Method download_change_to_file

atomic-remote/src/http/download.rs:32–84

Download a change file directly to disk. Downloads the change and writes it directly to a file on disk, avoiding the need to hold the full change in memory as a `Bytes` before persisting. # Arguments `hash` - The base32-encoded hash of the change. `dest` - The destination file path. # Returns The number of bytes written to disk.

(&self, hash: &str, dest: &Path)

    ///
    /// The number of bytes written to disk.
    pub async fn download_change_to_file(&self, hash: &str, dest: &Path) -> RemoteResult<u64> {
        let url = format!("{}?change={}", self.base_url, hash);
        debug!("GET change (to file): {} → {:?}", url, dest);

        let response = self
            .client
            .get(&url)
            .send()
            .await
            .map_err(|e| RemoteError::connection_failed(&url, e))?;

        crate::check_min_version_header(response.headers());
        let status = response.status();

        match status {
            StatusCode::OK => {
                let bytes = response
                    .bytes()
                    .await
                    .map_err(|e| RemoteError::connection_failed(&url, e))?;

                // Create parent directory if needed
                if let Some(parent) = dest.parent() {
                    tokio::fs::create_dir_all(parent).await.map_err(|e| {
                        RemoteError::other(format!(
                            "Failed to create directory {:?}: {}",
                            parent, e
                        ))
                    })?;
                }

                tokio::fs::write(dest, &bytes).await.map_err(|e| {
                    RemoteError::other(format!("Failed to write file {:?}: {}", dest, e))
                })?;

                let bytes_written = bytes.len() as u64;
                debug!(
                    "Downloaded change {} to {:?} ({} bytes)",
                    hash, dest, bytes_written
                );
                Ok(bytes_written)
            }
            StatusCode::NOT_FOUND => Err(RemoteError::change_not_found(hash)),
            StatusCode::UNAUTHORIZED | StatusCode::FORBIDDEN => {
                let msg = response.text().await.unwrap_or_default();
                Err(RemoteError::auth_failed(&url, msg))
            }
            _ => {
                let msg = response.text().await.unwrap_or_default();
                Err(RemoteError::http(status.as_u16(), msg))
            }
        }
    }

    /// Download a change with layer-selective filtering.
    ///