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Search Developer's Guide (PDF)

Search Developer's Guide — Chapter 31

Data Visualization Widgets

This chapter introduces the use of visualization widgets to display MarkLogic Server search results. These widgets provide a means to display data in picture or graph form. You can incorporate visualization widgets directly in the display output of applications you write, or incorporate them in applications created with Application Builder.

The following is the search page from the Oscars application created by Application Builder. Every object on the page is a visualization widget.

This chapter contains the following sections:

Overview of Visualization Widgets

MarkLogic Server provides six visualization widget types:

  • Line Chart; a two-dimensional graph that shows a left to right series of data points, with each two consecutive data points connected by a straight line. Though line graphs can be associated with any facet type, they are typically used to show a time series, with the line representing chronological movement.

  • Pie Chart: a two-dimensional circle, divided into different colored sections, one for each data value. A section's percentage of the circle's area is equivalent to the percentage of the data value's contents relative to the whole of the data (for example, if there are 16 total datums, and 8 of them have the value 'red', the pie chart section corresponding to the 'red' value will be half of the circle). Data values can be either non-continuous (colors, restaurant dishes) or continuous (height, weight, test scores).

  • Column Chart: a chart with horizontal rectangular bars representing the amount of a particular discrete value. Values can be either non-continuous (colors, restaurant dishes) or continuous (height, weight, test scores).

  • Bar Chart: a chart with vertical rectangular bars representing the amount of a particular discrete value. Values can be either non-continuous (colors, restaurant dishes) or continuous (height, weight, test scores).

  • Point Map: A Google map with data points representing search results, each associated with a geospatial value. For example, assuming the data is in the database and the map widget was configured for this, a pin would appear over the town of Nevada, Missouri, to indicate the birthplace of actor/director John Huston. You can zoom in and out on the map, as well as pan in all directions.

  • Heat Map: A Google map with results' geographic frequency represented as colored blobs located at distinct points on the map. For example, if there was a large number of results located in San Carlos, CA, there would be a large blob centered on that location on the map. If there was a small number of results located in Los Angeles, there would be a small blob centered on that map location.

Working with the Visualization Widgets

This section contains the following subsections:

Building The Oscars Example Application

The quickest and easiest way to learn how to use visualization widgets is to use Application Builder to build an example Oscars application, as described in Building the Oscars Sample Application in the Application Builder Developer's Guide.

To add all of the widget types to the Oscars application, navigate to the Assemble page in Application Builder and do the following:

  1. Click on the circled pointer at the right of the 'Layout your application' section in the top left of the page.

  2. A 'Select a Template' popup window appears, giving you layout choices for your applications results page. Select the four-widget layout at the bottom on the right.

  3. Click on the each widget box in your application layout:

  4. Select the widget on the right that you want to add to the layout:

  1. Each widget must be associated with a facet, which is set at the bottom of the Assemble page. For example, to have the column chart represent the number of awards on the data set, set the facet to ‘award' and the measure to ‘Count':

    Currently, Count is the only available measure for widgets.

  2. Deploy your application, as described in Deploy Page in the Application Builder Developer's Guide.

General Operation of Widgets

In general, clicking on a widget item (for example, a bar on a bar chart) changes the search query for the page and, as a result, the sidebar, results, and any other widgets on the page are updated to reflect the new search term. The only exceptions to this is the line chart widget and clicking on a marker in a map widget.

Searches initiated through the widgets are stemmed searches, which means the results returned for a term like 'name' also include ‘names,' ‘named', and so on.

Working with the Line Chart Widget

The following Line Chart shows the search results on the 'decade' facet, with each dot indicating the number of nominations during that 'decade.' The chart's y-axis is the number of nominations, and its x-axis is the year, going from the first Oscars in 1920 to the present.

If you mouse over the Line Chart, a tool tip window appears, giving the date and number of nominations associated with the nearest data point, for example 'Decade: 1970s' and 'Nominations: 44'

Line charts are currently read-only and do not update the sidebar, results, or other widgets on the page.

Working with the Bar and Column Chart Widgets

The following Bar and Column Charts show the search results on the 'decade' facet.

If you mouse over a Bar or Column Chart, a tool tip window appears, giving the number of nominations (either by decade or film, depending on which chart) and film name or decade (again, depending on which chart) associated with the nearest bar. Clicking and dragging the mouse over the chart does not do anything. Clicking a single bar changes the Results area of the page to only show the search results associated with the film or decade, depending on the chart. Clicks on charts also change other widgets on the page, applying the value of the clicked bar as an additional search term to those widgets.

