Improve resources caching

Update controllers to add an ETag information so that meta-data is cached
on the client.

Also enables the compression for json, css and html resources.

Closes gh-165

initializr-service/application.yml

@@ -6,6 +6,12 @@ info:
   spring-boot:
     version: 1.3.0.RELEASE
 
+server:
+  compression:
+    enabled: true
+    mime-types: application/json,text/css,text/html
+    min-response-size: 2048
+
 initializr:
   env:
     boms:

initializr/src/main/groovy/io/spring/initializr/web/MainController.groovy

@@ -16,6 +16,9 @@
 
 package io.spring.initializr.web
 
+import java.nio.charset.StandardCharsets
+import java.util.concurrent.TimeUnit
+
 import groovy.util.logging.Slf4j
 import io.spring.initializr.generator.CommandLineHelpGenerator
 import io.spring.initializr.mapper.InitializrMetadataJsonMapper
@@ -27,11 +30,13 @@ import io.spring.initializr.generator.ProjectRequest
 import io.spring.initializr.metadata.InitializrMetadata
 
 import org.springframework.beans.factory.annotation.Autowired
+import org.springframework.http.CacheControl
 import org.springframework.http.HttpHeaders
 import org.springframework.http.HttpStatus
 import org.springframework.http.MediaType
 import org.springframework.http.ResponseEntity
 import org.springframework.stereotype.Controller
+import org.springframework.util.DigestUtils
 import org.springframework.web.bind.annotation.ModelAttribute
 import org.springframework.web.bind.annotation.RequestHeader
 import org.springframework.web.bind.annotation.RequestMapping
@@ -86,16 +91,20 @@ class MainController extends AbstractInitializrController {
 		def builder = ResponseEntity.ok().contentType(MediaType.TEXT_PLAIN)
 		if (userAgent) {
 			if (userAgent.startsWith(WebConfig.CURL_USER_AGENT_PREFIX)) {
-				return builder.body(commandLineHelpGenerator.generateCurlCapabilities(metadata, appUrl))
+				def content = commandLineHelpGenerator.generateCurlCapabilities(metadata, appUrl)
+				return builder.eTag(createUniqueId(content)).body(content)
 			}
 			if (userAgent.startsWith(WebConfig.HTTPIE_USER_AGENT_PREFIX)) {
-				return builder.body(commandLineHelpGenerator.generateHttpieCapabilities(metadata, appUrl))
+				def content = commandLineHelpGenerator.generateHttpieCapabilities(metadata, appUrl)
+				return builder.eTag(createUniqueId(content)).body(content)
 			}
 			if (userAgent.startsWith(WebConfig.SPRING_BOOT_CLI_AGENT_PREFIX)) {
-				return builder.body(commandLineHelpGenerator.generateSpringBootCliCapabilities(metadata, appUrl))
+				def content = commandLineHelpGenerator.generateSpringBootCliCapabilities(metadata, appUrl)
+				return builder.eTag(createUniqueId(content)).body(content)
 			}
 		}
-		builder.body(commandLineHelpGenerator.generateGenericCapabilities(metadata, appUrl))
+		def content = commandLineHelpGenerator.generateGenericCapabilities(metadata, appUrl)
+		builder.eTag(createUniqueId(content)).body(content)
 	}
 
 	@RequestMapping(value = "/", produces = ["application/hal+json"])
@@ -120,7 +129,8 @@ class MainController extends AbstractInitializrController {
 	private ResponseEntity<String> serviceCapabilitiesFor(InitializrMetadataVersion version, MediaType contentType) {
 		String appUrl = generateAppUrl()
 		def content = getJsonMapper(version).write(metadataProvider.get(), appUrl)
-		return ResponseEntity.ok().contentType(contentType).body(content)
+		return ResponseEntity.ok().contentType(contentType).eTag(createUniqueId(content))
+				.cacheControl(CacheControl.maxAge(7, TimeUnit.DAYS)).body(content)
 	}
 
 	private static InitializrMetadataJsonMapper getJsonMapper(InitializrMetadataVersion version) {
@@ -220,4 +230,10 @@ class MainController extends AbstractInitializrController {
 		result
 	}
 
+	private String createUniqueId(String content) {
+		StringBuilder builder = new StringBuilder()
+		DigestUtils.appendMd5DigestAsHex(content.getBytes(StandardCharsets.UTF_8), builder)
+		builder.toString()
+	}
+
 }

initializr/src/main/groovy/io/spring/initializr/web/UiController.groovy

@@ -16,6 +16,8 @@
 
 package io.spring.initializr.web
 
+import java.nio.charset.StandardCharsets
+
 import groovy.json.JsonBuilder
 import io.spring.initializr.metadata.Dependency
 import io.spring.initializr.metadata.InitializrMetadataProvider
@@ -23,6 +25,9 @@ import io.spring.initializr.util.Version
 import io.spring.initializr.util.VersionRange
 
 import org.springframework.beans.factory.annotation.Autowired
+import org.springframework.http.MediaType
+import org.springframework.http.ResponseEntity
+import org.springframework.util.DigestUtils
 import org.springframework.web.bind.annotation.RequestMapping
 import org.springframework.web.bind.annotation.RequestParam
 import org.springframework.web.bind.annotation.RestController
@@ -40,7 +45,7 @@ class UiController {
 	protected InitializrMetadataProvider metadataProvider
 
