def _get_content(instance_or_content):
"""
Given a model instance or a sequence *(content_type, object_id)*
return a tuple *(content_type, object_id)*.
"""
try:
object_id = instance_or_content.pk
except AttributeError:
return instance_or_content
else:
return (managers.get_content_type_for_model(type(instance_or_content)), object_id)
def _get_content(instance_or_content):
"""
Given a model instance or a sequence *(content_type, object_id)*
return a tuple *(content_type, object_id)*.
"""
try:
object_id = instance_or_content.pk
except AttributeError:
return instance_or_content
else:
return (managers.get_content_type_for_model(type(instance_or_content)),
object_id)
def annotate_votes(queryset_or_model, key, user, score='score'):
"""
Annotate *queryset_or_model* with votes, in order to retreive from
the database all vote values in bulk.
The first argument *queryset_or_model* must be, of course, a queryset
or a Django model object. The argument *key* is the score key.
The votes are filtered using given *user*. For anonymous voters this
functionality is unavailable.
The score itself will be present in the attribute named *score* of
each instance of the returned queryset.
Usage example::
for article in annotate_votes(Article.objects.all(), 'main', myuser,
score='myscore'):
print 'your vote:', article.myscore
"""
# getting the queryset
if isinstance(queryset_or_model, models.base.ModelBase):
queryset = queryset_or_model.objects.all()
else:
queryset = queryset_or_model
# preparing arguments for *extra* query
opts = queryset.model._meta
content_type = managers.get_content_type_for_model(queryset.model)
mapping = {
'vote_table': Vote._meta.db_table,
'model_table': opts.db_table,
'model_pk_name': opts.pk.name,
'content_type_id': content_type.pk,
}
# building base query
template = """
SELECT score FROM ${vote_table} WHERE
${vote_table}.object_id = ${model_table}.${model_pk_name} AND
${vote_table}.content_type_id = ${content_type_id} AND
${vote_table}.user_id = %s AND
${vote_table}.key = %s
"""
select = {score: string.Template(template).substitute(mapping)}
return queryset.extra(select=select, select_params=[user.pk, key])
def annotate_votes(queryset_or_model, key, user, score='score'):
"""
Annotate *queryset_or_model* with votes, in order to retreive from
the database all vote values in bulk.
The first argument *queryset_or_model* must be, of course, a queryset
or a Django model object. The argument *key* is the score key.
The votes are filtered using given *user*. For anonymous voters this
functionality is unavailable.
The score itself will be present in the attribute named *score* of
each instance of the returned queryset.
Usage example::
for article in annotate_votes(Article.objects.all(), 'main', myuser,
score='myscore'):
print 'your vote:', article.myscore
"""
# getting the queryset
if isinstance(queryset_or_model, models.base.ModelBase):
queryset = queryset_or_model.objects.all()
else:
queryset = queryset_or_model
# preparing arguments for *extra* query
opts = queryset.model._meta
content_type = managers.get_content_type_for_model(queryset.model)
mapping = {
'vote_table': Vote._meta.db_table,
'model_table': opts.db_table,
'model_pk_name': opts.pk.name,
'content_type_id': content_type.pk,
}
# building base query
template = """
SELECT score FROM ${vote_table} WHERE
${vote_table}.object_id = ${model_table}.${model_pk_name} AND
${vote_table}.content_type_id = ${content_type_id} AND
${vote_table}.user_id = %s AND
${vote_table}.key = %s
"""
select = {score: string.Template(template).substitute(mapping)}
return queryset.extra(select=select, select_params=[user.pk, key])
def annotate_scores(queryset_or_model, key, **kwargs):
"""
Annotate *queryset_or_model* with scores, in order to retreive from
the database all score values in bulk.
The first argument *queryset_or_model* must be, of course, a queryset
or a Django model object. The argument *key* is the score key.
In *kwargs* it is possible to specify the values to retreive mapped
to field names (it is up to you to avoid name clashes).
