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https://issues.apache.org/jira/browse/TIKA-4856?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18115963#comment-18115963
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ASF GitHub Bot commented on TIKA-4856:
--------------------------------------
tballison commented on code in PR #3179:
URL: https://github.com/apache/tika/pull/3179#discussion_r4025045789
##########
docs/modules/ROOT/pages/using-tika/server/index.adoc:
##########
@@ -154,6 +154,39 @@ not (detectors, embedded-document extraction, exception
reporting, ...) and rais
limits above the per-request clamp. Every active preset resolves at startup,
so a bad preset
fails the server, not its first request.
+WARNING: An active preset is a public route: anyone who can reach the server
can call it, and
+it runs at config trust — it can bind components `/config` cannot and raise
timeout limits
+above the per-request clamp. Vet a preset as you would
`allowPerRequestConfig`, scoped to what
+the preset turns on. Tika's catalog presets are kept bounded (page and render
caps, no OCR
+unless the preset is about OCR, no timeout raises); hold your own to the same
bar. Startup
+logs one line per active preset naming the components it configures.
+
+==== The `thumbnails` catalog preset
+
+Tika ships one catalog preset, `thumbnails` (in `tika-pipes-core`), for
+`/unpack/preset/thumbnails`. Nothing is active until the operator names it:
+
+[source,json]
+----
+{ "presets": { "thumbnails": true } }
Review Comment:
We should talk about this. I'm really worried about presets going
automatically "live" by default. These two are good, but going forward, we have
to ensure that devs will not add a default that is dangerous in some
environment.
The current PR defines presents, but the operator still has to turn them on.
> /unpack/thumbnail: return the document thumbnail with its metadata
> ------------------------------------------------------------------
>
> Key: TIKA-4856
> URL: https://issues.apache.org/jira/browse/TIKA-4856
> Project: Tika
> Issue Type: New Feature
> Reporter: Dominik Schmidt
> Priority: Major
>
> With TIKA-4850 through TIKA-4855 every container format that carries a
> thumbnail emits it as a THUMBNAIL embedded document, the PDF parser renders
> pages as RENDERING documents, and the EMF/WMF renderer turns the vector
> thumbnails of Office documents into raster ones. Getting "the thumbnail of
> this file" out of that still takes format knowledge on the client: the
> THUMBNAIL of a Word or Excel file is an EMF/WMF whose usable form is the
> RENDERING underneath it, a PDF has no THUMBNAIL but a page RENDERING, the
> THUMBNAIL of a DOCX inside a ZIP is not the ZIP's, and with rendering enabled
> the picture of an embedded OLE object is a RENDERING too. Plus the request
> config that switches the renderers on.
> Proposal: POST /unpack/thumbnail next to /unpack and /unpack/all, multipart
> like them. It runs the usual forked parse in unpack mode with a fixed parse
> context (PDF page 1 rendered, EMF/WMF rendered) and picks, in this order: the
> raster THUMBNAIL at depth 1; the rendering of that thumbnail; the depth-1
> RENDERING of PDF page 1. The endpoint extracts what the document carries; it
> does not resize, convert or generate previews.
> The response is JSON: the /rmeta metadata object of the selected embedded
> document, and the image as base64. Thumbnails are small, so the encoding
> overhead does not matter, and the caller gets type, dimensions, origin
> (stored thumbnail or rendering, tk:rendering:rendered-by) and path in one
> round trip without unpacking a zip. 204 when the document has no thumbnail.
> {
> "metadata": {
> "Content-Type": "image/png",
> "Content-Length": "8459",
> "tiff:ImageWidth": "800",
> "tiff:ImageLength": "1131",
> "tk:embedded-resource-type": "RENDERING",
> "tk:embedded-resource-path": "/thumbnail.emf/thumbnail.png",
> "tk:embedded-depth": "2",
> "tk:rendering:rendered-by": "poi-metafile-renderer",
> "tk:resource-name": "thumbnail.png"
> },
> "image": "iVBORw0KGgoAAAANSUhEUgAA..."
> }
> To keep the selection rule short, the metafile renderer could give the
> rendering of a THUMBNAIL the THUMBNAIL type as well (its
> tk:rendering:rendered-by tells it apart), so a raster thumbnail is a
> THUMBNAIL regardless of whether the document stored it as PNG or as EMF.
> What do you think?
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