OpenAF programming quick-guide
List of functions to help you get started with any OpenAF script programming.
| My first Hello World |
| Print functions |
| Reading/Writing files |
| Convert JSON to a string and vice-versa |
| Running a shell command |
| Asking for user input |
| Continue learning |
My first Hello World
Step-by-step “Hello World”:
- Follow the instructions to install/setup OpenAF if you haven’t already
- Create a text file “test.js” in an folder with the following contents:
print("Hello World!")
- Run the file you just created:
[openaf install directory]/oaf -f test.js
# 'Hello World!' should appear as output
Print functions
| Function | Example | Description |
|---|---|---|
| print(aStr) | print("Hello World") | Prints a string to the screen |
| sprint(aObj) | sprint({ a: 123, b: true }) | Prints a javascript object structure to the screen |
Example
// Print a string
var str = "Hello!"
print(str)
// Print a number
var num = 123.456
print(num)
// Print a javascript object structure
var obj = { x: 1, y: -1, z: 0 }
sprint(obj)
// Print a javascript array
var arr = [ 1, 2, 3, 4 ]
sprint(arr)
Learn more
You can learn more how to print data with OpenAF in:
Reading/Writing files
| Function | Example | Description |
|---|---|---|
| io.readFileString(aFilename, anEncoding) | var str = io.readFileString("some/path/myfile.txt", "UTF-8") | Reads the contents of a provided filename into a string variable |
| io.readFileJSON(aFilename) | var obj = io.readFileJSON("some/path/myfile.json") | Reads and parses the contents of a provided filename, as JSON, into an object variable |
| io.writeFileString(aFilename, aString, anEnconding, shouldAppend) | io.writeFileString("some/path/myfile.txt", str, "UTF-8", false) | Writes the “str”ing variable contents into the provided filename |
| io.writeFileJSON(aFilename, aObj, aSpace) | io.writeFileJSON("some/path/myfile.json", obj, " ") | Writes an “obj”ect into a file, as JSON, with a provded spacing |
Example with a string:
// Assigning a string to a variable
var str = "This is a test!"
// Write the string variable to a file
io.writeFileString("mytext.txt", str)
// ...
// Reading a string from a file
var newStr = io.readFileString("mytext.txt")
// Print the string read from a file to the screen
print(newStr)
Example with JSON:
// Defining a variable with a JSON map structure
var obj = { name: "test", value: 123 }
// Print the structure to the screen
sprint(obj)
// Save the structure to a file
io.writeFileJSON("myobj.json", obj)
// ...
// Reading a structure from a file
var newObj = io.readFileJSON("myobj.json")
// Print the structure read from the file to the screen
sprint(newObj)
Learn more
You can learn more how to read and write files with OpenAF in:
Convert JSON to a string and vice-versa
| Function | Example | Description |
|---|---|---|
| stringify(aObj, aReplacerFn, space) | var str = stringify(obj) | Converts a provide javascript object structure into a string JSON representation of the same |
| jsonParse(aStr, useAlternative, useUnsafe, ignoreNonJson) | var obj = jsonParse(str) | Converts a string with a JSON representation of an object into a javascript object structure |
Example:
// Assign a javascript object structure to a variable
var obj = { text: "some text", number: 1234.56, boolean: false }
// Convert an object structure into a string
var str = stringify(obj)
// Print the converted string
print(str)
// ...
// Convert a string back to an object structure
var newObj = jsonParse(str)
// Print the new object structure
sprint(newObj)
// Print the 'text' string element of the object
print(newObj.text)
Running a shell command
| Function | Example | Description |
|---|---|---|
| $sh(aCmd).exec(aIdx) | $sh("ls -lad *").exec(0) | Executes aCmd without capturing stdout and stderr and just returning the exitcode |
| $sh(aCmd).get(aIdx) | var res = $sh("uname -a").get(0) | Executes aCmd and returns a map with stdout, stderr and exitcode |
Example of executing a command
// Executing a command
var res = $sh("ls -lad *").exec(0)
// Print to the screen the exit code of the command
print(res.exitcode)
Example of executing a command capturing the output
// Execute a command capturing the output
var res = $sh("uname -a").get(0)
// Print to the screen the stdout of the command
print(res.stdout)
Asking for user input
| Function | Example | Description |
|---|---|---|
| ask(aPrompt) | var str = ask("What's your name? ") | Stops executing, printing the provided prompt, to ask an user for input returning the same |
Example
// Ask for the user's name
var name = ask("What's your name? ")
// Printing the captured user answer
print("Your name is " + name)
Learn more
You can learn more how to interactively ask for user input in OpenAF in:
Continue learning
To continue you can check some base OpenAF concepts in Concepts. You don’t need to know them all but it will get you up-to-speed on some functionality you might be more interested on.
You can check the how-to guides that expand on the base core functionaly cover on the previous chapters.
You also have some specific guides for specific functionality. The beginner guides are a great place to start.
And lastly you can search this site (on the top search bar) and check the comprehensive reference.