Make it easy to parse a Pagination object to dict

[italomaia]

Being able to easely parse a Pagination object to dict would make it much more "ajax" friendly.

[kalombos]

Hello, i want to contribute but i didn't understand what you need. You want to realize additional method at Pagination class something like this:

def as_dct(self):
    return dict(items=self.items, page=self.page...)

?
Please give me more information and i will try to realize it. Thank you.

[ThiefMaster]

Not dct for sure. That abbreviation is only OK when the name would be dict otherwise (and thus shadow the builtin). I'd go for something like to_dict or as_dict.

[protream]

We can do it like this, add two methods to class Pagination:

class Pagination:
    ...

    def __getitem__(self, key):
        return getattr(self, key)

    def keys(self):
        return ('page', 'pages', 'total', 'has_prev', 'next_num', 'has_next', 'items')

Now, dict a Pagination Object jus do:

data = dict(pagination)
data['items'] = some_handle_for(data['items'])

Since items may be not JSON serializable, so it should be handle separately.

[spyoungtech]

Wouldn't it be most appropriate to implement a __iter__ for this? That way one can simply do dict(my_pagination_object)

[nicolashahn]

@protream's implementation as a PR: #580

[rtilk89]

@jab @davidism - I'm interested in giving this issue a shot, but looks like there is an unmerged PR. Is this still open for contributions?

[tomowind]

@rtilk89 I was reading two unmerged PRs #485 and #580. #485 doesn't address comments fully, and #580 doesn't seem to incorporate comments in #485. So, you may extend #580 with tests and addressing comments in #485?

You can work on this one. I will do another.

[davidism]

The problem with an as_dict method is that it does not guarantee that the result will be serializable by jsonify or json.dumps. Result rows can contain types that are not handled by the default JSON serializer, and it gets even worse when querying models, and it gets even worse when those models are not simple but use the multitude of features available to SQLAlchemy.

The direct way for a dev to handle this, although not the most powerful, is to implement their own Flask.json_encoder class to handle the things that would appear in Pagination.items. So if we do add a as_dict method, it needs to clearly explain that the developer still needs to do something else.

We do not want to take on maintaining a serialization library for result rows or SQLAlchemy models. This is better handled by a serialization library such as Marshmallow, Marshmallow-SQLAlchemy, and Marshmallow-Flask, or another API extension. At which point, that can also handle serializing a Pagination object, along with any other API data, at which point as_dict isn't needed.

[davidism]

Closing based on above comment and discussion in #748.