Adobe Campaign - Dynamically Create a New Sample File With Javascript

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This is a very particular sort of circumstance, but essentially I was trying to streamline a file ingestion process from an SFTP environment. These files potentially would be millions of records long, and of a different format every time - so a new sample file would be necessary.

Conceptually, I wanted to: take a file accessed via the File Collector activity, pull the first 50 lines, put them into a new file, which is saved to the same location as the original file with some sort of change to the file name to indicate it’s a new record.

FINAL CODE:


var sourceText = vars.filename;
var index = sourceText.split(".");
var trimmedFile = index[0];
var newFileName = trimmedFile + "_sample.csv";

var fileA = new File (newFileName)
fileA.open("w");
var fileB = new File (vars.filename);
fileB.open();

var counter = 0;
for each (var line in fileB){
if(counter > 50) {break;}
counter++;
fileA.writeln(line)}

fileB.close();
fileA.close();

instance.vars.sampleFile = newFileName;
instance.vars.loadedFile = vars.filename;

BREAKDOWN:


var sourceText = vars.filename;
var index = sourceText.split(".");
var trimmedFile = index[0];
var newFileName = trimmedFile + "_sample.csv";

1: The full file path of the file accessed by the File collector is declared to vars.filename, so it’s saved to a JS variable here

2: The file path in the first variable is split on the full stop into an array, meaning the index variable contains [”/sftp/path/folder/filename_goeshere”,”.csv”]

3: Accessing the array, the first item, is saved to a variable. (Arrays are 0 indexed, so 0 will return the first result). 4: Basic string concatenation to update the name, so it’ll be the same as the original file, but now with _sample at the end.


var fileA = new File (newFileName)
fileA.open("w");
var fileB = new File (vars.filename);
fileB.open();

1: Create an entirely new file in the SFTP environment, based on the file name/path we have defined above.

2: Open the new file within the JS environment in write mode. With no parameters passed, it’ll default to “read” mode and be unable to have data included.

Modes	Parameter	Behaviour
Write	W	Access and overwrite information in a file
Append	A	Add new information to the end of the file
Read	R (or none)	Read information, no write ability

3: Access the source file in the JS environment

4: Open the source file.


var counter = 0;
for each (var line in fileB){
if(counter > 50) {break;}
counter++;
fileA.writeln(line)}

1: Create a variable to log how many lines we have added to the new file.

2: Start a loop based on lines within the source file.

3: First step for each loop, check to see if the counter is less than 50. If it is not? End the loop.

4: Next, add 1 to the counter.

5: Finally, write the current line from the Source file to the new Sample file.


fileB.close();
fileA.close();

instance.vars.sampleFile = newFileName;
instance.vars.loadedFile = vars.filename;

1: Once the loop ends, close the original file.

2: Close the sample file.

3: Save the file path for the new file to an instance variable

4: Save the file path for the original file (just in case).

So once you’ve run this, you have a sample file ready to use! I’m working on seeing if there’s a good way to dynamically access this for a data loading activity, but it doesn’t look super promising.