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14. Server connections

Server connections are workspace resources that provide connections to remote services. These connections can then be used by other workspace resources. Some common example use cases:

  • JDBC connection: Used by SQL feature stores to access the database that stores the feature data
  • JDBC connection: Used by SQL ISO metadata stores to access the database that stores the metadata records
  • WMS connection: Used by remote WMS layers to access remote WMS
  • WMS connection: Used by remote WMS tile stores to access remote WMS
  • WMTS connection: Used by remote WMTS tile stores to access remote WMTS

There are currently two categories of server connection resources, JDBC connections (to connect to SQL databases) and remote OWS connections (to connect to other OGC webservices).

_images/workspace-overview-connection.png

Server connection resources define how to obtain a connection to a remote server

14.1. JDBC connections

These resources define connections to SQL databases, such as PostgreSQL/PostGIS, Oracle Spatial or Microsoft SQL Server.

deegree currently supports the following backends:

  • PostgreSQL 9.x with PostGIS extension 2.x
  • Oracle Spatial 12c
  • Microsoft SQL Server 2012

Tip

If you want to use Oracle Spatial or Microsoft SQL Server, you will need to add additional modules first. This is described in Adding database modules.

Hint

By default, deegree webservices includes JDBC drivers for connecting to PostgreSQL and Derby databases. If you want to make a connection to other SQL databases (e.g. Oracle), you will need to add a compatible JDBC driver manually. This is described in anchor-oraclejars.

14.1.1. Minimal configuration example (PostgreSQL)

This example defines a basic connection pool for a PostgreSQL/PostGIS database:

<DataSourceConnectionProvider configVersion="3.4.0"
  xmlns="http://www.deegree.org/connectionprovider/datasource" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.deegree.org/connectionprovider/datasource http://schemas.deegree.org/jdbc/datasource/3.4.0/datasource.xsd">

  <!-- Creation / lookup of javax.sql.DataSource instance -->
  <DataSource javaClass="org.apache.commons.dbcp.BasicDataSource" />

  <!-- Configuration of DataSource properties -->
  <Property name="driverClassName" value="org.postgresql.Driver" />
  <Property name="url" value="jdbc:postgresql://localhost/deegree-db" />
  <Property name="username" value="kelvin" />
  <Property name="password" value="s3cr3t" />
  <Property name="maxActive" value="10" />

</DataSourceConnectionProvider>
  • The DataSource object uses Java class org.apache.commons.dbcp.BasicDataSource (a connection pool class provided by Apache Commons DBCP.). If you don’t know what this means, then this is most likely what you want to use.
  • The JDBC driver class is org.postgresql.Driver (this is the Java class name to use for PostgreSQL/PostGIS databases).
  • The JDBC URL is jdbc:postgresql://localhost:5432/deegree-db. This means that PostgreSQL is running on the same machine, port 5432 (default). The database identifier is deegree-db. Adapt these values to match to your setup.
  • The database username is kelvin, password is s3cr3t. Adapt these parameters to match your setup.
  • The maximum number of simultaneous connections is 10.

Hint

There are additional properties that can be tweaked and which may improve performance. See Configuration options.

14.1.2. Configuration example (Oracle)

Hint

By default, deegree webservices includes JDBC drivers for connecting to PostgreSQL and Derby databases. In order to connect to Oracle databases, you need to add a compatible JDBC driver manually. This is described in anchor-oraclejars.

This example defines a connection pool for an Oracle database:

<DataSourceConnectionProvider configVersion="3.4.0"
  xmlns="http://www.deegree.org/connectionprovider/datasource" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.deegree.org/connectionprovider/datasource http://schemas.deegree.org/jdbc/datasource/3.4.0/datasource.xsd">

  <!-- Creation / lookup of javax.sql.DataSource instance -->
  <DataSource javaClass="org.apache.commons.dbcp.BasicDataSource" />

  <!-- Configuration of DataSource properties -->
  <Property name="driverClassName" value="oracle.jdbc.OracleDriver" />
  <Property name="url" value="jdbc:oracle:thin:@localhost:1521:deegree" />
  <Property name="username" value="kelvin" />
  <Property name="password" value="s3cr3t" />
  <Property name="poolPreparedStatements" value="true" />
  <Property name="maxActive" value="10" />
  <Property name="maxIdle" value="10" />

