change streaming support back to RestTemplate

pom.xml

@@ -266,10 +266,6 @@
       <artifactId>spring-security-jwt</artifactId>
       <version>1.0.9.RELEASE</version>
     </dependency>
-    <dependency>
-      <groupId>org.springframework.boot</groupId>
-      <artifactId>spring-boot-starter-webflux</artifactId>
-    </dependency>
 
     <!-- Apache HTTP -->
     <dependency>

src/main/java/ch/ethz/seb/sebserver/gui/service/remote/AbstractDownloadServiceHandler.java

@@ -8,6 +8,8 @@
 
 package ch.ethz.seb.sebserver.gui.service.remote;
 
+import java.io.OutputStream;
+
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
@@ -49,25 +51,32 @@ public abstract class AbstractDownloadServiceHandler implements DownloadServiceH
                     configId,
                     downloadFileName);
 
-            final byte[] configFile = webserviceCall(configId);
-
-            if (configFile == null) {
-                log.error("No or empty download received from webservice. Download request is ignored");
-                return;
-            }
-
-            log.debug("Sucessfully downloaded from webservice. File size: {}", configFile.length);
-
-            response.setContentType(MediaType.APPLICATION_OCTET_STREAM_VALUE);
-            response.setContentLength(configFile.length);
-
             final String header =
                     "attachment; filename=\"" + Utils.preventResponseSplittingAttack(downloadFileName) + "\"";
             response.setHeader(HttpHeaders.CONTENT_DISPOSITION, header);
+            response.setContentType(MediaType.APPLICATION_OCTET_STREAM_VALUE);
 
-            log.debug("Write the download data to response output");
+            webserviceCall(configId, response.getOutputStream());
 
-            response.getOutputStream().write(configFile);
+//            final byte[] configFile = webserviceCall(configId);
+//
+//            if (configFile == null) {
+//                log.error("No or empty download received from webservice. Download request is ignored");
+//                return;
+//            }
+//
+//            log.debug("Sucessfully downloaded from webservice. File size: {}", configFile.length);
+//
+//            response.setContentType(MediaType.APPLICATION_OCTET_STREAM_VALUE);
+//            response.setContentLength(configFile.length);
+//
+//            final String header =
+//                    "attachment; filename=\"" + Utils.preventResponseSplittingAttack(downloadFileName) + "\"";
+//            response.setHeader(HttpHeaders.CONTENT_DISPOSITION, header);
+//
+//            log.debug("Write the download data to response output");
+//
+//            response.getOutputStream().write(configFile);
 
         } catch (final Exception e) {
             log.error(
@@ -76,6 +85,6 @@ public abstract class AbstractDownloadServiceHandler implements DownloadServiceH
         }
     }
 
-    protected abstract byte[] webserviceCall(String configId);
+    protected abstract void webserviceCall(String configId, OutputStream downloadOut);
 
 }

src/main/java/ch/ethz/seb/sebserver/gui/service/remote/SebClientConfigDownload.java

@@ -8,6 +8,13 @@
 
 package ch.ethz.seb.sebserver.gui.service.remote;
 
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+import org.apache.tomcat.util.http.fileupload.IOUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.context.annotation.Lazy;
 import org.springframework.stereotype.Component;
@@ -22,6 +29,8 @@ import ch.ethz.seb.sebserver.gui.service.remote.webservice.api.seb.clientconfig.
 @GuiProfile
 public class SebClientConfigDownload extends AbstractDownloadServiceHandler {
 
+    private static final Logger log = LoggerFactory.getLogger(SebClientConfigDownload.class);
+
     private final RestService restService;
     public final String downloadFileName;
 
@@ -34,11 +43,27 @@ public class SebClientConfigDownload extends AbstractDownloadServiceHandler {
     }
 
     @Override
-    protected byte[] webserviceCall(final String modelId) {
+    protected void webserviceCall(final String modelId, final OutputStream downloadOut) {
-        return this.restService.getBuilder(ExportClientConfig.class)
+
+        final InputStream input = this.restService.getBuilder(ExportClientConfig.class)
                 .withURIVariable(API.PARAM_MODEL_ID, modelId)
                 .call()
                 .getOrThrow();
+
+        try {
+            IOUtils.copyLarge(input, downloadOut);
+        } catch (final IOException e) {
+            log.error(
+                    "Unexpected error while streaming incomming config data from web-service to output-stream of download response: ",
+                    e);
+        } finally {
+            try {
+                downloadOut.flush();
+                downloadOut.close();
+            } catch (final IOException e) {
+                log.error("Unexpected error while trying to close download output-stream");
+            }
+        }
     }
 
