XMLReader

Description:

Reads XML content and creates Record objects. Records are expected in the second level of XML data, embedded in an enclosing root tag.

Additional Details...

Tags:

xml, record, reader, parser

Properties:

In the list below, the names of required properties appear in bold. Any other properties (not in bold) are considered optional. The table also indicates any default values, and whether a property supports the NiFi Expression Language.

NameDefault ValueAllowable ValuesDescription
Schema Access Strategyschema-name
  • Use 'Schema Name' Property The name of the Schema to use is specified by the 'Schema Name' Property. The value of this property is used to lookup the Schema in the configured Schema Registry service.
  • Use 'Schema Text' Property The text of the Schema itself is specified by the 'Schema Text' Property. The value of this property must be a valid Avro Schema. If Expression Language is used, the value of the 'Schema Text' property must be valid after substituting the expressions.
  • HWX Schema Reference Attributes The FlowFile contains 3 Attributes that will be used to lookup a Schema from the configured Schema Registry: 'schema.identifier', 'schema.version', and 'schema.protocol.version'
  • HWX Content-Encoded Schema Reference The content of the FlowFile contains a reference to a schema in the Schema Registry service. The reference is encoded as a single byte indicating the 'protocol version', followed by 8 bytes indicating the schema identifier, and finally 4 bytes indicating the schema version, as per the Hortonworks Schema Registry serializers and deserializers, found at https://github.com/hortonworks/registry
  • Confluent Content-Encoded Schema Reference The content of the FlowFile contains a reference to a schema in the Schema Registry service. The reference is encoded as a single 'Magic Byte' followed by 4 bytes representing the identifier of the schema, as outlined at http://docs.confluent.io/current/schema-registry/docs/serializer-formatter.html. This is based on version 3.2.x of the Confluent Schema Registry.
Specifies how to obtain the schema that is to be used for interpreting the data.
Schema RegistryController Service API:
SchemaRegistry
Implementations: ConfluentSchemaRegistry
HortonworksSchemaRegistry
AvroSchemaRegistry		Specifies the Controller Service to use for the Schema Registry
Schema Name${schema.name}Specifies the name of the schema to lookup in the Schema Registry property
Supports Expression Language: true (will be evaluated using flow file attributes and variable registry)
Schema VersionSpecifies the version of the schema to lookup in the Schema Registry. If not specified then the latest version of the schema will be retrieved.
Supports Expression Language: true (will be evaluated using flow file attributes and variable registry)
Schema BranchSpecifies the name of the branch to use when looking up the schema in the Schema Registry property. If the chosen Schema Registry does not support branching, this value will be ignored.
Supports Expression Language: true (will be evaluated using flow file attributes and variable registry)
Schema Text${avro.schema}The text of an Avro-formatted Schema
Supports Expression Language: true (will be evaluated using flow file attributes and variable registry)
Expect Records as Arrayfalse
  • false Each FlowFile will consist of a single record without any sort of "wrapper".
  • true Each FlowFile will consist of zero or more records. The outer-most XML element is expected to be a "wrapper" and will be ignored.
  • Use attribute 'xml.stream.is.array' Whether to treat a FlowFile as a single Record or an array of multiple Records is determined by the value of the 'xml.stream.is.array' attribute. If the value of the attribute is 'true' (case-insensitive), then the XML Reader will treat the FlowFile as a series of Records with the outer element being ignored. If the value of the attribute is 'false' (case-insensitive), then the FlowFile is treated as a single Record and no wrapper element is assumed. If the attribute is missing or its value is anything other than 'true' or 'false', then an Exception will be thrown and no records will be parsed.
This property defines whether the reader expects a FlowFile to consist of a single Record or a series of Records with a "wrapper element". Because XML does not provide for a way to read a series of XML documents from a stream directly, it is common to combine many XML documents by concatenating them and then wrapping the entire XML blob with a "wrapper element". This property dictates whether the reader expects a FlowFile to consist of a single Record or a series of Records with a "wrapper element" that will be ignored.
Attribute PrefixIf this property is set, the name of attributes will be prepended with a prefix when they are added to a record.
Supports Expression Language: true (will be evaluated using flow file attributes and variable registry)
Field Name for ContentIf tags with content (e. g. <field>content</field>) are defined as nested records in the schema, the name of the tag will be used as name for the record and the value of this property will be used as name for the field. If tags with content shall be parsed together with attributes (e. g. <field attribute="123">content</field>), they have to be defined as records. For additional information, see the section of processor usage.
Supports Expression Language: true (will be evaluated using flow file attributes and variable registry)
Date FormatSpecifies the format to use when reading/writing Date fields. If not specified, Date fields will be assumed to be number of milliseconds since epoch (Midnight, Jan 1, 1970 GMT). If specified, the value must match the Java Simple Date Format (for example, MM/dd/yyyy for a two-digit month, followed by a two-digit day, followed by a four-digit year, all separated by '/' characters, as in 01/01/2017).
Time FormatSpecifies the format to use when reading/writing Time fields. If not specified, Time fields will be assumed to be number of milliseconds since epoch (Midnight, Jan 1, 1970 GMT). If specified, the value must match the Java Simple Date Format (for example, HH:mm:ss for a two-digit hour in 24-hour format, followed by a two-digit minute, followed by a two-digit second, all separated by ':' characters, as in 18:04:15).
Timestamp FormatSpecifies the format to use when reading/writing Timestamp fields. If not specified, Timestamp fields will be assumed to be number of milliseconds since epoch (Midnight, Jan 1, 1970 GMT). If specified, the value must match the Java Simple Date Format (for example, MM/dd/yyyy HH:mm:ss for a two-digit month, followed by a two-digit day, followed by a four-digit year, all separated by '/' characters; and then followed by a two-digit hour in 24-hour format, followed by a two-digit minute, followed by a two-digit second, all separated by ':' characters, as in 01/01/2017 18:04:15).

State management:

This component does not store state.

Restricted:

This component is not restricted.

System Resource Considerations:

None specified.