Budibase/budibase · error

Could not read CSV

Error message

Could not read CSV

What it means

During CSV streaming, readCsv sets csvError=true when the stream emits an error event (a malformed/invalid CSV row) and the promise's catch converts that into 'Could not read CSV' to hide the low-level parser error. It signals the CSV content itself could not be parsed, as opposed to transport failures which are rethrown unchanged.

Solutions

1. Open the S3 object and validate the CSV: check headers, quoting, delimiter, and that it is not an HTML/JSON error page — re-export the file correctly.
2. Re-upload the file ensuring UTF-8 encoding and consistent quoting (e.g. export with standard CSV tooling).
3. If the delimiter is non-comma, configure the query's CSV parsing options accordingly.
4. Check the object is fully uploaded and not truncated (compare sizes/checksums).

Example fix

// before: CSV with inconsistent columns / stray quotes
name,age
"Alice,30
Bob,not,a,number
// after: well-formed CSV re-exported
name,age
Alice,30
Bob,42

// Pre-validate the object parses before ingesting
const lines = csvText.split("\n")
const cols = lines[0].split(",").length
if (lines.some(l => l.trim() && l.split(",").length !== cols)) {
  throw new Error("Malformed CSV: inconsistent column counts")
}

function isCsvParseFailure(err: unknown): err is Error {
  return err instanceof Error && err.message === "Could not read CSV"
}

try {
  const csv = await s3Integration.readCsv(query)
} catch (err) {
  if (err instanceof Error && err.message === "Could not read CSV") {
    // re-export/repair the source file, then retry
  } else { throw err }
}

When it happens

Trigger: The fileStream emits an 'error' event while piping rows (csvError flag set) — i.e. the parser rejects the CSV content mid-stream during an S3 read CSV query execution.

Common situations: Downloading a CSV with inconsistent column counts, wrong delimiter/quote characters, non-UTF8 encoding, or an HTML/JSON error page saved as .csv; truncated uploads; exporting tool produced malformed quoting that the CSV parser rejects.

Related errors

• Unable to retrieve CSV - invalid stream
• Unable to determine delimiter
• Unable to retrieve stream - invalid response
• Access denied to object store bucket.
• Error constructing OIDC refresh strategy: message=

AI-assisted analysis of Budibase/budibase@a81a902e9a (2026-08-29). Data as JSON: /api/errors/e16983677976f366. Report an issue: GitHub.

Appendix: source

Thrown at packages/server/src/integrations/s3.ts:274

      throw new Error("Unable to retrieve CSV - invalid stream")
    }

    let csvError = false
    return new Promise((resolve, reject) => {
      fileStream.on("error", (err: Error) => {
        reject(err)
      })
      const response = csv()
        .fromStream(fileStream)
        .on("error", () => {
          csvError = true
        })
      fileStream.on("end", () => {
        resolve(response)
      })
    }).catch(err => {
      if (csvError) {
        throw new Error("Could not read CSV")
      } else {
        throw err
      }
    })
  }

  async delete(query: { bucket: string; delete: string }) {
    return await this.client.deleteObjects({
      Bucket: query.bucket,
      Delete: JSON.parse(query.delete),
    })
  }
}

export default {
  schema: SCHEMA,
  integration: S3Integration,
}

View on GitHub (pinned to a81a902e9a)