[SHIBUI-452]

implement service endpoint

backend/src/main/java/edu/internet2/tier/shibboleth/admin/ui/controller/MetadataProvidersController.java

@@ -0,0 +1,40 @@
+package edu.internet2.tier.shibboleth.admin.ui.controller;
+
+import edu.internet2.tier.shibboleth.admin.ui.service.MetadataResolverService;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.ResponseEntity;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.RequestMapping;
+
+import javax.xml.transform.OutputKeys;
+import javax.xml.transform.Transformer;
+import javax.xml.transform.TransformerException;
+import javax.xml.transform.TransformerFactory;
+import javax.xml.transform.dom.DOMSource;
+import javax.xml.transform.stream.StreamResult;
+import java.io.IOException;
+import java.io.StringWriter;
+
+@Controller
+@RequestMapping(value = "/api/metadataProviders")
+public class MetadataProvidersController {
+    private static final Logger logger = LoggerFactory.getLogger(MetadataProvidersController.class);
+
+    @Autowired
+    MetadataResolverService metadataResolverService;
+
+    @RequestMapping(produces = "application/xml")
+    public ResponseEntity<?> getXml() throws IOException, TransformerException {
+        // TODO: externalize
+        try (StringWriter writer = new StringWriter()) {
+            Transformer transformer = TransformerFactory.newInstance().newTransformer();
+            transformer.setOutputProperty(OutputKeys.INDENT, "yes");
+            transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2");
+
+            transformer.transform(new DOMSource(metadataResolverService.generateConfiguration()), new StreamResult(writer));
+            return ResponseEntity.ok(writer.toString());
+        }
+    }
+}