Following up Id9539a28f0f143539334002c3:
* Don't run the script twice.
* Wrap the decoded dump in an array with key "data".
* The default assignment for DJVU_DUMP and DJVU_TXT had the effect of
running the scripts anyway if the configuration variables are null.
Don't do that.
* If both $wgDjvuDump and $wgDjvuTxt are null, don't run the shellbox
script.
* Centralise shell location configuration.
* Factor out call to convertDumpToJSON().
* Instead of txt_exit_code, just use existence of the file to
communicate success. This avoids a deprecation warning if
txt_exit_code was not received, due to passing null to trim.
* Check for the existence of the result files instead of just trying to
use them.
* Check the exit status of the overall script.
* Confirm that the BoxedCommand branch is functional and works in CLI
mode by using it in DjvuTest.
* Change the service name from "media" to "djvu". Existing examples are
"pagedtiffhandler" and "pdfhandler", i.e. named after the extension,
there is no other core caller. I think it should be more fine-grained
than "media". The name was possibly a conflation with the
ProductionServices array key.
Also:
* Check the exit status of djvudump and don't use the output file if it
is non-zero.
* Check the return value of convertDumpToJSON().
* Don't use isset() unless error suppression is intended.
Bug: T352515
Change-Id: If41a2baada2e4e2462518c1f437af458feb29632
497efa4ed6