Note in the chart shown below, which has had the 1920s bar clicked, the number of Results is 10, the same as the number of results which occurred in the 1920s.

Working with the Pie Chart Widget

The following Pie Chart shows the search results on the 'name' facet.

If you mouse over a Pie Chart, a tool tip window appears, giving the name value and number of search matching nominations associated with the nearest section, for example 'Clint Eastwood: 3'. Clicking on a single Pie Chart section updates the Sidebar and Results sections, so that they only show the results for the Name value associated with that Pie Chart section. For example, if you click on the section for Clint Eastwood, only search results associated with Clint Eastwood appear in the page's Sidebar and Results sections.

Working with the Map Widget

Before you can select a map widget, you must create a geospatial element pair index. Navigate to the Search tab in Application Builder, click Add New at the bottom of the page, select Geospatial, and name it ‘map'. Click Create Geospatial Constraint.

Navigate to the Assemble page, select the map widget, and assign it the map facet. Deploy the application.

If you are writing an application in which you expect over 25,000 map loads per day, you will be required to purchase an a Map API Key from Google. Enter the key in the Map API Key field in the Map Setup section.

The map widget in the deployed application shows the search results on the entire Oscars data set. Each circle represents a cluster of markers. The color of and the number inside the marker cluster represents the number of results. If you select facets to narrow the data set, the map will change to represent that subset of results.

Clicking and dragging the mouse over the map widget causes the map display to pan or move in the drag direction. If you click on marker cluster, you can drill down to more marker clusters and finally to individual markers, which represent each nominee's birthplace.

Unlike the other widgets, clicking on a marker does not update the Sidebar or Results. Rather, it open an info window containing the actor's name, birth date, and birth place, such as 'Joan Crawford / Born 1905-03-23 / San Antonio, Texas'.

The Sidebar and Results will be updated if you use the Draw Shape tool to select one or more markers on the map. Click on the polygon icon to set the map to Draw Shape mode:

For example, to update the search results based on two markers, left-click points and drag lines around the markers to draw a polygon as shown below:

Overview of the Widget Architecture

The front end architecture of the widgets is based on modules that can both send messages and receive them, but no module has any knowledge of other modules or the page at large. Each module has a listener that listens for messages that meet specific parameters. Similarly, a module sends out messages into the common medium without specific knowledge of the recipient of that message, but other modules with the proper listeners will receive those messages. In this fashion, module can be added and removed in realtime without disrupting the flow of the application, and there is no need for a controller to keep tabs on all of the application's modules. This maintains a strong separation of interests and allows for easier unit testing.

Modules are not aware of other modules. They can only trigger events and listen for events. The only information exchange between modules is through listening to messages in the common medium. There is no tracking of the particular source of information or particular destination. Messages are released into the common medium and read by those modules that have the proper listeners for picking up those particular messages.

The widget architectural model makes heavy use of event bubbling in the Document Object Model (DOM). There are two basic types of modules: Widget modules and controller modules. In most instances, there is a single controller module and one or more widget modules.

This section contains the following topics:


Using event handlers, widgets listen for newData events in order to listen for new pieces of data to render. Similarly, widgets can generate newQuery events in order to communicate a change in the query based on internal changes to the widget.

Two simple degenerate cases are a search bar widget and a results widget:

  • The search bar is a widget which does not react to any newData messages, but it does generate newQuery messages in response to a user typing a text query and clicking Search.
  • The results widget does not typically send out newQuery messages, but rather, merely renders the results of a query. The exception to this is, if results have been implemented with pagination, then the results widget will send newQuery messages in order to paginate.

Widgets usually use a hybrid of the two types, both displaying information and updating the query in order to update the view into that query. An individual widget doesn't necessarily know the whole query, but tends to have control over a portion of it. Most visualizations take ownership of a particular facet and apply or remove a filter on the search based on that facet.


The controller is a module just like a widget. It's main job is listening to newQuery events and posting newData events. The controller makes use of a private comm (communicator) object that is responsible for making Ajax calls to the server for new data. For example, when panning a map widget, the map needs to update the marker clusters, which requires a query. The map widget sends out an event that the controller hears and passes on to the comm object, which requests the data and sends it back to the map widget.

