Sending CSV as a single byte stream

chunk.rs

#[async_trait]
impl Meetkunde for MeetkundeClient {
    async fn send_report(&mut self, table_name: &str, df: &DataFrame) -> Result<()> {
        let total_rows = df.height();

        if total_rows == 0 {
            return Ok(());
        }

        // 1. Convert the WHOLE DataFrame to a CSV string in memory
        // (This replaces the chunking loop logic)
        let csv_string = dataframe_to_csv(df)?;
        let total_bytes = csv_string.len();

        info!(
            "TESTING STREAM: Sending table '{}' ({} rows, {} bytes) as a single stream...",
            table_name, total_rows, total_bytes
        );

        // 2. Turn the String into a Stream
        // Cursor makes the bytes read like a file; ReaderStream makes it async.
        let cursor = Cursor::new(csv_string.into_bytes());
        let stream = ReaderStream::new(cursor);

        let vanilla_client = reqwest::Client::builder()
            .timeout(Duration::from_secs(300)) // Give it plenty of time to hang
            .build()?;

        // 3. Wrap in reqwest Body (forces Transfer-Encoding: chunked)
        let body = Body::wrap_stream(stream);

        // 4. Send ONE Request
        // We always truncate=true because we are sending the whole file at once.
        let url = self.build_url(table_name, true);

        let response = vanilla_client
            .post(url)
            .header("Content-Type", "text/csv")
            .body(body)
            .send()
            .await
            .context("Failed to stream request to Meetkunde")?;

        let status = response.status();

        if status == StatusCode::ACCEPTED {
            info!(
                "✅ Streaming Success: Server accepted the stream for '{}'",
                table_name
            );
            Ok(())
        } else {
            let error_text = response.text().await.unwrap_or_default();
            anyhow::bail!(
                "❌ Streaming Failed ({} {}): {}",
                status.as_u16(),
                status.canonical_reason().unwrap_or("Unknown"),
                error_text
            );
        }
    }
}