Interview Questions & Answers

Take the framework either from cake site or if you have changed according to your needs start from there. proceed with basic software engg. concepts as requirement gathering etc

Allow modules to interact with the Drupal core.
Drupal's module system is based on the concept of "hooks". A hook is a PHP function that is named foo_bar(), where "foo" is the name of the module (whose filename is thus foo.module) and "bar" is the name of the hook. Each hook has a defined set of parameters and a specified result type.
To extend Drupal, a module need simply implement a hook. When Drupal wishes to allow intervention from modules, it determines which modules implement a hook and calls that hook in all enabled modules that implement it.

A module is software (code) that extends Drupal features and/or functionality. Core modules are those included with the main download of Drupal, and you can turn on their functionality without installing additional software. Contributed modules are downloaded from the Modules download section of drupal.org, and installed within your Drupal installation. You can also create your own modules; this requires a thorough understanding of Drupal, PHP programming, and Drupal's module API.

A node in Drupal is the generic term for a piece of content on your web site. (Note that the choice of the word "node" is not meant in the mathematical sense as part of a network.)
Some examples of nodes:
• Pages in books
• Discussion topics in forums
• Entries in blogs
• News article stories
Each node on your site has a Content Type. It also has a Node ID, a Title, a creation date, an author (a user on the site), a Body (which may be ignored/omitted for some content types), and some other properties. By using modules such as the contributed Content Construction Kit (CCK) module, the core Taxonomy module, and the contributed Location module, you can add fields and other properties to your nodes.

XML-RPC is a protocol that uses XML messages to perform Remote Procedure Calls. Requests are encoded in XML and sent via HTTP POST; XML responses are embedded in the body of the HTTP response.
More succinctly, XML-RPC = HTTP + XML + Remote Procedure Calls.
Because XML-RPC is platform independent, diverse applications can communicate with one another. For example, a Java client can speak XML-RPC to a Perl server.
To get a quick sense of XML-RPC, here is a sample XML-RPC request to a weather service (with the HTTP Headers omitted):
<?xml version="1.0" encoding="ISO-8859-1"?>
<methodCall>
<methodName>weather.getWeather</methodName>
<params>
<param><value>10016</value></param>
</params>
</methodCall>
The request consists of a simple element, which specifies the method name (getWeather) and any method parameters (zip code).
Here is a sample XML-RPC response from the weather service:
<?xml version="1.0" encoding="ISO-8859-1"?>
<methodResponse>
<params>
<param>
<value><int>65</int></value>
</param>
</params>
</methodResponse>
The response consists of a single element, which specifies the return value (the current temperature). In this case, the return value is specified as an integer.
In many ways, XML-RPC is much simpler than SOAP, and therefore represents the easiest way to get started with Web services.
The official XML-RPC specification is available at XML-RPC.com. Dozens of XML-RPC implementations are available in Perl, Python, Java, and Ruby. See the XML-RPC home page for a complete list of implementations.

The Web service protocol stack is an evolving set of protocols used to define, discover, and implement Web services.
The core protocol stack consists of four layers:
Service Transport: This layer is responsible for transporting messages between applications. Currently, this includes HTTP, SMTP, FTP, and newer protocols, such as Blocks Extensible Exchange Protocol (BEEP).
XML Messaging: This layer is responsible for encoding messages in a common XML format so that messages can be understood at either end. Currently, this includes XML-RPC and SOAP.
Service Description: This layer is responsible for describing the public interface to a specific Web service. Currently, service description is handled via the WSDL.
Service Discovery: This layer is responsible for centralizing services into a common registry, and providing easy publish/find functionality. Currently, service discovery is handled via the UDDI.
Beyond the essentials of XML-RPC, SOAP, WSDL, and UDDI, the Web service protocol stack includes a whole zoo of newer, evolving protocols. These include WSFL (Web Services Flow Language), SOAP-DSIG (SOAP Security Extensions: Digital Signature), and USML (UDDI Search Markup Language).
Fortunately, you do not need to understand the full protocol stack to get started with Web services. Assuming you already know the basics of HTTP, it is best to start at the XML Messaging layer and work your way up.

If you want a more intuitive feel for Web services, try out the IBM Web Services Browser, available on the IBM Alphaworks site. The browser provides a series of Web services demonstrations. Behind the scenes, it ties together SOAP, WSDL, and UDDI to provide a simple plug-and-play interface for finding and invoking Web services. For example, you can find a stock-quote service, a traffic-report service, and a weather service. Each service is independent, and you can stack services like building blocks. You can, therefore, create a single page that displays multiple services--where the end result looks like a stripped-down version of my.yahoo or my.excite.