The controller and comm object offer a lot of extensibility room for features like caching and data manipulations. The controller accepts an option configuration object that specifies things like the endpoint to access on the server, the application wrapper, the widget class, etc. By specifying a limited application wrapper, multiple controllers, for example, can be created on the page each running a separate application. They only respond to messages within their application container. Similarly, two applications can share a container on the page and use different widget classes to control their individual widgets.

The controller receives newQuery events and translates the query object into a structured query, which is appended to the Ajax call generated in the comm object.


Widgets are identified and linked to a controller using an HTML class. Applications generated by Application Builder name this class 'widget.'

For example, to add the results widget to the page, specify the following:

<div id="results" class="widget"></div>

Interaction within a Widget

Interactions within widgets consist of selecting data or pagination. Each widget has an internal updateQuery method that can be called with a query object to send out a newQuery event. In the case of visual widgets, it makes "selections" on facets to update the query. A column chart or pie chart takes a single selection and a map takes an area (a polygon). For example, clicking on a bar in a column chart generates a selection event which bubbles up from the DOM and is read by the widget, which translates the selection into a newQuery event. The translation logic lives in the widget.

Shadow Queries

The basic idea of a shadow query is that, with many widgets on a page, multiple selections can be made at once and, if widgets are updating with each search, clicking on a widget essentially nullifies its further usefulness in searching because it will only display the one result that is the current selection.

The idea of shadow queries is to provide a 'context' or 'shadow' for these selected widgets. When a widget is selected, the selection is highlighted, but the other categories remain visible while the other widgets on the page update. When the next widget is selected, two queries are fired, one is the general search that's updating unselected widgets and the results pane; the other is the 'shadow query' for the selected widget. This shadow query is a copy of the main search query, except without the selected widget's contribution to that search. This renders a view "around" the selection in the widget and greatly expands the power of widgets on the page by offering a very deep view into the data.

Shadow Queries work by taking advantage of the datastream. The datastream is set in two places, once in each widget upon instantiation (datastream is a parameter in the createWidget method described in ML.createWidget (Null Widget) Method) and also upon creation of shadow queries in the controller. The datastream is used to match a shadow query to the widget that it is shadowing.

Here is how datastreams work:

  • If a query has no datastream, it will update all unselected widgets (or widgets with no datastream of their own set).
  • If a query has a datastream and it matches the widget's datastream, then the widget will update; whether the widget is selected or not.
  • If a query has a datastream and it does not match the widget's datastream, then the widget will do nothing.

    When a widget sets off a shadow query by making a selection, it will not render the next update it receives, as that update is informing the widget of its already current state.

Adding Visualization Widgets to an HTML Page

Some code is common to both chart widgets (Bar, Column, Line, and Pie Charts) and map widgets (Point and Heat).

Common JavaScript And CSS In The <head> Element

In your <head> element, first, add your external library dependencies for line, bar, column, and pie charts:

<!-- external library dependencies -->
<script src="lib/external/jquery-1.7.1.min.js"
<script src="lib/external/highscharts.src.js"

If you are using map widgets, you must also include the following external libraries:

<!-- external web map files... -->
<script src="lib/external/mxn-2.0.18/mxn.js?(googlev3)" type="text/javascript"></script>
<script src="lib/external/heatmap.js" type="text/javascript"></script>
<script src="lib/external/heatmap-gmaps.js" type="text/javascript"></script>
<script src="lib/external/markerclusterer_min.js" type="text/javascript"></script>

Then add calls to the internal widget framework library. Of course, if you are not using histograph widgets, you do not need to include the chart.js library, and if you are not using map widgets you do not need to include the map.js library:

<!-- internal widget framework library -->
<script src="lib/controller.js" type="text/javascript"></script>
<script src="lib/widget.js" type="text/javascript"></script>
<script src="/lib/viz/chart/chart.js" type-"text/javascript"></script>
<script src="/lib/viz/map/map.js" type-"text/javascript"></script>

Finally, you may want to define a CSS style for your widget elements: This is optional, as there is a set of default CSS styles for the various widget types in the library (see /lib/viz/chart.css and /lib/viz/map.css). If you do define a custom style, do something similar to the following, defining your widgets' display parameters to meet your application's requirements. Of course, you do not have to call your element widget, especially if you want to have different display parameters for different visualization widgets and thus need to define several different elements.

