyptosis> Then turned the water off
<chrisa> I feel like you live in "MANmerica" and I live in some pansy ass
         settlement within it

From #sancho on irc.lunarnet.org.

Hyptosis’s homepage
chrisa’s homepage

Sophia has been chomping at the bit to make more games. Since it’s been going on two years since I last flexed my gamemaking muscles fully, and since I rather adore Sophia, I’ve been chasing this rainbow.

I’ve been ever more intrigued by the idea of a pure html/javascript game engine of late, and have started taking existing, established tools (like mapeditor.org’s tiled) and putting them into the browser.

Here’s the result: (currently firefox-only). To fully get the pleasure, inspect elements on this example in firebug.

The idea is simple: html/js has affordances baked-in to parse xml documents. This can handle traditional map data. css sprite-sheet techniques have been used for years now, which directly mimic old tilset/vsp-style assets. Combine the two… and you have a effen map. Throw in browser optimizations for visible/hidden elements, and we should have a relatively cheap rendering method.

The above test is fairly simple: one 30×30 map, one layer. It loads instantaneously fast. It’s tiles are a single gif sized 304×144. Fairly economical. I decided to shove each of these boys into a div for now and use the background-image css spriting technique to get a “purist” tiling implementation going.

I opted against using canvas for now because I wanted to see how far I could get without it. So far so good, but I’ve not yet really stressed the system. The next jump will be to take some of my epic 6-layer maps from SotS, translate them into xml, and see how they fair in the browser.

Of the code I wrote, I suppose the “sauce” was a fairly common offset calculation. Although this sort of endeavor may not be so common in the modern age, it’s pretty commonplace to those of us who labored in 320×240 back in DOS. Get off my lawn.

var tileset = {
    tileWidth: 16,
    tileHeight: 16,
    setWidth: 304,
    setHeight: 144,

    getCoordsfromIdx : function( idx ) {
        var idx = parseInt(idx);
        idx--; //tmx is 1-based, not 0-based.  We need to sub 1 to get to a proper mapping.
        //idx--;

        var perRow = this.setWidth / this.tileWidth;

        var x = idx % perRow;
        var y = (idx / perRow);

        return [
            -(parseInt(x)*parseInt(this.tileWidth)),
            -(parseInt(y)*parseInt(this.tileHeight))
        ];
    }
}

This is converting a single tile index into two coordinates for the renderer to consume. For instance, if you want tile 2, it takes a ’2′ at the top, does some maths, and tells you that tile 2′s offset is 16 pixels in from the top-left corner, and 0 pixels down (ie, on the top row). Some strange quirks of this code: I had to decrement the idx, because Tiled’s xml format is 1-based, not 0 (ie, the first tile, the one at (0,0), is index 1, not index 0); and I negate the two numbers I return because the consumer of these coordinates is a css background-position style, and that’s how they work.

Also of note was a small hiccup when I uploaded this to my server. My sandbox had no trouble serving a .tmx file as Content-Type: text/xml, but my big-boy server threw a conniption about it. I didn’t realize that was a problem until I threw some debugger statements into the code that “should’ve just worked” and found that all of the proper stuff was in the responseText attribute, but responseXML was null. So I renamed the mapfile to .xml on the server and everything worked fine.

I guess next step, before trying to stress the system with a super macho map, is to figure out why this isn’t working in Safari/Chrome/IE/Opera/Whatever…

The most pedestrian screenshot ever. To what depths has this once-mighty work-journal fallen?

My gruedorf showings are shameful of late, and so are all of yours. The only one holding the line at this moment is Ustor. Perhaps this should be called “UstorUstor”. Or “TorUs”.

At any rate, my small token to personal projects this week is the file management section’s edit page. Woo, now you can edit your files once they exist. Necessary, and very quotidian to a web developer.

Up next on this mystical journey is the upload section’s frontpage, featuring most downloaded recently, newest files, and staff picks (aka, Demo Alarms). After that, we’re a docs section from release. At this point, I think I should screen-scrape my old site’s documentation and import all of that into a wiki. Anyone have objections?

I’ve mainly been dealing with code concerning the files section.  I’ve improved the quality of the upload process, corrected the file lineage graph and made strides towards a saner system, have made it so you can comment upon file entries, and made it so anyone can upload screenshots of any file.

Also I made an schema-application tool to keep track of which .sql files have been applied in what environment.  Trust me, this is useful.

So where did I go for two months, far, far away from Gruedorf?  I honestly can say I was shocked to crack open this dev folder to find the last svn log from July 10.  So wherever I went, it didn’t seem as long as it was. :(

PHP seems so arbitrary sometimes.

function test_nine() {
	$$"9" = 22;
}

fails to parse.
(which is good, I suppose)

This passes:

function test_nine() {
	$n = 9;
	$$n = 22;
	$this->assertEqual($$n, 22);
}

-Andy Friesen,
of giant-communist-robots.com.

Between putting in incredible hours at work, and a few Magic: the Gathering pre-release events in the last week, I haven’t had much time for gruedorfing.

However, I still got 14 commits in.  (All of them Friday morning.)

The work done was all in finalizing the /downloads/complete-new-os/ page, and tracking down and fixing errors that had cropped up in the upload process.

The second item distresses me, presently, since a solid upload system was the main impetus for the rewrite.  finding out that uploads are still fragile and very prone to breaking with forward development, combined with the fact that I don’t have a testing strategy for roundtrip uploads, means I’m kinda nervous.

So, anyone out there have a good solution for a round-trip integration test where you upload, via flash and javascript, a unique file, and then verify that the file exists on a unix filesystem, and then verify that a corresponding database entry and further corresponding webpage works?

Moving forward, I’ll be working on an administrative page to allow file owners/admins to associate file instances as older/newer versions of the same file.

After some prodding, I managed to get the dorf back into gruedorf. Let the games resume.

Since last I posted about beta.vrpg, 58 revisions have occurred. In that time:

• I got file submissions up.
• I got (simple, title-based) file searches up.
• I got most of the file details page up (thread spawning, screenshot uploading pending).
• I did a lot of database reworking and massaging, mainly to get to a point where…
• …single file entries can have multiple physical files attached, so one game can have file links to every OS it’s released on

Oh, and I made a Silly 500 Internal Service Error page.

Definitely the most important part of this work.

Going forward will be finishing the file management side of things (letting you deprecate old versions of files in favor of new ones, showing a browsable history, letting you edit and delete files you own), and cranking out the community-based side of things (ie, image uploading and talkback threads on file pages.) After that, advanced search options and a browsable file index, and the section should be complete.

I’m mainly excited to see a upload system that hasn’t seen a failure yet. This was one of the major failures of the current vrpg that prompted the rewrite. I used swfupload for the actual UI/handling of the upload, and integrating it went very smoothly.

If I’m in an instanced class, and I call another class’s method statically inside of a method in the first class, and that static method should happen to (erroneously) have $this->whatever inside of it…

…it sets $whatever on my outer instanced class.

Here’s some illustrative code:

<?
    class Inner_Static {
        function burrito() {
            $this->_member = ‘A keyboard. How quaint.’;
        }
    }

    class Outer_Instance {
        function taco() {
            Inner_Static::burrito();
        }
    }

    $my_guy = new Outer_Instance();
    $my_guy->taco();

    print ‘$my_guy->_member: ‘ . $my_guy->_member; 

This boggles my mind a bit. Tracking it down cost me a bit of time. Is there actually a sane use for this little tidbit, or am I justified in thinking that a good language would warn you that scope shenanigans are going on here?