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Python Extension Development (Labs)

These classes can be used by developers to implement their own Python nodes for KNIME. For a more detailed description see the Pure Python Node Extensions Guide

Note

Before KNIME AP 4.7, the module used to access KNIME functionality was called knime_extension. This module has been renamed to knime.extension.

Nodes

.. autoclass:: knime.extension.PythonNode
   :members:
   :noindex:
   :inherited-members:

A node is part of a category:

.. autofunction:: knime.extension.category
   :noindex:

A node has a type:

.. autoclass:: knime.extension.NodeType
   :members:
   :noindex:
   :inherited-members:

A node's configure method receives a configuration context that lets you interact with KNIME

.. autoclass:: knime.extension.ConfigurationContext
   :members:
   :noindex:
   :inherited-members:

A node's execute method receives an execution context that lets you interact with KNIME and e.g. check whether the user has cancelled the execution of your Python node.

.. autoclass:: knime.extension.ExecutionContext
   :members:
   :noindex:
   :inherited-members:

The dialog creation context is used to create dialogs for the configuration of the node. It can be accessed indirectly, by passing its method's as arguments to specific parameters (see the example below).

.. autoclass:: knime.extension.DialogCreationContext
   :members:
   :noindex:
   :inherited-members:

Decorators

These decorators can be used to easily configure your Python node.

.. autofunction:: knime.extension.node
   :noindex:

Port Decorators

Port decorators in the KNIME Python extension allow you to define input and output ports for your nodes. Each port is of a specific type, such as "Table" or "Binary", and is used for nodes that require a fixed number of inputs or outputs. We recommend using unique and descriptive names for each port.

.. autofunction:: knime.extension.input_table
   :noindex:


.. autofunction:: knime.extension.input_binary
   :noindex:


.. autofunction:: knime.extension.input_port
   :noindex:


.. autofunction:: knime.extension.output_table
   :noindex:


.. autofunction:: knime.extension.output_image
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.. autofunction:: knime.extension.output_binary
   :noindex:


.. autofunction:: knime.extension.output_port
   :noindex:


.. autofunction:: knime.extension.output_view
   :noindex:

Port Group Decorators

The group decorators allow you to define input and output port groups for your nodes. A port group means that you can dynamically add and remove ports in KNIME.

.. autofunction:: knime.extension.input_table_group
   :noindex:


.. autofunction:: knime.extension.input_binary_group
   :noindex:


.. autofunction:: knime.extension.output_table_group
   :noindex:


.. autofunction:: knime.extension.output_image_group
   :noindex:


.. autofunction:: knime.extension.output_binary_group
   :noindex:

Parameters

To add parameterization to your nodes, the configuration dialog can be defined and customized. Each parameter can be used in the nodes execution by accessing self.param_name. These parameters can be set up by using the following parameter types. For a more detailed description see Defining the node's configuration dialog.

.. autoclass:: knime.extension.IntParameter
   :members:
   :noindex:
   :inherited-members:
   :exclude-members: validator, rule


.. autoclass:: knime.extension.DoubleParameter
   :members:
   :noindex:
   :inherited-members:
   :exclude-members: validator, rule



.. autoclass:: knime.extension.BoolParameter
   :members:
   :noindex:
   :inherited-members:
   :exclude-members: validator, rule



.. autoclass:: knime.extension.StringParameter
   :members:
   :noindex:
   :inherited-members:
   :exclude-members: validator, rule



.. autoclass:: knime.extension.ColumnParameter
   :members:
   :noindex:
   :inherited-members:
   :exclude-members: validator, rule



.. autoclass:: knime.extension.MultiColumnParameter
   :members:
   :noindex:
   :inherited-members:
   :exclude-members: validator, rule


.. autoclass:: knime.extension.ColumnFilterParameter
   :members:
   :noindex:
   :inherited-members:
   :exclude-members: validator, rule


.. autoclass:: knime.extension.ColumnFilterConfig
   :members:
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   :inherited-members:


.. autoclass:: knime.extension.EnumParameter
   :members:
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   :inherited-members:
   :exclude-members: validator, rule



.. autoclass:: knime.extension.EnumParameterOptions
   :members:
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   :inherited-members:



.. autoclass:: knime.extension.EnumSetParameter
   :members:
   :noindex:
   :inherited-members:
   :exclude-members: validator, rule



.. autoclass:: knime.extension.DateTimeParameter
   :members:
   :noindex:
   :inherited-members:
   :exclude-members: validator, rule


.. autoclass:: knime.extension.LocalPathParameter
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   :inherited-members:


.. autoclass:: knime.extension.ParameterArray
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   :inherited-members:

Validation

While each parameter type listed above has default type validation (eg checking if the IntParameter contains only Integers), they also support custom validation via a property-like decorator notation. For instance, this can be used to verify that the parameter value matches a certain criteria (see example below). The validator should be placed below the definition of the corresponding parameter.

