How to make a sow’s ear into a silk purse/Comment faire d’une buse un épervier

As the proverb says, you can’t turn a buzzard into a sparrow-hawk. But here’s how I went about producing a TEI-conformant minimally encoded edition of the 1611 King James bible, starting from an all-singing, all-dancing, vastly over-complicated, web site to the existence of which Martin Mueller had alerted me last Friday in a plaintive posting to TEI-L

The problem with web sites like this is that they expose only various HTML views of their underlying data, usually heavily infested with javascript, often deploying all sorts of nonstandard gizmos to make the pages look just so. I’ve no quarrel with their doing that, I just wish they’d make it a bit easier to get at the real data, i.e. the transcribed text and the pointers to the images that go with them. This site is a case in point: after spending some time looking at some of the gazillion HTML files a simple-minded wget -r starts hoovering up, I hypothesize that the data is actually stashed away somewhere inaccessible and all that you see on the site is a bunch of variously configured static web pages which have been created from it. The good thing about that is that the static web pages were created by an automaton, and the process can therefore be reversed by another automaton. The bad thing is that (in this case at least) clearly different automata have been used to generate vaguely different versions of the same page. For example: the following three URLs all show subtly different versions of the same first page of the 1611 bible : and

These are not simple redirects: each URL delivers a file in a different format. Well, I could have asked whoever runs this site what was going on, but that would have spoiled the fun, so I chose the format I liked best (the last of the three above) and wrote a script to generate requests for just those pages. I had to assume that the URLs would follow a consistent naming format, encouraged by a table of the names of the books of the bible I found in one of the chunks of embedded javascript, and which I moved into my little perl script. Running this script produced a bash script which grabbed each page using curl and saved it as an HTML file on my machine.
What went wrong with this process? Surprisingly little: I didn’t find out till Sunday lunchtime that not only had I completely overlooked the Apocryphal books, but also that the file naming conventions used for these were not quite the same as for the canonical chapters (« Judith » for example is actually spelled « Iudeth »), but for the bulk of the 1300 or so chapters my guesses about the URL to use were spot on.  [This was Hubris. See my comment below]
The real challenge was disentangling the useful data from the resulting screen-scraped mess of pottage. My usual approach here is to run the HTML I get through Dave Ragget’s utterly wonderful tidy utility to turn it into kosher XML, and then write an XSLT script to pick out the bits I want. In this case, however, the pottage I got was so messy even tidy threw up its metaphorical hands and refused to proceed with it, so I had to concoct a little perl script to pre-process each file and extract just the useful part, before running it through tidy, and processing the resulting XML into conformant TEI by means of saxon and a little XSLT stylesheet. Like this:

for f in webScraped/*.html; do \
FNAME=`basename $f .html`;\ 
echo ${FNAME} ;\ 
perl extract.prl $f | \ 
tidy -q  --error-file tidyerrs --doctype omit --numeric-entities yes - asxml | \ 
saxon -o:chaps/${FNAME}.xml -s:- -xsl:postGrab.xsl chapId=${FNAME};\ 

And what went wrong with this process? Well, quite a lot, as you might expect, but nothing that couldn’t be fixed by tweaking and rerunning the process (this is why I always put the effort into writing bash scripts for jobs like this: they can be rerun till I get it right). For example, I was deriving an XML id for each chapter from the name of the input file, but some of the files had names beginning with digits. My plan was to put each chapter into a separate XML file and then use xInclude to munge them together into a TEI document (to maximize the flexibility of said mungeing) — but for this to work I had to get namespace declarations in the right place, and as anyone who has used them knows, anything involving namespace declarations never works the first time. To say nothing of unexpected inconsistencies in the data : which in fact were really very few. In fact so far, the only thing that has so far caught me out was a handful of chunks which looked like biblical data in the HTML markup but were not. Fortunately these were detectable because they wound up with an invalid @n attribute in the XML output and could therefore be weeded out after the event.
While all this was going on, I wrote my driver file and did some further sniffing around on the interwebs for sources from which to complete the work. The 1611 Bible has a title page and loads of prefatory matter not all of which is available on (for the record, I found the title page on Wikimedia, and the rest of the front matter at several places, but in page image form only).
How should the Bible be modelled as a TEI document? In my first view, each verse is an <ab>, each chapter is a <div>, each book is a <text>, each testament is a <group>. This made sense to me, but then I realised that processing would be simpler if instead each book were regarded as a <div> of a different type; hence, that is what the current versions of both driver file and ODD say. Considerations of where to put the genealogies, tables for Easter, almanachs etc. which arguably do not belong in the front matter may lead me to review that decision, so I have left <group> lurking in my ODD. It should be easy to produce a separate driver file representing that alternative view.

A more pressing need, however, is to sort out the placement of the page image links: in the HTML source, and therefore in my XML, links to the page images for the whole of a chapter are given as a sequence at the start of the transcribed text for that chapter, rather than being placed at the point in the transcript where that page begins. In some cases that point is identifiable because the transcribers have chosen to include part of the running page header in the transcription there (it winds up as a <fw> element); but in many it isn’t. Most chapters only occupy a few pages so sorting this out would not be a major effort, just a rather tedious one, and not-easily-automatable one.
So what have we learned? Actually it’s not that hard to make a usable TEI document even from something as idiosyncratic as this web site. Which is encouraging. Let me also hasten to add that I mean no disrespect for the hard work (still less for the generosity) which must have gone into the production of that website: everyone is entitled to their own design decisions. I am pleased to express my thanks to the anonymous people who have put in that effort, and decided to share its fruits even with the godless multitude. As the 1611 translators say in their preface ‘Zeale to promote the common good, whether it be by devising any thing our selves, or revising that which hath bene laboured by others, deserveth certainly much respect and esteeme’.

Une réflexion au sujet de « How to make a sow’s ear into a silk purse/Comment faire d’une buse un épervier »

  1. Hubris. A week later I was advised by a colleague that she’d just noticed one of the files allegedly containing a chapter of Psalms in fact contained a chapter from Genesis. Further investigation revealed that my guesses about the filenames used, and hence the URLs to scrape from, were seriously wrong on several occasions, mostly because of varying policies about whether to use I or J, U or V on the part of the website editors. I would have detected this a lot sooner if someone (or something) had not also decided that the right response to a request for a non-existent URL (say, « Habbakuk_01 » instead of « Habbakvk_01 ») was not a 404 (or even a helpful page saying « no such book ») but the corresponding chapter from the Book of Genesis. I’m as fond of Genesis as the next sinner, but I really don’t want to read it that often. (Full disclosure: out of 1362 chapters, 567 chapters, or 25 books, had to be rescraped.) On the plus side, while fixing this problem I noticed a minor misapprehension in my XSLT script, and fixed that as well.

Laisser un commentaire

Votre adresse de messagerie ne sera pas publiée. Les champs obligatoires sont indiqués avec *