nv-file-reader

• simple async wrap of node fs.createReadStream AND readdir
• walk , generator, read-file, read-symbol-link

install

• npm install nv-file-reader

usage

  const {rfile,rwalk,rfltr} = require("nv-file-reader")

example

rfile

    > await rfile.rstr("./package.json")
    '{\n' +
      '  "dependencies": {\n' +
      '    "nv-facutil-promise": "^1.0.29",\n' +
      '    "nv-file-basic": "^1.0.5",\n' +
      '    "nv-path-basic": "^1.0.1"\n' +
      '  }\n' +
      '}\n'
    >
    >


    var ag = rfile.agen_str("./package.json",20)

    var sarr =[]

    for await(let each of ag) {sarr.push(each)}

    /*
    > sarr
    [
      '{\n  "dependencies": ',
      '{\n    "nv-facutil-pr',
      'omise": "^1.0.29",\n ',
      '   "nv-file-basic": ',
      '"^1.0.5",\n    "nv-pa',
      'th-basic": "^1.0.1"\n',
      '  }\n}\n'
    ]
    >

    */


    nv-file-reader# ln -s package.json s0
    nv-file-reader# ln -s s0 s1


    > await rfile.rstr("./s1")
    '{\n' +
      '  "dependencies": {\n' +
      '    "nv-facutil-promise": "^1.0.29",\n' +
      '    "nv-file-basic": "^1.0.5",\n' +
      '    "nv-path-basic": "^1.0.1"\n' +
      '  }\n' +
      '}\n'
    >



    //fs.writeFileSync("123.set",v8.serialize(new Set([1,2,new Date()])))
    > await robj("./123.set")
    Set(3) { 1, 2, 2022-03-06T03:04:29.438Z }
    >

rwalk

treat symbolic_link as leaf

    nv-file-reader# mkdir TEST
    nv-file-reader# cd TEST/
    TEST# touch txt
    TEST# ln -s txt s0
    TEST# ln -s s0 s1
    TEST# mkdir subdir
    TEST# cd subdir/
    subdir# touch json
    subdir# ln -s ../subdir s10
    subdir# cd ../
    TEST# cd ../

    nv-file-reader# tree TEST/
    TEST/
    ├── s0 -> txt
    ├── s1 -> s0
    ├── subdir
    │   ├── json
    │   └── s10 -> ../subdir
    └── txt


    ag = rwalk.agen("./TEST")

    > (await ag.next()).value.path
    '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/TEST'
    > (await ag.next()).value.path
    '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/TEST/s0'
    > (await ag.next()).value.path
    '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/TEST/s1'
    > (await ag.next()).value.path
    '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/TEST/subdir'
    > (await ag.next()).value.path
    '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/TEST/txt'
    > (await ag.next()).value.path
    '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/TEST/subdir/json'
    > (await ag.next()).value.path
    '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/TEST/subdir/s10'


	var with_full_info = true
    ag = rwalk.agen("./TEST",with_full_info)

    /*
    > ((await ag.next()).value.stat)
    Stat {
      dev: 2050,
      mode: 16877,
      nlink: 3,
      uid: 0,
      gid: 0,
      rdev: 0,
      blksize: 4096,
      ino: 696986,
      size: 4096,
      blocks: 8,
      atimeMs: 1646017500405.9639,
      mtimeMs: 1646017491345.81,
      ctimeMs: 1646017491345.81,
      birthtimeMs: 1646017381243.771,
      atime: 2022-02-28T03:05:00.406Z,
      mtime: 2022-02-28T03:04:51.346Z,
      ctime: 2022-02-28T03:04:51.346Z,
      birthtime: 2022-02-28T03:03:01.244Z,
      permission: Permission {
        owner_can_read: true,
        owner_can_write: true,
        owner_can_exec: true,
        group_can_read: true,
        group_can_write: false,
        group_can_exec: true,
        other_can_read: true,
        other_can_write: false,
        other_can_exec: true
      },
      type: 'dir'
    }
    > ((await ag.next()).value.stat)
    Stat {  
      dev: 2050,
      mode: 41471,
      nlink: 1,
      uid: 0,
      gid: 0,
      rdev: 0,
      blksize: 4096,
      ino: 692004,
      size: 3,
      blocks: 0,
      atimeMs: 1646017484881.6992,
      mtimeMs: 1646017470829.4548,
      ctimeMs: 1646017470829.4548,
      birthtimeMs: 1646017470829.4548,
      atime: 2022-02-28T03:04:44.882Z,
      mtime: 2022-02-28T03:04:30.829Z,
      ctime: 2022-02-28T03:04:30.829Z,
      birthtime: 2022-02-28T03:04:30.829Z,
      permission: Permission {
        owner_can_read: true,
        owner_can_write: true,
        owner_can_exec: true,
        group_can_read: true,
        group_can_write: true,
        group_can_exec: true,
        other_can_read: true,
        other_can_write: true,
        other_can_exec: true
      },
      type: 'slink'
    }
    >
	.....
    */