You can annotate the queryset with the number of votes (*num_votes*),
the average score (*average*) and the total sum of all votes (*total*).
For example, the following call::
annotate_scores(Article.objects.all(), 'main',
average='average', num_votes='num_votes')
Will return a queryset of article and each article will have two new
attached fields *average* and *num_votes*.
Of course it is possible to sort the queryset by a score value, e.g.::
for article in annotate_scores(Article, 'by_staff',
staff_avg='average', staff_num_votes='num_votes'
).order_by('-staff_avg', '-staff_num_votes'):
print 'staff num votes:', article.staff_num_votes
print 'staff average:', article.staff_avg
"""
# getting the queryset
if isinstance(queryset_or_model, models.base.ModelBase):
queryset = queryset_or_model.objects.all()
else:
queryset = queryset_or_model
# annotations are done only if fields are requested
if kwargs:
# preparing arguments for *extra* query
select = SortedDict() # not really needed (see below)
select_params = []
opts = queryset.model._meta
content_type = managers.get_content_type_for_model(queryset.model)
mapping = {
'score_table': Score._meta.db_table,
'model_table': opts.db_table,
'model_pk_name': opts.pk.name,
'content_type_id': content_type.pk,
}
# building base query
template = """
SELECT ${field_name} FROM ${score_table} WHERE
${score_table}.object_id = ${model_table}.${model_pk_name} AND
${score_table}.content_type_id = ${content_type_id} AND
${score_table}.key = %s
"""
template = string.Template(template).safe_substitute(mapping)
# building one query for each requested field
for alias, field_name in kwargs.items():
query = string.Template(template).substitute(
{'field_name': field_name})
select[alias] = query
# and that's why SortedDict are not really needed
select_params.append(key)
return queryset.extra(select=select, select_params=select_params)
return queryset
def annotate_scores(queryset_or_model, key, **kwargs):
"""
Annotate *queryset_or_model* with scores, in order to retreive from
the database all score values in bulk.
The first argument *queryset_or_model* must be, of course, a queryset
or a Django model object. The argument *key* is the score key.
In *kwargs* it is possible to specify the values to retreive mapped
to field names (it is up to you to avoid name clashes).
You can annotate the queryset with the number of votes (*num_votes*),
the average score (*average*) and the total sum of all votes (*total*).
For example, the following call::
annotate_scores(Article.objects.all(), 'main',
average='average', num_votes='num_votes')
Will return a queryset of article and each article will have two new
attached fields *average* and *num_votes*.
Of course it is possible to sort the queryset by a score value, e.g.::
for article in annotate_scores(Article, 'by_staff',
staff_avg='average', staff_num_votes='num_votes'
).order_by('-staff_avg', '-staff_num_votes'):
print 'staff num votes:', article.staff_num_votes
print 'staff average:', article.staff_avg
"""
# getting the queryset
if isinstance(queryset_or_model, models.base.ModelBase):
queryset = queryset_or_model.objects.all()
else:
queryset = queryset_or_model
# annotations are done only if fields are requested
if kwargs:
# preparing arguments for *extra* query
select = SortedDict() # not really needed (see below)
select_params = []
opts = queryset.model._meta
content_type = managers.get_content_type_for_model(queryset.model)
mapping = {
'score_table': Score._meta.db_table,
'model_table': opts.db_table,
'model_pk_name': opts.pk.name,
'content_type_id': content_type.pk,
}
# building base query
template = """
SELECT ${field_name} FROM ${score_table} WHERE
${score_table}.object_id = ${model_table}.${model_pk_name} AND
${score_table}.content_type_id = ${content_type_id} AND
${score_table}.key = %s
"""
template = string.Template(template).safe_substitute(mapping)
# building one query for each requested field
for alias, field_name in kwargs.items():
query = string.Template(template).substitute(
{'field_name': field_name})
select[alias] = query
# and that's why SortedDict are not really needed
select_params.append(key)
return queryset.extra(select=select, select_params=select_params)
return queryset
