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Posted to commits@camel.apache.org by ac...@apache.org on 2016/08/25 10:24:51 UTC
[2/6] camel git commit: Added javascript language to gitbook
Added javascript language to gitbook
Project: http://git-wip-us.apache.org/repos/asf/camel/repo
Commit: http://git-wip-us.apache.org/repos/asf/camel/commit/705951bf
Tree: http://git-wip-us.apache.org/repos/asf/camel/tree/705951bf
Diff: http://git-wip-us.apache.org/repos/asf/camel/diff/705951bf
Branch: refs/heads/master
Commit: 705951bf05f9df52b5e7392bad8cc394b6077e38
Parents: f70ae04
Author: Andrea Cosentino <an...@gmail.com>
Authored: Thu Aug 25 12:09:21 2016 +0200
Committer: Andrea Cosentino <an...@gmail.com>
Committed: Thu Aug 25 12:09:21 2016 +0200
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.../src/main/docs/javaScript-language.adoc | 199 +++++++++++++++++++
1 file changed, 199 insertions(+)
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http://git-wip-us.apache.org/repos/asf/camel/blob/705951bf/components/camel-script/src/main/docs/javaScript-language.adoc
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diff --git a/components/camel-script/src/main/docs/javaScript-language.adoc b/components/camel-script/src/main/docs/javaScript-language.adoc
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+[[JavaScript-JavaScript]]
+JavaScript
+~~~~~~~~~~
+
+Camel supports
+http://en.wikipedia.org/wiki/JavaScript[JavaScript/ECMAScript] among
+other link:scripting-languages.html[Scripting Languages] to allow an
+link:expression.html[Expression] or link:predicate.html[Predicate] to be
+used in the link:dsl.html[DSL] or link:xml-configuration.html[Xml
+Configuration].
+
+To use a JavaScript expression use the following Java code
+
+[source,java]
+-----------------------------------------------
+... javaScript("someJavaScriptExpression") ...
+-----------------------------------------------
+
+For example you could use the *javaScript* function to create an
+link:predicate.html[Predicate] in a link:message-filter.html[Message
+Filter] or as an link:expression.html[Expression] for a
+link:recipient-list.html[Recipient List]
+
+[[JavaScript-Language-options]]
+Javascript Language Options
+^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+// language options: START
+The JavaScript language supports 1 options which are listed below.
+
+
+
+{% raw %}
+[width="100%",cols="2,1m,1m,6",options="header"]
+|=======================================================================
+| Name | Default | Java Type | Description
+| trim | true | Boolean | Whether to trim the value to remove leading and trailing whitespaces and line breaks
+|=======================================================================
+{% endraw %}
+// language options: END
+
+[[JavaScript-Example]]
+Example
+^^^^^^^
+
+In the sample below we use JavaScript to create a
+link:predicate.html[Predicate] use in the route path, to route exchanges
+from admin users to a special queue.
+
+[source,java]
+----------------------------------------------------------------------------------------------
+ from("direct:start")
+ .choice()
+ .when().javaScript("request.headers.get('user') == 'admin'").to("seda:adminQueue")
+ .otherwise()
+ .to("seda:regularQueue");
+----------------------------------------------------------------------------------------------
+
+And a Spring DSL sample as well:
+
+[source,xml]
+-------------------------------------------------------------------------------
+ <route>
+ <from uri="direct:start"/>
+ <choice>
+ <when>
+ <javaScript>request.headers.get('user') == 'admin'</javaScript>
+ <to uri="seda:adminQueue"/>
+ </when>
+ <otherwise>
+ <to uri="seda:regularQueue"/>
+ </otherwise>
+ </choice>
+ </route>
+-------------------------------------------------------------------------------
+
+[[JavaScript-ScriptContext]]
+ScriptContext
+^^^^^^^^^^^^^
+
+The JSR-223 scripting languages ScriptContext is pre configured with the
+following attributes all set at `ENGINE_SCOPE`:
+
+[width="100%",cols="10%,10%,80%",options="header",]
+|=======================================================================
+|Attribute |Type |Value
+
+|context |`org.apache.camel.CamelContext` |The Camel Context ( It cannot be used in groovy)
+
+|camelContext |`org.apache.camel.CamelContext` |The Camel Context
+
+|exchange |`org.apache.camel.Exchange` |The current Exchange
+
+|request |`org.apache.camel.Message` |The message (IN message)
+
+|response |`org.apache.camel.Message` |*Deprecated*: The OUT message. The OUT message if null by default. Use
+IN message instead.
