Version 38 (modified by 15 years ago) ( diff ) | ,
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Server-Side Pagination
Currently we do all pagination client-side which won't be possible to keep doing as we accumulate more data
This will be needed for:
Status
- The Back-end is now done for HTML representation
- The Back-end was already done for JSON representation, now done in the dataTables way
- The Front-end is done: 50 records at a time :)
- ToDo:
Push from Dev to LiveRender as .represent- Render the ID as View/Edit button depending on perms
-
Done via a .represent for RMS
-
- Return RMS to Live (1 line in Controller functions: response.s3.pagination = True)
- Handle Component Views (use list_fields instead of all readable)
- Sort Columns (orderby)
- Search (filtering)
- XSLT to generate dataTables-compliant JSON?
Front-end implementation
- http://datatables.net/examples/data_sources/server_side.html
- http://datatables.net/usage/server-side
- We'll also need to hand-off the Searching & Sorting!
Client-side, we need to add these options to views/dataTables.html
[make them Optional per-REST Controller?]:
"bProcessing": true, "bServerSide": true, "sAjaxSource": "{{=URL(r=request, c='module', r='resource', vars={'...':'...'})}}"
Server-side, we need to understand these vars:
# Pagination iDisplayStart - maps to 'start' iDisplayLength - maps to 'limit' # Ordering iSortCol_0 iSortingCols iSortCol_x iSortDir_x # Filtering (Search) - across all fields! sSearch
response should be sent in this format:
{ "sEcho": 1, "aaData": [ [row1.id, row1.field2, ...], [row2.id, row2.field2, ...], [row3.id, row3.field2, ...] ], "iTotalRecords": 3, "iTotalDisplayRecords": 3 }
e.g. using a function like (although we've integarted into models/01_RESTlike_controller.py
):
def callback(): iDisplayStart = int(request.vars.iDisplayStart) iDisplayLength = int(request.vars.iDisplayLength) from gluon.serializers import json _table = '%s_%s' % (request.controller, request.function) table = db[_table] query = (table.id > 0) rows = db(query).select(limitby = (iDisplayStart, iDisplayStart + iDisplayLength)) r = dict(sEcho = 1, iTotalRecords = len(rows), iTotalDisplayRecords = len(rows), aaData = [[row[f] for f in table.fields if table[f].readable] for row in rows]) return json(r)
Problems:
http://datatables.net/forums/comments.php?DiscussionID=1156&page=1#Item_1No .represent rendered- Represent doesn't handle ID, so can't pledge Aid for Requests in RMS (or see record details in OR)
Represent doesn't handle the marker_id, so gis_location has the big image for each marker visible
JSON Back-end implementation
- Support already present in
modules\s3xrc.py
http://S3_PUBLIC_URL/module/resource.json?limit=x&start=y
- needs patching for dataTables-expectations:
if "start" in self.request.vars: start = int(self.request.vars["start"]) elif "iDisplayStart" in self.request.vars: # dataTables start = int(self.request.vars["iDisplayStart"]) else: start = None if "limit" in self.request.vars: limit = int(self.request.vars["limit"]) elif "iDisplayLength" in self.request.vars: # dataTables limit = int(self.request.vars["iDisplayLength"]) else: limit = None
- actually needs a complete new representation unless this could be done via XSLT!?
- still needs extension adding to shn_xml_export_formats in
models\01_RESTlike_controller.py
- still needs extension adding to shn_xml_export_formats in
HTML Back-end implementation
Patched the models\01_RESTlike_Controller
to support http://S3_PUBLIC_URL/module/resource?limit=x&start=y
shn_list() ... if request.vars.limit: limit = int(request.vars.limit) if request.vars.start: start = int(request.vars.start) limitby = (start, start + limit) else: limitby = (0, limit) else: limitby = None ... items = crud.select(table, query=query, ... limitby=limitby, ... )
Other Options
- ExtJS
- Maybe look at the currently-unused
modules/webgrid.py
: http://www.web2pyslices.com/main/slices/take_slice/39- pagenav in
models\01_RESTlike_Controller
was an older implementation of a webgrid...has been removed.
- pagenav in
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