File LFS Lua module initial commit (#3332)

* File LFS module initial commit

* LFS file module update #1

* LFS file module update #2 - doc update and file.stat() returning read only attribute

* Implementing file.list()

* Fine-tuning `file_lfs` module

* Adding `file_lfs` to mkdocs.yml

* Implementing file.list() update #1

* Fine-tuning

* Fine-tuning #2
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Lukáš Voborský 2021-05-06 06:52:39 +02:00 committed by GitHub
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# File LFS module
| Since | Origin / Contributor | Maintainer | Source |
| :----- | :-------------------- | :---------- | :------ |
| 2020-11-30 | [vsky279](https://github.com/vsky279) | [vsky279](https://github.com/vsky279) | [file_lfs.lua](../../lua_modules/file_lfs/file_lfs.lua)|
Provides access to arbitrary files stored in LFS.
An arbitrary file can be stored in LFS and still can be accessed using `file` functions. This module is an overlay over `file` base functions providing access to such LFS files.
The module tries to be transparent as much as possible so it makes no difference where LFS file or standard SPIFFS file is accessed. LFS file is read only. If the file is open for writing a standard SPIFFS file is opened instead.
Both basic and object model can be used to access LFS file (see [file](../../docs/modules/file.md) module documentation).
## `resource.lua` file
Files to be stored in LFS needs to be preprocessed, i.e. a Lua file with its contents needs to be generated. This file called `resource.lua` is then included in the LFS image. A Lua script [`make_resource.lua`](../../lua_modules/file_lfs/make_resource.lua) can be used to generate `resource.lua` script.
A structure of the `resource.lua` file is simple. It returns a string, i.e. file content, depending on filename parameter passed to it. It returns table with list of files stored when called without any parameter.
```Lua
local arg = ...
if arg == "index.html" then return "<!DOCTYPE html><html><body>Hi, there!</body></html>" end
if arg == "favicon.ico" then return ""\000\000\000\000\000\000..." end
if arg == nil then return {"index.html", "favicon.ico"} end
```
## `make_resource.lua` script
Lua script to be run on PC to generate `resource.lua` file.
### Syntax
```bash
./make_resource.lua [-o outputfile] file1 [file2]
```
### Example
Create `resource.lua` file with all files in the `resource` directory
```bash
./make_resource resource/*
```
## Basic usage
```Lua
file = require("file_lfs")
f = file.open("index.html") -- let's assume the above resource.lua file is embedded in LFS
print(f:readline())
-- prints: <!DOCTYPE html><html><body>Hi, there!</body></html>
f:close()
f = file.open("init.lua")
-- init.lua file is not stored in LFS (does not have entry in resource.lua stored in LFS) -> SPIFFS files is opened instead
print(f:readline())
f:close()
```
Methods implemented - basically all `file` module functions are available though only some of them work with LFS files. The other functions are just passed through to the base `file` functions.
## file_lfs.list()
Lists all files in the file system. It works almost in the same way as [`file.list()`](../../docs/modules/file.md#filelist)
#### Syntax
`file.list([pattern], [SPIFFs_only])`
#### Parameters
- `pattern` only files matching the Lua pattern will be returned
- `SPIFFs_only` if not `nil` LFS files won't be included in the result (LFS files are returned only if the parameter is `nil`)
#### Returns
a Lua table which contains all {file name: file size} pairs, if no pattern
given. If a pattern is given, only those file names matching the pattern
(interpreted as a traditional [Lua pattern](https://www.lua.org/pil/20.2.html),
not, say, a UNIX shell glob) will be included in the resulting table.
`file.list` will throw any errors encountered during pattern matching.
## file.rename()
Renames a file. If a file is currently open, it will be closed first. It works almost in the same way as [`file.rename()`](../../docs/modules/file.md#filerename)
