Nodejs function gets called multiple times - node.js

Question

I am working on a parser in nodejs. Therefore I request a website and parse the HTML.
I am working with require("htmlparser") and require('follow-redirects').http for the requests.
requestSite(options);
console.log("Done\n");
parser.done();
function requestSite(options) {
http.get(options, function(res) {
console.log("Got response: " + res.statusCode);
res.setEncoding('utf8');
res.on('data', function (chunk) {
parser.parseChunk(chunk.toString('utf8'));
});
}).on('error', function(e) {
console.log("Got error: " + e.message);
});
}
My problem now is that the done() is called before the requestSite function actually has finished its chunks resulting in following error:
Writing to the handler after done() called is not allowed without
calling a reset()
How can I wait for the chunks to finish?

Answer 1

You are not taking account the asynchronous nature of nodejs. It will call requestSite and then moveon to execute the next statement and call parser.done before requestSite is done executing. Do this instead.
requestSite(options, parser);
console.log("Done\n");
function requestSite(options, parser) {
http.get(options, function(res) {
console.log("Got response: " + res.statusCode);
res.setEncoding('utf8');
res.on('data', function (chunk) {
parser.parseChunk(chunk.toString('utf8'));
})
.on("end", function(){
parser.done();
})
}).on('error', function(e) {
console.log("Got error: " + e.message);
});
}

Answer 2

well this is the basic of node.js and the event driven architecture.
Node is not a line by line programing like php, python etc...
look at this simple example:
console.log(1);
setTimeout (function(err, res) {
console.log(2);
}, 0);
console.log(3);
as you will think it should print: 1,2,3
but this will print 1,3,2.
In your example you should move the
parser.done();
to the "end" of the http request.
currently you have an event for getting chunks of data, so simply use:
onEnd or something similar and than place the "parser.done()"