 }

src/main/java/ch/ethz/seb/sebserver/gui/service/remote/SebExamConfigDownload.java

@@ -8,6 +8,13 @@
 
 package ch.ethz.seb.sebserver.gui.service.remote;
 
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+import org.apache.tomcat.util.http.fileupload.IOUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import org.springframework.context.annotation.Lazy;
 import org.springframework.stereotype.Component;
 
@@ -21,6 +28,8 @@ import ch.ethz.seb.sebserver.gui.service.remote.webservice.api.seb.examconfig.Ex
 @GuiProfile
 public class SebExamConfigDownload extends AbstractDownloadServiceHandler {
 
+    private static final Logger log = LoggerFactory.getLogger(SebExamConfigDownload.class);
+
     private final RestService restService;
 
     protected SebExamConfigDownload(final RestService restService) {
@@ -28,11 +37,27 @@ public class SebExamConfigDownload extends AbstractDownloadServiceHandler {
     }
 
     @Override
-    protected byte[] webserviceCall(final String modelId) {
+    protected void webserviceCall(final String modelId, final OutputStream downloadOut) {
-        return this.restService.getBuilder(ExportPlainXML.class)
+
+        final InputStream input = this.restService.getBuilder(ExportPlainXML.class)
                 .withURIVariable(API.PARAM_MODEL_ID, modelId)
                 .call()
                 .getOrThrow();
+
+        try {
+            IOUtils.copyLarge(input, downloadOut);
+        } catch (final IOException e) {
+            log.error(
+                    "Unexpected error while streaming incomming config data from web-service to output-stream of download response: ",
+                    e);
+        } finally {
+            try {
+                downloadOut.flush();
+                downloadOut.close();
+            } catch (final IOException e) {
+                log.error("Unexpected error while trying to close download output-stream");
+            }
+        }
     }
 
 }

src/main/java/ch/ethz/seb/sebserver/gui/service/remote/webservice/api/AbstractExportCall.java

@@ -8,25 +8,19 @@
 
 package ch.ethz.seb.sebserver.gui.service.remote.webservice.api;
 
-import java.io.IOException;
+import java.io.InputStream;
 
-import org.apache.http.HttpHeaders;
+import org.apache.commons.io.IOUtils;
-import org.apache.tomcat.util.http.fileupload.ByteArrayOutputStream;
-import org.apache.tomcat.util.http.fileupload.IOUtils;
-import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.MediaType;
-import org.springframework.security.oauth2.client.OAuth2RestTemplate;
+import org.springframework.http.client.ClientHttpRequest;
-import org.springframework.security.oauth2.common.OAuth2AccessToken;
-import org.springframework.web.reactive.function.BodyInserters;
-import org.springframework.web.reactive.function.client.WebClient;
 
 import ch.ethz.seb.sebserver.gbl.util.Result;
 
-public abstract class AbstractExportCall extends RestCall<byte[]> {
+public abstract class AbstractExportCall extends RestCall<InputStream> {
 
     protected AbstractExportCall(
-            final TypeKey<byte[]> typeKey,
+            final TypeKey<InputStream> typeKey,
             final HttpMethod httpMethod,
             final MediaType contentType,
             final String path) {
@@ -34,85 +28,22 @@ public abstract class AbstractExportCall extends RestCall<byte[]> {
         super(typeKey, httpMethod, contentType, path);
     }
 
-    // We need a WebClient here to separate the request from the usual RestTemplate
-    // and allow also to get async responses
-    // The OAut2 bearer is get from the current OAuth2RestTemplate
-    // TODO create better API for this on RestCallBuilder site
     @Override
-    protected Result<byte[]> exchange(final RestCallBuilder builder) {
+    protected Result<InputStream> exchange(final RestCallBuilder builder) {
-        try {
 
-            final OAuth2RestTemplate restTemplate = (OAuth2RestTemplate) builder.getRestTemplate();
+        return Result.tryCatch(() -> {
-            final OAuth2AccessToken accessToken = restTemplate.getAccessToken();
-            final String value = accessToken.getValue();
 
