NOTE: SEE MY OWN ANSWER BELOW
I have been looking through the slim documentation for hours. What I need is this:
I have an incoming GET request from a system that can ONLY send GET requests. My back-end service requires a POST request.
Can someone point me in the right direction in regards to what APIM policy I should be using or a combination of policies.
I am using the policy reference but still can't come up with a decent solution: https://msdn.microsoft.com/en-us/library/azure/dn894081.aspx
I found a solution to this.
Here is the scenario: I have a requirement for a client to call an APIM endpoint and only get simple responses back. ie.... authenticated = true / false.
I have an incoming GET request from a system that can ONLY send GET requests. My back-end service requires a POST request.
Here is my GET call from a client that can only send GET requests: https:///api/v1//10010810?pin=1212&property=Sydney&subscription-key=XXXXXXXXXXXXXX&debugging=1
Here is my policy:
<policies>
<inbound>
<set-header name="Content-Type" exists-action="override">
<value>application/json</value>
</set-header>
<trace source="defaultTrace">
@{
return System.String.Format("The passed in querystring paramters were | pin: {0} | debugging: {1} | property: {2} | subscription-key: {3}",
context.Request.Url.Query.GetValueOrDefault("pin"),
context.Request.Url.Query.GetValueOrDefault("debugging"),
context.Request.Url.Query.GetValueOrDefault("property"),
context.Request.Url.Query.GetValueOrDefault("subscription-key")
);
}
</trace>
<set-variable name="requestPin" value="@(context.Request.Url.Query.GetValueOrDefault("pin"))" />
<set-variable name="debugging" value="@(context.Request.Url.Query.GetValueOrDefault("debugging"))" />
<trace source="defaultTrace">
@{
return System.String.Format(
"Removing the following querystring parameters from url as we don't want to pass these ones to the backend service debugging: {0} | subscription-key: {1} | pin: {2}",
context.Request.Url.Query.GetValueOrDefault("debugging"),
context.Request.Url.Query.GetValueOrDefault("subscription-key"),
context.Request.Url.Query.GetValueOrDefault("pin")
);
}
</trace>
<set-query-parameter name="subscription-key" exists-action="delete" />
<set-query-parameter name="debugging" exists-action="delete" />
<set-query-parameter name="pin" exists-action="delete" />
<base />
</inbound>
<backend>
<!-- Setup a response-variable-name to hold the response from the backend service-->
<send-request mode="copy" response-variable-name="microservice-response" timeout="20" ignore-error="false">
<!-- Set the method to POST as the backend service MUST receive a POST call-->
<set-method>POST</set-method>
<set-body>
@{
// Get the pin from the url as we need it to construct the POST body
var requestPin = context.Variables.GetValueOrDefault<string>("requestPin");
var postBody = new JObject(
new JProperty("Type", "Pin"),
new JProperty("Value", requestPin)
).ToString();
return postBody;
}
</set-body>
</send-request>
</backend>
<outbound>
<choose>
<when condition="@(((IResponse)context.Variables["microservice-response"]).StatusCode == 200)">
<!-- When the micro-service returned a valid response we put the response into the previously created variable called microservice-response -->
<return-response>
<set-status code="200" reason="Ok" />
<set-body>
@{
var debuggingVariable = context.Variables.GetValueOrDefault<string>("debugging");
var microserviceResponse = ((IResponse)context.Variables["microservice-response"]).Body.As<JObject>();
if(debuggingVariable == "1")
{
var returnResponse = new JObject(
new JProperty("Authenticated", true),
new JProperty("MicroserviceResponse", microserviceResponse),
new JProperty("StatusCode", ((IResponse)context.Variables["microservice-response"]).StatusCode)
).ToString();
return returnResponse.ToString();
}
else
{
var returnResponse = new JObject(new JProperty("Authenticated", true)).ToString();
return returnResponse.ToString();
}
}
</set-body>
</return-response>
</when>
<when condition="@(((IResponse)context.Variables["microservice-response"]).StatusCode == 401)">
<!-- When the micro-service returned a valid response we put the response into the previously created variable called microservice-response -->
<return-response>
<set-status code="401" reason="Error" />
<set-body>
@{
var debuggingVariable = context.Variables.GetValueOrDefault<string>("debugging");