<style type="text/css">
       .widget {
                width: 500px;
                display: block;
                float: left;

Common Code In The <body> Element

You must define each widget as a separate <div> element with either the default class "widget" or the class name you specified when initializing widgets with ML.controller.init and its widgetClass option (see ML.controller Methods). In the example later on, which has three visualization widgets (two charts and one map), you have:

<div id="decadeContainer" class="widget"></div>
<div id="actorContainer" class="widget"></div>
<div id="locationContainer" class="widget"></div>

Next, define a <script> that:

  1. Define the PHP search proxy that authenticates with the server and forwards queries to the REST endpoint on MarkLogic Server: :
    ML.controller.init({proxy: "proxy.php"});

    For details on how to define the PHP proxy, see Set Up A Proxy

  2. Still in the <script>, define configuration variables for each of your visualization widgets. The configuration parameters differ for chart and map widgets (and also for Point Map and Heat Map map widgets), so see below for detailed examples and later for a complete list of possible configuration parameters for all visualization widget types. But placeholders for the three widgets in our full example would look like:
    var yearConfig = {
    ...chart configuration parameters...
    var actorConfig = {
    ...chart configuration parameters...
    var mapConfig = {
    ...point and heat map configuration parameters...
  3. Finally, activate the widget controller and the widgets themselves and close the <script>. ML.controller.init takes as its argument the variable you defined back in 1) that contains the information about the proxy server and this application's search endpoint, in this case config.

    ML.chartWidget and ML.mapWidget both have the same signature of widget element name, widget type, and configuration parameters variable name, and only differ in whether a chart or map widget is created.

    ML.controller.init(config); //connect to the var with our proxy value
    //chartWidget can take 'line' or 'bar' or 'column' or 'pie'
    //mapWidget just takes 'map'
    ML.chartWidget('decadeContainer', 'line', yearConfig);
    ML.chartWidget('actorContainer', 'bar', actorConfig);
    ML.mapWidget('locationContainer', 'map', mapConfig);

Initialize the Display

To initialize the widgets' display, use the use the ML.controller.loadData method of the controller:


End the script with the usual </script>.

Example: Adding Widgets to Applications

This section describes how to add visualization widgets to an existing search application. In order to add visualization widgets, you must do the following:

  • Obtain a set of files for creating the visualization widgets.
  • Create an App Server that implements an instance of the MarkLogic REST API.
  • Set up a proxy to connect to the REST server. For this document, we make use of a PHP server to host the proxy.
  • Define a search options node to expose facet data to the widgets.
  • Create an HTML page that configures and displays the widgets in your application.

It is assumed that you have a MarkLogic database set up when you begin the following process.

  1. Create a database, named restaurants, in MarkLogic Server.
  2. Create a REST server for the database, as described in Creating a REST API Instance in the Information Studio Developer's Guide. This will automatically create a modules database that starts with the name of the REST server, followed by -modules. For example, if you name the REST server restaurants, a database, named restaurants-modules, is automatically created. In this example, the REST server is located at: myhost:5437.
  3. Using the Admin interface, create the following element range indexes in the restaurants database. These correspond to the facets to visualize using the widget:
    scalar type localname
  4. Use Query Console execute the following query to load some documents into your restaurants database:
    xquery version "1.0-ml";
        <DBA> 123 Deli - Lee's </DBA>
        <Type> Restaurant, &lt; 500 sq' </Type>
        <SqFtEst> 500 </SqFtEst>
        <StreetAddress> 123 1st St </StreetAddress>
        <City> San Francisco </City>
        <State> CA </State>
        <FullAddress> 123 1st St, San Francisco CA </FullAddress>
        <DBA> Dave's Dive </DBA>
        <Type> Restaurant, &lt; 700 sq' </Type>
        <SqFtEst> 700 </SqFtEst>
        <StreetAddress>2 1 Mission St </StreetAddress>
        <City> Bismarck </City>
        <State> ND </State>
        <FullAddress> 21 Mission St, Bismarck ND </FullAddress>
        <DBA> Wayne's Steakhouse </DBA>
        <Type> Restaurant, &lt; 1000 sq' </Type>
        <SqFtEst> 1000 </SqFtEst>
        <StreetAddress> 444 Feick St </StreetAddress>
        <City> Albany </City>
        <State> NY </State>
        <FullAddress>444 Feick St, Albany NY</FullAddress>
        <DBA> Megha </DBA>
        <Type> Restaurant, &lt; 1000 sq' </Type>
        <SqFtEst> 1000 </SqFtEst>
        <StreetAddress> 4531 Front St </StreetAddress>
        <City> Carlsbad </City>
        <State> NM </State>
        <FullAddress> 4531 Front St, Carlsbad NM </FullAddress>
        <DBA> Gordon's Grubhaus </DBA>
        <Type> Restaurant, &lt; 300 sq' </Type>
        <SqFtEst> 300 </SqFtEst>
        <StreetAddress> 3421 Capital Wy </StreetAddress>
        <City> El Paso </City>
        <State> TX </State>
        <FullAddress> 421 Capital Wy, El Paso TX </FullAddress>
  5. Use Query Console to load the following search options node into the restaurants-modules database. This exposes the facets required for the visualizations.

