planet

Introducing fluxkraft - web automation simplified with the power of Rules!

You might have heard some rumors about a tool called "fluxkraft": something like ifttt.com, but with Rules? Or what? Indeed, fluxkraft is one of our latest drunomics lab projects funded by netidee - a Austrian grant for powerful - and open - innovations, and yes - fluxkraft will be a tool for rule-based web automation, built as an open platform on top of Rules and Drupal! So, finally here are some first details on it:

So the idea is to build an easy to use Drupal distribution that allows you to automate various web-based tools like twitter, facebook and dropbox. Yes, you can do that already with services like ifttt.com, but fluxkraft will be an open platform, open-source and free for everyone to use and extend. That way, you can install it on your own servers and keep all the keys to your valuable data secured - and most importantly - under your control!

Then, as it's open source and will come with an API for adding connectors to new services you can simply integrate it with any service you want. So while the tool will provide some essential integrations for services like twitter and facebook from the start, the hope is that community will chime in and provide connectors to a variety of different online services.

Rules?

So how does that tie into Rules? Well, Rules already provides a solid technical base, but we'll add an API for easy-integration with external services to it - so we've got the kraft. But for the flux to gain enough strength, we'll build a new UI that makes it super-simple to create, mix, and share the rules that connect the various services together. So yes - we'll build a new Rules UI! Initially, it will be built separately and power fluxkraft, but if everything works out we'll see a new Rules UI pretty soon!

All fine, Doc? So what's the time(line)? We've mostly finished some initial wireframes, so expect a first shout for feedback on the the new UI at the Rules g.d.o. group soon! Then, the fluxkraft team will be working eagerly on the project such that - maybe - we might have a first preview release out for Drupalcon Portland in May. Howsoever, we'd love to share our learnings and show how we are reloading the Rules UX with fluxkraft, so I've proposed session!

Finally, so who's in the boat? Well, it's me "fago" who will be leading the project during the next months - in fact I'll dedicate most of my time to it. But, fortunately I've got some help of Christian Ziegler aka criz (Strategy, Community Management), Sebastien Siemssen aka fubhy (Development) and Nico Grienauer (Design, Inspirator).

If you are interested, follow @fluxkraft on twitter and provide feedback in a short comment below!

Semantic content enhancements with Drupal, Apache Stanbol and VIE.js

As previously announced on the IKS blog I’ve been recently working together with Stéphane Corlosquet on integrating the tools provided by the IKS project to do semantic content enhancements in Drupal as part of the IKS early adopter program.

The Interactive Knowledge Stack (IKS) project is an open source community which got funded by the EU to build an open and flexible technology platform for semantically enhanced Content Management Systems. Thanks to IKS, open source projects like Apache Stanbol, VIE.js or Create.js got started. While VIE.js and Create.js are already on their way to Drupal 8 via the Spark initiative, our focus was on integrating Apache Stanbol with Drupal 7. In short, Apache Stanbol is a java web application that leverages tools like Apache Solr, Apache Tika or Apache OpenNLP to provide a set of reusable components for semantic content management via RESTful web services. On the front-end side, VIE.js (“Vienna IKS Editables”) is the JavaScript library for implementing decoupled Content Management Systems and semantic interaction in web applications.

For leveraging Apache Stanbol with Drupal we send Drupal’s data over to Apache Stanbol’s EntityHub component for indexing, such that it is available to Apache Stanbol’s content enhancer. That means, we can use VIE widgets like annotate.js to send pieces of text over to Apache Stanbol for auto-linking content items indexed to Stanbol, which by default includes DBpedia entities, but could be easily extended by any source providing data in RDF. Next, the VIE autocomplete widget allows for easy tagging based upon entities indexed with Apache Stanbol - regardless of whether they come from DBPedia or from one of the Drupal sites your organization runs!

There must be Rules at the Drupalcon Munich

As there must be Rules at the Drupalcon Munich as well, I've had a Rules session together with Richard Jones from i-KOS.

Head over to the session page for a summary and find the slides attached attached to this post as well. Moreover, you can find all the screencasts we've used during the presentation here as well. It's a real Drupal commerce site we've been using in the session to show how Rules can be used to solve real life problems.

1 - No VAT for certain products

2 - Discounts for products that are not belts or bags

and then to make it work the same way years ahead

3 - Subscribe to back in stock notifications via Flag module.

4 - Notify me when something needs review with Workbench moderation

5 - Execute Rules components from Views Bulk Operations

6 - Let's do promitions, but only on Monday please!

7. Message users if they abandoned their carts

8. Log user communication with the Message module

A New Entity Property API for Drupal 8

Why?

