XQuery/图像库
< XQuery
您想要一个脚本，它将显示图像集合中所有图像的小缩略图。这些图像可能具有许多文件后缀（jpg、png、gif 等）。
我们将编写一个 XQuery，它会找到集合中具有正确文件类型的所有子资源。
xquery version "1.0";
declare option exist:serialize "method=xhtml media-type=text/html";
(: look for the collection parameter in the incoming URL. If not assume a default collection like /db/images. :)
let $collection := request:get-parameter('collection', '/db/images')
(: you can also change the number of images per row :)
let $images-per-row := xs:integer(request:get-parameter('images-per-row', 10))
(: first get all the files in the collection :)
let $all-files := xmldb:get-child-resources($collection)
(: now just get the files with known image file type extensions :)
let $image-files :=
for $file in $all-files[
ends-with(.,'.png') or
ends-with(.,'.jpg') or
ends-with(.,'.tiff') or
ends-with(.,'.gif')]
return $file
let $image-count := count($image-files)
let $rows-count := xs:integer(ceiling($image-count div $images-per-row))
return
<html>
<head>
<title>Images for collection {$collection}</title>
</head>
<body>
Images in collection: {$collection}
<table>{
for $row in (1 to $rows-count)
return
<tr>{
for $col in (1 to $images-per-row)
let $n := ($row - 1 ) * $images-per-row + $col
return
if ($n <= $image-count)
then
let $image := $image-files[position() = $n ]
let $path := concat('/exist/rest', $collection, '/', $image)
return
<td>
<a href="{$path}"><img src="{$path}" height="100px" width="100px"/></a>
</td>
else <td/> (: blank cells at the end of the last row :)
}</tr>
}</table>
</body>
</html>