    You must be logged into MarkLogic Server as a user with the rest-admin privilege to run this query.

    <options xmlns="xdmp:http">
      <authentication method="digest">
    text { xdmp:quote( 
    <options xmlns="http://marklogic.com/appservices/search">
      <constraint name="Type">
        <range type="xs:string" facet="true">
          <element ns="" name="Type"/>
        <constraint name="SqFtEst">
          <range type="xs:int" facet="true">
            <element ns="" name="SqFtEst"/>
    ) }
  6. Enter the following URL, where <server>:<rest-port> identify your REST server. You should see an options node file with all your constraints set up.
  7. Navigate to the public directory for your PHP-enabled Apache server. In this example, this is /var/www/html.
  8. Download the files for the visualization widgets from:
  9. Unzip the customappfiles.xqy file and copy the five subfolders (constraint, css, images, lib, and skins) to the public directory for your PHP-enabled Apache server.

    In this example, there is no ‘application' directory, as there is in applications created by Application Builder.

  10. Create a PHP proxy file, named proxy.php, in the public directory for your PHP-enabled Apache server with the following contents. Make sure the CURLOPT_URL option points to your restaurants server (myhost:5437, in this example) and that the CURLOPT_USERPWD option contains your login credentials for MarkLogic Server.
    $queryString = $_SERVER['QUERY_STRING'];
    parse_str($queryString, $vars);
    $queryString = http_build_query($vars);
    $options = array(
    CURLOPT_URL => 'http://myhost:5437' . $_GET["proxyPath"] . '?' . $queryString, // location of the rest server. Be sure to preserve the query string unaltered
    CURLOPT_HTTPAUTH => CURLAUTH_DIGEST, // it is very important to set the authentication type to digest
    CURLOPT_USERPWD => 'admin:admin', // this is your username and password for the server. be sure your role has read permissions on the database
    CURLOPT_HTTPHEADER => array('Content-type: application/json'), // the server won't respond properly unless the content-type is application/json
    // Only set POST options for POSTs, not GETs
    if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $options[CURLOPT_POST] =  1; // queries are sent in the post body, with options like pagination in the query string 
    $options[CURLOPT_POSTFIELDS] = file_get_contents('php://input'); // we are not sending a traditional form map through the post, so avoid using the standard $_POST
    $ch = curl_init(); // create curl
    curl_setopt_array($ch, $options); // set curl options
    curl_exec($ch); // execute curl
  11. Create an HTML file with the following contents in the public directory for your PHP-enabled Apache server.
      <title>Custom App</title>
      <!-- external library dependencies -->
      <script src="lib/external/jquery-1.7.1.min.js"
      <script src="lib/external/highcharts.src.js"
      <!-- internal widget framework library --> 
      <script src="lib/controller.js" type="text/javascript"></script> 
      <script src="lib/widget.js" type="text/javascript"></script>
      <!-- visualization framework libraries --> 
      <script src="lib/viz/chart/chart.js" type="text/javascript">
      <link media="screen, print" href="lib/viz/chart/chart.css"
        rel="stylesheet" type="text/css">
      <style type="text/css"> 
        .widget {
           width: 500px; display: block; float: left;
      <h2>MarkLogic Custom Application</h2> 
      <div id="typeContainer" class="widget"></div> 
      <div id="sqftContainer" class="widget"></div> 
      <script type="text/javascript"> 
    <!-- If you have a proxy, identify it here. -->
      var config = { proxy: "proxy.php" };
      var typeConfig = { constraint: 'Type',
                         constraintType: 'range-unbucketed', 
                         dataType: 'xs:string', 
                         title: 'Type', 
                         dataLabel: 'Type' };
      var sqftConfig = { constraint: 'SqFtEst',
                         constraintType: 'range-unbucketed', 
                         dataType: 'xs:int', 
                         title: 'Square Feet', 
                         dataLabel: 'Square Feet' };
      ML.chartWidget('typeContainer', 'column', typeConfig); 
      ML.chartWidget('sqftContainer', 'bar', sqftConfig); 
    <!-- This will trigger the intial empty search -->
  12. Make sure all of the files in the public directory for your PHP-enabled Apache server are publicly accessible.
  13. In a browser, enter the URL for your PHP-enabled Apache server host. For example:
  14. You should see a page like the following:

