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<title>DataTables example - Pipelining data to reduce Ajax calls for paging</title>
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//
// Pipelining function for DataTables. To be used to the `ajax` option of DataTables
//
$.fn.dataTable.pipeline = function ( opts ) {
// Configuration options
var conf = $.extend( {
pages: 5, // number of pages to cache
url: '' // script url
}, opts );
// Private variables for storing the cache
var cacheLower = -1;
var cacheUpper = null;
var cacheLastRequest = null;
var cacheLastJson = null;
return function ( request, drawCallback, settings ) {
var ajax = false;
var requestStart = request.start;
var requestLength = request.length;
var requestEnd = requestStart + requestLength;
if ( cacheLower < 0 || requestStart < cacheLower || requestEnd > cacheUpper ) {
// outside cached data - need to make a request
ajax = true;
}
else if ( JSON.stringify( request.order ) !== JSON.stringify( cacheLastRequest.order ) ||
JSON.stringify( request.columns ) !== JSON.stringify( cacheLastRequest.columns ) ||
JSON.stringify( request.search ) !== JSON.stringify( cacheLastRequest.search )
) {
// properties changed (ordering, columns, searching)
ajax = true;
}
// Store the request for checking next time around
cacheLastRequest = $.extend( true, {}, request );
if ( ajax ) {
// Need data from the server
if ( requestStart < cacheLower ) {
requestStart = requestStart - (requestLength*(conf.pages-1));
if ( requestStart < 0 ) {
requestStart = 0;
}
}
cacheLower = requestStart;
cacheUpper = requestStart + (requestLength * conf.pages);
request.start = requestStart;
request.length = requestLength*conf.pages;
settings.jqXHR = $.ajax( {
"url": conf.url,
"data": request,
"dataType": "json",
"cache": false,
"success": function ( json ) {
cacheLastJson = $.extend(true, {}, json);
if ( cacheLower != requestStart ) {
json.data.splice( 0, requestStart-cacheLower );
}
json.data.splice( requestLength, json.data.length );
drawCallback( json );
}
} );
}
else {
json = $.extend( true, {}, cacheLastJson );
json.draw = request.draw; // Update the echo for each response
json.data.splice( 0, requestStart-cacheLower );
json.data.splice( requestLength, json.data.length );
drawCallback(json);
}
}
};
//
// DataTables initialisation
//
$(document).ready(function() {
$('#example').dataTable( {
"processing": true,
"serverSide": true,
"ajax": $.fn.dataTable.pipeline( {
url: 'scripts/server_processing.php',
pages: 5 // number of pages to cache
} )
} );
} );
</script>
</head>
<body class="dt-example">
<div class="container">
<section>
<h1>DataTables example <span>- Pipelining data to reduce Ajax calls for paging</span></h1>
<div class="info">
<p>Sever-side processing can be quite hard on your server, since it makes an Ajax call to the server
for every draw request that is made. On sites with a large number of page views, you could potentially
end up DDoSing your own server with your own applications!</p>
<p>This example shows one technique to reduce the number of Ajax calls that are made to the server by
caching more data than is needed for each draw. This is done by intercepting the Ajax call and routing
it through a data cache control; using the data from the cache if available, and making the Ajax
request if not. This intercept of the Ajax request is performed by giving the <a href=
"//datatables.net/init/ajax"><code class="option" title="Initialisation option">ajax</code></a> option
as a function. This function then performs the logic of deciding if another Ajax call is needed, or if
data from the cache can be used.</p>
<p>Keep in mind that this caching is for paging only; the pipeline must be cleared for other
interactions such as ordering and searching since the full data set, when using server-side processing,
is only available at the server.</p>
</div>
<table id="example" class="display" cellspacing="0" width="100%">
