The VelocityResponseWriter is an optional plugin available in the contrib/velocity directory. It powers the /browse user interfaces when using configurations such as "_default", "techproducts", and "example/files".
Its JAR and dependencies must be added (via <lib> or solr/home lib inclusion), and must be registered in solrconfig.xml like this:
<queryResponseWriter name="velocity" class="solr.VelocityResponseWriter">
<str name="template.base.dir">${velocity.template.base.dir:}</str>
<!--
<str name="init.properties.file">velocity-init.properties</str>
<bool name="params.resource.loader.enabled">true</bool>
<bool name="solr.resource.loader.enabled">false</bool>
<lst name="tools">
<str name="mytool">com.example.MyCustomTool</str>
</lst>
-->
</queryResponseWriter>The above example shows the optional initialization and custom tool parameters used by VelocityResponseWriter; these are detailed in the following table. These initialization parameters are only specified in the writer registration in solrconfig.xml, not as request-time parameters. See further below for request-time parameters.
Configuration & Usage
VelocityResponseWriter Initialization Parameters
template.base.dir-
If specified and exists as a file system directory, a file resource loader will be added for this directory. Templates in this directory will override "solr" resource loader templates.
init.properties.file-
Specifies a properties file name which must exist in the Solr
conf/directory (not under avelocity/subdirectory) or root of a JAR file in a <lib>. params.resource.loader.enabled-
The "params" resource loader allows templates to be specified in Solr request parameters. For example:
http://localhost:8983/solr/gettingstarted/select?q=\*:*&wt=velocity&v.template=custom&v.template.custom=CUSTOM%3A%20%23core_namewhere
v.template=customsays to render a template called "custom" and the value ofv.template.customis the custom template. This isfalseby default; it’d be a niche, unusual, use case to need this enabled. solr.resource.loader.enabled-
The "solr" resource loader is the only template loader registered by default. Templates are served from resources visible to the SolrResourceLoader under a
velocity/subdirectory. The VelocityResponseWriter itself has some built-in templates (in its JAR file, undervelocity/) that are available automatically through this loader. These built-in templates can be overridden when the same template name is in conf/velocity/ or by using thetemplate.base.diroption. tools-
External "tools" can be specified as list of string name/value (tool name / class name) pairs. Tools, in the Velocity context, are simply Java objects. Tool classes are constructed using a no-arg constructor (or a single-SolrCore-arg constructor if it exists) and added to the Velocity context with the specified name.
A custom registered tool can override the built-in context objects with the same name, except for
$request,$response,$page, and$debug(these tools are designed to not be overridden).
VelocityResponseWriter Request Parameters
v.template-
Specifies the name of the template to render.
v.layout-
Specifies a template name to use as the layout around the main,
v.template, specified template.The main template is rendered into a string value included into the layout rendering as
$content. v.layout.enabled-
Determines if the main template should have a layout wrapped around it. The default is
true, but requiresv.layoutto specified as well. v.contentType-
Specifies the content type used in the HTTP response. If not specified, the default will depend on whether
v.jsonis specified or not.The default without
v.json=wrf:text/html;charset=UTF-8.The default with
v.json=wrf:application/json;charset=UTF-8. v.json-
Specifies a function name to wrap around the response rendered as JSON. If specified, the content type used in the response will be "application/json;charset=UTF-8", unless overridden by
v.contentType.Output will be in this format (with
v.json=wrf):wrf("result":"<Velocity generated response string, with quotes and backslashes escaped>") v.locale-
Locale to use with the
$resourcetool and other LocaleConfig implementing tools. The default locale isLocale.ROOT. Localized resources are loaded from standard Java resource bundles namedresources[_locale-code].properties.Resource bundles can be added by providing a JAR file visible by the SolrResourceLoader with resource bundles under a velocity sub-directory. Resource bundles are not loadable under
conf/, as only the class loader aspect of SolrResourceLoader can be used here. v.template.template_name-
When the "params" resource loader is enabled, templates can be specified as part of the Solr request.
VelocityResponseWriter Context Objects
| Context Reference | Description |
|---|---|
|
SolrQueryRequest javadocs |
|
QueryResponse most of the time, but in some cases where QueryResponse doesn’t like the request handler’s output (AnalysisRequestHandler, for example, causes a ClassCastException parsing "response"), the response will be a SolrResponseBase object. |
|
A Velocity EscapeTool instance |
|
A Velocity ComparisonDateTool instance |
|
A Velocity ListTool instance |
|
A Velocity MathTool instance |
|
A Velocity NumberTool instance |
|
A Velocity SortTool instance |
|
A Velocity DisplayTool instance |
|
A Velocity ResourceTool instance |
|
The current VelocityEngine instance |
|
An instance of Solr’s PageTool (only included if the response is a QueryResponse where paging makes sense) |
|
A shortcut to the debug part of the response, or null if debug is not on. This is handy for having debug-only sections in a template using |
|
The rendered output of the main template, when rendering the layout ( |
[custom tool(s)] |
Tools provided by the optional "tools" list of the VelocityResponseWriter registration are available by their specified name. |