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4.1. "Boundary" Parameter of multipart/form-data

4.1. "Boundary" Parameter of multipart/form-data​

As with other multipart types, a boundary is selected that does not occur in any of the data. Each part is expected to contain:

  • A Content-Disposition header field (described in Section 4.2) with a value of "form-data", and a name parameter.
  • Optional additional header fields.
  • A body.

Each part is separated by a boundary delimiter constructed using the value of the boundary parameter. The boundary delimiter MUST NOT appear inside any of the encapsulated parts, and the final boundary delimiter line has two hyphens after the boundary parameter value.