-            final ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
+            return builder
-            WebClient.create()
+                    .getRestTemplate()
-                    .method(this.httpMethod)
+                    .execute(
-                    .uri(
                             builder.buildURI(),
-                            builder.getURIVariables())
+                            this.httpMethod,
-                    .header(HttpHeaders.AUTHORIZATION, "Bearer " + value)
+                            (final ClientHttpRequest requestCallback) -> {
-                    .headers(h -> h.addAll(builder.buildRequestEntity().getHeaders()))
+                            },
-                    .body(BodyInserters.fromObject("grant_type=client_credentials&scope=read,write"))
+                            response -> IOUtils.toBufferedInputStream(response.getBody()),
-                    .accept(MediaType.APPLICATION_OCTET_STREAM)
+                            builder.getURIVariables());
-                    .retrieve()
-                    .bodyToFlux(DataBuffer.class)
-                    .map(source -> {
 
-                        try {
+        });
-                            IOUtils.copyLarge(source.asInputStream(), byteArrayOutputStream);
-                        } catch (final IOException e) {
-                            // TODO Auto-generated catch block
-                            e.printStackTrace();
-                        }
-                        return source;
-                    })
-                    .blockLast();
-
-            final byte[] byteArray = byteArrayOutputStream.toByteArray();
-
-            return Result.of(byteArray);
-
-//            final byte[] value = builder
-//                    .getRestTemplate()
-//                    .execute(
-//                            builder.buildURI(),
-//                            this.httpMethod,
-//                            request -> {
-//                            },
-//                            response -> {
-//                                final InputStream input = IOUtils.toBufferedInputStream(response.getBody());
-//                                final ByteArrayOutputStream output = new ByteArrayOutputStream();
-//                                IOUtils.copyLarge(input, output);
-//                                return output.toByteArray();
-//                            },
-//                            builder.getURIVariables());
-//
-//            System.out.println("************************ getResponse " + Utils.toString(value));
-//
-//            return Result.of(value);
-//
-//            final ResponseEntity<byte[]> responseEntity = builder
-//                    .getRestTemplate()
-//                    .exchange(
-//                            builder.buildURI(),
-//                            this.httpMethod,
-//                            builder.buildRequestEntity(),
-//                            byte[].class,
-//                            builder.getURIVariables());
-
-//            if (responseEntity.getStatusCode() == HttpStatus.OK) {
-//                final byte[] body = responseEntity.getBody();
-//                System.out.println("************************ getResponse " + Utils.toString(body));
-//                return Result.of(body);
-//            }
-//
-//            return Result.ofRuntimeError(
-//                    "Error while trying to export from webservice. Response: " + responseEntity);
-        } catch (final Throwable t) {
-            return Result.ofError(t);
-        }
     }
 
 }

src/main/java/ch/ethz/seb/sebserver/gui/service/remote/webservice/api/seb/clientconfig/ExportClientConfig.java

@@ -8,6 +8,8 @@
 
 package ch.ethz.seb.sebserver.gui.service.remote.webservice.api.seb.clientconfig;
 
+import java.io.InputStream;
+
 import org.springframework.context.annotation.Lazy;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.MediaType;
@@ -29,7 +31,7 @@ public class ExportClientConfig extends AbstractExportCall {
         super(new TypeKey<>(
                 CallType.UNDEFINED,
                 EntityType.SEB_CLIENT_CONFIGURATION,
-                new TypeReference<byte[]>() {
+                new TypeReference<InputStream>() {
                 }),
                 HttpMethod.GET,
                 MediaType.APPLICATION_FORM_URLENCODED,

src/main/java/ch/ethz/seb/sebserver/gui/service/remote/webservice/api/seb/examconfig/ExportPlainXML.java

@@ -8,6 +8,8 @@
 
 package ch.ethz.seb.sebserver.gui.service.remote.webservice.api.seb.examconfig;
 
+import java.io.InputStream;
+
 import org.springframework.context.annotation.Lazy;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.MediaType;
@@ -29,7 +31,7 @@ public class ExportPlainXML extends AbstractExportCall {
         super(new TypeKey<>(
                 CallType.UNDEFINED,
                 EntityType.CONFIGURATION_NODE,
-                new TypeReference<byte[]>() {
+                new TypeReference<InputStream>() {
                 }),
                 HttpMethod.GET,
                 MediaType.APPLICATION_FORM_URLENCODED,