Merge pull request #122 from networknt/121-path-params-are-not-present-proxy-event-object-when-light-native-lambda-deployed-behind-aws-load-balancer

Added method of resolving path parameters and attaching them to the request event.

Author: stevehu

src/main/java/com/networknt/aws/lambda/handler/middleware/specification/OpenApiMiddleware.java

@@ -61,6 +61,9 @@ public Status execute(LightLambdaExchange exchange) {
         final NormalisedPath openApiPathString = maybeApiPath.get();
         final Path path = helper.openApi3.getPath(openApiPathString.original());
 
+        /* populate the event with the path parameter values. */
+        exchange.getRequest().setPathParameters(this.getPathParamsMap(requestPath, openApiPathString));
+
         final String httpMethod = exchange.getRequest().getHttpMethod().toLowerCase();
         final Operation operation = path.getOperation(httpMethod);
 
@@ -85,6 +88,41 @@ public Status execute(LightLambdaExchange exchange) {
         return successMiddlewareStatus();
     }
 
+    /**
+     * Grabs the path parameters from the original path based on the provided specification path.
+     *
+     * @param original - The original path containing potential parameter values.
+     * @param specPath - The specification path that contains potential parameter keys.
+     * @return - returns a map containing the path parameter names and values.
+     */
+    private Map<String, String> getPathParamsMap(final NormalisedPath original, final NormalisedPath specPath) {
+
+        if (!specPath.original().contains("{")) {
+            LOG.debug("Provided path does not contain any path parameters.");
+            return new HashMap<>();
+
+        } else if (original.parts().size() != specPath.parts().size()) {
+            LOG.warn("Number of path parts in original does not match the specification.");
+            return new HashMap<>();
+        }
+
+        final var params = new HashMap<String, String>();
+        final var originalParts = original.parts();
+        final var specParts = specPath.parts();
+
+        for (int x = 0; x < original.parts().size(); x++) {
+            final var specPart = specParts.get(x);
+
+            if (specPart.startsWith("{") && specPart.endsWith("}")) {
+                final var paramKey = specPart.substring(1, specPart.length() - 1);
+                final var pathParamValue = originalParts.get(x);
+                LOG.trace("Specification path part {} with a key of {} and a value of {}", x, paramKey, pathParamValue);
+                params.put(paramKey, pathParamValue);
+            }
+        }
+        return params;
+    }
+
     /**
      * Validates the injectMap and openapiMap.Throws an exception if not valid.
      *

src/test/java/com/networknt/aws/lambda/middleware/specification/OpenApiMiddlewareTest.java

@@ -22,6 +22,7 @@
 
 public class OpenApiMiddlewareTest {
     private static final Logger LOG = LoggerFactory.getLogger(OpenApiMiddlewareTest.class);
+
     @Test
     public void testConstructor() {
         OpenApiMiddleware openApiMiddleware = new OpenApiMiddleware();
@@ -57,4 +58,37 @@ public void testOpenApiMiddleware() {
         Assertions.assertNotNull(openApiOperation);
 
     }
+
+    @Test
+    public void testOpenApiMiddlewarePathParams() {
+        var requestEvent = TestUtils.createTestRequestEvent();
+        requestEvent.setPath("/v1/pets/44");
+        requestEvent.setHttpMethod("GET");
+
+        InvocationResponse invocation = InvocationResponse.builder()
+                .requestId("12345")
+                .event(requestEvent)
+                .build();
+
+        Context lambdaContext = new LambdaContext(invocation.getRequestId());
+        final var exchange = new LightLambdaExchange(lambdaContext, null);
+        exchange.setInitialRequest(requestEvent);
+        OpenApiMiddleware openApiMiddleware = new OpenApiMiddleware();
+        openApiMiddleware.execute(exchange);
+        requestEvent = exchange.getRequest();
+        Assertions.assertNotNull(requestEvent);
+
+        Map<String, Object> auditInfo = (Map<String, Object>)exchange.getAttachment(AUDIT_ATTACHMENT_KEY);;
+        Assertions.assertNotNull(auditInfo);
+        String endpoint = (String)auditInfo.get(Constants.ENDPOINT_STRING);
+        Assertions.assertNotNull(endpoint);
+        Assertions.assertEquals("/pets/{petId}@get", endpoint);
+
+        final var pathParameter = requestEvent.getPathParameters().get("petId");
+        Assertions.assertNotNull(pathParameter);
+        Assertions.assertEquals("44", pathParameter);
+
+        Object openApiOperation = auditInfo.get(Constants.OPENAPI_OPERATION_STRING);
+        Assertions.assertNotNull(openApiOperation);
+    }
 }