Add ability to specify URL for an image

NEWS.txt

@@ -15,6 +15,7 @@
 - (functionality)  name of category/country in Russian now are optional fields
 - (functionality)  preview now is generated after uploading an image
 - (functionality)  add interface for adding buyers and sellers
+- (functionality)  add capability to specify image URL (as alternative to providing a file)
 
 0.3
 - (functionality)  implemented possibility to user to add series to his collection

src/main/config/findbugs-filter.xml

@@ -8,6 +8,15 @@
 		<Class name="~.*\.dto\..*" />
 		<Bug pattern="EI_EXPOSE_REP,EI_EXPOSE_REP2" />
 	</Match>
+	<Match>
+		<!--
+			String[] allowedContentTypes: potentially caller can modify data after passing it to the
+			constructor. I don't want to fix it because all such places are known and under our
+			control.
+		-->
+		<Class name="ru.mystamps.web.service.HttpURLConnectionDownloaderService" />
+		<Bug pattern="EI_EXPOSE_REP2" />
+	</Match>
 	<Match>
 		<!--
 			It's ok, that we're don't override parent's equals() method.

src/main/java/ru/mystamps/web/config/ControllersConfig.java

@@ -20,6 +20,7 @@
 import org.springframework.context.MessageSource;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Profile;
 
 import lombok.RequiredArgsConstructor;
 
@@ -131,4 +132,10 @@ public SuggestionController getSuggestionController() {
 		);
 	}
 
+	@Bean
+	@Profile({ "test", "travis" })
+	public TestController getTestController() {
+		return new TestController();
+	}
+
 }

src/main/java/ru/mystamps/web/config/MvcConfig.java

@@ -47,6 +47,7 @@
 
 import ru.mystamps.web.Url;
 import ru.mystamps.web.controller.converter.LinkEntityDtoGenericConverter;
+import ru.mystamps.web.controller.interceptor.DownloadImageInterceptor;
 import ru.mystamps.web.support.spring.security.CurrentUserArgumentResolver;
 
 @Configuration
@@ -126,6 +127,10 @@ public Validator getValidator() {
 	@Override
 	public void addInterceptors(InterceptorRegistry registry) {
 		registry.addInterceptor(getLocaleChangeInterceptor());
+
+		registry
+			.addInterceptor(getDownloadImageInterceptor())
+			.addPathPatterns(Url.ADD_SERIES_PAGE, Url.ADD_IMAGE_SERIES_PAGE);
 	}
 
 	@Override
@@ -149,4 +154,8 @@ private static HandlerInterceptor getLocaleChangeInterceptor() {
 		return interceptor;
 	}
 
+	private HandlerInterceptor getDownloadImageInterceptor() {
+		return new DownloadImageInterceptor(servicesConfig.getDownloaderService());
+	}
+
 }

src/main/java/ru/mystamps/web/config/ServicesConfig.java

@@ -89,6 +89,11 @@ public CronService getCronService() {
 		);
 	}
 
+	@Bean
+	public DownloaderService getDownloaderService() {
+		return new HttpURLConnectionDownloaderService(new String[]{"image/jpeg", "image/png"});
+	}
+
 	@Bean
 	public ImageService getImageService() {
 		return new ImageServiceImpl(

src/main/java/ru/mystamps/web/controller/SeriesController.java

@@ -29,6 +29,7 @@
 import java.util.Map;
 import java.util.Objects;
 
+import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import javax.validation.Valid;
 import javax.validation.groups.Default;
@@ -62,6 +63,8 @@
 import ru.mystamps.web.controller.dto.AddImageForm;
 import ru.mystamps.web.controller.dto.AddSeriesForm;
 import ru.mystamps.web.controller.dto.AddSeriesSalesForm;
+import ru.mystamps.web.controller.dto.NullableImageUrl;
+import ru.mystamps.web.controller.interceptor.DownloadImageInterceptor;
 import ru.mystamps.web.dao.dto.EntityWithIdDto;
 import ru.mystamps.web.dao.dto.LinkEntityDto;
 import ru.mystamps.web.dao.dto.PurchaseAndSaleDto;
@@ -72,6 +75,7 @@
 import ru.mystamps.web.service.SeriesSalesService;
 import ru.mystamps.web.service.SeriesService;
 import ru.mystamps.web.service.TransactionParticipantService;
+import ru.mystamps.web.service.dto.DownloadResult;
 import ru.mystamps.web.service.dto.FirstLevelCategoryDto;
 import ru.mystamps.web.service.dto.SeriesDto;
 import ru.mystamps.web.support.spring.security.Authority;
@@ -176,15 +180,34 @@ public View showFormWithCountry(
 		return view;
 	}
 
-	@PostMapping(Url.ADD_SERIES_PAGE)
+	@PostMapping(path = Url.ADD_SERIES_PAGE, params = "imageUrl")
+	public String processInputWithImageUrl(
+		@Validated({ Default.class,
+			AddSeriesForm.ImageUrlChecks.class,
+			AddSeriesForm.ReleaseDateChecks.class,
+			AddSeriesForm.ImageChecks.class }) AddSeriesForm form,
+		BindingResult result,
+		@CurrentUser Integer currentUserId,
+		Locale userLocale,
+		Model model,
+		HttpServletRequest request) {
+
+		return processInput(form, result, currentUserId, userLocale, model, request);
+	}
+
+	@PostMapping(path = Url.ADD_SERIES_PAGE, params = "!imageUrl")
 	public String processInput(
 		@Validated({ Default.class,
+			AddSeriesForm.RequireImageCheck.class,
 			AddSeriesForm.ReleaseDateChecks.class,
 			AddSeriesForm.ImageChecks.class }) AddSeriesForm form,
 		BindingResult result,
 		@CurrentUser Integer currentUserId,
 		Locale userLocale,
-		Model model) {
+		Model model,
+		HttpServletRequest request) {
+
+		loadErrorsFromDownloadInterceptor(form, result, request);
 
 		if (result.hasErrors()) {
 			String lang = LocaleUtils.getLanguageOrNull(userLocale);
@@ -199,6 +222,7 @@ public String processInput(
 
