Programming Pipes With Delicious and Sharing SPARQL Queries As A Result

In the post Sharing Linked Data Queries With Mortals… I described a rather clunky pattern for sharing SPARQL queries onto a sparql endpoint using delicious, along with a Yahoo pipe to generate a SPARQLProxy URI that identified a CSV formatted output from the query that could be consumed in something like Google spreadsheets (e.g. Viewing SPARQLed Data in a Google Spreadsheet).

In this post, I’ll refine that pattern a little more and show how to use delicious to bookmark a “processed” form of the output of the query, along with all the ingredients needed to generate that output. In a later post (hopefully before Christmas) I’ll try to show how the pattern can be used to share queries into other datastores, such as Google visualization API queries into a Google spreadsheet.

[The post describes two independent operations – firstly, how to generate a sparqlproxy uri from a set of delicious tags; secondly, how to generate a map from sparqlproxy output.]

In what follows, I’m using delicious as a database, and delicious tags as machine tags that can be used as arguments within a Yahoo pipe. The intention is not to suggest that this is even a good way of sharing SPARQL queries and demo outputs, but it does show an improvised way of how to share them,. It also provides just enough raw material to allow UI designers to think how we might capture, share and display sample use cases that go from SPARQL query to human meaningful output.

So here’s what a “finished” delicious bookmark looks like:

The three “machine tags”:
– endpoint:
– output:csv
– query:
are used as instructions in a Yahoo pipe that generates a query using SPARQLProxy:

A feed of bookmarked queries is pulled in from delicious, and checked to see that all the programming arguments that are required are there. (The sparlproxy_demo tag requirement is just a convenience.)

If all the arguments are available, their values are captured and passed to a routine to construct the SPARQLProxy URIs:

The query bookmarked by the tags is a query onto the transport database that pulls out the location traffic monitoring points on thee M5. The bookmarked URI is a demonstration of how to use the output of that query. In the current example, the bookmarked demo URI looks like this:

That is, it is a bookmark to a Google map that is displaying a KML feed pulled in from a Yahoo pipe.

This is the Google Map:

This is the Yahoo pipe the KML is pulled from:

And this is a peek inside that pipe:

The URI for the fetched CSV file is on that was generated from the bookmarked query tags by the first pipe shown above.

So to recap – this bookmark:

links through to a Google map showing traffic monitoring locations on the M5. The map is an ‘end-user’ demo that shows how Government data may be displayed in a meaningful way. In addition, th tags in the bookmark carry enough information for the user to construct a SPARQL qury that will generate the data that is displayed by the map. A utility Yahoo pipe (ID 22059ac6f967d7117b1262586c92b371) can take a delicious RSS feed containing the bookmark and generate a SPARQLProxy URI that calls the tagged endpoint with the tagged query and generates the tag specified output. There is then a break in the chain. A utility pipe capable of handling SPPARQLProxy generated CSV from transport data generates a KML version of the data, which is then passed to a Google map.

So what? So I don’t know what… but it has got me thinking that what might be useful is a quick way of sharing:
– info that is sufficient to generate and run a particular SPARQL query.
– along with a link to an ‘end user’ demo showing how that data might be used or displayed
– all in one handy package…

Which is what the above does… sort of.. though it’s still way too complicated for mortals…

PS It occurs to me that it might be possible to define a pipeline using delicious tags too? Maybe something like:

where the first step in the pipeline (2059ac6f967d7117b1262586c92b371?name=psychemedia&tag=transportDemo) says “run the delicious RSS feed from psychemedia/transportDemo (assuming I had recursively bookmarked that record with transportDemo) through the pipe with ID 2059ac6f967d7117b1262586c92b371 to generate the SPARQLProxy URI, then pass that to the pipe with ID 1c77faa95919df9dbea678a6bf4881c6 which should generate a KML output, which in turn should be sent to a Google map?!

Author: Tony Hirst

I'm a Senior Lecturer at The Open University, with an interest in #opendata policy and practice, as well as general web tinkering...