Function downloadFile

src/services/api/filesApi.ts:133–181

(
  fileId: string,
  config: FilesApiConfig,
)

 * @returns The file content as a Buffer
 */
export async function downloadFile(
  fileId: string,
  config: FilesApiConfig,
): Promise<Buffer> {
  const baseUrl = config.baseUrl || getDefaultApiBaseUrl()
  const url = `${baseUrl}/v1/files/${fileId}/content`

  const headers = {
    Authorization: `Bearer ${config.oauthToken}`,
    'anthropic-version': ANTHROPIC_VERSION,
    'anthropic-beta': FILES_API_BETA_HEADER,
  }

  logDebug(`Downloading file ${fileId} from ${url}`)

  return retryWithBackoff(`Download file ${fileId}`, async () => {
    try {
      const response = await axios.get(url, {
        headers,
        responseType: 'arraybuffer',
        timeout: 60000, // 60 second timeout for large files
        validateStatus: status => status < 500,
      })

      if (response.status === 200) {
        logDebug(`Downloaded file ${fileId} (${response.data.length} bytes)`)
        return { done: true, value: Buffer.from(response.data) }
      }

      // Non-retriable errors - throw immediately
      if (response.status === 404) {
        throw new Error(`File not found: ${fileId}`)
      }
      if (response.status === 401) {
        throw new Error('Authentication failed: invalid or missing API key')
      }
      if (response.status === 403) {
        throw new Error(`Access denied to file: ${fileId}`)
      }

      return { done: false, error: `status ${response.status}` }
    } catch (error) {
      if (!axios.isAxiosError(error)) {
        throw error
      }
      return { done: false, error: error.message }
    }
  })
}

/**
 * Normalizes a relative path, strips redundant prefixes, and builds the full