#### Syntax
`file.rename(oldname, newname)`
#### Parameters
- `oldname` old file name
- `newname` new file name
#### Returns
`true` on success, `false` when the file is stored in LFS (so read-only) or on error
## file_lfs.open()
Opens a LFS file included in LFS in the `resource.lua` file. If it cannot be found in LFS not standard [`file.open()`](../../docs/modules/file.md#fileopen) function is called.
LFS file is opened only when "r" access is requested.
#### Syntax
`file.open(filename, mode)`
#### Parameters
- `filename` file to be opened
- `mode`:
- "r": read mode (the default). If file of the same name is present in SPIFFS then SPIFFS file is opened instead of LFS file.
- "w": write mode - as LFS file is read-only a SPIFFS file of the same name is created and opened for writing.
- "r+", "w+", "a", "a+": as LFS file is read-only and all these modes allow file updates the LFS file is copied to SPIFFS and then it is opened with correspondig open mode.
#### Returns
LFS file object (Lua table) or SPIFFS file object if file opened ok. `nil` if file not opened, or not exists (read modes).
## file.read(), file.obj:read()
Read content from the open file. It has the same parameters and returns values as [`file.read()` / `file.obj:read()`](../../docs/modules/file.md#fileread-fileobjread)
#### Syntax
`file.read([n_or_char])`
`fd:read([n_or_char])`
#### Parameters
- `n_or_char`:
- if nothing passed in, then read up to `FILE_READ_CHUNK` bytes or the entire file (whichever is smaller).
- if passed a number `n`, then read up to `n` bytes or the entire file (whichever is smaller).
- if passed a string containing the single character `char`, then read until `char` appears next in the file, `FILE_READ_CHUNK` bytes have been read, or EOF is reached.
#### Returns
File content as a string, or `nil` when EOF
## file.readline(), file.obj:readline()
Read the next line from the open file. Lines are defined as zero or more bytes ending with a EOL ('\n') byte. If the next line is longer than 1024, this function only returns the first 1024 bytes.
It has the same parameters and return values as [`file.readline()` / `file.obj:readline()`](../../docs/modules/file.md#filereadline-fileobjreadline)
#### Syntax
`file.readline()`
`fd:readline()`
#### Parameters
none
#### Returns
File content in string, line by line, including EOL('\n'). Return `nil` when EOF.
## file.seek(), file.obj:seek()
Sets and gets the file position, measured from the beginning of the file, to the position given by offset plus a base specified by the string whence.
It has the same parameters and return values as [`file.seek()` / `file.obj:seek()`](../../docs/modules/file.md#fileseek-fileobjseek)
#### Syntax
`file.seek([whence [, offset]])`
`fd:seek([whence [, offset]])`
#### Parameters
- `whence`
- "set": base is position 0 (beginning of the file)
- "cur": base is current position (default value)
- "end": base is end of file
- `offset` default 0
If no parameters are given, the function simply returns the current file offset.
#### Returns
the resulting file position, or `nil` on error
## file.stat()
Get attribtues of a file or directory in a table. Elements of the table are:
- `size` file size in bytes
- `name` file name
- `time` table with time stamp information. Default is 1970-01-01 00:00:00 in case time stamps are not supported (on SPIFFS).
- `year`
- `mon`
- `day`
- `hour`
- `min`
- `sec`
- `is_dir` flag `true` if item is a directory, otherwise `false`
- `is_rdonly` flag `true` if item is read-only, otherwise `false`
- `is_hidden` flag `true` if item is hidden, otherwise `false`
- `is_sys` flag `true` if item is system, otherwise `false`
- `is_arch` flag `true` if item is archive, otherwise `false`
- `is_LFS` flag `true` if item is stored in LFS, otherwise it is not present in the `file.stat()` result table - **the only difference to `file.stat()`**
#### Syntax
`file.stat(filename)`
#### Parameters
`filename` file name
#### Returns
table containing file attributes

