Adding parameters to the endpoint url wso2 esb - wso2

Question

I am new to the WSO2 esb. I want to create a api in which i want to add a dynamic parameter from api Url to endpoint url.
My end point url is like http://example.com/api/sync/{session_id}.json
I tried to create api like
<api name="rest" context="/sync">
<resource methods="GET" uri-template="/{id}">
<inSequence>
<log level="full">
<property xmlns:ns="http://org.apache.synapse/xsd"
name="uri.var.session"
expression="get-property('uri.var.id')"
scope="axis2"/>
</log>
<property name="REST_URL_POSTFIX" scope="axis2" action="remove"/>
<send>
<endpoint name="Mecars">
<http trace="enable"
method="get"
uri-template="http://example.com/sync/{+uri.var.session}.json"/>
</endpoint>
</send>
</inSequence>
</resource>
</api>
In log i get the value of uri.var.session But on the endpoint Uri-template it is not appending.
Please guid me how append the {id} value in the api uri-template to end point uri-template?

Answer 1

Check this sample
I recommend you to do string concatenation at property mediator adn use that directly at uri-template, rather adding "variable +.json" at uri-template.
That is;
<property xmlns:ns="http://org.apache.synapse/xsd"
name="uri.var.session"
expression="get-property('uri.var.id')"
scope="axis2"/>
In the above for expression do string concatenation to construct full variable with ".json" ending.

Answer 2

Please remove the '+' symbol from your http end point.Its working fine to me
sample API
<api xmlns="http://ws.apache.org/ns/synapse" name="Elastic Search Using NPI" context="/api/npi/professional/npi.json">
<resource methods="OPTIONS GET" uri-template="/{npi}">
<inSequence>
<log level="full">
<property name="uri.var.npi" expression="get-property('uri.var.npi')"></property>
</log>
<send>
<endpoint>
<http method="get" uri-template="example.com/{uri.var.npi}"></http>
</endpoint>
</send>
</inSequence>
</resource>
</api>

Answer 3

Change the http endpoint uri template like follows.
<http trace="enable" method="get" uri-template="http://example.com/sync/{uri.var.id}.json"></http>
Following is the modified api configuration.
<api xmlns="http://ws.apache.org/ns/synapse" name="rest" context="/sync">
<resource methods="GET" uri-template="/{id}">
<inSequence>
<log level="full">
<property xmlns:ns="http://org.apache.synapse/xsd" name="uri.var.session" expression="get-property('uri.var.id')"></property>
</log>
<property name="REST_URL_POSTFIX" scope="axis2" action="remove"></property>
<send>
<endpoint name="Mecars">
<http trace="enable" method="get" uri-template="http://example.com/sync/{uri.var.id}.json"></http>
</endpoint>
</send>
</inSequence>
</resource>
</api>

Answer 4

You can do the string concatenation at the property mediator as follows.
<property xmlns:ns="http://org.apache.synapse/xsd"
name="uri.var.session"
expression="fn:concat(get-property('uri.var.id'),'.json')"
scope="axis2"/>