While the conversion to full CRUD for entities and classed objects for Drupal 8 made good progress, we’ve not yet reached the goals of fully translatable entities and having a default entity serialization for import/export, content staging and web services. For those points we need to know what’s in an entity! Yes we can look up the fields, but there are also base entity properties and further stuff modules put on entities, which both are no fields so we do not know anything about them.

That is what the new Entity Property API is supposed to change: It’s about providing a unified interface to entity properties and fields, avoiding the split between fields and non-field properties. So fields will be entity properties working with the same API as well! Then, it’s about being able to instrospect what’s going to be in an entity - regardless whether it has been added by a module or by the user via field UI. But furthermore, with classed entity objects as the basis we can improve the developer facing API and make it easier to access property and field values (I’m looking at you, $entity->field_body[LANGUAGE_NONE][0][‘value’]).

What?

As we’ve outlined in the WSCCI Web Services Format Sprint report we want to have a modern OOP, interface based API for properties. The API should allow for introspection, so that it’s possible to look up the defined properties of an entity type in advance. If you know the Entity property information system of the Drupal 7 Entity module, it’s a bit similar to that, but instead of adding an extra layer above the existing entities it’s about supporting it natively. So there will be no need for entity wrappers - all the easy API and information will be directly available in $entity.

See the Entity Property API meta issue for a more complete list of planned features.

It's done: Rules 2 is out!

Finally, slightly more than two years after I started the initial development I'm happy to announce the release of Rules 2.0 for Drupal 7!

So what's new compared to Rules 1.x?

While the fundamental concepts of "Event-Condition-Action rules" and parametrized actions remain, Rules 2.x is a complete re-write - quite some things changed. Now, it's building upon the Entity API module to fully leverage the power of entities and fields in Drupal 7. Change a taxonomy term? - No problem. Moreover that, Rules 2 now allows you to just select any entity property or field via it's so called "data selection" widget:

Data selection

The Rules data selection widget shows all suiting data properties when configuring an action or condition argument. Let's consider, you configure an action to send a mail - by using the data selector comment:node:author:mail you can easily send mail to the comment's node's author. For that the data selection auto-complete helps you finding suiting data selector:

You might note, that data selectors like node:title look like token replacements. But as actions need more than just textual data, the data selector gives them back the raw data, e.g. full entity objects or whatever fits depending on the data type. Thus, data selectors are not implement via token replacements, but via the entity.module's Entity property info system. Still, the Entity Tokens module (comes with Entity API) makes sure there are token replacements available for all the data selectors too.

The very same way one can naturally access fields too - e.g. node:field-tags gets you all the tags of your article node. However as only articles have tags, for that to work Rules needs to know that the variable node is an article first. Thus, make sure you've used the "Content is of type" or the "Data comparison" condition to check it's an article. Analogously, if you have an "entity" data item you can use the Entity is of type condition to make sure it's a node and access node-specific properties afterwards!

Read more about data selection in the drupal.org handbooks.

Switching parameter input modes

Related, Rules 2 allows you to switch the input modes while configuring the argument for an action parameter. Consider, you have an action that works with a vocabulary. Usually people might select the vocabulary to work with from the list of available vocabularies, but in some circumstances one wants the action to use the vocabulary of a specific taxonomy term. This is, where switching parameter input modes comes into play as it allows you to switch from fixed input mode (= configuring a specific vocabulary) to the data selection input mode - so you could just configure term:vocabulary as an argument by using the data selection widget.

Rules 2 provides small buttons below each parameter's configuration form which allow you to switch the input mode:

Components

Components are standalone Rules configurations that can be re-used from your reaction rules or from code. In Rules 1.x there are already "rule sets" available as "components" - but with Rules 2.x there are multiple component types: Rule Sets, Actions Sets, Rules, "AND Conditions Sets" and "OR condition sets". Rule sets come with maximum flexibility, but if the extra layer of having multiple rules is unnecessary for your use case, you can go with the simpler action set or a single "rule" component now! Next, the conditions sets make it possible to define re-usable condition components.

Components work upon a set of pre-defined variables (e.g. a node), just as for Rules 1.x. However with Rules 2.x it's now possible to provide new variables back to the caller, too.

Read more about components in the drupal.org handbooks.

Loops and lists

Rules 2 is finally able to properly deal with loops and lists! That means you can now access all your fields with multiple items, e.g. the tags of an article node. So you can easily loop over the list of tags and apply an action to each tag. That's also very handy in combination with node-reference or user-reference fields. Send a notification mail to all the referenced users? No problem.

Furthermore, one can access individual list items directly using the data selector - just use node:field-tags:0:name to access the first tag. If you do so, you might want to check whether a tag has been specified by using the "Data value is empty" condition though.

Read more about loops in the drupal.org handbooks.