<thead>
<tr>
<th>Name</th>
<th>Position</th>
<th>Office</th>
<th>Extn.</th>
<th>Start date</th>
<th>Salary</th>
</tr>
</thead>
<tfoot>
<tr>
<th>Name</th>
<th>Position</th>
<th>Office</th>
<th>Extn.</th>
<th>Start date</th>
<th>Salary</th>
</tr>
</tfoot>
</table>
<ul class="tabs">
<li class="active">Javascript</li>
<li>HTML</li>
<li>CSS</li>
<li>Ajax</li>
</ul>
<div class="tabs">
<div class="js">
<p>The Javascript shown below is used to initialise the table shown in this example:</p>
<pre class="brush: js;">
//
// Pipelining function for DataTables. To be used to the `ajax` option of DataTables
//
$.fn.dataTable.pipeline = function ( opts ) {
// Configuration options
var conf = $.extend( {
pages: 5, // number of pages to cache
url: '' // script url
}, opts );
// Private variables for storing the cache
var cacheLower = -1;
var cacheUpper = null;
var cacheLastRequest = null;
var cacheLastJson = null;
return function ( request, drawCallback, settings ) {
var ajax = false;
var requestStart = request.start;
var requestLength = request.length;
var requestEnd = requestStart + requestLength;
if ( cacheLower < 0 || requestStart < cacheLower || requestEnd > cacheUpper ) {
// outside cached data - need to make a request
ajax = true;
}
else if ( JSON.stringify( request.order ) !== JSON.stringify( cacheLastRequest.order ) ||
JSON.stringify( request.columns ) !== JSON.stringify( cacheLastRequest.columns ) ||
JSON.stringify( request.search ) !== JSON.stringify( cacheLastRequest.search )
) {
// properties changed (ordering, columns, searching)
ajax = true;
}
// Store the request for checking next time around
cacheLastRequest = $.extend( true, {}, request );
if ( ajax ) {
// Need data from the server
if ( requestStart < cacheLower ) {
requestStart = requestStart - (requestLength*(conf.pages-1));
if ( requestStart < 0 ) {
requestStart = 0;
}
}
cacheLower = requestStart;
cacheUpper = requestStart + (requestLength * conf.pages);
request.start = requestStart;
request.length = requestLength*conf.pages;
settings.jqXHR = $.ajax( {
"url": conf.url,
"data": request,
"dataType": "json",
"cache": false,
"success": function ( json ) {
cacheLastJson = $.extend(true, {}, json);
if ( cacheLower != requestStart ) {
json.data.splice( 0, requestStart-cacheLower );
}
json.data.splice( requestLength, json.data.length );
drawCallback( json );
}
} );
}
else {
json = $.extend( true, {}, cacheLastJson );
json.draw = request.draw; // Update the echo for each response
json.data.splice( 0, requestStart-cacheLower );
json.data.splice( requestLength, json.data.length );
drawCallback(json);
}
}
};
//
// DataTables initialisation
//
$(document).ready(function() {
$('#example').dataTable( {
"processing": true,
"serverSide": true,
"ajax": $.fn.dataTable.pipeline( {
url: 'scripts/server_processing.php',
pages: 5 // number of pages to cache
} )
} );
} );
</pre>
<p>In addition to the above code, the following Javascript library files are loaded for use in this
example:</p>
<ul>
<li><a href="../../media/js/jquery.js">../../media/js/jquery.js</a></li>
<li><a href="../../media/js/jquery.dataTables.js">../../media/js/jquery.dataTables.js</a></li>
</ul>
</div>
<div class="table">
<p>The HTML shown below is the raw HTML table element, before it has been enhanced by
DataTables:</p>
</div>
<div class="css">
<div>
<p>This example uses a little bit of additional CSS beyond what is loaded from the library
files (below), in order to correctly display the table. The additional CSS used is shown
below:</p>
<pre class="brush: js;">
</pre>
</div>
<p>The following CSS library files are loaded for use in this example to provide the styling of the
table:</p>
<ul>
<li><a href=
"../../media/css/jquery.dataTables.css">../../media/css/jquery.dataTables.css</a></li>
</ul>
</div>
<div class="ajax">
<p>This table loads data by Ajax. The latest data that has been loaded is shown below. This data
