Source code for labelbox.pagination

# Size of a single page in a paginated query.
_PAGE_SIZE = 100

[docs]class PaginatedCollection: """ An iterable collection of database objects (Projects, Labels, etc...). Implements automatic (transparent to the user) paginated fetching during iteration. Intended for use by library internals and not by the end user. For a list of attributes see __init__(...) documentation. The params of __init__ map exactly to object attributes. """
[docs] def __init__(self, client, query, params, dereferencing, obj_class): """ Creates a PaginatedCollection. Args: client (labelbox.Client): the client used for fetching data from DB. query (str): Base query used for pagination. It must contain two '%d' placeholders, the first for pagination 'skip' clause and the second for the 'first' clause. params (dict): Query parameters. dereferencing (iterable): An iterable of str defining the keypath that needs to be dereferenced in the query result in order to reach the paginated objects of interest. obj_class (type): The class of object to be instantiated with each dict containing db values. """ self.client = client self.query = query self.params = params self.dereferencing = dereferencing self.obj_class = obj_class self._fetched_pages = 0 self._fetched_all = False self._data = [] self._data_ind = 0
def __iter__(self): self._data_ind = 0 return self def __next__(self): if len(self._data) <= self._data_ind: if self._fetched_all: raise StopIteration() query = self.query % (self._fetched_pages * _PAGE_SIZE, _PAGE_SIZE) self._fetched_pages += 1 results = self.client.execute(query, self.params) for deref in self.dereferencing: results = results[deref] page_data = [ self.obj_class(self.client, result) for result in results ] self._data.extend(page_data) if len(page_data) < _PAGE_SIZE: self._fetched_all = True if len(page_data) == 0: raise StopIteration() rval = self._data[self._data_ind] self._data_ind += 1 return rval