Signed Standard Uploads for Small Files TaskFlow - Full Stack Developer 2026
When to use it Supabase recommends standard uploads for small files and TUS resumable uploads when files exceed roughly 6MB, network reliability matters, or progress events are required.
API creates an intent async createIntent(taskId: string, user: AuthenticatedUser, input: CreateAttachmentIntent) { const task = await this.tasks.findScopedById(taskId, user.id) if (!task) throw new TaskNotFoundException(taskId)
const attachmentId = randomUUID() const objectPath = buildAttachmentObjectPath({ workspaceId: task.workspaceId, taskId, attachmentId, mimeType: input.mimeType, })
const row = await this.attachments.createPending({ id: attachmentId, taskId, uploadedById: user.id, bucket: ATTACHMENT_BUCKET, objectPath, ...input, })
try {
const signed = await this.storage.createSignedUploadUrl(objectPath)
return { attachment: row, upload: signed }
} catch (error) {
await this.attachments.deletePending(attachmentId)
throw error
}
}Browser transfers bytes const { error } = await supabase.storage .from(intent.attachment.bucket) .uploadToSignedUrl( intent.attachment.objectPath, intent.upload.token, file, { contentType: file.type }, )
if (error) throw error
await completeAttachment(intent.attachment.id)No upsert by default Each attachment gets a new UUID path, so overwriting is unnecessary. Supabase also recommends new paths instead of overwrites to avoid stale CDN propagation behavior.
Authentication answers who the request represents. Treating decoded or client-supplied identity as trusted is a security boundary failure.
Restate the goal of “Signed Standard Uploads for Small Files” as one observable behavior. Write the success signal before touching code.
Trace the boundary map: credentials/session → token → verification → trusted identity → protected operation. Mark the one boundary this lesson changes.
Inspect the current repository state and record the exact files, route, table, or runtime involved. Avoid creating an abstraction before you can name the existing owner.
Implement the smallest vertical slice. Add one coherent change, run the narrowest verification command, and read the output before continuing.
Connect the slice to TaskFlow’s phase artifact: Task attachment upload/download/delete workflow using Supabase Storage plus application metadata.. Verify behavior from the outside as a user or API client would.
Create one controlled failure that is safe to reproduce. Predict the symptom first, capture evidence, locate the earliest broken boundary, then fix only that cause.
Close the reference and rebuild or explain the core change from memory. Record what you would monitor or test before trusting the same change in production.
const token = readBearerToken(request);
const claims = await verifier.verify(token);
request.user = {
id: claims.sub,
email: claims.email,
};Do not copy this as a finished answer. Predict what each boundary does, type the smallest useful slice, run it, then compare the result with your prediction.
Inspect whether a token exists, whether it is expired, which issuer/audience signed it, and what the API verifier expects.
Trust only verified server claims; never repair identity by accepting a client-sent user id.
Without copying the final source, create a second small scenario that applies “Signed Standard Uploads for Small Files” to a different TaskFlow resource or input. Write the acceptance criteria first, implement it, and provide the evidence that each criterion is satisfied.
Implement delete/cleanup behavior for abandoned uploads and metadata/object mismatch.
Use the smallest change that demonstrates this lesson. Stop after it works and capture evidence.Public bucket for private tenant files
Predict the symptom before causing the failure. Then locate the earliest boundary where reality diverges from expectation.Why does this responsibility live here, what input does it trust, what output proves success, and what would go wrong if another layer owned it?
If your explanation is vague, repeat the boundary trace before moving on.Close the reference. Reproduce the core idea from memory or explain the exact request/data flow aloud. Then check your diff or notes for accidental shortcuts that bypass validation, authorization, error handling, or verification earned in earlier phases.