Improved debug log

Fortunately, there has been another Rules related Google Summer of Code project this year. Sebastian Gilits worked on improving the rules debug log as part of his project! Now, the debug log makes use of some Javascript and appears all collapsed by default, so it's much easier to get which events have been triggered and which rules have fired in the first place. Also, we've included edit links so you can easily jump from the debug log to the Rules UI in order to fix up a miss-configured rule.

Publishing Linked Open Data of Austria at the Vienna Create Camp 11

The last weekend I attended the Vienna Create camp 11, a great event for collaboratively creating applications related to open data and accessibility.

6 members of Drupal Austria formed a team to make use of open data published by the cities of Vienna and Linz. Unfortunately, it turned out that the data is published in various different data structures and formats, so re-using the data in an efficient manner is hard. It's nice to see that the city of Linz is using CKAN to publish the data, so there is some basic information about the data sources (format, url, ..) available. However, still each data set is published using different data structures, so making use of a data source requires writing or configuring a specific adapter.

So, we've started "drupalizing" the data by using feed importers, whereby we've configured one content type and feeds importer per data source. Fortunately, once the data is in Drupal we can use it with all of Drupal's tools. So publishing the data as Linked Open Data is as easy as enabling the "rdf" module of Drupal and providing some meaningful mappings. For that, we've made use of Schema.org vocabularies as far as possible.

Now, all imported data items are available via RDFa, RDF, JSON or XML. But most convenient is probably the Sparql endpoint, which enables one to directly query the published datasets. So finally, we have real Linked Open Data of Austria - yeah! Then, we've made use of Openlayers with some nice base layers from the TileStream powered kartenwerkstatt.at to create nice looking maps - check out the demonstration site.

Next, we've published our open data features at drupal.org, so everyone can easily make use of our work and quickly use all that data by using Drupal. See http://drupal.org/project/odv.

Unfortunately, the data of the city of Linz required some custom massaging in order to get proper geo coordinates from the project they used. Thus, we were not able to create easy to use feeds configurations for Linz as we've done for Vienna. Maybe the city of Linz improves that in the future...

Nginx clean-URLs for Drupal installed in various sub-directories

klausi has already posted a nice, actually working nginx configuration for Drupal on his blog. This configuration is intended for Drupal installations installed on separate (sub)domains. However, recently I came up with the need of having multiple Drupal installations in sub-directories for my development environment. To achieve that I've created the following location directive:

        location ~ ^/([^/]*)/(.*)$ {
                try_files $uri /$1/index.php?q=$2&$args;
        }

That way, you can just add as many Drupal installations as you want in sub-folders, while they are automatically clean-URL enabled. :)

Drupal 8: Entities and data integration

As follow-up to my previous blog post Drupal 8: Approaching Content and Configuration Management, I'm going to shortly cover how the Entity API could help us with two more of Dries' points: Web services and information integration.

First off, for getting RESTful web services into core, having a unified API to build upon makes lots of sense. That way we make sure we locally have the same uniform interface for CRUD functions available as we expose it to the web. But moreover, the possibility of having remote entities can help us a lot with integrating with remote systems. In a way, we'll get that anyway once we implement pluggable entity storage controllers (and you can even do so already in D7).

But for that really being useful, we need to know the data we want to work with. This is why, I come up with the hook_entity_property_info() in the Entity API module for d7. While for d7 it is built on top of the stuff that is there anyway, I think it should play a much more central role in D8 for various reasons:

  • A description of all the data properties of an entity enables modules to deal with any entity regardless of the entity type just based on the available data properties (and their data types). That way, modules can seamlessly continue to work even with entities stemming from remote systems. This is how, the RestWS, SearchAPI and Rules modules already work in d7.
  • With pluggable storage backends, I see no point in SQL-centric schema information except we are going to use SQL based storage. By defining the property info, storage backends can work based on that though, i.e. generate the sql backend can generate the schema out of the property information.
  • When working with entities, what bothers is the data actually available in the object. To a module, the internal storage format doesn't matter. In a way, the property information defines the "contract" how the entity has to look like. Given that, all APIs should be built based on that, i.e. efq should accept the value to query for exactly the same way it appears in the entity and not in storage-backend dependend way (no one can predict once storage is pluggable). The very same way display formatters and form widgets could just rely on the described data too.

As we discussed in the entity API bof, it might make sense to build it around "field types" evolving to "data types" - thus being decoupled from being a "field". The very same way we can start building the display components around the entity properties, thus not necessarily being based on fields (bye bye field api "extra fields"). Any way the implementation will look like, let's let the entity API become our long missing data API!

Drupal 8: Approaching Content and Configuration Management

As a follow-up to heyrocker's great core conversations talk I'd like to share my thoughts on that topic. So is X content? Or configuration? As heyrocker pointed out: We shouldn't have to care.

