• XMLValidation

XMLValidation

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Validation of XML inputs#

All SUMO applications support XML validation for their inputs. To enable this, the following options can be used:

Option	Description
-X <STRING> --xml-validation <STRING>	Set schema validation scheme of XML inputs ("never", "local", "auto" or "always"); default: local
--xml-validation.net <STRING>	Set schema validation scheme of SUMO network inputs ("never", "local", "auto" or "always"); default: never
--xml-validation.routes <STRING>	Set schema validation scheme of SUMO route inputs ("never", "local", "auto" or "always"); default: local

Validation is performed by activating XML schema processing in the XML parser. This catches many common input errors such as spelling mistakes and attributes which should have been placed within another element.

Another prerequisite for validation is a schema declaration within the root element of the input file such as

<routes xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://sumo.dlr.de/xsd/routes_file.xsd">

When setting the validation options to always the schemata for networks, additional files and routes are pre-parsed from the local schema file. For all other file types a missing declaration will lead to an error in this case.

The validation option auto (which was the default before SUMO 1.15.0) in contrast only validates the file if the schema declaration is present. It tries to parse the schema first from the local path, see the section schema files and falls back to the web version if SUMO_HOME is not set or the file could not be found. The current default local has no fallback, so validation will fail if the local file is not accessible (or SUMO_HOME is not set). This is to prevent unintended network access and XXE attacks.

Schema validation may slowdown XML parsing considerably and is therefore disabled for the network input by default (because networks should not be edited by hand and therefore be valid anyway).

Adding a schema declaration#

Files that are written by one of the SUMO applications automatically receive the appropriate schema declaration. When writing an input file from scratch the schema declaration must be added manually to the root element as follows:

    <ROOT_ELEMENT xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:noNamespaceSchemaLocation="http://sumo.dlr.de/xsd/SCHEMA_FILE">

where ROOT_ELEMENT and SCHEMA_FILE should be set according to the following table:

Application Option	ROOT_ELEMENT	SCHEMA_FILE
--route-files, --trip-files, --flow-files	routes	routes_file.xsd
--additional-files	add	additional_file.xsd
--node-files	nodes	nodes_file.xsd
--edge-files	edges	edges_file.xsd
--connection-files	connections	connections_file.xsd
--tllogic-files	tlLogics	tllogic_file.xsd
--type-files	types	types_file.xsd
--weight-files	meandata	meandata_file.xsd

Schema Files#

The schema files can be found in the <SUMO_HOME>/data/xsd directory of your SUMO installation. If the environment variable SUMO_HOME is set, these files will be used when validating inputs.

Otherwise, the files are loaded from http://sumo.dlr.de/xsd/SCHEMA_FILE which may slow down the application (or fail if there is no internet connection).

SUMO File Types#

A complete listing of file extensions used by SUMO Applications is given at File_Extensions.

Disabling Schema Validation#

To disable schema validation any of the following actions is sufficient

• set the option --xml-validation never
• Remove the xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://sumo.dlr.de/xsd/....xsd" attribute from the top of the XML input file.