Web Services Created with Previous Versions of the Denodo Platform

In the previous versions of the Denodo Platform, there was only one type of Web service, which combined the SOAP and REST representations. In the current version of the Platform, the Web services have been divided into two: the SOAP ones and the REST ones because the REST Web services have changed from an “operation-oriented” approach to a “RESTful” approach.

The Web services created with the previous versions of the Platform still work, but they are deprecated. This appendix explains how to manage the old Web services.

The Syntax of the CREATE SOAP WEBSERVICE statement shows the syntax for creating a new Web service that publishes a view or a stored procedure.

Syntax of the CREATE WEBSERVICE statement
CREATE [ OR REPLACE ] WEBSERVICE <name:identifier>
    CHUNKSIZE = <integer>
    CHUNKTIMEOUT = <integer>
    QUERYTIMEOUT = <integer>
    POOLENABLED = <boolean>
    POOLINITSIZE = <integer>
    POOLMAXACTIVE = <integer>
    I18N <name:identifier>
    [ NOWRAPARRAYS ]     [ AUTHENTICATION ( HTTP <http_authentication> SOAP <soap_authentication> )
         REST [ ( OPCONFIGS( <rest_xml_config> [, <rest_xml_config>]* ) )]      | JSON [ ( OPCONFIGS( <rest_config> [, <rest_config>]* ) )]
       | SOAP ( STYLE { DOCUMENT | RPC }
           [ XSLT ( <xslt_config> [, <xslt_config> ]* ) ]
           [ JMS (
               DESTINATION = <name:literal>
           [ REPLYTO = <name:literal> ]
           { QUEUE | TOPIC }
           [ USER = <name:literal>
             PASSWORD = <name:literal> [ ENCRYPTED ]
           PROPERTIES ( <properties> [, <properties> ]* )
           ]       )
       | HTML [ ( CSS = <css:literal> ) ]
       | RSS ( [ <rss mapping> ]*
               [OPCONFIGS( <rest_config> [, <rest_config> ]* ] ) )
    ]+ )
    [ <operation> ]+
    [ FOLDER = <literal> ]
    [ DESCRIPTION = <literal> ]
    [ CASE_SENSITIVE = <boolean> ]

<http_authentication> ::= {
    | BASIC <credentials>
    | BASIC VDP [ VDPACCEPTEDUSERS <users_list> ]
    | DIGEST <credentials>

<soap_authentication> ::= {
    | BASIC <credentials>
    | BASIC VDP [ VDPACCEPTEDUSERS <users_list:users_list> ]
    | DIGEST <credentials>
    | WSS BASIC <credentials>
    | WSS BASIC VDP [ VDPACCEPTEDUSERS <users_list:users_list> ]
    | WSS DIGEST <credentials>

<credentials> ::=
    USER <user_name:literal> PASSWORD <password:literal> [ ENCRYPTED ]

<users_list> ::=
  <user_name:literal> [, <user_name:literal> ]*

<operation> ::=
  OPERATION <name:literal> (
            <schema name:literal>
    VQL = <literal>
    INPUTS ( [ <inputparameter> ]* )
    OUTPUT <returnparameter>

<inputparameter> ::=
   <paramName:literal> <name in the view/query:literal>
   [ : <paramType:literal> ] <operator:literal> [ OBL ]
   [ ( <renamed field> ) ]

<returnparameter> ::=
  | <regType:literal> : ARRAY OF ( <returnparameter_register> ) [ <renamed field> [, <renamed field> ]* ]

<returnparameter_register> ::=
  <regName:literal> : REGISTER OF ( <registerfield> [, <registerfield>]* )

<registerfield> ::=
  <fieldName:literal> [: <fieldType:literal>]

<renamed field> ::=
  <XPath of the field:literal> = <displayed Name:literal>

<rss mapping> ::=
    <schemaName:literal> (
      CHANNEL ( <mapping> [, <mapping> ]* )
      ITEM ( <itemMapping> [, <itemMapping> ]* )

<xslt_config> ::=
  OPERATION = <name:literal>
  [ SOAPACTION = <action:literal> ]
  [ INPUTXSLT = <xslt:literal> <isEnabled> ]
  [ OUTPUTXSLT = <xslt:literal <isEnabled> ]

