Search results pagination using Flask and MongoDB. Visit Ask GitHub.com to see pagination in action.

gistfile1.py

#All code is visible at https://github.com/harishvc/githubanalytics

#Reference:
# [Flask paginate extension] (http://flask-paginate.readthedocs.org/en/latest/)
# http://flask-paginate.readthedocs.org/en/latest/

#Step 1: Install flask paginate extension
$> pip install flask-paginate


#Step 2: Initialize
from flask.ext.paginate import Pagination
page, per_page, offset = get_page_items()  
..

(total, processed_text1) = DBQueries.ProcessQuery(query,offset, per_page)  #MongoDB query
pagination = get_pagination(page=page,
                            per_page=per_page,   #results per page
                            total=total,         #total number of results 
                            format_total=True,   #format total. example 1,024
                            format_number=True,  #turn on format flag
                            record_name='repositories', #provide context
                            )                     
                            
#Step 3: Render template
return render_template("index-bootstrap.html",
        page=page,
        total=total,
        per_page=per_page,
        pagination=pagination,                   
        title = 'Ask GitHub',
        ...
        )

#Step 4: Invoke pagination options and module
def get_css_framework():
    return 'bootstrap3'
def get_link_size():
    return 'sm'  #option lg
def show_single_page_or_not():
    return False
def get_page_items():
    page = int(request.args.get('page', 1))
    per_page = request.args.get('per_page')
    if not per_page:
        per_page = PER_PAGE
    else:
        per_page = int(per_page)
    offset = (page - 1) * per_page
    return page, per_page, offset
def get_pagination(**kwargs):
    kwargs.setdefault('record_name', 'repositories')
    return Pagination(css_framework=get_css_framework(),
                      link_size=get_link_size(),
                      show_single_page=show_single_page_or_not(),
                      **kwargs
                      )

#Step5: Include pagination tags in template
{% if total > 1 %}              #Ignore pagination if you get no results
    {{ pagination.info }}
{% endif %}     
{{ pagination.links }}

#Step 6: CSS (optional)
.pagination-page-info {
    padding: .6em;
    padding-left: 0;
    width: 40em;
    margin: .5em;
    margin-left: 0;
    font-size: 12px;
}
.pagination-page-info b {
    color: black;
    //background: #FFFF00;
    padding-left: 2px;
    padding: .1em .25em;
    font-size: 150%;
}

#Step 7: MongoDB queries to handle pagination
pipeline = [
            { '$match': {'$and': [ {'type': {'$in': ["PushEvent"]}},{'organization':query}] }}, 
            { '$group':  {'_id': {'full_name': "$full_name", 'organization': '$organization'},'_a1': {"$addToSet": "$actorname"},'_a3': {"$addToSet": "$ref"},'count': { '$sum' : 1 }}},
            { '$sort':  {'count': -1}},
            { "$group" : {"_id" : 'null',"my_documents" : {"$push" : {"_id" : "$_id",'actorname':'$_a1','ref':'$_a3','count':"$count"}},"TOTAL" : {"$sum" : 1}}},
            { "$unwind" : "$my_documents" },
            { "$project" : {"_id" : 0,"my_documents" : 1,"TOTAL" : "$TOTAL"}},
            { "$skip": offset},
            { "$limit": per_page} 
          ]
mycursor = db.aggregate(pipeline)