Azure APIM URL rewrite with Dynamic Path from Payload

Question

I need to rewrite URL with a value from payload.
Below code is not working.
Error:
rewrite-uri (0.122 ms) { "messages": [ null, "Variable variables.dynamicValue has no value.", "Variable variables.dynamicValue has no value." ] }

Able to fetch value from payload using set-variable.

set-variable (0.002 ms) { "message": "Context variable was successfully set.", "name": "dynamicValue", "value": "1234" }

<policies>
    <inbound>
        <base />
        <!-- Extract value from the payload -->
        <set-variable name="dynamicValue" value="@{
            var requestBody = context.Request.Body.As<JObject>();
            return requestBody.GetValue('ValuationID');
        }" />

        <!-- Rewrite the URI dynamically using the extracted value -->
        <rewrite-uri template="/newpath/@{variables.dynamicValue}" />
    </inbound>
    <backend>
        <base />
    </backend>
    <outbound>
        <base />
    </outbound>
    <on-error>
        <base />
    </on-error>
</policies>

Answer 1

Hi @Avula, Akhila,

Below is my api and policy which takes body payload:

API:

{
    "openapi": "3.0.1",
    "info": {
        "title": "TestAPi",
        "description": "API to test dynamic URL rewriting in APIM",
        "version": "1.0"
    },
    "servers": [{
        "url": "https://testapirith.azure-api.net/anything"
    }],
    "paths": {
        "/valuation": {
            "get": {
                "summary": "Get valuation by ValuationID",
                "description": "Get valuation by ValuationID",
                "operationId": "GetValuation",
                "responses": {
                    "200": {
                        "description": "Success"
                    }
                }
            }
        }
    },
    "components": {
        "securitySchemes": {
            "apiKeyHeader": {
                "type": "apiKey",
                "name": "Ocp-Apim-Subscription-Key",
                "in": "header"
            },
            "apiKeyQuery": {
                "type": "apiKey",
                "name": "subscription-key",
                "in": "query"
            }
        }
    },
    "security": [{
        "apiKeyHeader": []
    }, {
        "apiKeyQuery": []
    }]
}

Policy:

<policies>
    <inbound>
        <base />
        <set-variable name="rithtest" value="@((string)context.Request.OriginalUrl.Query.GetValueOrDefault("ValuationID"))" />
        <rewrite-uri template="/anything/@(context.Variables["rithtest"])" />
    </inbound>
    <backend>
        <base />
    </backend>
    <outbound>
        <base />
    </outbound>
    <on-error>
        <base />
    </on-error>
</policies>

Output:

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