 			// don't try to re-display file upload field
 			form.setImage(null);
+			form.setDownloadedImage(null);
 			return null;
 		}
 
@@ -242,14 +266,47 @@ public String showInfo(
 		return "series/info";
 	}
 
-	@PostMapping(Url.ADD_IMAGE_SERIES_PAGE)
+	@SuppressWarnings("checkstyle:parameternumber")
+	@PostMapping(path = Url.ADD_IMAGE_SERIES_PAGE, params = "imageUrl")
+	public String processImageWithImageUrl(
+		@Validated({
+			AddImageForm.ImageUrlChecks.class,
+			AddImageForm.ImageChecks.class
+		}) AddImageForm form,
+		BindingResult result,
+		@PathVariable("id") Integer seriesId,
+		Model model,
+		@CurrentUser Integer currentUserId,
+		Locale userLocale,
+		HttpServletRequest request,
+		HttpServletResponse response)
+		throws IOException {
+
+		return processImage(
+			form,
+			result,
+			seriesId,
+			model,
+			currentUserId,
+			userLocale,
+			request,
+			response
+		);
+	}
+
+	@SuppressWarnings("checkstyle:parameternumber")
+	@PostMapping(path = Url.ADD_IMAGE_SERIES_PAGE, params = "!imageUrl")
 	public String processImage(
-		@Valid AddImageForm form,
+		@Validated({
+			AddImageForm.RequireImageCheck.class,
+			AddImageForm.ImageChecks.class })
+		AddImageForm form,
 		BindingResult result,
 		@PathVariable("id") Integer seriesId,
 		Model model,
 		@CurrentUser Integer currentUserId,
 		Locale userLocale,
+		HttpServletRequest request,
 		HttpServletResponse response)
 		throws IOException {
 
@@ -265,6 +322,8 @@ public String processImage(
 			return null;
 		}
 
+		loadErrorsFromDownloadInterceptor(form, result, request);
+
 		boolean maxQuantityOfImagesExceeded = !isAdmin() && !isAllowedToAddingImages(series);
 		model.addAttribute("maxQuantityOfImagesExceeded", maxQuantityOfImagesExceeded);
 
@@ -475,6 +534,48 @@ private void addSeriesSalesFormToModel(Model model) {
 		model.addAttribute("buyers", buyers);
 	}
 
+	private static void loadErrorsFromDownloadInterceptor(
+		NullableImageUrl form,
+		BindingResult result,
+		HttpServletRequest request) {
+
+		Object downloadResultErrorCode =
+			request.getAttribute(DownloadImageInterceptor.ERROR_CODE_ATTR_NAME);
+
+		if (downloadResultErrorCode == null) {
+			return;
+		}
+
+		if (downloadResultErrorCode instanceof DownloadResult.Code) {
+			DownloadResult.Code code = (DownloadResult.Code)downloadResultErrorCode;
+			switch (code) {
+				case INVALID_URL:
+					// Url is being validated by @URL, to avoid showing an error message
+					// twice we're skipping error from an interceptor.
+					break;
+				case INSUFFICIENT_PERMISSIONS:
+					// A user without permissions has tried to download a file. It means that he
+					// didn't specify a file but somehow provide a URL to an image. In this case,
+					// let's show an error message that file is required.
+					result.rejectValue(
+						"image",
+						"ru.mystamps.web.support.beanvalidation.NotEmptyFilename.message"
+					);
+					form.nullifyImageUrl();
+					break;
+				default:
+					result.rejectValue(
+						DownloadImageInterceptor.DOWNLOADED_IMAGE_FIELD_NAME,
+						DownloadResult.class.getName() + "." + code.toString(),
+						"Could not download image"
+					);
+					break;
+			}
+		}
+
+		request.removeAttribute(DownloadImageInterceptor.ERROR_CODE_ATTR_NAME);
+	}
+
 	private static void addImageFormToModel(Model model) {
 		AddImageForm form = new AddImageForm();
 		model.addAttribute("addImageForm", form);

src/main/java/ru/mystamps/web/controller/TestController.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2009-2017 Slava Semushin <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+package ru.mystamps.web.controller;
+
+import java.io.IOException;
+
+import javax.servlet.http.HttpServletResponse;
+
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.ResponseBody;
+
+import ru.mystamps.web.Url;
+
+@Controller
+public class TestController {
+
+	@GetMapping("/test/invalid/response-301")
+	public void redirect(HttpServletResponse response) {
+		response.setStatus(HttpServletResponse.SC_MOVED_PERMANENTLY);
+		response.setHeader("Location", Url.SITE);
+	}
+
+	@GetMapping("/test/invalid/response-400")
+	public void badRequest(HttpServletResponse response) throws IOException {
+		response.sendError(HttpServletResponse.SC_BAD_REQUEST);
+	}
+
+	@GetMapping("/test/invalid/response-404")
+	public void notFound(HttpServletResponse response) throws IOException {
+		response.sendError(HttpServletResponse.SC_NOT_FOUND);
+	}
+
+	@GetMapping("/test/invalid/empty-jpeg-file")
+	public void emptyJpegFile(HttpServletResponse response) {
+		response.setContentType("image/jpeg");
+		response.setContentLength(0);
+	}
+
+	@GetMapping(path = "/test/invalid/not-image-file", produces = "application/json")
+	@ResponseBody
+	public String simpleJson() {
+		return "test";
+	}
+
+}