Visualization Widget Limitations

There are several limitations common to most or all widget types. These are:

  • Non-map widgets size to their given container and do not scroll. Map widgets can be scrolled within the map itself, just as in most common map programs. You can zoom in or out, pan left, right, up, and down, etc. This does not affect the map's container, only the view of the map itself. The map can be set so as to disable zooming or panning. Panning is restricted North to South, so you are not allowed to pan past the North or South poles.
  • Non-map widgets do not support multiple-dimension visualizations (i.e. one facet per widget).
  • Map results are taken from the geo facet, rather than the search results themselves. ... it maybe useful to highlight that and give a screen shot of /v1/search?options=all&view=facets
  • In maps, panning and zoom generate a new query that is consumed by the map to 'paint' markers and marker clusters. The reason for this approach is to have an efficient mechanism to display maps that potentially have large data sets so that data queries are incremental, rather than returning all data points.
  • Tooltip behavior is defined by the chart widget and cannot be customized through Application Builder

Set Up A Proxy

In order to run a custom app, you generally need to run your queries through a proxy in order to authenticate on your MarkLogic REST server instance.

There is a proxy variable in the controller configuration that should be set to the base path of your proxy. The controller will append a 'proxyPath' URL parameter that your proxy should read. The proxyPath will point to the absolute path on the MarkLogic REST sever instance that the query needs to be proxied to. If the proxy is called with a POST, it should pass along the POST data to the MarkLogic REST server instance unchanged. It should also pass all url parameters aside from the proxyPath parameter. In the case of a GET request, just the url parameters are needed. The responses should be passed straight through unaltered.

An example PHP implementation is described in Example: Adding Widgets to Applications. Note that several options, such as the location of the REST server and the username and password values, may not be the same as your values. Edit the code so that it uses your values. Put this code in a publicly accessible file on your PHP server, for example, proxy.php, which will serve as your application's search endpoint.

After confirming you have the proxy working correctly, add a proxy option to the ML.controller.init method in your index.html page to identify the PHP proxy. For example:

ML.controller.init({proxy: "proxy.php"});

Widget API Reference

This section serves as a reference to the configuration options for each visualization widget and related methods. Bar, Column, Line, and Pie Charts all have the same configuration options. While it may seem odd to include Pie Charts with the others, if you consider a "slice" of a Pie Chart as serving the same basic purpose as a bar/column/datapoint on the other charts, it should make sense.

The topics in this section are:

ML.controller Methods

initTakes an optional config object made up of name/value pair configuration options in the above table. All values are optional and default to those used in the application built by Application Builder.
getData(query)This is the direct method to call with a query for such actions as doing an initial load of data, or wanting to reset a search for some reason. The query object is required, but can be empty. For example: ML.controller.getData({});
loadDataPerforms the initial data loading on the page. Will read the url for a bookmarked query if bookmarking is enabled. Call loadData() after initializing all the widgets.

The ML.controller.init method has the signature:

ML.controller.init ({option1: value1, option2: value2...});

Valid options are:


Lets you wrap your application in a section of the page so it doesn't interfere with the rest of it. This is the uppermost element of the widget application. It defaults to the body tag, encompassing the whole page, but can be passed any jQuery selector to allow for multiple separate widget applications to be on a single page (for example, if you want to display data from different databases) or as a safety measure for preventing interference with an exiting application. Events and interactions are completely contained within the appWrapper.

Default: body


Version of the MarkLogic Server REST API.

Default: v1


The options node that contains the constraints being queried against.

Default: all


Sets the default starting page for results pagination. This does not affect visualization widgets, just the end search results.

Default: 1


Turns shadows queries on or off globally in the application.

Default: true


This is the jQuery selector that identifies widgets within the app. Any element with the class widget will receive newData events automatically in the default setup.

Default: .widget


If using a proxy, provide the path to the proxy here. See proxies section for instructions on setting up a proxy.

Default: false


Turns on bookmarking support.

Default: true


Delimiters to be used encoding the current query in the URL.

Default: ['*_*', '*__*']


Number of results returned for a query (does not affect constraints displayed in widgets).

