Footer's contents don't seem to work - node.js

Question

I'm trying create custom footers such in phantomjs examples: https://github.com/ariya/phantomjs/blob/master/examples/printheaderfooter.js
Here is my code:
var phantom = require('node-phantom');
phantom.create(function (err, ph) {
ph.createPage(function (err, page) {
page.set('paperSize', {
format: 'A4',
orientation: 'portrait',
footer: {
contents: ph.callback(function (pageNum, numPages) {
if (pageNum == 1) {
return "";
}
return "<h1>Header <span style='float:right'>" + pageNum + " / " + numPages + "</span></h1>";
})
}
}, function () {
page.open('http://www.google.com', function () {
})
})
})
});
But unfortunately I get the following error:
TypeError: Object #<Object> has no method 'callback';
Is it bug that ph does not expose callback method?

Answer 1

There are two problems in your script :
ph is not the classic phantom object, but a proxy object. node-phantom use web sockets to invoke phantomjs. Of course, some features are lost using this implementation.
functions are not serialized when calling page.set
Printing custom header/footer also requires to call phantom.callback. This method is not documented and so not exposed by node-phantom (and can't be). We need to find a way to apply this method in this package.
There are many solutions. Here is my possible solution :
Serialize your functions in a string in your script
var phantom = require('node-phantom');
phantom.create(function (err, ph) {
ph.createPage(function (err, page) {
page.set('paperSize', {
format: 'A4',
orientation: 'portrait',
header: {
height: "1cm",
contents: 'function(pageNum, numPages) { return pageNum + "/" + numPages; }'
},
footer: {
height: "1cm",
contents: 'function(pageNum, numPages) { return pageNum + "/" + numPages; }'
}
}, function () {
page.open('http://www.google.fr', function () {
page.render('google.pdf');
ph.exit();
})
})
})
});
edit bridge.js and add phantom.callback + eval. This allow us to re-plug the header/footer .contents.
case 'pageSet':
eval('request[4].header.contents = phantom.callback('+request[4].header.contents+')');
eval('request[4].footer.contents = phantom.callback('+request[4].footer.contents+')');
page[request[3]]=request[4];
respond([id,cmdId,'pageSetDone']);
break;
As you can see this works ! (Google in French)

Answer 2

Unfortunately, node-phantom doesn't appear to support phantom.callback. Since the project is inactive for more than a year, I think it's unlikely to be updated in the near future.
On the other hand, phantomjs-node supports phantom.callback() since version 0.6.6. You can use it like this:
var phantom = require('phantom');
phantom.create(function (ph) {
ph.createPage(function (page) {
page.open("http://www.google.com", function (status) {
var paperConfig = {
format: 'A4',
orientation: 'portrait',
border: '1cm',
header: {
height: '1cm',
contents: ph.callback(function(pageNum, numPages) {
return '<h1>My Custom Header</h1>';
})
},
footer: {
height: '1cm',
contents: ph.callback(function(pageNum, numPages) {
return '<p>Page ' + pageNum + ' / ' + numPages + '</p>';
})
}
};
page.set('paperSize', paperConfig, function() {
// render to pdf
page.render('path/to/file.pdf', function() {
page.close();
ph.exit();
});
});
});
});
});
As you can also see on this gist.

Answer 3

node phantom seems to expose this proxy-object via the create function (this should be your ph-object):
var proxy={
createPage:function(callback){
request(socket,[0,'createPage'],callbackOrDummy(callback));
},
injectJs:function(filename,callback){
request(socket,[0,'injectJs',filename],callbackOrDummy(callback));
},
addCookie: function(cookie, callback){
request(socket,[0,'addCookie', cookie],callbackOrDummy(callback));
},
exit:function(callback){
request(socket,[0,'exit'],callbackOrDummy(callback));
},
on: function(){
phantom.on.apply(phantom, arguments);
},
_phantom: phantom
};
that means, that you can probably acces the phantoms callback like this:
ph._phantom.callback

Answer 4

Here what I did to access phantom.callback:
add this to node-phantom.js line 202:
callback: function(callback){
request(socket,[0,'callback'],callbackOrDummy(callback));
},
just before _phantom: phantom
and add this to bridge.js line 45:
case 'callback':
phantom.callback(request[3]);
break;
Hope it helps!