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# Advanced Blueprint Tips

## Iterator Stages

This training only focused on one stage, but iterators have three stages!
Learn more about this at
<https://5.docs.plone.org/external/collective.transmogrifier/docs/source/transmogrifier.html#iterators-have-3-stages>

## Migrating Users & Groups

Jsonify will not export user and group information.
These will need to be exported separately.
See {doc}`users-migration` for example code.

## Updating Rich Text

When updating your sites, you may have add-ons that will change in the process.
This can adjust text that appears in the body text of pages.
Check out [PyQuery](https://pypi.org/project/pyquery) to help parse the HTML for you.
Here's an example that updates oembed tags to [uwosh.snippets](https://pypi.org/project/uwosh.snippets/) style:

```python
def new_snippet(self, itemuid):
     return '<span class="snippet-tag snippet-tag-html_snippet" \
         contenteditable="false" data-type="snippet_tag" \
         data-snippet-id="{0}" data-header="">\
         Snippet:[ID={0}]</span>'.format(itemuid)

 def __iter__(self):
     for item in self.previous:
         if 'text' not in item:
             yield item
             continue
         if 'oembed oembed-responsive' not in item['text']:
             yield item
             continue
         txt = PyQuery(item['text'])
         full_text = txt.html()
         for snippet in txt(".oembed"):
             link = PyQuery(snippet)
             href = link("a").attr("href")
             if not href:
                 continue
             if 'resolveuid' in href:
                 linkuid = href.replace('resolveuid/', '')
                 if not api.content.get(UID=linkuid):
                     # leave link as is if we can't find the new one
                     continue
                 # replace link with new snippet
                 full_text = full_text.replace(PyQuery(snippet).outer_html(), self.new_snippet(linkuid))
             else:
                 html_snippets = api.content.find(path='/Plone/' + href)
                 if not html_snippets:
                     continue
                 new = self.new_snippet(html_snippets[0].UID)
                 full_text = full_text.replace(PyQuery(snippet).outer_html(), new)
         item['text'] = full_text
```

## Taking parameters in custom blueprints

See how the `PartialCommit` blueprint does this.

In the pipeline, we have:

```ini
[savepoint]
blueprint = collective.jsonmigrator.partialcommit
every = 1000
```

Here is the blueprint.
`options` contains any extra parameters that have been passed in.
If `every` is not in the options, `100` is used as the default.

```python
@provider(ISectionBlueprint)
@implementer(ISection)
class PartialCommit(object):


    def __init__(self, transmogrifier, name, options, previous):
        self.previous = previous
        self.step = int(options.get('every', 100))

    def __iter__(self):
        count = 1
        for item in self.previous:
            yield item
            if count % self.step == 0:
                transaction.commit()
                logging.info('Committed after %s' % count)
            count += 1
```