Default: 10

ML.createWidget (Null Widget) Method

The 'null widget' is the core class of a widget in the application. The role of the null widget is to handle general communication behavior and incoming data. Visualizations, such as charts and maps, as well as controls, such as the search bar or displays like the results pane, are all extensions of the basic null widget.

ML.createWidget(container, renderCB, datastream, constraintType)


id of the container element for the widget. Recommended to be a div.



A callback function to execute when the widget receives a 'newData' event. The function is passed the server's response for the purpose of rendering those results.



An identifier that allows a widget to respond to shadow queries. Generally should be set to the constraint name for the widget



the constraintType must be set if the widget is using faceted data. It must match the type of constraint on the server's index for that constraint.

Must be "range", "constraint", or "geo". Determines how the structured query is generated. Map data is always of type geo. Other data can be range or constraint, depending on whether they are range indexes or collections on the server.

*required for shadow queries to work

General Widget Methods

updateQuery(queryUpdate)Takes a queryUpdate object as an argument (see controller objects above) and causes the widget to trigger an updateQuery method. Abstract method for widgets without selection that need to update the query, like a searchbox.
getSelection()Returns the currently selected value of the widget if it exists, null otherwise.

ML.chartWidget Method

The method used to create line, bar, column, and pie widgets is:

ML.chartWidget(containerID, type, config);
containerIDId of the container element for the widget. Recommended to be a div. (required)
typeType of chart. This can be:
  • line - line chart
  • bar - bar graph
  • column - column chart
  • pie - pie chart
configThe configuration object consisting of the options listed in the table below.

The ML.chartWidget configuration options are:

constraintName of the constraint facet whose data the chart renders. If invalid, the chart will not render. Defaults to "".
constraintTypeType of the constraint facet whose data the chart renders. Used to construct the query. Allowed values: range, constraint, geo. Value must specify the type of constraint the query is being run on in order to run the search. If invalid, either the query will not execute or cause an error on the server. Defaults to "" (no actual default value).
titleString of the widget's displayed title. Defaults to "".
subtitleString of the widget's displayed subtitle. Defaults to "".
dataLabelString of the displayed label of type of values in the graph. Defaults to "".
dataTypeString of the type of data displayed in the graph. Use the datatype of the constraint in the database. To disable the setting of the range, set dataType to "string". Takes "string", "datetime", "int", etc. Defaults to "string".
includeOthersWhen true, an "other" category is in the chart for when results are limited. For example, when showing the top 10 actors in terms of number of Oscar nominations as well as an others category for the total number of other actors with an Oscar nomination. Takes true or false Defaults to false.
othersLabelString of the displayed label for "other" results as described in includeOthers. Defaults to "Other".
hideXAxisValuesWhen true, hides the x-axis labels otherwise seen below the graph. Useful when dense columns result in unreadable labels. Note: Pie Charts have no x-axis, and Column Charts' x-axis is the vertical, not horizontal, axis. Takes true or false. Defaults to false

ML.mapWidget Method

The method used to create map widgets is:

ML.mapWidget('locationContainer', 'map', mapConfig);

The following are configuration options for map widgets. They are used to define a configuration variable similar to:

var mapConfig = {
       constraintType: 'geo',
       dataStream: 'results',
       statusContainerId: 'debug',
       width: 698,
       height: 512,

The point map configuration options are:

geoConstraintDefine a geographic constraint on the search results. Has the value of the geo constraint from the database associated with the map. Defaults to "".
mapWidthWidth of map (and its container) in pixels. Defaults to 485.
mapHeightHeight of map (and its container) in pixels. Defaults to 300.
mapProviderSource of maps. At present, only the default value for Google Maps is supported. Defaults to "googlev3".
zoomControlTypeShow zoom control. Takes either "small" or "large" Defaults to "small".
showMapTypesShow the available types of maps (satellite, road, etc.). Takes either "true" or "false". Defaults to "false".
showSelectControlsShow the Map widget search selection controls for selecting an area as an overlay. Takes either "true" or "false". "Defaults to "false".
showMapControlsShow the Map widget controls (switch from Point to Heat Map and vice versa) overlay. Takes either "true" or "false". Defaults to "false".
minZoomLevelDefines lower limit of map's zoom values. Defaults to 2.
maxZoomLevelDefines upper limit of map's zoom values. Defaults to 14.
constrainPanDetermines if map's pan function is constrained (i.e. if true, the visual area of the map is fixed). Takes "true" or "false". Defaults to "true".
constrainZoomDetermines if map's zoom function is constrained (i.e. if true, you cannot zoom in or out). Takes "true" or "false". Defaults to "true".
autoCenterZoomWhen true, auto centers on any object on the screen (markers, polygons) Takes "true" or "false". Defaults to "true".
showMarkersOnLoadWhen true, shows the map pointers indicating search matches when the map is loaded. Takes "true" or "false". Defaults to "true".
showHeatmapDetermines if the map is a Heat Map ("true") or a Point Map ("false"). Takes "true" or "false". Defaults to "false".
defaultMarkerIconImage used to display a search result hit on a map. Takes an image file. Defaults to "/images/map_red_shadow.png".

