xquery version "1.0" encoding "utf-8";

declare namespace response="http://exist-db.org/xquery/response";
declare namespace image="http://exist-db.org/xquery/image";
import module "http://exist-db.org/xquery/util";

let $pathToBinaryResource := '/db/img/ztj/a0001.png'
let $original-path := '/exist/img/cropped.png'
let $img := util:binary-doc( xs:anyURI($pathToBinaryResource ) )

return response:stream-binary(
(: 
     The maximum dimension of the cropped image. expressed in 
     pixels (x1, y1, x2, y2) 
:)
  image:crop($img, (200, 150, 240, 240 ), 
             'image/png' ), 'image/png' ,
             xs:anyURI( $original-path )
)

Thanks to Christian Wittern @exist-open

Sometimes, on a production server, you may want to store the application within the database, but without allowing users to browse the database contents. By setting hidden=true, you can expose defined URLs to the outside world via URL rewriting while hiding the rest of the database.

Add the following code to EXistServlet in web.xml:

 <init-param>
  <param-name>hidden</param-name>
  <param-value>false</param-value>
 </init-param>

If parameter "hidden" is set to true, direct access to the REST interface will be denied. Only requests coming from the URL rewriting will be processed.

this is available on eXist-db version 1.5 only (yet)

Problem: locked 'webapps' files

When eXist-db is running under windows, all files that are stored in the 'webapps' directory (e.g. .xql files, .css files etc) are locked by the Operating system. As a result these files cannot be edited anymore, until the database is stopped.

Work around

The webserver Jetty tries to buffer static content (html, xql css js etc), for this memory mapped files are used. Under Windows however, memory mapping of files result into a lock of these files.

This behaviour can be changed by editing the jetty configuration file tools/jetty/etc/webdefault.xml:

<init-param>
  <param-name>useFileMappedBuffer</param-name>
  <param-value>true</param-value> <!-- change to false -->
</init-param>

References

• Exist-open: Jetty is locking JavaScript and CSS files used in page (Win XP)
• Jetty: Files are locked on Windows and cant be replaced

Although sorting text seems to be a simple process, it actually is not the case. Many languages have 'special' characters which should be taken into account in the sorting process.

Collation provide a choice of four ordering strengths: PRIMARY, SECONDARY, TERTIARY and IDENTICAL. The actual implementation is 'locale' dependent:

• Primary: deals with base letters e.g. "a" vs "b"
• Secondary: differences in accented forms of the same base letter: "a" vs "ä"
• Tertiary: case differences, "a" vs "A"
• Identical: Primary, Secondary and Tertiary, but different in control characters.

In xquery the collection can be used as demonstrated in the following code example:

for $a in $b
order by $a collation "?strength=tertiary"
return $a

References

• Java Collator
• Wikipedia: collation complications
• W3C