message: getFile throw on file not found
diff: @@ -22,6 +22,7 @@ import { Logger } from '../logger'
  import { UserSession } from '../auth/userSession'
  import { getGlobalObject } from '../utils'
  import { fetchPrivate } from '../fetchUtil'
  +import { FileNotFound } from '../errors'
  import { getResponseDescription } from '../utils'
  /**
  @@ -243,12 +244,13 @@ function getFileContents(path: string, app: string, username: string | undefined
  .then(readUrl => fetchPrivate(readUrl))
  .then<string | ArrayBuffer | null>((response) => {
  if (response.status !== 200) {
  + const errorMsg = `getFile ${path} failed.`
  if (response.status === 404) {
  Logger.debug(`getFile ${path} returned 404, returning null`)
  - return null
  + throw new FileNotFound(errorMsg)
  } else {
  getResponseDescription(response).then(responseDescription => {
  - throw new Error(`getFile ${path} failed. ${responseDescription}`)
  + throw new Error(errorMsg + ' ' + responseDescription)
  })
  }
  }
  