In addition to the point map options above, heat maps also have the following options:

heatMapRadiusLarger values mean each point contributes to a larger "hot" area on the map. Takes an integer. Defaults to 15.
heatMapOpacityTakes an integer between 0 and 100 (least and most opaque) that determines entity opacity. Defaults to 90.
searchColorDefines a color for lines (polygon, circle, square, etc.) in search results. Takes an HTML hexadecimal color value. Defaults to "#FF0000" (red).
searchFillColorDefines a color for fill in the search results, i.e. the search polygon area. Takes an HTML hexadecimal color value. Defaults to "".
searchOpacityDefines the level of opacity in the color of search result circles. Takes a value between 0 and 1 inclusive, where 0 is least opaque and 1 is most opaque. Defaults to 1.
searchFillOpacityDefines the level of search fill opacity (i.e. in the search polygon area). Takes a value between 0 and 1 inclusive, where 0 is least opaque and 1 is most opaque. Defaults to 0.

Widget Events

updateQueryThis event is posted by widgets making selections. The controller listens for this event bubbling up the DOM tree on the appWrapper element. See below for the data structure of the attached JSON object.
newDataThis event is posted to all of the application's widgets with an attached Data object of the following form:
    data: <server results>,
    query: <query object for search>
newQueryResets the current query to the provided query instead of updating the current search query
getBoundsGets the upper and lower bounds for the provided constraint from the values endpoint on the REST server. The constraint is attached to the event
newBoundsPublishes a bounds object to the widgets which will set the xAxis scale of the visualization widgets using constraint in the bounds object. It has the following form:
    min: <min_value>
    max: <max_value>
    constraint: <constraint>

Widget Query Structure

Query Structure (can be empty)

textText query that is passed directly to server unaltered. Supports all the query syntax of previous build app versions. (optional)
facetsAn array of facet objects representing selections from widgets on the page. See Facet Structure Below (optional)
pagePage number for use in paginating the search results (optional)
datastreamUsed to determine which widgets will render the query (optional)

Widget Query Update Structure

facetName of the facet/constraint to update
valueName of the selected value within the facet to search on
textText query that is passed directly to server unaltered. Supports all the query syntax of previous build app versions.
constraintTypeMust be "range", "constraint", or "geo". Determines how the structured query is generated. Map data is always of type geo. Other data can be range or constraint, depending on whether they are range indexes or collections on the server.

Search Results Format

The search results format (REST API)

totalTotal results returned by the search
startResult number of the first returned result
page-lengthNumber of results returned in this query
resultsArray of result objects
facetsList of all facets and facet-results for the search.
<facet-name>: {
    type: "xs:<data-type>",
    facetValues: [
       {name: <record name>, count: 
reportString report with information about the query.
metricsMetrics on the search from the server

Facet Structure

value'name' of facet value that is selected and will be used to update the search. For example, in the actors facet of the Oscars app, this might be "Humphrey Bogart"
constraintTypeMust be "range", "constraint", or "geo". Determines how the structured query is generated. Map data is always of type geo. Other data can be range or constraint, depending on whether they are range indexes or collections on the server.
geoThe geo property contains one of the following:
  • geo.poly - an array of lat/lng points
  • geo.box - 4 properties: north, south, east, west; whose values are lat/lng points
  • geo.circle - radius and a point object with latitude and longitude.

Internal Widget Events


Selection events are caught by the widget container and used to generate queryUpdate events (see controller events). A selection event has an attached selection object of the following form:

{ facet: 
  <facet name>, 
  value: <selected value> 

To unselect, simply pass a facet with no value property like so:

{facet: "decade"}
pagePage events are used for adjusting the pagination of the search results. The data passed along with the event has a page property that specifies the page number to display.

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