var microserviceResponse = ((IResponse)context.Variables["microservice-response"]);
if(debuggingVariable == "1")
{
var returnResponse = new JObject(
new JProperty("Authenticated", false),
new JProperty("MicroserviceResponse", microserviceResponse.Body.As<JObject>().ToString()),
new JProperty("StatusCode", ((IResponse)context.Variables["microservice-response"]).StatusCode)
).ToString();
return returnResponse.ToString();
}
else
{
var returnResponse = new JObject(new JProperty("Authenticated", false)).ToString();
return returnResponse.ToString();
}
}
</set-body>
</return-response>
</when>
<when condition="@(((IResponse)context.Variables["microservice-response"]).StatusCode == 400)">
<!-- When the micro-service returned a valid response we put the response into the previously created variable called microservice-response -->
<return-response>
<set-status code="200" reason="Ok" />
<set-body>
@{
var debuggingVariable = context.Variables.GetValueOrDefault<string>("debugging");
var microserviceResponse = ((IResponse)context.Variables["microservice-response"]);
if(debuggingVariable == "1")
{
var returnResponse = new JObject(
new JProperty("Authenticated", false),
new JProperty("MicroserviceResponse", microserviceResponse.Body.As<JObject>().ToString()),
new JProperty("StatusCode", ((IResponse)context.Variables["microservice-response"]).StatusCode)
).ToString();
return returnResponse.ToString();
}
else
{
var returnResponse = new JObject(new JProperty("Authenticated", false)).ToString();
return returnResponse.ToString();
}
}
</set-body>
</return-response>
</when>
<otherwise>
<return-response>
<!-- When the micro-service threw an exception we just want to show the caller Authenticated = false -->
<!--<set-status code="500" reason="Error" />-->
<set-body>
@{
var debuggingVariable = context.Variables.GetValueOrDefault<string>("debugging");
var microserviceResponse = ((IResponse)context.Variables["microservice-response"]);
if(debuggingVariable == "1")
{
var returnResponse = new JObject(
new JProperty("Authenticated", false),
new JProperty("MicroserviceResponse", microserviceResponse.Body.As<JObject>().ToString()),
new JProperty("StatusCode", ((IResponse)context.Variables["microservice-response"]).StatusCode)
).ToString();
return returnResponse.ToString();
}
else
{
var returnResponse = new JObject(new JProperty("Authenticated", false)).ToString();
return returnResponse.ToString();
}
}
</set-body>
</return-response>
</otherwise>
</choose>
<base />
</outbound>
<on-error>
<!-- When APIM threw an exception -->
<trace source="defaultTrace">
@{
var returnResponse = new JObject
(
new JProperty("Authenticated", false),
new JProperty("Source", context.LastError.Source),
new JProperty("Reason", context.LastError.Reason),
new JProperty("Message", context.LastError.Message),
new JProperty("Scope", context.LastError.Scope),
new JProperty("Section", context.LastError.Section),
new JProperty("Path", context.LastError.Path),
new JProperty("PolicyId", context.LastError.PolicyId)
).ToString();
return returnResponse.ToString();
}
</trace>
<return-response>
<set-status code="500" reason="Error" />
<set-body>
@{
var debuggingVariable = context.Variables.GetValueOrDefault<string>("debugging");
if(debuggingVariable == "1")
{
var returnResponse = new JObject
(
new JProperty("Authenticated", false),
new JProperty("Source", context.LastError.Source),
new JProperty("Reason", context.LastError.Reason),
new JProperty("Message", context.LastError.Message),
new JProperty("Scope", context.LastError.Scope),
new JProperty("Section", context.LastError.Section),
new JProperty("Path", context.LastError.Path),
new JProperty("PolicyId", context.LastError.PolicyId)
).ToString();
return returnResponse.ToString();
}
else
{
var returnResponse = new JObject(new JProperty("Authenticated", false)).ToString();
return returnResponse.ToString();
}
}
</set-body>
</return-response>
</on-error>
The policy does the following:
IN-BOUND
BACK-END - Send Request
OUT-BOUND
ON-ERROR
Here is an example of context.LastError:
I hope this helps someone as it took me a long time to get to this point. The documentation on this is good but there is not much out there
You can use the tag to change the HTTP method for a request. Please refer to https://msdn.microsoft.com/en-us/library/azure/dn894085.aspx#SetRequestMethod for more info
