Semantic Web, Structured Dynamics, OSF for Drupal, OSF Web Services

conStruct: a skin for structWSF

As I said in my previous blog post, a conStruct instance is nothing more than a skin for one or multiple structWSF instances. conStruct is a user of a structWSF network.

But… what that means?

That means that each conStruct tools communicate with one or multiple structWSF instances. Each each feature of conStruct comes from structWSF. The only thing it does is presenting information to users, and give them some tool to manipulate the data.

A structWSF instances network

A structWSF instance is a set of web service endpoints. Each endpoint gets registered in a network. Each query sent to any of the web service endpoint of the network gets authenticated (and possibly rejected) by the network.

All structWSF instances share the same basic web services endpoints, however some specialized structWSF instance can add new functionality to the framework by developing new endpoints that does special things. Others can un-register services that has nothing to do with the mission of the instance, etc.

Not all structWSF instances are the same, but all of them share the same interface.

Individual people or organizations can choose to create structWSF nodes. The purposes can be quite different. Some organizations could choose to create structWSF nodes for internal purposes only: to help their departments to share different kind of data for example. Some people could want to setup a structWSF node where they can archive and share all data specific to their hobbies. Whatever the use-case is: they want a platform to ingest, manage, interact with and publish data; publicly or privately.

In the schema above, we can notice that different structWSF instances have been created and are maintained by different organizations, for different purposes. Some of the clients will communicate with these structWSF instances as a public user of the datasets published on the node(s), and other users will access to datasets that only them have access to.

As you can see, some users communicate with multiple structWSF instances. This means that these user cares about data of different datasets, maintained by different organizations. Why and what for? We don’t know. It can be for any reasons. It can be as a web portal that aggregates all the information about a specific domain that is shared amongst multiple nodes or it can be because the user get information from his client’s networks to get things done.

What is important to keep in mind with the schema above is that any kind of people, any kind of organizations and any kind of systems can leverage the structured data they have access to that is hosted by different organizations that make available different datasets and different web services endpoints (maybe some organizations can even create a web service endpoint that works with their dataset and to expose some special algorithms they use to disambiguate/tag entities, etc.)

A network in action

You are probably telling yourself: well, the grand vision is good… but where is the meat around the bone?

Lets take a look at the conStructSCS sandbox demo. You have two datasets in there: (1) the Sweet Tools and (2) RePEc. There is one thing that you probably don’t notice: both datasets live on two different structWSF instances (each structWSF instance is hosted on a different web server). This means that if you perform a search, or a browse query, all results you get in the conStruct user interface come from two totally different servers, with different data maintainers, hosted by different organizations, etc. Still, all results are displayed in the same user interface, which is the conStructSCS demo sandbox.

Under the curtain

Lets take a look at what is happening. First, run this search query for “rdf”. You see what appears in the yellow box? This is a list of the queries exchanged between conStruct and two structWSF instances. You want more? Try this other search query for “rdf”. Now you also have access to the body of the messages.

For this demo sandbox, we enabled the “wsf_debug” parameter so that users of the sandbox can see how a conStruct node can interact with structWSF instances. If the value of this URL parameter is “1”, then the header + body of the query is displayed to the users. If the value is “2”, only the header is displayed.

This means that you can happen the “&wsf_debug=1” parameter to any URL of the demo sandbox and you will be able to see the messages exchanged between the systems. Why? Because all conStruct tools communicate with one or multiple web service endpoint(s) and one or multiple structWSF instances.

Now, lets take a look at the output of the search query above.