will update automatically as any additional data is loaded.</p>
</div>
</div>
</section>
</div>
<section>
<div class="footer">
<div class="gradient"></div>
<div class="liner">
<h2>Other examples</h2>
<div class="toc">
<div class="toc-group">
<h3><a href="../basic_init/index.html">Basic Init</a></h3>
<ul class="toc">
<li><a href="../basic_init/zero_configuration.html">Zero configuration</a></li>
<li><a href="../basic_init/filter_only.html">Feature enable / disable</a></li>
<li><a href="../basic_init/table_sorting.html">Default ordering (sorting)</a></li>
<li><a href="../basic_init/multi_col_sort.html">Multi-column ordering</a></li>
<li><a href="../basic_init/multiple_tables.html">Multiple tables</a></li>
<li><a href="../basic_init/hidden_columns.html">Hidden columns</a></li>
<li><a href="../basic_init/complex_header.html">Complex headers (rowspan and
colspan)</a></li>
<li><a href="../basic_init/dom.html">DOM positioning</a></li>
<li><a href="../basic_init/flexible_width.html">Flexible table width</a></li>
<li><a href="../basic_init/state_save.html">State saving</a></li>
<li><a href="../basic_init/alt_pagination.html">Alternative pagination</a></li>
<li><a href="../basic_init/scroll_y.html">Scroll - vertical</a></li>
<li><a href="../basic_init/scroll_x.html">Scroll - horizontal</a></li>
<li><a href="../basic_init/scroll_xy.html">Scroll - horizontal and vertical</a></li>
<li><a href="../basic_init/scroll_y_theme.html">Scroll - vertical with jQuery UI
ThemeRoller</a></li>
<li><a href="../basic_init/language.html">Language options</a></li>
</ul>
</div>
<div class="toc-group">
<h3><a href="../advanced_init/index.html">Advanced Init</a></h3>
<ul class="toc">
<li><a href="../advanced_init/events_live.html">DOM / jQuery events</a></li>
<li><a href="../advanced_init/dt_events.html">DataTables events</a></li>
<li><a href="../advanced_init/column_render.html">Column rendering</a></li>
<li><a href="../advanced_init/length_menu.html">Page length options</a></li>
<li><a href="../advanced_init/dom_multiple_elements.html">Multiple table control
elements</a></li>
<li><a href="../advanced_init/complex_header.html">Complex headers (rowspan /
colspan)</a></li>
<li><a href="../advanced_init/html5-data-attributes.html">HTML5 data-* attributes</a></li>
<li><a href="../advanced_init/language_file.html">Language file</a></li>
<li><a href="../advanced_init/defaults.html">Setting defaults</a></li>
<li><a href="../advanced_init/row_callback.html">Row created callback</a></li>
<li><a href="../advanced_init/row_grouping.html">Row grouping</a></li>
<li><a href="../advanced_init/footer_callback.html">Footer callback</a></li>
<li><a href="../advanced_init/dom_toolbar.html">Custom toolbar elements</a></li>
<li><a href="../advanced_init/sort_direction_control.html">Order direction sequence
control</a></li>
</ul>
</div>
<div class="toc-group">
<h3><a href="../styling/index.html">Styling</a></h3>
<ul class="toc">
<li><a href="../styling/display.html">Base style</a></li>
<li><a href="../styling/no-classes.html">Base style - no styling classes</a></li>
<li><a href="../styling/row-border.html">Base style - row borders</a></li>
<li><a href="../styling/cell-border.html">Base style - cell borders</a></li>
<li><a href="../styling/hover.html">Base style - hover</a></li>
<li><a href="../styling/order-column.html">Base style - order-column</a></li>
<li><a href="../styling/stripe.html">Base style - stripe</a></li>
<li><a href="../styling/jqueryUI.html">jQuery UI ThemeRoller</a></li>
<li><a href="../styling/bootstrap.html">Bootstrap</a></li>
<li><a href="../styling/foundation.html">Foundation</a></li>
</ul>
</div>
<div class="toc-group">
<h3><a href="../data_sources/index.html">Data Sources</a></h3>
<ul class="toc">
<li><a href="../data_sources/dom.html">DOM sourced data</a></li>
<li><a href="../data_sources/ajax.html">Ajax sourced data</a></li>
