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File Download

This page explains the current Geelato file download and preview capability, including runtime entry points and the difference between local files and OSS files.

The description is based on:

  • DownloadController
  • FileHandler
  • BaseHandler
  • AttachController

Download Entry​

The main runtime entry is:

  • GET /api/resources/file

Common parameters include:

  • id
  • isPdf
  • isPreview
  • isThumbnail

How the Runtime Resolves the File​

The runtime does not directly expose a disk path.

The flow is:

  1. load attachment metadata by attachment ID
  2. optionally switch to a thumbnail record
  3. decide whether the attachment is local or OSS based
  4. open a stream or local file
  5. write the response in preview or download mode

Local File Download​

When:

  • objectId is empty

the runtime treats the attachment as a local file and reads:

  • Attachment.path

as a local filesystem path.

OSS File Download​

When:

  • objectId is not empty

the runtime treats the attachment as an OSS object.

It then:

  1. uses Attachment.path as the object name
  2. calls FileHelper.getFile(...)
  3. reads the OSS input stream
  4. sends it through the same unified download output

Preview and PDF Conversion​

The download entry supports:

  • isPreview
  • isPdf

If isPdf=true, the runtime converts the original file to PDF first, then outputs the PDF file.

The temporary converted PDF file is stored under:

  • geelato.upload.convert-directory

There is also:

  • GET /api/attach/toPdf/{id}

which converts an Excel attachment into a new PDF attachment record.

Config File Download​

The runtime also provides:

  • GET /api/resources/json

to read .config files from:

  • geelato.upload.config-directory

Related attachment APIs include:

  • GET /api/attach/get/{id}
  • POST /api/attach/image/{id}
  • POST /api/attach/valid
  • POST /api/attach/storage/{type}
  • DELETE /api/attach/remove/{id}

These support validation, storage migration, and deletion workflows around download.

Suggested Reading​