RequestDispatcher
The requestDispatcher
element of solrconfig.xml
controls the way the Solr HTTP RequestDispatcher
implementation responds to requests.
Included are parameters for defining if it should handle /select
urls (for Solr 1.1 compatibility), if it will support remote streaming, the maximum size of file uploads and how it will respond to HTTP cache headers in requests.
handleSelect Element
|
The first configurable item is the handleSelect
attribute on the <requestDispatcher>
element itself.
This attribute can be set to one of two values, either "true" or "false".
It governs how Solr responds to requests such as /select?qt=XXX
.
The default value "false" will ignore requests to /select
if a request handler is not explicitly registered with the name /select
.
A value of "true" will route query requests to the parser defined with the qt
value if a request handler is not explicitly registered with the name /select
.
In recent versions of Solr, a /select
request handler is defined by default, so a value of "false" will work fine.
See the section Request Handlers and Search Components for more information.
<requestDispatcher handleSelect="true" >
...
</requestDispatcher>
requestParsers Element
The <requestParsers>
sub-element controls values related to parsing requests.
This is an empty XML element that doesn’t have any content, only attributes.
multipartUploadLimitInKB
-
Optional
Default:
-1
This attribute sets an upper limit in kilobytes on the size of a document that may be submitted in a multi-part HTTP POST request. The value specified is multiplied by 1024 to determine the size in bytes. A value of
-1
means MAX_INT, which is also the system default if omitted. formdataUploadLimitInKB
-
Optional
Default:
-1
This attribute sets a limit in kilobytes on the size of form data (
application/x-www-form-urlencoded
) submitted in a HTTP POST request, which can be used to pass request parameters that will not fit in a URL. A value of-1
means MAX_INT, which is also the system default if omitted. addHttpRequestToContext
-
Optional
Default: none
This attribute can be used to indicate that the original
HttpServletRequest
object should be included in the context map of theSolrQueryRequest
using the keyhttpRequest
. ThisHttpServletRequest
is not used by any Solr component, but may be useful when developing custom plugins.
<requestParsers multipartUploadLimitInKB="2048"
formdataUploadLimitInKB="2048"
addHttpRequestToContext="false" />
httpCaching Element
The <httpCaching>
element controls HTTP cache control headers.
Do not confuse these settings with Solr’s internal cache configuration.
This element controls caching of HTTP responses as defined by the W3C HTTP specifications.
This element allows for three attributes and one sub-element.
The attributes of the <httpCaching>
element control whether a 304 response to a GET request is allowed, and if so, what sort of response it should be.
When an HTTP client application issues a GET, it may optionally specify that a 304 response is acceptable if the resource has not been modified since the last time it was fetched.
never304
-
Optional
Default: none
If present with the value
true
, then a GET request will never respond with a 304 code, even if the requested resource has not been modified. When this attribute is set totrue
, the next two attributes are ignored. Setting this totrue
is handy for development, as the 304 response can be confusing when tinkering with Solr responses through a web browser or other client that supports cache headers. lastModFrom
-
Optional
Default:
openTime
This attribute may be set to either
openTime
ordirLastMod
.The value
openTime
indicates that last modification times, as compared to the If-Modified-Since header sent by the client, should be calculated relative to the time the Searcher started.Use
dirLastMod
if you want times to exactly correspond to when the index was last updated on disk. etagSeed
-
Optional
Default: none
This value of this attribute is sent as the value of the
ETag
header. Changing this value can be helpful to force clients to re-fetch content even when the indexes have not changed; for example, when you’ve made some changes to the configuration.
<httpCaching never304="false"
lastModFrom="openTime"
etagSeed="Solr">
<cacheControl>max-age=30, public</cacheControl>
</httpCaching>
cacheControl Element
In addition to these attributes, <httpCaching>
accepts one child element: <cacheControl>
.
The content of this element will be sent as the value of the Cache-Control header on HTTP responses.
This header is used to modify the default caching behavior of the requesting client.
The possible values for the Cache-Control header are defined by the HTTP 1.1 specification in Section 14.9.
Setting the max-age field controls how long a client may re-use a cached response before requesting it again from the server.
This time interval should be set according to how often you update your index and whether or not it is acceptable for your application to use content that is somewhat out of date.
Setting must-revalidate
will tell the client to validate with the server that its cached copy is still good before re-using it.
This will ensure that the most timely result is used, while avoiding a second fetch of the content if it isn’t needed, at the cost of a request to the server to do the check.