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@ -168,7 +168,7 @@ Lists all files in the file system.
`file.list([pattern])`
#### Parameters
none
- `pattern` only files matching the Lua pattern will be returned
#### Returns
a Lua table which contains all {file name: file size} pairs, if no pattern

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local FILE_READ_CHUNK = 1024
local _file = file
local file_exists, file_open, file_getcontents, file_rename, file_stat, file_putcontents, file_close, file_list =
_file.exists, _file.open, _file.getcontents, _file.rename, _file.stat, _file.putcontents, _file.close, _file.list
local node_LFS_resource = node.LFS.resource or function(filename) if filename then return else return {} end end -- luacheck: ignore
local file_lfs = {}
local current_file_lfs
local function file_lfs_create (filename)
local content = node_LFS_resource(filename)
local pos = 1
local read = function (_, n_or_char)
local p1, p2
n_or_char = n_or_char or FILE_READ_CHUNK
if type(n_or_char) == "number" then
p1, p2 = pos, pos + n_or_char - 1
elseif type(n_or_char) == "string" and #n_or_char == 1 then
p1 = pos
local _
_, p2 = content:find(n_or_char, p1, true)
if not p2 then p2 = p1 + FILE_READ_CHUNK - 1 end
else
error("invalid parameter")
end
if p2 - p1 > FILE_READ_CHUNK then p2 = pos + FILE_READ_CHUNK - 1 end
if p1>#content then return end
pos = p2+1
return content:sub(p1, p2)
end
local seek = function (_, whence, offset)
offset = offset or 0
local len = #content + 1 -- position starts at 1
if whence == "set" then
pos = offset + 1 -- 0 offset means position 1
elseif whence == "cur" then
pos = pos + offset
elseif whence == "end" then
pos = len + offset
elseif whence then -- not nil not one of above
return -- on error return nil
end
local pos_ok = true
if pos < 1 then pos = 1; pos_ok = false end
if pos > len then pos = len; pos_ok = false end
return pos_ok and pos - 1 or nil
end
local obj = {}
obj.read = read
obj.readline = function(self) return read(self, "\n") end
obj.seek = seek
obj.close = function() current_file_lfs = nil end
setmetatable(obj, {
__index = function (_, k)
return function () --...)
error (("LFS file unsupported function '%s'") % tostring(k))
--return _file[k](...)
end
end
})
return obj
end
file_lfs.exists = function (filename)
return (node_LFS_resource(filename) ~= nil) or file_exists(filename)
end
file_lfs.open = function (filename, mode)
mode = mode or "r"
if file_exists(filename) then
return file_open(filename, mode)
elseif node_LFS_resource(filename) then
if mode ~= "r" and mode:find("^[rwa]%+?$") then
-- file does not exist in SPIFFS but exists in LFS -> copy to SPIFFS
file_putcontents(filename, node_LFS_resource(filename))
return file_open(filename, mode)
else -- "r" or anything else
current_file_lfs = file_lfs_create (filename)
return current_file_lfs
end
else
return file_open(filename, mode)
end
end
file_lfs.close = function (...)
current_file_lfs = nil
return file_close(...)
end
file_lfs.getcontents = function(filename)
if file_exists(filename) then
return file_getcontents(filename)
else
return node_LFS_resource(filename) or file_getcontents(filename)
end
end
file_lfs.rename = function(oldname, newname)
if node_LFS_resource(oldname) ~= nil and not file_exists(oldname) then
-- error "LFS file cannot be renamed"
return false
else
return file_rename(oldname, newname)
end
end
file_lfs.stat = function(filename)
if node_LFS_resource(filename) ~= nil and not file_exists(filename) then
return {
name = filename,
size = #node_LFS_resource(filename),
time = {day = 1, hour = 0, min = 0, year = 1970, sec = 0, mon = 1},
is_hidden = false, is_rdonly = true, is_dir = false, is_arch = false, is_sys = false, is_LFS = true
}
else
return file_stat(filename)
end
end
file_lfs.list = function (pattern, SPIFFs_only)
local filelist = file_list(pattern)
if not SPIFFs_only then
local fl = node_LFS_resource()
if fl then
for _, f in ipairs(fl) do
if not(filelist[f]) and (not pattern or f:match(pattern)) then
filelist[f] = #node_LFS_resource(f)
end
end
end
end
return filelist
end
setmetatable(file_lfs, {
__index = function (_, k)
return function (...)
local t = ...
if type(t) == "table" then
return t[k](...)
elseif not t and current_file_lfs then
return current_file_lfs[k](...)
else
return _file[k](...)
end
end
end
})
print ("[file_lfs] LFS file routines loaded")
return file_lfs

