@krantho/media-vercel-blob

The media file store on Vercel Blob, so uploads survive deploys on Vercel Functions.

Intermediate

The media file store for media.provider: 'vercel-blob'. It writes each uploaded file to a Vercel Blob store as a public blob with a one-year cache lifetime. It fits Vercel, whose functions have no persistent disk, and works from any other host too.

Install#

pnpm add @krantho/media-vercel-blob

Configure#

Create a Blob store with public access, then set:

.env

KRANTHO_MEDIA_PROVIDER=vercel-blob
KRANTHO_MEDIA_VERCEL_BLOB_TOKEN=vercel_blob_rw_...
KRANTHO_MEDIA_MAX_SIZE=4194304   # on Vercel, stay under the 4.5 MB function body limit

Setting	Variable	Default
`media.vercelBlob.token`	`KRANTHO_MEDIA_VERCEL_BLOB_TOKEN` (secret)	unset, required

The token is passed explicitly on every call, so krantho does not read BLOB_READ_WRITE_TOKEN and the store needs no project connection. Like every secret, the token also accepts KRANTHO_MEDIA_VERCEL_BLOB_TOKEN_FILE.

How it stores files#

Blobs are written with access: 'public', no random suffix and no overwrite: each key is fresh and never reused.
A file's URL is the blob URL Vercel returns.
A replace writes a new blob and deletes the old one; a delete removes the blob.

How it is verified#

krantho's tests check the calls the store makes through a mocked @vercel/blob. They do not run against a live Blob store. Before relying on it in production, upload, replace and delete one image on a staging deployment and open its URL.

Next steps#

Everything specific to Vercel, including the upload cap and CDN caching: Deploy to Vercel
The other stores and image URLs: Media

How this page is made

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level: intermediate
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title: @krantho/media-vercel-blob
status: published
related: deploy-vercel, package-media-local, package-media-s3, package-media-gcs, configuration
description: The media file store on Vercel Blob, so uploads survive deploys on Vercel Functions.
prerequisites: media

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