 	@RequestMapping(value = "/ui/dependencies", produces = ["application/json"])
-	String dependencies(@RequestParam(required = false) String version) {
+	ResponseEntity<String> dependencies(@RequestParam(required = false) String version) {
 		def dependencyGroups = metadataProvider.get().dependencies.content
 		def content = []
 		Version v = version ? Version.parse(version) : null
@@ -55,7 +60,9 @@ class UiController {
 				}
 			}
 		}
-		writeDependencies(content)
+		def json = writeDependencies(content)
+		ResponseEntity.ok().contentType(MediaType.APPLICATION_JSON).
+				eTag(createUniqueId(json)).body(json)
 	}
 
 	private static String writeDependencies(List<DependencyItem> items) {
@@ -96,4 +103,10 @@ class UiController {
 		}
 	}
 
+	private String createUniqueId(String content) {
+		StringBuilder builder = new StringBuilder()
+		DigestUtils.appendMd5DigestAsHex(content.getBytes(StandardCharsets.UTF_8), builder)
+		builder.toString()
+	}
+
 }

initializr/src/test/groovy/io/spring/initializr/web/MainControllerIntegrationTests.groovy

@@ -24,6 +24,7 @@ import org.junit.Ignore
 import org.junit.Test
 import org.skyscreamer.jsonassert.JSONCompareMode
 
+import org.springframework.http.HttpHeaders
 import org.springframework.http.HttpStatus
 import org.springframework.http.MediaType
 import org.springframework.http.ResponseEntity
@@ -32,6 +33,7 @@ import org.springframework.web.client.HttpClientErrorException
 
 import static org.hamcrest.CoreMatchers.allOf
 import static org.hamcrest.CoreMatchers.containsString
+import static org.hamcrest.CoreMatchers.nullValue
 import static org.hamcrest.core.IsNot.not
 import static org.junit.Assert.assertEquals
 import static org.junit.Assert.assertFalse
@@ -169,6 +171,7 @@ class MainControllerIntegrationTests extends AbstractInitializrControllerIntegra
 	@Test
 	void metadataWithCurrentAcceptHeader() {
 		ResponseEntity<String> response = invokeHome(null, 'application/vnd.initializr.v2.1+json')
+		assertThat(response.getHeaders().getFirst(HttpHeaders.ETAG), not(nullValue()))
 		validateContentType(response, CURRENT_METADATA_MEDIA_TYPE)
 		validateCurrentMetadata(new JSONObject(response.body))
 	}
@@ -184,6 +187,7 @@ class MainControllerIntegrationTests extends AbstractInitializrControllerIntegra
 	@Test
 	void metadataWithHalAcceptHeader() {
 		ResponseEntity<String> response = invokeHome(null, 'application/hal+json')
+		assertThat(response.getHeaders().getFirst(HttpHeaders.ETAG), not(nullValue()))
 		validateContentType(response, MainController.HAL_JSON_CONTENT_TYPE)
 		validateCurrentMetadata(new JSONObject(response.body))
 	}
@@ -283,6 +287,7 @@ class MainControllerIntegrationTests extends AbstractInitializrControllerIntegra
 
 	private void validateCurlHelpContent(ResponseEntity<String> response) {
 		validateContentType(response, MediaType.TEXT_PLAIN)
+		assertThat(response.getHeaders().getFirst(HttpHeaders.ETAG), not(nullValue()))
 		assertThat(response.body, allOf(
 				containsString("Spring Initializr"),
 				containsString('Examples:'),
@@ -291,6 +296,7 @@ class MainControllerIntegrationTests extends AbstractInitializrControllerIntegra
 
 	private void validateHttpIeHelpContent(ResponseEntity<String> response) {
 		validateContentType(response, MediaType.TEXT_PLAIN)
+		assertThat(response.getHeaders().getFirst(HttpHeaders.ETAG), not(nullValue()))
 		assertThat(response.body, allOf(
 				containsString("Spring Initializr"),
 				containsString('Examples:'),
@@ -300,6 +306,7 @@ class MainControllerIntegrationTests extends AbstractInitializrControllerIntegra
 
 	private void validateGenericHelpContent(ResponseEntity<String> response) {
 		validateContentType(response, MediaType.TEXT_PLAIN)
+		assertThat(response.getHeaders().getFirst(HttpHeaders.ETAG), not(nullValue()))
 		assertThat(response.body, allOf(
 				containsString("Spring Initializr"),
 				not(containsString('Examples:')),
@@ -308,6 +315,7 @@ class MainControllerIntegrationTests extends AbstractInitializrControllerIntegra
 
 	private void validateSpringBootHelpContent(ResponseEntity<String> response) {
 		validateContentType(response, MediaType.TEXT_PLAIN)
+		assertThat(response.getHeaders().getFirst(HttpHeaders.ETAG), not(nullValue()))
 		assertThat(response.body, allOf(
 				containsString("Service capabilities"),
 				containsString("Supported dependencies"),