.. autoclass:: knime.extension.IntParameter
   :members:
   :noindex:
   :inherited-members:
   :exclude-members: rule

Parameter Visibility Rules

By default, each parameter of a node is visible in the node's configuration dialog. Parameters can be marked as advanced by setting is_advanced=True, which will only show them once the user has clicked "Show advanced settings" in the configuration dialog.

Sometimes a parameter should only be visible to the user if another parameter has a certain value. For this, each parameter type listed above has a method rule. In this method, one can specify a condition based on another parameter, which we call subject, and the effect that should be applied to this parameter when the condition becomes true.

.. autoclass:: knime.extension.IntParameter
   :members:
   :noindex:
   :inherited-members:
   :exclude-members: validator


.. autoclass:: knime.extension.Condition
   :members:
   :noindex:
   :inherited-members:
   :exclude-members: to_dict, subjects


.. autoclass:: knime.extension.And
   :members:
   :noindex:
   :inherited-members:
   :exclude-members: to_dict, subjects


.. autoclass:: knime.extension.Contains
   :members:
   :noindex:
   :inherited-members:
   :exclude-members: to_dict, subjects


.. autoclass:: knime.extension.OneOf
   :members:
   :noindex:
   :inherited-members:
   :exclude-members: to_dict, subjects


.. autoclass:: knime.extension.Or
   :members:
   :noindex:
   :inherited-members:
   :exclude-members: to_dict, subjects


.. autoclass:: knime.extension.Effect
   :members:
   :noindex:
   :inherited-members:

Parameter Groups

Additionally these parameters can be combined in parameter_groups. These groups are visualized as sections in the configuration dialog. Another benefit of defining parameter groups is the ability to provide group validation. As opposed to only being able to validate a single value when attaching a validator to a parameter, group validators have access to the values of all parameters contained in the group, allowing for more complex validation routines.

.. autofunction:: knime.extension.parameter_group
   :noindex:

Tables

Table and Schema are the two classes that are used to communicate tabular data (Table) during execute, or the table structure (Schema) in configure between Python and KNIME.

.. autoclass:: knime.extension.Table
   :members:
   :noindex:
   :inherited-members:
   :special-members: __getitem__



.. autoclass:: knime.extension.BatchOutputTable
   :members:
   :noindex:
   :inherited-members:
   :special-members: __getitem__



.. autoclass:: knime.extension.Schema
   :members:
   :noindex:
   :inherited-members:
   :special-members: __getitem__



.. autoclass:: knime.extension.Column
   :members:
   :noindex:
   :inherited-members:
   :special-members: __init__

Data Types

These are helper functions to create KNIME compatible datatypes. For instance, if a new column is created.

.. autofunction:: knime.extension.int32
   :noindex:


.. autofunction:: knime.extension.int64
   :noindex:


.. autofunction:: knime.extension.double
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.. autofunction:: knime.extension.bool_
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.. autofunction:: knime.extension.string
   :noindex:


.. autofunction:: knime.extension.blob
   :noindex:


.. autofunction:: knime.extension.list_
   :noindex:


.. autofunction:: knime.extension.struct
   :noindex:


.. autofunction:: knime.extension.logical
   :noindex:


.. autofunction:: knime.extension.datetime
   :noindex:

Views

.. autofunction:: knime.scripting.io.view
   :noindex:


.. autofunction:: knime.scripting.io.view_matplotlib
   :noindex:


.. autofunction:: knime.scripting.io.view_seaborn
   :noindex:


.. autofunction:: knime.scripting.io.view_plotly
   :noindex:


.. autofunction:: knime.scripting.io.view_html
   :noindex:


.. autofunction:: knime.scripting.io.view_svg
   :noindex:


.. autofunction:: knime.scripting.io.view_png
   :noindex:


.. autofunction:: knime.scripting.io.view_jpeg
   :noindex:


.. autofunction:: knime.scripting.io.view_ipy_repr
   :noindex:


.. autoclass:: knime.scripting.io.NodeView
   :members:
   :noindex:

Port Objects

Port Object Specs

.. autoclass:: knime.extension.PortObjectSpec
   :members:
   :noindex:
   :inherited-members:


.. autoclass:: knime.extension.BinaryPortObjectSpec
   :members:
   :noindex:
   :inherited-members:


.. autoclass:: knime.extension.ImagePortObjectSpec
   :members:
   :noindex:
   :inherited-members:


.. autoclass:: knime.extension.ImageFormat
   :members:
   :noindex:
   :inherited-members:

Custom Port Object Types

.. autoclass:: knime.extension.PortObject
   :members:
   :noindex:
   :inherited-members:


.. autoclass:: knime.extension.ConnectionPortObject
   :members:
   :noindex:
   :exclude-members: serialize, deserialize
   :inherited-members:

Environment Variables

This module provides access to the different environment variables that are available in KNIME.

.. autoclass:: knime.extension.ProxySettings
   :members:
   :noindex:
   :inherited-members:


.. autoclass:: knime.extension.get_proxy_settings
   :members:
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   :inherited-members: