= Add Batch Support for Importer =

This assumes you already have a working importer, and wish to add "dynamic batch" support to it.

As usual, the word "import" is used generically; in some cases "export" might make more sense.

Here are the specifics behind the example shown in these instructions:

 * import command is: `rattail import-sample`
 * import handler is at: `rattail.importing.sample:FromSampleToRattail`
 * importer is identified by `'Product'` and is at: `rattail.importing.sample:ProductImporter`
 * importer does not yet support dynamic batches

== Declare Batch Support ==

The first step is simple enough.  You just need to declare support within the importer's class.  (This is the 3rd bullet from above.)

In our example we would edit the `ProductImporter` class within `~/src/rattail/rattail/importing/sample.py`:

{{{#!highlight python
class ProductImporter(FromSample, importing.model.ProductImporter):

    # must add this
    batches_supported = True
}}}

== Make Things Pretty ==

Each row within an import batch will have an "object description" which is displayed in the Tailbone UI for instance.  By default this description is basically `str(obj)` where `obj` is the source "object" being imported.  Many times that default object description is not very helpful or pretty, in which case you can override.  To do so you must add the `'_object_str'` field to the normalized data returned by your importer (3rd bullet from above).

In our example we would edit the `normalize_host_object()` method of the `ProductImporter` class within `~/src/rattail/rattail/importing/sample.py`:

{{{#!highlight python
class ProductImporter(FromSample, importing.model.ProductImporter):

    def normalize_host_object(self, csvrow):
        data = super(ProductImporter, self).normalize_host_object(csvrow)

        # must add this
        data['_object_str'] = "custom description for object: {}".format(csvrow)

        return data
}}}