Content Management Systems - MongoDB Applied Design Patterns - page 129

'posted' : datetime . utcnow (),
'author' : author_info ,
'text' : comment_text })

To insert a comment for a system with threaded comments, we first need to generate the ap-
propriate slug and full_slug values based on the parent comment:

posted = datetime . utcnow ()

# generate the unique portions of the slug and full_slug
slug_part = generate_pseudorandom_slug ()
full_slug_part = posted . strftime ( '%Y.%m. %d .%H.%M.%S' ) + ':' + slug_part
# load the parent comment (if any)
iif parent_slug :
parent = db . comments . find_one (
{ 'node_id' : node_id , 'slug' : parent_slug })
slug = parent [ 'slug' ] + '/' + slug_part
full_slug = parent [ 'full_slug' ] + '/' + full_slug_part

else else :

slug = slug_part
full_slug = full_slug_part

# actually insert the comment
db . comments . insert ({
'node_id' : node_id ,
'slug' : slug ,
'full_slug' : full_slug ,
'posted' : posted ,
'author' : author_info ,
'text' : comment_text })

Operation: View paginated comments

To view comments that are not threaded, we just need to select all comments participating in
a discussion and sort by the posted field. For example:

cursor = db . comments . find ({ 'node_id' : node_id })
cursor = cursor . sort ( 'posted' )
cursor = cursor . skip ( page_num * page_size )
cursor = cursor . limit ( page_size )