Provide endpoints to submit tasks to re-generate previews

The scaling factor can be given in the config file. When this changes,
images can be regenerated via POSTing to certain endpoints. It is
possible to regenerate just one attachment preview or all within a
collective.

modules/extract/src/main/scala/docspell/extract/ExtractConfig.scala

@@ -1,5 +1,6 @@
 package docspell.extract
 
 import docspell.extract.ocr.OcrConfig
+import docspell.extract.pdfbox.PreviewConfig
 
-case class ExtractConfig(ocr: OcrConfig, pdf: PdfConfig)
+case class ExtractConfig(ocr: OcrConfig, pdf: PdfConfig, preview: PreviewConfig)

modules/extract/src/main/scala/docspell/extract/pdfbox/PdfboxPreview.scala

@@ -21,11 +21,13 @@ trait PdfboxPreview[F[_]] {
 
 object PdfboxPreview {
 
-  def apply[F[_]: Sync](dpi: Float): F[PdfboxPreview[F]] =
+  def apply[F[_]: Sync](cfg: PreviewConfig): F[PdfboxPreview[F]] =
     Sync[F].pure(new PdfboxPreview[F] {
 
       def previewImage(pdf: Stream[F, Byte]): F[Option[BufferedImage]] =
-        PdfLoader.withDocumentStream(pdf)(doc => Sync[F].delay(getPageImage(doc, 0, dpi)))
+        PdfLoader.withDocumentStream(pdf)(doc =>
+          Sync[F].delay(getPageImage(doc, 0, cfg.dpi))
+        )
 
       def previewPNG(pdf: Stream[F, Byte]): F[Option[Stream[F, Byte]]] =
         previewImage(pdf).map(_.map(pngStream[F]))

modules/extract/src/main/scala/docspell/extract/pdfbox/PreviewConfig.scala

@@ -0,0 +1,3 @@
+package docspell.extract.pdfbox
+
+case class PreviewConfig(dpi: Float)

modules/extract/src/test/scala/docspell/extract/pdfbox/PdfboxPreviewTest.scala

@@ -21,7 +21,7 @@ object PdfboxPreviewTest extends SimpleTestSuite {
       val data = file.readURL[IO](8192, blocker)
       val sha256out =
         Stream
-          .eval(PdfboxPreview[IO](48))
+          .eval(PdfboxPreview[IO](PreviewConfig(48)))
           .evalMap(_.previewPNG(data))
           .flatMap(_.get)
           .through(fs2.hash.sha256)