resolve symbolic-link recursively

    nv-file-reader# mkdir TEST-ANOTHER
    nv-file-reader# cd TEST-ANOTHER
    TEST-ANOTHER# mkfifo fifo
    TEST-ANOTHER# touch some.js
    TEST-ANOTHER# ln -s ../TEST/subdir ptr
    TEST-ANOTHER# touch noexist
    TEST-ANOTHER# ln -s noexist s0
    TEST-ANOTHER# ln -s s0 s1
    TEST-ANOTHER# rm noexist
    TEST-ANOTHER# ls -l
    total 0
    prw-r--r-- 1 root root  0 Feb 28 03:13 fifo
    lrwxrwxrwx 1 root root 14 Feb 28 03:14 ptr -> ../TEST/subdir
    lrwxrwxrwx 1 root root  7 Feb 28 03:21 s0 -> noexist
    lrwxrwxrwx 1 root root  2 Feb 28 03:21 s1 -> s0
    -rw-r--r-- 1 root root  0 Feb 28 03:13 some.js



    TEST-ANOTHER# cd ../
    nv-file-reader# cd TEST
    TEST# ln -s noexist noexist
    TEST# cd subdir/
    subdir# ln -s ../../TEST-ANOTHER/  ptr-to-grandfather
    subdir# cd ../
    subdir# cd ../

    TEST# ls -l
    total 4
    lrwxrwxrwx 1 root root    7 Feb 28 03:24 noexist -> noexist
    lrwxrwxrwx 1 root root    3 Feb 28 03:04 s0 -> txt
    lrwxrwxrwx 1 root root    2 Feb 28 03:04 s1 -> s0
    drwxr-xr-x 2 root root 4096 Feb 28 03:24 subdir
    -rw-r--r-- 1 root root    0 Feb 28 03:04 txt
    TEST#



    nv-file-reader# tree TEST
    TEST
    ├── noexist -> noexist
    ├── s0 -> txt
    ├── s1 -> s0
    ├── subdir
    │   ├── json
    │   ├── ptr-to-grandfather -> ../../TEST-ANOTHER/
    │   └── s10 -> ../subdir
    └── txt

    3 directories, 5 files
    nv-file-reader# tree TEST-ANOTHER/
    TEST-ANOTHER/
    ├── fifo
    ├── ptr -> ../TEST/subdir
    ├── s0 -> noexist
    ├── s1 -> s0
    └── some.js


    var ag = rwalk.agen_dig_softlink("./TEST")

    async function tst() {
        let arr = []
        for await(let each of ag) {
            arr.push([each.path,each.type])
        }
        return(arr)
    }


    > Object.fromEntries(rslts)
    {
      '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/TEST': 'dir',
      '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/TEST/noexist': 'slink',
      '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/TEST/s0': 'slink',
      '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/TEST/s1': 'slink',
      '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/TEST/subdir': 'dir',
      '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/TEST/txt': 'file',
      '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/TEST/subdir/json': 'file',
      '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/TEST/subdir/ptr-to-grandfather': 'slink',
      '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/TEST/subdir/s10': 'slink',
      '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/TEST-ANOTHER': 'dir',
      '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/TEST-ANOTHER/fifo': 'fifo',
      '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/TEST-ANOTHER/ptr': 'slink',
      '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/TEST-ANOTHER/s0': 'slink',
      '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/TEST-ANOTHER/s1': 'slink',
      '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/TEST-ANOTHER/some.js': 'file',
      '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/TEST-ANOTHER/noexist': 'noexist'
    }
    >

    > rslts.length
    16
    >

handle circular

    nv-file-reader# tree TEST2/
    TEST2/
    └── circular -> ../TEST3/circular


    nv-file-reader# tree TEST3
    TEST3
    └── circular -> ../TEST2/circular


    > ag = rwalk.agen_dig_softlink("./TEST2/circular")
    Object [AsyncGenerator] {}
    > await ag.next()
    {
      value: _Ele {
        ino: 692002,
        path: '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/TEST2/circular',
        type: 'slink',
        '#children': []
      },
      done: false
    }
    > await ag.next()
    {
      value: _Ele {
        ino: 692064,
        path: '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/TEST3/circular',
        type: 'slink',
        '#children': []
      },
      done: false
    }
    > await ag.next()
    { value: undefined, done: true }

hard link

• this is slow, coz it cmp ino between each other

    const {
        find_hard_link,
        find_hard_link_dig_softlink
    } = require("nv-file-reader").hlink;


         nv-file-reader# mkdir HARD
         nv-file-reader#
         nv-file-reader# cd HARD/
         HARD#
         HARD# touch a
         HARD# mkdir sub0
         HARD# mkdir sub1
         HARD# ln a sub0/hard
         HARD# ln a sub1/hard
         HARD#
         
         
         nv-file-reader# tree HARD
         HARD
         ├── a
         ├── sub0
         │   └── hard
         └── sub1
             └── hard
         
         2 directories, 3 files


            /*
            > await find_hard_link("./HARD")
            {
              '692002': [
                '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/HARD/a',
                '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/HARD/sub0/hard',
                '/opt/JS/NV5_/nv-file-/pkgs/nv-file-reader/HARD/sub1/hard'
              ]
            }
            >
            
            */

APIS

rfile

> async 
{
  _rbytes: [AsyncFunction: _rbytes],
  _agen_bytes: [AsyncGeneratorFunction: _agen_bytes],
  _rstr: [AsyncFunction: _rstr],
  _agen_str: [AsyncGeneratorFunction: _agen_str],
  _rjson: [AsyncFunction: _rjson],
  rbytes: [AsyncFunction: rbytes],
  agen_bytes: [AsyncGeneratorFunction: agen_bytes],
  rstr: [AsyncFunction: rstr],
  agen_str: [AsyncGeneratorFunction: agen_str],
  rjson: [AsyncFunction: rjson]
  robj: [AsyncFunction: robj]
}
>

rwalk

    {
      creat_ele: [AsyncFunction: creat_ele],
      agen: [AsyncGeneratorFunction: agen],
      agen_dig_softlink: [AsyncGeneratorFunction: agen_dig_softlink],
      walk,
      walk_dig_softlink
    }

rfltr

    {
      filter: [AsyncFunction: filter],
      filter_dig_softlink: [AsyncFunction: filter_dig_softlink],
      by_type: [AsyncFunction: by_type],
      dir: [AsyncFunction: dir],
      file: [AsyncFunction: file],
      char_dev: [AsyncFunction: char_dev],
      blk_dev: [AsyncFunction: blk_dev],
      fifo: [AsyncFunction: fifo],
      sock: [AsyncFunction: sock],
      slink: [AsyncFunction: slink],
      noexist: [AsyncFunction: noexist],
      valid_slink: [AsyncFunction: valid_slink],
      invalid_slink: [AsyncFunction: invalid_slink]
    }

hlink

    {
      find_hard_link: [AsyncFunction: find_hard_link],
      find_hard_link_dig_softlink: [AsyncFunction: find_hard_link_dig_softlink]
    }

PERFORMANCE

• bad

    async function tst(fn) {
        let now = (new Date).getTime()
        let rslts = await walk_dig_softlink(fn,false,true)
        console.log((new Date).getTime() - now)
        return(rslts)
    }

    > var rslts = await tst("/dev")
    308
    > var rslts = await tst("/dev")
    121
    > var rslts = await tst("/dev")
    157
    > var rslts = await tst("/dev")
    148
    > var rslts = await tst("/dev")
    131

    > var rslts = await tst("/root")
    37109





    > var linux = await tst("/")

    // very long time.....
    > linux.length
    1608673

    fs.writeFileSync("linux-path.json",JSON.stringify(linux))

LICENSE

• ISC