Friday, March 28, 2014

Fixing issue in WSO2 API Manager due to matching resource found or API authentication failure for a API call with valid access token

 

No matching resource found error or authentication failure can happen due to few reasons. Here we will discuss about errors can happen due to resource define

Here in this article we will see how resource mapping work in WSO2 API Manager. When you create API with resource we will store them in API Manager database and synapse configuration. When some request comes to gateway it will first look for matching resource and then dispatch to inside that. For this scenario resource is as follows.

/resource1/*

In this configuration * means you can have any string(in request url) after that point. If we take your first resource sample then matching request would be something like this.

http://gatewayhostname:8280/t/test.com/apicontext/resource1/

Above request is the minimum matching request. In addition to that following requests also will map to this resource.

http://gatewayhostname:8280/t/test.com/apicontext/resource1/data?name=value

http://gatewayhostname:8280/t/test.com/apicontext/resource1/data?name=value&id=97

And following requests will not map properly to this resource. The reason for this is we specifically expecting /resource1/ in the request(* means you can have any string after that point).

http://gatewayhostname:8280/t/test.com/apicontext/resource1?name=value&id=97

From the web service call you will get following error response.

<am:fault xmlns:am="403Status'>http://wso2.org/apimanager"><am:code>403</am:code><am:type>Status report</am:type><am:message>Runtime Error</am:message><am:description>No matching resource found in the API for the given request</am:description></am:fault>

If you sent request to t/test.com/apicontext/1.0/resource1?id=97&Token=cd it will not work. Because unfortunately there is no matching resource for that. Because as i explained earlier you resource definition is having  /resource1/*. Then request will not map to any resource and you will get no matching resource found error and auth failure(because trying to authenticate against none existing resource).

Solution for this issue would be something like this.

In API Manager we do support both uri-template and url mapping support. If you create API from API Publisher user interface then it will create url-mapping based definition. From API Manager 1.7.0 on wards we will support both options from UI level. Normally when we need to do some kind of complex pattern matching we use uri-template. So here we will update synapse configuration to use uri-template instead of url-mapping. For this edit wso2admin-AT-test.com--apicontext_v1.0.xml file as follows.

Replace <resource methods="GET" url-mapping="/resource1/*"> with <resource methods="GET" uri-template="/resource1?*">

Hope this will help you to to understand how resource mapping work. You will find more information from this link[1]

[1]http://charithaka.blogspot.com/2014/03/common-mistakes-to-avoid-in-wso2-api.html

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