Cannot send request in mediation synapse in wso2 apim - wso2

Question

We have two ways to send requests in wso2 APIM:
1- send mediator
2- call mediator
Unfortunately, I cannot use any of these mediators!
for example this request: http://jsonplaceholder.typicode.com/posts/
I need this approach for get token from a server and then use it in payload of main request for authentication.
could anyone help me please?! :)
I didn't get any error or special log!
<log level="custom">
<property name="text" value="###############################33"/>
</log>
<call blocking="false">
<endpoint>
<http method="GET" uri-template="http://jsonplaceholder.typicode.com/posts/"/>
</endpoint>
</call>
<log level="custom">
<property name="text" value="###############################"/>
</log>

Answer 1

You could find related blogs "WSO2 API Manager & OAuth2 Protected Endpoint" and answer to this question
The idea is to
call the token endpoint with the appropriate grant type(usually client secret grant is used for system to system calls).
Then extract the token using the script mediator
Then use the that token to call the API attaching the token to "Authorisation Bearer:" header.
Please give this a try.

Answer 2

Let's use the below properties before the call mediator. If your response is not a json payload, you need to set the expected payload content type to the ContentType and messageType properties.
<property action="remove" name="NO_ENTITY_BODY" scope="axis2"/>
<property name="ContentType" scope="axis2" value="application/json"/>
<property name="messageType" scope="axis2" value="application/json"/>
After adding the above properties into the sequence, it should look like the below.
<sequence>
<property action="remove" name="NO_ENTITY_BODY" scope="axis2"/>
<property name="ContentType" scope="axis2" value="application/json"/>
<property name="messageType" scope="axis2" value="application/json"/>
<call blocking="true">
<endpoint>
<http method="GET"
uri-template="http://www.mocky.io/v2/5c9ddf51330000b12c3f253a"/>
</endpoint>
</call>
</sequence>