I have an endpoint that receives a CSV file through HTTP. To generate the server code I use oapi-codegen with net/http go 1.22.2 in strict-server mode.

The endpoint OpenAPI definition looks like this:

paths:
  /api/v1/shipments:
    post:
      summary: Add new shipments
      operationId: AddShipments
      tags:
        - Shipments
      requestBody:
        required: true
        content:
          text/csv:
            schema:
              description: Shipments encoded as a CSV file
              type: string
            example: |-
              'Delivery Place', 'Pickup Place', 'Size', 'Pallete', 'Pickup Times', 'Delivery Times'
              'eb256bda-217d-4ae8-8559-f806abd92aca', 'ddb8a0f5-7f40-4cf9-92b3-6dc61fe5bf6a', 1, euro1, '{[2024-03-16 18:50+02, 2024-03-23 10:00+02:00], [2024-03-26 10:00-3, 2024-03-28 17:00-03]}', '{}'
              ...

And the generated interface looks like this:

type AddShipmentsRequestObject struct {
    Body     io.Reader
}

type StrictServerInterface interface {
    // Add new shipments
    // (POST /api/v1/shipments)
    AddShipments(ctx context.Context, request AddShipmentsRequestObject) (AddShipmentsResponseObject, error)
}

The problem I face and I don’t understand how to resolve is that lines in the CSV (delimited by n) are not correctly parsed by the csv.NewReader(request.Body) reader, resulting in something of the following:

Example CSV:

Header1,Header2,Header3
Field1Line1,Field2Line1,Field3Line1
Field1Line2,Field2Line2,Field3Line2

Request:

curl -X 'POST'                                                                                                                                                             
         'http://172.23.0.4:10000/api/v1/shipments' 
         -H 'Content-Type: text/csv' 
         -d @test.csv

Printed results in logs:

Records: [[Header1 Header2 Header3Field1Line1 Field2Line1 Field3Line1Field1Line2 Field2Line2 Field3Line2]]

instead of the expected output:

Records: [[Header1 Header2 Header3] [Field1Line1 Field2Line1 Field3Line1] [Field1Line2 Field2Line2 Field3Line2]]

Finally, my simple implementation is this:

func (impl *ServerImpl) AddShipments(ctx context.Context, request server.AddShipmentsRequestObject) (server.AddShipmentsResponseObject, error) {
    impl.mux.Lock()
    defer impl.mux.Unlock()
    tx, err := impl.pool.Begin(ctx)
    if err != nil {
        return server.AddShipments500Response{}, err
    }
    defer tx.Rollback(ctx)
    qtx := impl.db.WithTx(tx)

    if request.Body == nil {
        return server.AddShipments422Response{}, fmt.Errorf("request body is nil")
    }

    r := csv.NewReader(request.Body)

    if r == nil {
        return server.AddShipments500Response{}, fmt.Errorf("csv reader is nil")
    }

    records, err := r.ReadAll()
    if err != nil && err != io.EOF {
        return server.AddShipments500Response{}, err
    }

    fmt.Printf("Records: %vn", records)

    return nil, nil
}

I also tried using gocsv (which I intend to use in the end to decode the CSV into structs), but faced the exact same issue. This happens with every CSV file I have tried, either handwritten or generated.