<isEnabled> ::=
  ENABLED | DISABLED  <rest_config> ::=
    OPERATION = <name:literal>
    CUSTOMURL = url:literal

<rest_xml_config> ::=
    OPERATION = <name:literal>
    [ CUSTOMURL = url:literal
      CUSTOMNAMESPACE = ns:literal

<rest_xslt_config> ::=
    [ INPUTXSLT = <xslt:literal> <isEnabled> ]
    [ OUTPUTXSLT = <xslt:literal <isEnabled> ]

<properties> ::=
    <key:literal> = <value:literal>

<mapping> ::=
    <rss tag:literal> = <value:literal>

<item mapping> ::=
    <rss tag:literal> = <field:identifier>

<wrapper type> ::=
  | DF
  | GS
  | ITP
  | JDBC
  | JSON
  | LDAP
  | ODBC
  | WS
  | XML

Below is a brief description of the use of the statement. A Web service published by Virtual DataPort is formed by a list of operations defined using the OPERATION clause. Each operation will run a VQL statement that is indicated in the VQL property of the operation. The operation may act on a view, a wrapper, a stored procedure or execute a specific VQL statement (SCHEMA property). The type of the statement (TYPE property) can be: select (most common), insert, update or delete. Each operation contains a list of input parameters and one output parameter. In the case of query operations, the output parameter will be an array of registers containing the results of the query run. Insert / update and delete operations return the number of tuples affected by the operation.

The versions in which the service is to be published are indicated in the OUTPUT_TYPE clause. The I18N parameter allows specifying the internationalization configuration used by the service.

The parameters CHUNKSIZE, CHUNKTIMEOUT, QUERYTIMEOUT, POOLENABLED, POOLINITSIZE and POOLMAXACTIVE control the connection between the Web service and the Virtual DataPort server.

The section Connection Parameters explains the meaning of these parameters.

The clause NOWRAPARRAYS modifies the SOAP output of the Web service only if the value of the clause STYLE is DOCUMENT. If this clause is present, the output of the SOAP Web service is simpler than if it is not. However, the output is not backward compatible with the SOAP Web services published from previous versions of the Denodo Platform. We recommend adding it.

Having this clause in your CREATE WEBSERVICE statement is equivalent to clearing the Old SOAP DOCUMENT output check box of the Publish Web service wizard.

The RSS format specifies a series of specific fields for each item. Therefore, on exporting a view in RSS format, the correspondence between the fields of the view and the fields in RSS format must be specified. This is possible through the MAPPING clause. An RSS feed contains a channel element that specifies general information on the feed. The CHANNEL parameter of the MAPPING clause allows specifying constant values for each of the channel subelements permitted by the RSS format. An RSS feed contains a list of item elements. Virtual DataPort will generate an item element for each tuple returned by the query made on the view or stored procedure used in the service. The ITEM parameter of the MAPPING clause allows selecting the attribute of the view corresponding to each item subelement defined in RSS format. The RSS format specifies that at least one value must be assigned either to the title subelement or to the description subelement.

The Web services published by Virtual DataPort can subscribe to a JMS server to listen to SOAP messages (SOAP over Java Message Service). To do that, add the parameter JMS and its appropriate parameters. The section Defining JMS Listeners explains the meaning of the parameters related to establishing connections with JMS servers.

In an environment with existing SOAP/REST clients and services, we do not need to modify those clients to work with Virtual DataPort Web services. We can define XSLT stylesheets (XSL Transformations) to transform the incoming SOAP or REST messages to adapt them to the format that the new Web service expects. We also can define stylesheets to transform the SOAP and REST responses before sending them to the existing clients. To do this, use the parameter XSLT.

For more information about this, read the section XSLT Transformations of the Administration Guide.

Add the clause CASE_SENSITIVE = true if you want the input fields of the REST version of the Web Service to be case sensitive. If false (default value), the input parameters are case insensitive.

E.g. if the CASE_SENSITIVE = false and the service has a parameter called REGION, in the URL you can provide the parameter “REGION” or “ReGiOn” and the service will return a response.