Introduction
This post describes how to interact with an interactive console application and similate user interaction. In this case we are goint to interact with the app called mongo.exe wich is the console client for the NoSql database MongoDb.
Background
Command line applications have been very useful because they allow us to perform actions easy and fast, the problem here is when you need to call a console application and such application require user interaction. Sometimes it becomes a headache for developers who want to call those apps to perform x or y actions, so here comes Perl to help us.
Using the code
The following piece of code shows how to create a set of actions to execute when we call a console app.
#create a set of instructions
my @instructions = ();
push(@instructions, qq{use test;});
push(@instructions, qq{db.book.remove()});
push(@instructions, qq{db.book.save({name:"Code complete", author:"Steve Mcconnell"});});
push(@instructions, qq{db.book.save({name:"Perl: The Complete Reference", author:"Martin Brown"});});
push(@instructions, qq{db.book.find();});
push(@instructions, qq{exit});
#pipe the app in a handler
open MONGO, "| mongo.exe" || die "can't pipe mongo.exe";
#execute set of instructions
print MONGO join("\n",@instructions);
To execute the previous code you just need to type perl filename.pl
Points of Interest
Simulate user interaction in console apps may be tricky with other languages, in Perl is easy.