</DataSourceConnectionProvider>

This defines a database connection with the following properties:

  • The DataSource object uses the Java class org.apache.commons.dbcp.BasicDataSource (a connection pool class provided by Apache DBCP). If you are not familiar with J2EE containers, this is most likely what you want to use.
  • The JDBC driver class is oracle.jdbc.OracleDriver. This is the Java class name to use for Oracle.
  • The so-called JDBC URL is jdbc:oracle:thin:@localhost:1521:deegree. This means that Oracle is running on the local machine, port 1521 (adapt host name and port as required). The database identifier is deegree.
  • The database username is kelvin, password is s3cr3t.
  • The maximum number of simultaneous connections is 10.

14.1.3. Configuration example (Microsoft SQL Server)

Hint

By default, deegree webservices includes JDBC drivers for connecting to PostgreSQL and Derby databases. In order to connect to Microsoft SQL Server, you need to add a compatible JDBC driver manually. This is described in anchor-oraclejars.

This example defines a connection pool for a Microsoft SQL Server:

<DataSourceConnectionProvider configVersion="3.4.0"
  xmlns="http://www.deegree.org/connectionprovider/datasource" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.deegree.org/connectionprovider/datasource http://schemas.deegree.org/jdbc/datasource/3.4.0/datasource.xsd">

  <!-- Creation / lookup of javax.sql.DataSource instance -->
  <DataSource javaClass="org.apache.commons.dbcp.BasicDataSource" />

  <!-- Configuration of DataSource properties -->
  <Property name="driverClassName" value="org.postgresql.Driver" />
  <Property name="url" value="jdbc:postgresql://localhost/deegree-db" />
  <Property name="username" value="kelvin" />
  <Property name="password" value="s3cr3t" />
  <Property name="poolPreparedStatements" value="true" />
  <Property name="maxActive" value="10" />
  <Property name="maxIdle" value="10" />

</DataSourceConnectionProvider>

This defines a database connection with the following properties:

  • The DataSource object uses the Java class org.apache.commons.dbcp.BasicDataSource (a connection pool class provided by Apache DBCP). If you are not familiar with J2EE containers, this is most likely what you want to use.
  • The JDBC driver class is org.postgresql.Driver. This is the Java class name to use for PostgreSQL/PostGIS.
  • The so-called JDBC URL is jdbc:postgresql://localhost:5432/deegree-db. This means that PostgreSQL is running on the local machine, port 5432 (adapt host name and port as required). The database identifier is deegree-db.
  • The database username is kelvin, password is s3cr3t.
  • The maximum number of simultaneous connections is 10.

14.1.4. Configuration example (JNDI)

This example uses a connection pool that is defined externally by the servlet container that runs deegree webservices (e.g. Apache Tomcat):

<DataSourceConnectionProvider configVersion="3.4.0"
  xmlns="http://www.deegree.org/connectionprovider/datasource" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.deegree.org/connectionprovider/datasource http://schemas.deegree.org/jdbc/datasource/3.4.0/datasource.xsd">

  <!-- Creation / lookup of javax.sql.DataSource instance -->
  <DataSource javaClass="org.deegree.db.datasource.JndiLookup" factoryMethod="lookup">
    <Argument value="java:comp/env/jdbc/DatabaseName" javaClass="java.lang.String" />
  </DataSource>

</DataSourceConnectionProvider>
  • The DataSource object is retrieved using Java method lookup of class org.deegree.db.datasource.JndiLookup. This is the correct value for retrieving a JNDI-defined connection pool.
  • The JNDI name to look for is java:comp/env/jdbc/DatabaseName. Adapt this value to match your setup.

14.1.5. Configuration example (Oracle UCP)

Hint

By default, deegree webservices includes JDBC drivers for connecting to PostgreSQL and Derby databases. In order to connect to Oracle databases, you need to add a compatible JDBC driver manually. This is described in anchor-oraclejars.