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#!/usr/bin/lua
--------------------------------------------------------------------------------
-- Script to be used on PC to build resource.lua file
-- Parameters: [-o outputfile] file1 [file2] ...
-- Example: ./make_resource resource/*
-- creates resource.lua file with all files in resource directory
--------------------------------------------------------------------------------
local OUT = "resource.lua"
local function readfile(file)
local f = io.open(file, "rb")
if f then
local lines = f:read("*all")
f:close()
return lines
end
end
-- tests the functions above
print(string.format("make_resource script - %d parameter(s)", #arg))
if #arg==0 or arg[1]=="--help" then
print("parameters: [-o outputfile] file1 [file2] ...")
return
end
local larg = {}
local outpar = false
for i, a in pairs(arg) do
if i>0 then
if outpar then
OUT = a
outpar = false
else
if a == "-o" then
outpar = true
else
table.insert(larg, a)
end
end
end
end
print(string.format("output set to: %s", OUT))
local res = io.open(OUT, "w")
res:write("-- luacheck: max line length 10000\nlocal arg = ...\n")
res:close(file)
local filelist = ""
for _, a in pairs(larg) do
local inp = string.match(a, ".*[/](.*)")
if not inp then inp = a end
local content = readfile(a)
print(string.format("# processing %s", inp))
if content then
res = io.open(OUT, "a")
filelist = filelist .. ('"%s",'):format(inp)
res:write(('if arg == "%s" then return %q end\n\n'):format(inp, content))
res:close(file)
end
end
res = io.open(OUT, "a")
res:write(('if arg == nil then return {%s} end\n'):format(filelist))
res:close(file)

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@ -54,6 +54,7 @@ pages:
- 'ds3231': 'lua-modules/ds3231.md'
- 'fifo' : 'lua-modules/fifo.md'
- 'fifosock' : 'lua-modules/fifosock.md'
- 'file_lfs': 'lua-modules/file_lfs.md'
- 'ftpserver': 'lua-modules/ftpserver.md'
- 'gossip': 'lua-modules/gossip.md'
- 'hdc1000': 'lua-modules/hdc1000.md'

102
tests/NTest_file_lfs.lua Normal file
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-- luacheck: globals file
-- luacheck: new read globals node.LFS.resource
file = require("file_lfs")
local Nt = ...
Nt = (Nt or require "NTest")
-- check standard SPIFFS file functions
loadfile("NTest_file.lua")(Nt)
local N = Nt("file_lfs")
N.test('resource.lua in LFS', function()
ok(node.LFS.resource~=nil, "resource.lua embedded in LFS")
end)
local testfile = "index.html"
if node.LFS.resource("index.html") then
testfile = "index.html"
elseif node.LFS.resource("favicon.ico") then
testfile = "favicon.ico"
elseif node.LFS.resource("test.txt") then
testfile = "test.txt"
else
error "No 'index.html' nor 'favicon.ico' nor 'text.txt' file stored in LFS resource module. Can't run LFS file tests."
end
N.test('exist file LFS', function()
ok(file.exists(testfile), "existing file")
end)
N.test('getcontents file LFS', function()
local testcontent = node.LFS.resource(testfile)
local content = file.getcontents(testfile)
ok(eq(testcontent, content),"contents")
end)
N.test('read more than 1K file LFS', function()
local f = file.open(testfile,"r")
local size = #node.LFS.resource(testfile)
local buffer = f:read()
print(#buffer)
ok(eq(#buffer < 1024 and size or 1024, 1024), "first block")
buffer = f:read()
f:close()
ok(eq(#buffer, size-1024 > 1024 and 1024 or size-1024), "second block")
end)
N.test('open existing file LFS', function()
file.remove(testfile)
local function testopen(mode, position)
file.putcontents(testfile, "testcontent")
ok(file.open(testfile, mode), mode)
file.write("")
ok(eq(file.seek(), position), "seek check")
file.close()
end
testopen("r", 0)
testopen("w", 0)
file.remove(testfile)
testopen("a", 11)
file.remove(testfile)
testopen("r+", 0)
file.remove(testfile)
testopen("w+", 0)
file.remove(testfile)
testopen("a+", 11)
file.remove(testfile)
end)
N.test('seek file LFS', function()
local testcontent = node.LFS.resource(testfile)
local content
local f = file.open(testfile)
f:seek("set", 0)
content = f:read(10)
ok(eq(testcontent:sub(1,10), content),"set 0")
f:seek("set", 99)
content = f:read(10)
ok(eq(testcontent:sub(100,109), content),"set 100")
f:seek("cur", 10)
content = f:read(10)
ok(eq(testcontent:sub(120,129), content),"cur 10")
f:seek("cur", -50)
content = f:read(10)
ok(eq(testcontent:sub(80,89), content),"cur -50")
f:seek("end", -50)
content = f:read(10)
ok(eq(testcontent:sub(#testcontent+1-50,#testcontent+1-41), content),"end -50")
end)
N.test('rename file LFS', function()
nok(file.rename(testfile, "testfile"), "cannot rename LFS file")
end)