So yes, the line between content and configuration is blurry - stuff being content on a site, would more fit the configuration bill on another site. Still this doesn't mean we have to treat content and configuration exactly the same way. We can and we need to build separate systems for configuration management and content deployment, but the point is: We need one and the same type of objects to be able to behave as content and configuration dependent on the actual requirements of the site. Not necessarily out-of-the box, but well, it should be doable such that people can implement their use-cases. To facilitate that, we need a foundational unified API, an API that deals with objects the same way regardless whether its configuration or content, an API that allows us to fetch any object, to export it, and to import and save it on another site.

As said in the core conversation, I think the entity API perfectly fits into that. That way, an entity would be basically any data object which is integrated into Drupal, such we have a unified CRUD API - and a unified way to import and export that data. It should be able to deal with machine names or auto-incremented numeric id, but as well we might want it to be able to deal with UUIDs out of the box. So we'd finally get a unified data API and exportability, the very much foundation for solving the configuration management and content deployment problems.
But for that to take off, we need to keep the entity concept slim and don't bake too much assumptions into it. Is it content or configuration? Is it user-facing? Is it fieldable or viewable/renderable? Well maybe, maybe not. So while it makes a lot of sense to build more APIs around entities, we should never actually require them. Instead, we could just provide the APIs such that any entity type is able to opt-in, if it fits the bill.

In addition to that, I'd like to share my thoughts on how the Entity API could help us to cover 2 more points Dries mentioned in his key-note: Web services, and information integration. I'll come back to that in a follow-up post.

Restful web services in Drupal 7

During the work on my thesis over the last year, I played around a lot with RESTful services based upon the Entity API. What I needed was a simple service that just exposes Drupal's entities in a RESTful manner, while obeying Drupal's permission and access systems. Now, me and klausi have created a small module that does exactly that: Restful web services.

So how does it work?

The module makes use of the Entity API and the information about entity properties (provided via hook_entity_property_info()) to provide resource representations for all entity types (nodes, comments, users, taxonomy terms, ..). It aims to be fully compliant to the REST principles. Drupal's entities are exposed at the unified $entity_type/$id paths, while respecting the Content Accept/Content Type headers of the HTTP requests. That means if a client requests node/1 with usual HTTP accept headers it will get Drupal's usual output, if it requests node/1 while accepting only JSON, it will get the JSON representation of the node. Similarly, all CRUD operations are supported as common for RESTful services. Then, the module supports GET requests on paths like node/1.json, node/1.xml or node/1.rdf too.

And authentication...?

As mentioned above, the solution just obeys Drupal's permission and access system. If there is an active session and the user has sufficient permission for the request, it will be served. So any add-on authentication strategies would have to plug into Drupal's usual user system. For example, the RestWS module comes with a small add-on module that authenticates users via HTTP basic authentication. So you can define a regular user for a client, configure their access permissions as usual, and just pass its credentials with a request.

So what about the property information?

The module makes use of the property information the entity API collects for all entity types, as well as the accompanying wrapper classes. While the API also allows providing non-entities as resources, it requires the existence of property information. Representations of entities are provided according to their property information. What does that mean?
So let's have a look at an example: The node author. In the property information about nodes, there is no uid property, instead there is an 'author' property, pointing to the according user entity. So the module makes use of that information to output a proper reference to the author, being the author's URI (URIs are the proper way to do references in RESTful designs). So instead of just outputting user id as uid property with an integer value, we output a proper reference to the node's author. Apart from that, the property information includes access permissions - so updating the node author will only be possible if you have sufficient permissions.
Then the property information could be used to provide a description of the web service for the caller, in a human as well as in a machine-readable way.

Which formats are supported?

The module currently comes with support for JSON, XML and RDF/XML whereas modules may add more formatters. As the property information is available to the formatters too, it's possible to do formatters that output some properties in a certain way, e.g. using a special XML namespace. Similarly the RDF formatter looks up the RDF mapping being defined for a property, in order to generate meaningful RDF output.

What's different to the Services module?

The main differences are:

  • RestWS provides only RESTful services (no message-oriented or RPC-style web services like SOAP, XML-RPC etc.).
  • RestWS strongly builds upon the Entity API and its property information, thus utilizes it for CRUD, access checks, getting property information, ..
  • Property information is built into the API, so formatters may make use of it to format the data in a sensible way.
  • There are no "service endpoints" to configure as resources are just available at uniform paths like node/1, user/1. We do not see a need to have multiple endpoints for the same resource in a RESTful desgin.

For more about the relation and partial overlap to the Services module, read and participate in the discussion over at http://drupal.org/node/1042512.

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