This example uses a connection pool based on Oracle UCP (Universal Connection Pool):

<DataSourceConnectionProvider configVersion="3.4.0"
  xmlns="http://www.deegree.org/connectionprovider/datasource" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.deegree.org/connectionprovider/datasource http://schemas.deegree.org/jdbc/datasource/3.4.0/datasource.xsd">

  <!-- Creation / lookup of javax.sql.DataSource instance -->
  <DataSource javaClass="oracle.ucp.jdbc.PoolDataSourceFactory" factoryMethod="getPoolDataSource" />

  <!-- Configuration of DataSource properties -->
  <Property name="connectionFactoryClassName" value="oracle.jdbc.pool.OracleDataSource" />
  <Property name="URL" value="jdbc:oracle:thin:@//localhost:1521/XE" />
  <Property name="user" value="kelvin" />
  <Property name="password" value="s3cr3t" />
  <Property name="initialPoolSize" value="5" />
  <Property name="minPoolSize" value="5" />
  <Property name="maxPoolSize" value="10" />
  <Property name="maxStatements" value="50" />

</DataSourceConnectionProvider>
  • The DataSource object is retrieved using Java method getPoolDataSource of class oracle.ucp.jdbc.PoolDataSourceFactory. This is the correct value for creating an Oracle UCP connection pool.

14.1.6. Configuration options

The database connection config file format is defined by schema file http://schemas.deegree.org/jdbc/datasource/3.4.0/datasource.xsd. The root element is DataSourceConnectionProvider and the config attribute must be 3.4.0. The following table lists the available configuration options. When specifiying them, their order must be respected.

Option Cardinality Value Description
DataSource 1..1 Complex Creation/lookup of javax.sql.DataSource object
Property 0..n Complex Configuration of javax.sql.DataSource object

Technically, the DataSource element defines how the javax.sql.DataSource object is retrieved. The retrieved object provides the actual database connections. The DataSource element allows for the following options:

Option Cardinality Value Description
javaClass 1..1 String Java class to use for instantiation/creation
factoryMethod 0..1 String If present, this static method is used (instead of constructor)
destroyMethod 0..1 String Configuration of javax.sql.DataSource object
Argument 0..1 Complex Argument to use for instantiation/method call

Depending on the presence of attribute factoryMethod, either the constructor of the specified javaClass will be invoked, or the static method of this class will be called. Here are two example snippets for clarification:

...
<DataSource javaClass="org.apache.commons.dbcp.BasicDataSource" />
...

In this snippet, no factoryMethod attribute is present. Therefore, the constructor of Java class org.apache.commons.dbcp.BasicDataSource is invoked. The returned instance must be an implementation of javax.sql.DataSource, and this is guaranteed, because the class implements this interface. There are no arguments passed to the constructor.

...
<DataSource javaClass="org.deegree.db.datasource.JndiLookup" factoryMethod="lookup">
  <Argument value="java:comp/env/jdbc/DatabaseName" javaClass="java.lang.String" />
</DataSource>
...

In this snippet, a factoryMethod attribute is present (lookup). Therefore, the static method of Java class org.deegree.db.datasource.JndiLookup is called. The value returned by this method must be a javax.sql.DataSource object, which is guaranteed by the implementation. A single String-valued argument with value java:comp/env/jdbc/DatabaseName is passed to the method.

For completeness, here’s the list of configuration options of element Attribute:

Option Cardinality Value Description
javaClass 1..1 String Java class of the argument (e.g. java.lang.String)
value 1..1 String Argument value

The Property child elements of element DataSourceConnectionProvider are used to configure properties of the javax.sql.DataSource instance:

...
<Property name="driverClassName" value="org.postgresql.Driver" />
<Property name="url" value="jdbc:postgresql://localhost/deegree-db" />
<Property name="username" value="kelvin" />
<Property name="password" value="s3cr3t" />
<Property name="poolPreparedStatements" value="true" />
<Property name="maxActive" value="10" />
<Property name="maxIdle" value="10" />
...

The properties available for configuration depend on the implementation of javax.sql.DataSource:

For completeness, here’s the list of options of element Property:

Option Cardinality Value Description
name 1..1 String Name of the property
value 1..1 String Property value

14.1.7. Legacy configuration format

Prior to deegree webservices release 3.4, a simpler (but limited) configuration format was used. Here’s an example that connects to a PostgreSQL database on localhost, port 5432. The database to connect to is called ‘inspire’, the database user is ‘postgres’ and password is ‘postgres’.