  • Web service query: [[url: http://localhost/ws/search/] [method: post] [mime: text/xml] [parameters: ] [execution time: 0.279745101929]] (status: 200) OK – .
  • Web service query: [[url: http://bknetwork.org/ws/search/] [method: post] [mime: text/xml] [parameters: query=rdf&types=all&datasets=http%3A%2F%2Fbknetwork.org%2Fwsf%2Fdatasets%2F283%2F%3Bhttp%3A%2F%2Fconstructscs.com%2Fwsf%2Fdatasets%2F160%2F&items=10&page=0&inference=on&include_aggregates=true&registered_ip=self%3A%3A0] [execution time: 0.289397001266]] (status: 200) OK – .
  • Web service query: [[url: http://localhost/ws/dataset/read/] [method: get] [mime: text/xml] [parameters: uri=all&registered_ip=self%3A%3A0] [execution time: 0.123399972916]] (status: 200) OK – .
  • Web service query: [[url: /ws/dataset/read/] [method: get] [mime: text/xml] [parameters: uri=all&registered_ip=self%3A%3A0] [execution time: 0.18315911293]] (status: 200) OK – .

Each dot is a query sent to a specific structWSF instance. For each query, you have this information:

  • URL of the web service endpoint where the query has been sent.
  • HTTP method used to send the query
  • MIME type (Accept HTTP header parameters) requested
  • Parameters of the query
  • Time it took to execute the query (including network latency & query processing)
  • Status of the query from the web service endpoint

Since this conStruct instance is linked to two different structWSF instances, the search tool will send a search query to two different search web service endpoints. Additionally, it will query these structWSF instances to get the description of the searched dataset (to display the proper name of the datasets in the user interface).

Each query is validated by the structWSF instances to make sure that they are legitimate queries. If they are, then results are returned. Once these queries are sent and answers received, the structSearch tool can then generate the page and display it to the user.

Do you want more? Here is a list of queries sent by different conStruct tools to different web services endpoints:

(Note: this debug info tabs has been added so that people can see what is happening under the hood. However this information is only accessible to the registered conStruct instance and the administrator of that instance).

Do it by yourself, from your desktop computer

I said that people or organizations that managed to create content data on these structWSF instances were able to manage/manipulate their data from anywhere: not only from within conStruct. Lets test this.

I changed the permissions on the Sweet Tools List dataset so that it is publicly available for reading. That way, any anyone will be able to send Curl queries against the dataset, to that structWSF instance.

Now, lets try a couple of queries to different web services endpoints. Let start with a query for the keyword “rdf” on the Sweet Tools dataset:

curl -H “Accept: text/xml” “http://constructscs.com/ws/search/” -d “query=rdf&types=all&datasets=http%3A%2F%2Fconstructscs.com%2Fwsf%2Fdatasets%2F122%2F&items=10&inference=on”

What you will get for this query is a list of 10 instance records that match this query. You don’t like the internal XML representation of the system? Then try the internal JSON representation by running this query:

Maybe this is not good enough for you? Then lets try in RDF+XML:

curl -H “Accept: application/rdf+xml” “http://constructscs.com/ws/search/” -d “query=rdf&types=all&datasets=http%3A%2F%2Fconstructscs.com%2Fwsf%2Fdatasets%2F122%2F&items=10&inference=on”

I think you understood the point here, so I won’t continue.

Now, lets send a query to get all the datasets accessible by you:

curl -H “Accept: application/rdf+xml” “http://constructscs.com/ws/auth/lister/” -d “mode=adataset”

If you can query all these things with Curl, this mean that anything can query these services. Standalone softwares can be developed to leverage these content nodes as well as other online applications.

Conclusion

As you probably learned with this blog post, one of the powers of structWSF is that it creates networks of structured content nodes that can be accessed by any thing, from anywhere, publicly or privately.

As you noticed, all this stuff is not only about integrating any kind of data, but also to publish it in a flexible way.

Semantic Web, Structured Dynamics, OSF for Drupal, OSF Web Services

Release of structWSF, conStruct and the Community Web Site

The last few months have been challenging in term of amount of work to get done, in focusing on deliverables and in getting ready for the release of conStruct and structWSF sources codes, documentations, tutorials, web sites and demos.

I am now really happy to be able to finally announce the release of both software code sources along with a new development community website where users and developers can exchange ideas about these two news projects.

The biggest milestone of the last months is now behind us. However, this is just the beginning of everything!

I think that many things have been written about these two projects already. I don’t want to write any tutorial at this point. So the only thing I will do right now is to point you the more relevant documentation, web sites, blog posts and demos about each project. The next step will be to write about specific use cases, features, etc.