<li><a href="../data_sources/js_array.html">Javascript sourced data</a></li>
<li><a href="../data_sources/server_side.html">Server-side processing</a></li>
</ul>
</div>
<div class="toc-group">
<h3><a href="../ajax/index.html">Ajax</a></h3>
<ul class="toc">
<li><a href="../ajax/simple.html">Ajax data source (arrays)</a></li>
<li><a href="../ajax/objects.html">Ajax data source (objects)</a></li>
<li><a href="../ajax/deep.html">Nested object data (objects)</a></li>
<li><a href="../ajax/objects_subarrays.html">Nested object data (arrays)</a></li>
<li><a href="../ajax/null_data_source.html">Generated content for a column</a></li>
<li><a href="../ajax/custom_data_property.html">Custom data source property</a></li>
<li><a href="../ajax/custom_data_flat.html">Flat array data source</a></li>
<li><a href="../ajax/defer_render.html">Deferred rendering for speed</a></li>
</ul>
</div>
<div class="toc-group">
<h3><a href="./index.html">Server Side</a></h3>
<ul class="toc active">
<li><a href="./simple.html">Server-side processing</a></li>
<li><a href="./custom_vars.html">Custom HTTP variables</a></li>
<li><a href="./post.html">POST data</a></li>
<li><a href="./ids.html">Automatic addition of row ID attributes</a></li>
<li><a href="./object_data.html">Object data source</a></li>
<li><a href="./row_details.html">Row details</a></li>
<li><a href="./select_rows.html">Row selection</a></li>
<li><a href="./jsonp.html">JSONP data source for remote domains</a></li>
<li><a href="./defer_loading.html">Deferred loading of data</a></li>
<li class="active"><a href="./pipeline.html">Pipelining data to reduce Ajax calls for
paging</a></li>
</ul>
</div>
<div class="toc-group">
<h3><a href="../api/index.html">Api</a></h3>
<ul class="toc">
<li><a href="../api/add_row.html">Add rows</a></li>
<li><a href="../api/multi_filter.html">Individual column filtering (text inputs)</a></li>
<li><a href="../api/multi_filter_select.html">Individual column filtering (select
inputs)</a></li>
<li><a href="../api/highlight.html">Highlighting rows and columns</a></li>
<li><a href="../api/row_details.html">Child rows (show extra / detailed
information)</a></li>
<li><a href="../api/select_row.html">Row selection (multiple rows)</a></li>
<li><a href="../api/select_single_row.html">Row selection and deletion (single
row)</a></li>
<li><a href="../api/form.html">Form inputs</a></li>
<li><a href="../api/counter_columns.html">Index column</a></li>
<li><a href="../api/show_hide.html">Show / hide columns dynamically</a></li>
<li><a href="../api/api_in_init.html">Using API in callbacks</a></li>
<li><a href="../api/tabs_and_scrolling.html">Scrolling and jQuery UI tabs</a></li>
<li><a href="../api/regex.html">Filtering API (regular expressions)</a></li>
</ul>
</div>
<div class="toc-group">
<h3><a href="../plug-ins/index.html">Plug-ins</a></h3>
<ul class="toc">
<li><a href="../plug-ins/api.html">API plug-in methods</a></li>
<li><a href="../plug-ins/sorting_auto.html">Ordering plug-ins (with type
detection)</a></li>
<li><a href="../plug-ins/sorting_manual.html">Ordering plug-ins (no type
detection)</a></li>
<li><a href="../plug-ins/range_filtering.html">Custom filtering - range filter</a></li>
<li><a href="../plug-ins/dom_sort.html">Live DOM ordering</a></li>
</ul>
</div>
</div>
<div class="epilogue">
<p>Please refer to the <a href="http://www.datatables.net">DataTables documentation</a> for full
information about its API properties and methods.<br>
Additionally, there are a wide range of <a href="http://www.datatables.net/extras">extras</a> and
<a href="http://www.datatables.net/plug-ins">plug-ins</a> which extend the capabilities of
DataTables.</p>
<p class="copyright">DataTables designed and created by <a href=
"http://www.sprymedia.co.uk">SpryMedia Ltd</a> © 2007-2013<br>
DataTables is licensed under the <a href="http://www.datatables.net/mit">MIT license</a>.</p>
</div>
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