<JDBCConnection configVersion="3.4.0" xmlns="http://www.deegree.org/jdbc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                xsi:schemaLocation="http://www.deegree.org/jdbc http://schemas.deegree.org/jdbc/3.0.0/jdbc.xsd">
  <Url>jdbc:postgresql://localhost:5432/inspire</Url>
  <User>postgres</User>
  <Password>postgres</Password>
</JDBCConnection>

The legacy connection config file format is defined by schema file http://schemas.deegree.org/jdbc/3.0.0/jdbc.xsd. The root element is JDBCConnection and the config attribute must be 3.0.0. The following table lists the available configuration options. When specifiying them, their order must be respected.

Option Cardinality Value Description
Url 1..1 String JDBC URL (without username / password)
User 1..n String DB username
Password 1..1 String DB password

14.2. Remote OWS connections

Remote OWS connections are typically configured with a capabilities document reference and optionally some HTTP request parameters (such as timeouts etc.). Contrary to earlier experiments these resources only define the actual connection to the service, not what is requested. This resource is all about how to request, not what to request. Other resources (such as a remote WMS tile store) which make use of such a server connection typically define what to request.

14.2.1. Remote WMS connection

The remote WMS connection can be used to connect to OGC WMS services. Versions 1.1.1 and 1.3.0 (with limitations) are supported.

Let’s have a look at an example:

<RemoteWMS xmlns="http://www.deegree.org/remoteows/wms" configVersion="3.4.0">
  <CapabilitiesDocumentLocation
    location="http://deegree3-demo.deegree.org/utah-workspace/services?request=GetCapabilities&amp;service=WMS&amp;version=1.1.1" />
  <ConnectionTimeout>10</ConnectionTimeout>
  <RequestTimeout>30</RequestTimeout>
  <HTTPBasicAuthentication>
    <Username>hans</Username>
    <Password>moleman</Password>
  </HTTPBasicAuthentication>
</RemoteWMS>
  • The capabilities document location is the only mandatory option. You can also use a relative path to a local copy of the capabilities document to improve startup time.
  • The connection timeout defines (in seconds) how long to wait for a connection before throwing an error. Default is 5 seconds.
  • The request timeout defines (in seconds) how long to wait for data before throwing an error. Default is 60 seconds.
  • The http basic authentication options can be used to provide authentication credentials to use a HTTP basic protected service. Default is not to authenticate.

The WMS version will be detected from the capabilities document version. When using 1.3.0, there are some limitations (eg. GetFeatureInfo is not supported), and it is tested to a lesser extent compared with the 1.1.1 version.

14.2.2. Remote WMTS connection

The remote WMTS connection can be used to connect to a OGC WMTS service. Version 1.0.0 is supported. The configuration format is almost identical to the remote WMS configuration.

Let’s have a look at an example:

<RemoteWMTS xmlns="http://www.deegree.org/remoteows/wmts" configVersion="3.4.0">
  <CapabilitiesDocumentLocation
    location="http://deegree3-testing.deegree.org/utah-workspace/services?request=GetCapabilities&amp;service=WMTS&amp;version=1.0.0" />
  <ConnectionTimeout>10</ConnectionTimeout>
  <RequestTimeout>30</RequestTimeout>
  <HTTPBasicAuthentication>
    <Username>hans</Username>
    <Password>moleman</Password>
  </HTTPBasicAuthentication>
</RemoteWMTS>
  • The capabilities document location is the only mandatory option. You can also use a relative path to a local copy of the capabilities document to improve startup time.
  • The connection timeout defines (in seconds) how long to wait for a connection before throwing an error. Default is 5 seconds.
  • The request timeout defines (in seconds) how long to wait for data before throwing an error. Default is 60 seconds.
  • The http basic authentication options can be used to provide authentication credentials to use a HTTP basic protected service. Default is not to authenticate.

GetTile and GetFeatureInfo operations are supported for remote WMTS resources.

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