Docs

Torch Object Storage

Document preview

The document preview (doc-preview) feature lets you see document files stored in a bucket online without opening them. This topic introduces the parameters and provides examples of the document preview feature.

Notes

This feature is currently in closed beta. Please contact your account manager for access.

You must use custom domains to preview documents in buckets created after January 3, 2024, due to restrictions on domain names. For instructions, see Associating a custom domain.

tip

For buckets created after January 3, 2024, accessing objects via the default domain name—whether through a presigned URL or anonymous access—will cause TOS to download the object directly to your device rather than providing an online preview. For more information, see Notice Regarding Restricting the Use of Torch Object Storage Default Domains.

Supported parameters

Request parameters

Parameter	Description	Value	Required
x-tos-doc-src-type	Specifies the type of file you want to preview. tip Currently, TOS uses the file name extension of an object to determine its source data type during file conversion. This parameter must be specified if an object lacks a file name extension.	pptx, ppt, doc, docx, xls, xlsx, and pdf.	No
x-tos-doc-dst-type	Specifies the output format. tip When you preview a spreadsheet file as images, one sheet can be split into several images during conversion.	png, jpg, pdf, and html. The default value is jpg.	No
x-tos-doc-page	Specifies the page number to be converted when the output format is an image. tip The page parameter does not apply when the output format is pdf or html because page selection is unavailable for those formats.	[1,5000] The default value is 1.	No
x-tos-doc-image-dpi	Renders the image at the specified DPI. This parameter only applies when the output format is png or jpg. Setting a low value decreases processing time, whereas setting a high value increases it.	[96-600] The default value is 300.	No
x-tos-doc-image-quality	Specifies the quality of the transcoded image. For example, a value of 90 indicates 90% image quality.	[1,100] The default value is 90.	No

Response fields

Field	Description	Value
content-type	Returns a value based on the actual format of the image.	image/jpeg, image/png, application/pdf, and text/html.
x-tos-total-page	Returns the total number of pages in the document. For spreadsheet files, the value of this field indicates the total number of images converted from the current sheet.	-