Static data load

Description

data = static_data_load(path)
data = static_data_load(path, options) (from AM/AP 3.6 or later)
static_data_load(path, callback)
static_data_load(path, options, callback) (from AM/AP 3.6 or later)

static_data_load is used to get load static data from a JSON, CSV or text file.

Return value

Argument	Type	Description
data	Object	The data in the static file. Will only return data when reading data synchronously.

Arguments

#	Argument	Type	Description
1	path	String	The location of the static file inside the resource folder (*.csv, *.json or *.txt).
2	options	String	(Options) Extra options. See the table below for available options.
3	callback	Function	(Optional) Function is called when data has been loaded. Data argument contains the data, is nil on error. The file will be read synchronously when the callback function is not provided.

Options

Name	Type	Default	Description
csv_header	Boolean	true	Determines if the CSV has a header.

Synchronous vs Asynchronous

Reading a file takes some time, depending on the size of the file and the speed of your hard drive and your PC.

When you don't want your instrument or panel to have to wait for the file access, you can choose for asynchronous mode. The reading will happen in the background, and you will get a callback when the file has been read.

You can also read the file synchronous, which means that your instrument or panel will wait for the file to become ready. This is okay for the initial execution, but should be avoided when the instrument or panel is running.

Example (JSON)

Example person.json file:

{
  "firstName": "John",
  "lastName": "Smith",
  "age": 27,
  "address": {
    "streetAddress": "21 2nd Street",
    "city": "New York",
    "state": "NY",
    "postalCode": "10021-3100"
  },
  "phoneNumbers": [
    "212 555-1234",
    "646 555-4567",
    "123 456-7890"
  ]
}

Synchronous

Lua code to read JSON example above synchronously.

data = static_data_load("person.json")

-- Print first name
print(data["firstName"])

-- Print street address
print(data["address"]["streetAddress"])

-- Print all phone numbers
for key,value in pairs(data["phoneNumbers"]) do
  print(value)
end

Asynchronous

Lua code to read JSON example above asynchronously.

static_data_load("person.json", function(data)
  -- Print first name
  print(data["firstName"])

  -- Print street address
  print(data["address"]["streetAddress"])
  
  -- Print all phone numbers
  for key,value in pairs(data["phoneNumbers"]) do
    print(value)
  end
end)

Example (CSV)

Example cars.csv file:

Year,Make,Model,Description,Price
1997,Ford,E350,"ac, abs, moon",$3000.00
1999,Chevy,Venture,"Extended Edition",$4900.00
1999,Chevy,Venture,"Extended Edition, Very Large",$5000.00
1996,Jeep,Grand Cherokee,"MUST SELL!",$2500.00

Synchronous

Lua code to read CSV example above synchronously.

data = static_data_load("cars.csv", "csv_header=true")
-- Print all cars
for key,value in pairs(data) do
  print(value["Make"] .. " " .. value["Model"] .. " " .. value["Description"] .. " from " .. value["Year"] .. ", now only for " .. value["Price"] .. "!")
end

Asynchronous

Lua code to read CSV example above asynchronously.

static_data_load("cars.csv", function(data)
  -- Print all cars
  for key,value in pairs(data) do
    print(value["Make"] .. " " .. value["Model"] .. " " .. value["Description"] .. " from " .. value["Year"] .. ", now only for " .. value["Price"] .. "!")
  end
end)

Example (Text)

Example cars.txt file:

 Ford
 Chevy
 Jeep

Synchronous

Lua code to read Txt example above synchronously. Data will be split in lines. The new line character can be either \r\n (Windows) or \n (Unix).

data = static_data_load("cars.txt")
-- Print all cars
for key, value in pairs(data) do
  print("line " .. key .. "has car: " .. value)
end

Asynchronous

Lua code to read Txt example above asynchronously. Data will be split in lines. The new line character can be either \r\n (Windows) or \n (Unix).

static_data_load("cars.txt", function(data)
  -- Print all cars
  for key, value in pairs(data) do
    print("line " .. key .. "has car: " .. value)
  end
end)