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Nikita

Action "fs.base.createWriteStream"

Example

const {$status} = await nikita.fs.base.createWriteStream({
  target: '/path/to/file'
  stream: function(ws){
    ws.write('some content')
    ws.end()
  }
})
console.info(`Stream was created: ${$status}`)

Hooks

on_action =
  after: [
    '@nikitajs/core/src/plugins/execute'
  ]
  before: [
    '@nikitajs/core/src/plugins/metadata/schema'
    '@nikitajs/core/src/plugins/metadata/tmpdir'
  ]
  handler: ({config, metadata, tools: {find}}) ->
    config.sudo ?= await find ({metadata: {sudo}}) -> sudo
    metadata.tmpdir = true if config.sudo or config.flags?[0] is 'a'

Schema definitions

definitions =
  config:
    type: 'object'
    properties:
      'flags':
        type: 'string'
        default: 'w'
        description: '''
        File system flag as defined in the [Node.js
        documentation](https://nodejs.org/api/fs.html#fs_file_system_flags)
        and [open(2)](http://man7.org/linux/man-pages/man2/open.2.html)
        '''
      'target_tmp':
        type: 'string'
        description: '''
        Location where to write the temporary uploaded file before it is
        copied into its final destination, default to
        "{tmpdir}/nikita_{YYMMDD}_{pid}_{rand}/{hash target}"
        '''
      'mode':
        $ref: 'module://@nikitajs/core/src/actions/fs/base/chmod#/definitions/config/properties/mode'
      'stream':
        typeof: 'function'
        description: '''
        User provided function receiving the newly created writable stream.
        The user is responsible for writing new content and for closing the
        stream.
        '''
      'target':
        oneOf: [{type: 'string'}, {instanceof: 'Buffer'}]
        description: '''
        Final destination path.
        '''
    required: ['target', 'stream']

Handler

handler = ({config, metadata, ssh, tools: {find, log}}) ->
  # Normalize config
  if config.sudo or config.flags[0] is 'a'
    config.target_tmp ?= "#{metadata.tmpdir}/#{utils.string.hash config.target}"
  # config.mode ?= 0o644 # Node.js default to 0o666
  # In append mode, we write to a copy of the target file located in a temporary location
  try if config.flags[0] is 'a'
    await @execute """
    [ ! -f '#{config.target}' ] && exit
    cp '#{config.target}' '#{config.target_tmp}'
    """
    log message: "Append prepared by placing a copy of the original file in a temporary path", level: 'INFO'
  catch err
    log message: "Failed to place original file in temporary path", level: 'ERROR'
    throw err
  # Start writing the content
  log message: 'Writting file', level: 'DEBUG'
  await new Promise (resolve, reject) ->
    ws = await fs.createWriteStream ssh, config.target_tmp or config.target,
      flags: config.flags,
      mode: config.mode
    config.stream ws
    err = false # Quick fix ws sending both the error and close events on error
    ws.on 'error', (err) ->
      if err.code is 'ENOENT'
        err = errors.NIKITA_FS_CWS_TARGET_ENOENT config: config
      reject err
    ws.on 'end', ->
      ws.destroy()
    ws.on 'close', ->
      resolve() unless err
  # Replace the target file in append or sudo mode
  if config.target_tmp
    await @execute
      command: """
      mv '#{config.target_tmp}' '#{config.target}'
      """

Exports

module.exports =
  handler: handler
  metadata:
    argument_to_config: 'target'
    log: false
    raw_output: true
    definitions: definitions
  hooks:
    on_action: on_action

Errors

errors =
  NIKITA_FS_CWS_TARGET_ENOENT: ({config}) ->
    utils.error 'NIKITA_FS_CWS_TARGET_ENOENT', [
      'fail to write a file,'
      unless config.target_tmp
      then "location is #{JSON.stringify config.target}."
      else "location is #{JSON.stringify config.target_tmp} (temporary file, target is #{JSON.stringify config.target})."
    ],
      errno: -2
      path: config.target_tmp or config.target # Native Node.js api doesn't provide path
      syscall: 'open'

Dependencies

fs = require 'ssh2-fs'
utils = require '../../../utils'
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Nikita is an open source project hosted on GitHub and developed by Adaltas.