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Lua offers an IO library specific for handling file operations. Our FIL Library is based on these simple functions.

Page Treeroot@selfstartDepth1Basic file operations will follow a standard framework:

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title	1) Retrieve Files

Use os.fs.glob() to iterate over files matching a given pattern. In this case, we are iterating over all files with the extension .txt in the defined directory.

Code Block

language	lua

-- 1) Retrieve Files 
local sourceDir = '/filePickup/'
for filePath, fileInfo in os.fs.glob(sourceDir..'*.txt') do
   -- add file processing here 
end

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title	2) Process Files

Depending on your workflow you can use the IO library or our FIL Library to:

Read files - io.read()
Open files - io.open()
Write data to files - io.write()

Code Block

language	lua

-- 1) Retrieve Files 
local sourceDir = '/filePickup/'
for filePath, fileInfo in os.fs.glob(sourceDir..'*.txt') do
   
   -- 2) Open each file to read
   local F = io.open(filePath, 'r')
   -- read or write
   local Content = F:read('*a')
   F:write('new data')

end

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title	3) Close File Handles

It is important to close file handles when finished with processing to release system resources and avoid file locks.

Code Block

language	lua

-- 1) Retrieve files 
local sourceDir = '/filePickup/'
for filePath, fileInfo in os.fs.glob(sourceDir..'*.txt') do
   
   -- 2) Open each file to read
   local F = io.open(filePath, 'r')
   -- read or write
   local Content = F:read('*a')
   F:write('new data')
   
   -- 3) Close file handles
   F:close() 
   
end

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title	4) Handle Processed Files

Typically, when ingesting files, any processed files should either be moved with os.rename() or deleted from the source directory with os.remove().

Code Block

language	lua

-- 1) Retrieve files 
local sourceDir = '/filePickup/'
for filePath, fileInfo in os.fs.glob(sourceDir..'*.txt') do
   
   -- 2) Open each file to read
   local F = io.open(filePath, 'r')
   -- read or write
   local Content = F:read('*a')
   F:write('new data')
   
   -- 3) Close file handles
   F:close()
  
   -- 4) Rename or move a file
   local filepathTable = filePath:split('/')
   local filename = filepathTable[#filepathTable] 
   os.rename(filename, '/Users/awiebe/demo/processed/')    
   -- Remove/delete a file   
   os.remove(filePath)  
   
end

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