+
+|properties |`org.apache.camel.builder.script.PropertiesFunction` |*Camel 2.9:* Function with a `resolve` method to make it easier to use
+Camels link:properties.html[Properties] component from scripts. See
+further below for example.
+|=======================================================================
+
+See link:scripting-languages.html[Scripting Languages] for the list of
+languages with explicit DSL support.
+
+[[JavaScript-AdditionalargumentstoScriptingEngine]]
+Additional arguments to ScriptingEngine
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+*Available as of Camel 2.8*
+
+You can provide additional arguments to the `ScriptingEngine` using a
+header on the Camel message with the key `CamelScriptArguments`. +
+ See this example:
+
+[[JavaScript-Usingpropertiesfunction]]
+Using properties function
+^^^^^^^^^^^^^^^^^^^^^^^^^
+
+*Available as of Camel 2.9*
+
+If you need to use the link:properties.html[Properties] component from a
+script to lookup property placeholders, then its a bit cumbersome to do
+so. +
+ For example to set a header name myHeader with a value from a property
+placeholder, which key is provided in a header named "foo".
+
+[source,java]
+--------------------------------------------------------------------------------------------------------------
+.setHeader("myHeader").groovy("context.resolvePropertyPlaceholders('{{' + request.headers.get('foo') + '}}')")
+--------------------------------------------------------------------------------------------------------------
+
+From Camel 2.9 onwards you can now use the properties function and the
+same example is simpler:
+
+[source,java]
+-------------------------------------------------------------------------------
+.setHeader("myHeader").groovy("properties.resolve(request.headers.get('foo'))")
+-------------------------------------------------------------------------------
+
+[[JavaScript-Loadingscriptfromexternalresource]]
+Loading script from external resource
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+*Available as of Camel 2.11*
+
+You can externalize the script and have Camel load it from a resource
+such as `"classpath:"`, `"file:"`, or `"http:"`. +
+ This is done using the following syntax: `"resource:scheme:location"`,
+eg to refer to a file on the classpath you can do:
+
+[source,java]
+-------------------------------------------------------------------
+.setHeader("myHeader").groovy("resource:classpath:mygroovy.groovy")
+-------------------------------------------------------------------
+
+[[JavaScript-Howtogettheresultfrommultiplestatementsscript]]
+How to get the result from multiple statements script
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+*Available as of Camel 2.14*
+
+As the scripteengine evale method just return a Null if it runs a
+multiple statments script. Camel now look up the value of script result
+by using the key of "result" from the value set. If you have multiple
+statements script, you need to make sure you set the value of result
+variable as the script return value.
+
+[source,text]
+-------------------------------------------------------------
+bar = "baz";
+# some other statements ...
+# camel take the result value as the script evaluation result
+result = body * 2 + 1
+-------------------------------------------------------------
+
+�
+
+[[JavaScript-Dependencies]]
+Dependencies
+^^^^^^^^^^^^
+
+To use scripting languages in your camel routes you need to add the a
+dependency on *camel-script* which integrates the JSR-223 scripting
+engine.
+
+If you use maven you could just add the following to your pom.xml,
+substituting the version number for the latest & greatest release (see
+link:download.html[the download page for the latest versions]).
+
+[source,xml]
+---------------------------------------
+<dependency>
+ <groupId>org.apache.camel</groupId>
+ <artifactId>camel-script</artifactId>
+ <version>x.x.x</version>
+</dependency>
+---------------------------------------