Creative Workflow Hacks

Last time, we talked about using a Socket Object in After Effects CS3 to parse a data feed with E4X XML parsing. There are a lot of useful workflow operations I can think of that could make use of data feeds, but After Effects is a visual medium, so let’s do something visual, let’s import a set of flickr photos matching a tag. This is a proof of concept script, and before you plunge into experimenting you should check the terms of service of the web feed provider and respect the use of images you download. That said, let’s take a look at some code.

First of all, we create a Socket Object, and connect to our web feed. In this case we are looking for all photos tagged red referenced by this line

webConnect.write (' GET /services/feeds/photos_public.gne?tags=red HTTP/1.0nn');

We then fetch and parse the XML, and loop through looking for a link element with an enclosure attribute like so

for(entry in elements)
{
		
	if(elements[entry].localName() == "entry")
	{
		var entryNodes = elements[entry].elements();
		for(x = 0; x < entryNodes.length(); x++){
				if(entryNodes[x].localName() == 'link')
				{
					if(entryNodes[x].@rel.toString() == "enclosure")
					{
						pictureArray.push(entryNodes[x].@href.toString());
					}	
				}
		}
		
	}
}

Once we've gathered up an array of links, we download the photos using system.callSystem() and a command line app called curl. There is probably a Windows version of curl, but it probably won't be installed on your machine which makes this a mostly Mac script. This code handles the download and import. Note, my version of WordPress is really upset about using the keyword system in code listing, thus there is extra whitespace around the system.callSystem() call in the code listing below.

for(y =0; y < pictureArray.length; y++)
{
	
	var picNameSet = pictureArray[y].split("/");
	var picName = "/" +  picNameSet[picNameSet.length -1];

	
	var curlString  = "curl -O " + pictureArray[y];
	var retVal = sys  tem.callSyste  m(curlString);

		

	
	var fileToImport = new File(picName);
	var myProject = app.project;
	
	if(fileToImport.exists)
	{
		
			var my_io = new ImportOptions(fileToImport);
			
			if(my_io.canImportAs(ImportAsType.FOOTAGE)){
				try{
					myItem = myProject.importFile(my_io);

				}catch(e){
					alert('couldn't import flickr item with error: r' + e.toString())
				}
	
			}
	}

	
	
}

I mentioned this code was slightly flawed. Network activities are by their nature asynchronous, our tasks go out into the ether and we don't now when or how they return. In this case I start the download and quickly check to see if the file is available. If it's not, I just skip it. In the real world of network activities this will never do. AE scripting by it's nature is a pretty synchronous activity, we do one thing and then another. As I explore this style of scripting I'm investigating work arounds on how to mesh the two styles of programming a bit better. For now, I just ignore it. grin. If you've got ideas about smart ways to handle asynch network scripting in After Effects, I'd love to hear about it.

Anyway, I run the script and import 20 or so photos matching the tag red. In this case I'm just discarding all the metadata and context information that make the photos really interesting, but it's a fun experiment and I get to see a bunch of cool photos. As I continue to explore, hopefully I'll come up with more robust network programming and more concrete tools for using web feeds in an interesting way.

zip download of db_flickrExperiment