Community Web Site

The community Web site is a place where developers and users of structWSF and conStruct can meet to talk about both projects, to report bugs and issues, to submit new enhancements, to find tips and tricks, etc.

I would suggest you to create a new user profile on the community Web site if you are interested in communicating with other members.

structWSF

structWSF is a platform-independent Web services framework for accessing and exposing structured RDF data. Its central organizing perspective is that of the dataset. These datasets contain instance records, with the structural relationships amongst the data and their attributes and concepts defined via ontologies (schema with accompanying vocabularies).

The structWSF middleware framework is generally RESTful in design and is based on HTTP and Web protocols and open standards. The initial structWSF framework comes packaged with a baseline set of about a dozen Web services in CRUD, browse, search and export and import. All Web services are exposed via APIs and SPARQL endpoints. Each request to an individual Web service returns an HTTP status and optionally a document of resultsets. Each results document can be serialized in many ways, and may be expressed as either RDF or pure XML.

conStruct

conStruct is a distro of the Drupal framework that aims to set a new standard in data integration and as a structured content system (SCS). With conStruct, you can let your data and its structure drive your applications. You can easily interoperate your diverse internal information with public content on the Web. And you can leverage a platform designed from the ground up for knowledge management and collaboration.

Semantic Web, Structured Dynamics, OSF for Drupal, OSF Web Services

structWSF and conStruct websites unveiled

I am proud to announce the release the websites of two of our products to come: structWSF and conStruct. Both products will be available in open source under the Apache 2 license. Mike just unveiled and demoed the two projects in his talk at SemTech 2009.

As we describe them on Structured Dynamics‘ website:

structWSF

structWSF is a platform-independent Web services framework for accessing and exposing structured  RDF data. Its central organizing perspective is that of the dataset. These datasets contain instance records, with the structural relationships amongst the data and their attributes and concepts defined via ontologies (schema with accompanying vocabularies).

The structWSF middleware framework is generally RESTful in design and is based on HTTP and Web protocols and open standards. The initial structWSF framework comes packaged with a baseline set of about a dozen Web services in CRUD, browse, search and export and import.

All Web services are exposed via APIs and SPARQL endpoints. Each request to an individual Web service returns an HTTP status and optionally a document of resultsets. Each results document can be serialized in many ways, and may be expressed as either RDF or pure XML.

In initial release, structWSF has direct interfaces to the Virtuoso RDF triple store (via ODBC, and later HTTP) and the Solr faceted, full-text search engine (via HTTP). However, structWSF has been designed to be fully platform-independent. Support for additional datastores and engines is planned. The design also allows other specialized systems to be included, such as analysis or advanced inference engines.

The framework is open source (Apache 2 license) and designed for extensibility. structWSF and its extensions and enhancements are distributed and documented on the OpenStructs Web site.

conStruct

conStruct SCS is a structured content system that extends the basic Drupal content management framework. conStruct  enables structured data and its controlling vocabularies (ontologies) to drive applications and user interfaces.

Users and groups can flexibly access and manage any or all datasets exposed by the system depending on roles and permissions. Report and presentation templates are easily defined, styled or modified based on the underlying datasets and structure. Collaboration networks can readily be established across multiple installations and non-Drupal endpoints. Powerful linked data integration can be included to embrace data anywhere on the Web.

Depending on roles and permissions, a given user may or may not see specific datasets or tools within the Drupal interface. Search and browse results are similarly sequestered depending on access rights.

conStruct provides Drupal-level CRUD (create – read – update – delete), data display templating, faceted browsing, full-text search, and import and export over structured data stores based on RDF. It also provides a system for additional tools additions and expansions for this structured data. conStruct SCS is built on the platform-independent structWSF Web services framework.

Like Drupal and structWSF, conStruct is free and open source (GPL license). Versions of conStruct SCS are planned to adopt it to other content management systems (CMS).

Next

The alpha version of the code with all the proper documentation will be released later this summer. Everybody will be able to contribute to the project by enhancing/developing the core code or by extending it with new modules and web services. Stay tuned!