On 03/18/2021 04:30 PM, Paul Heinlein wrote:> On Thu, 18 Mar 2021, H wrote: > >> I have a challenge I am interested in getting feedback on. >> >> I will on a regular basis download a series of data files from the web where the data is in XML-format. The format is known in advance but is different between the various data files. I then plan to extract the various data items ("elements?") from each data file, do some light formatting and then save desired parts of each original data file as a formatted CSV-file for later importing into a database. >> >> As the plan is to use a bash shell script using curl to get the files, I have begun looking at external XML parsers that I can call from my script, perhaps specify which elements I want, get the data back in some kind of bash data structure and finally format and save as CSV-files. >> >> There seems to be a number of XML parsers available but perhaps someone on the list has a recommendation for which one might suit my needs best? I should add that I am running CentOS 7. > > Will you be using an XSLT stylesheet to do the work? There's a somewhat steep learning curve, but in my experience it's the most reliable method for parsing XML except in the very simplest of cases. > > In that case, the libxslt stuff may be what you want: > > ? http://xmlsoft.org/libxslt/ > > The command-line tool is xsltproc. > > Again, it's not easy to use, but once you've built a toolchain, it will be reliable and fairly easy to modify if the source XML schema change. >I just checked and I cannot see that the organization publishing these data files offer any XSLT stylesheet. IOW, I am, perhaps incorrectly, assuming that the publisher of the data would be one with said stylesheet. (Although perhaps that is something an end-user could put together as well??) Although the data format of each data series is unique, it is simple and could conceivably be parsed using grep but I am looking for a more "forward-looking" solution for other applications in the future. If XSLT stylesheets are not available - would you suggest another tool? Or, would you suggest I design sheets, presumably one for for each data series?
On Thu, 18 Mar 2021, H wrote:> I just checked and I cannot see that the organization publishing > these data files offer any XSLT stylesheet. IOW, I am, perhaps > incorrectly, assuming that the publisher of the data would be one > with said stylesheet. (Although perhaps that is something an > end-user could put together as well??)Some high-profile XML schemata (e.g., DocBook) have published stylesheets, but mostly I've written my own. I have a very trivial example in a blog post from several years ago: https://www.madboa.com/blog/2014/09/10/strip-rss/ (My site is completely non-commercial. I gain nothing by you visiting it -- or ignoring it.) -- Paul Heinlein heinlein at madboa.com 45.38? N, 122.59? W
On 18/03/2021 22:08, H wrote:> On 03/18/2021 04:30 PM, Paul Heinlein wrote: >> On Thu, 18 Mar 2021, H wrote: >> >>> I have a challenge I am interested in getting feedback on. >>> >>> I will on a regular basis download a series of data files from the web where the data is in XML-format. The format is known in advance but is different between the various data files. I then plan to extract the various data items ("elements?") from each data file, do some light formatting and then save desired parts of each original data file as a formatted CSV-file for later importing into a database. >>> >>> As the plan is to use a bash shell script using curl to get the files, I have begun looking at external XML parsers that I can call from my script, perhaps specify which elements I want, get the data back in some kind of bash data structure and finally format and save as CSV-files. >>> >>> There seems to be a number of XML parsers available but perhaps someone on the list has a recommendation for which one might suit my needs best? I should add that I am running CentOS 7. >> >> Will you be using an XSLT stylesheet to do the work? There's a somewhat steep learning curve, but in my experience it's the most reliable method for parsing XML except in the very simplest of cases. >> >> In that case, the libxslt stuff may be what you want: >> >> ? http://xmlsoft.org/libxslt/ >> >> The command-line tool is xsltproc. >> >> Again, it's not easy to use, but once you've built a toolchain, it will be reliable and fairly easy to modify if the source XML schema change. >> > I just checked and I cannot see that the organization publishing these data files offer any XSLT stylesheet. IOW, I am, perhaps incorrectly, assuming that the publisher of the data would be one with said stylesheet. (Although perhaps that is something an end-user could put together as well??) > > Although the data format of each data series is unique, it is simple and could conceivably be parsed using grep but I am looking for a more "forward-looking" solution for other applications in the future. > > If XSLT stylesheets are not available - would you suggest another tool? Or, would you suggest I design sheets, presumably one for for each data series? >I used in the past xmlstarlet (available in epel) for quick parsing from within bash scripts. For something more robust, maybe switch to python ? (ymmv) -- Fabian Arrotin The CentOS Project | https://www.centos.org gpg key: 17F3B7A1 | twitter: @arrfab