feat: add support for providing download from a CDN instead of local storage

src/main/java/io/papermc/bibliothek/BibliothekApplication.java

@@ -24,13 +24,15 @@
 package io.papermc.bibliothek;
 
 import io.papermc.bibliothek.configuration.AppConfiguration;
+import io.papermc.bibliothek.configuration.StorageConfiguration;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.boot.web.servlet.ServletComponentScan;
 
 @EnableConfigurationProperties({
-  AppConfiguration.class
+  AppConfiguration.class,
+  StorageConfiguration.class
 })
 @SpringBootApplication
 @ServletComponentScan

src/main/java/io/papermc/bibliothek/configuration/AppConfiguration.java

@@ -23,57 +23,15 @@
  */
 package io.papermc.bibliothek.configuration;
 
-import jakarta.validation.constraints.NotNull;
 import java.net.URL;
-import java.nio.file.Path;
 import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.validation.annotation.Validated;
 
 @ConfigurationProperties(prefix = "app")
 @Validated
-public class AppConfiguration {
-  private URL apiBaseUrl;
-  private String apiTitle;
-  private String apiVersion;
-  private @NotNull Path storagePath;
-
-  @SuppressWarnings("checkstyle:MethodName")
-  public URL getApiBaseUrl() {
-    return this.apiBaseUrl;
-  }
-
-  @SuppressWarnings("checkstyle:MethodName")
-  public void setApiBaseUrl(final URL apiBaseUrl) {
-    this.apiBaseUrl = apiBaseUrl;
-  }
-
-  @SuppressWarnings("checkstyle:MethodName")
-  public String getApiTitle() {
-    return this.apiTitle;
-  }
-
-  @SuppressWarnings("checkstyle:MethodName")
-  public void setApiTitle(final String apiTitle) {
-    this.apiTitle = apiTitle;
-  }
-
-  @SuppressWarnings("checkstyle:MethodName")
-  public String getApiVersion() {
-    return this.apiVersion;
-  }
-
-  @SuppressWarnings("checkstyle:MethodName")
-  public void setApiVersion(final String apiVersion) {
-    this.apiVersion = apiVersion;
-  }
-
-  @SuppressWarnings("checkstyle:MethodName")
-  public Path getStoragePath() {
-    return this.storagePath;
-  }
-
-  @SuppressWarnings("checkstyle:MethodName")
-  public void setStoragePath(final Path storagePath) {
-    this.storagePath = storagePath;
-  }
+public record AppConfiguration(
+  URL apiBaseUrl,
+  String apiTitle,
+  String apiVersion
+) {
 }

src/main/java/io/papermc/bibliothek/configuration/OpenAPIConfiguration.java

@@ -42,10 +42,10 @@ OpenAPI openAPI(final AppConfiguration configuration) {
     final OpenAPI api = new OpenAPI();
     api.info(
       new Info()
-        .title(configuration.getApiTitle())
-        .version(configuration.getApiVersion())
+        .title(configuration.apiTitle())
+        .version(configuration.apiVersion())
     );
-    final URL apiBaseUrl = configuration.getApiBaseUrl();
+    final URL apiBaseUrl = configuration.apiBaseUrl();
     if (apiBaseUrl != null) {
       api.servers(List.of(new Server().url(apiBaseUrl.toExternalForm())));
     }

src/main/java/io/papermc/bibliothek/configuration/StorageConfiguration.java

@@ -0,0 +1,49 @@
+/*
+ * This file is part of bibliothek, licensed under the MIT License.
+ *
+ * Copyright (c) 2019-2024 PaperMC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package io.papermc.bibliothek.configuration;
+
+import jakarta.validation.constraints.NotEmpty;
+import jakarta.validation.constraints.NotNull;
+import java.nio.file.Path;
+import java.util.List;
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.validation.annotation.Validated;
+
+@ConfigurationProperties(prefix = "app.storage")
+@Validated
+public record StorageConfiguration(
+  @NotNull Path cache,
+  @NotEmpty List<Source> sources
+) {
+  public record Source(
+    String name,
+    Type type,
+    String value
+  ) {
+    public enum Type {
+      LOCAL,
+      REMOTE;
+    }
+  }
+}

src/main/java/io/papermc/bibliothek/controller/v2/DownloadController.java

@@ -23,7 +23,6 @@
  */
 package io.papermc.bibliothek.controller.v2;
 
-import io.papermc.bibliothek.configuration.AppConfiguration;
 import io.papermc.bibliothek.database.model.Build;
 import io.papermc.bibliothek.database.model.Project;
 import io.papermc.bibliothek.database.model.Version;
@@ -35,6 +34,7 @@
 import io.papermc.bibliothek.exception.DownloadNotFound;
 import io.papermc.bibliothek.exception.ProjectNotFound;
 import io.papermc.bibliothek.exception.VersionNotFound;
+import io.papermc.bibliothek.service.DownloadService;
 import io.papermc.bibliothek.util.HTTP;
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.Parameter;
@@ -48,6 +48,7 @@
 import java.time.Duration;
 import java.util.Map;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.core.io.AbstractResource;
 import org.springframework.core.io.FileSystemResource;
 import org.springframework.http.CacheControl;
 import org.springframework.http.HttpHeaders;
@@ -64,22 +65,22 @@
 @SuppressWarnings("checkstyle:FinalClass")
 public class DownloadController {
   private static final CacheControl CACHE = HTTP.sMaxAgePublicCache(Duration.ofDays(7));
-  private final AppConfiguration configuration;
   private final ProjectCollection projects;
   private final VersionCollection versions;
   private final BuildCollection builds;
+  private final DownloadService service;
 
   @Autowired
   private DownloadController(
-    final AppConfiguration configuration,
     final ProjectCollection projects,
     final VersionCollection versions,
-    final BuildCollection builds
+    final BuildCollection builds,
+    final DownloadService service
   ) {
-    this.configuration = configuration;
     this.projects = projects;
     this.versions = versions;
     this.builds = builds;
+    this.service = service;
   }
 
   @ApiResponse(
@@ -132,17 +133,12 @@ public ResponseEntity<?> download(
     final Version version = this.versions.findByProjectAndName(project._id(), versionName).orElseThrow(VersionNotFound::new);
     final Build build = this.builds.findByProjectAndVersionAndNumber(project._id(), version._id(), buildNumber).orElseThrow(BuildNotFound::new);
 
-    for (final Map.Entry<String, Build.Download> download : build.downloads().entrySet()) {
-      if (download.getValue().name().equals(downloadName)) {
+    for (final Map.Entry<String, Build.Download> entry : build.downloads().entrySet()) {
+      final Build.Download download = entry.getValue();
+      if (download.name().equals(downloadName)) {
         try {
-          return new JavaArchive(
-            this.configuration.getStoragePath()
-              .resolve(project.name())
-              .resolve(version.name())
-              .resolve(String.valueOf(build.number()))
-              .resolve(download.getValue().name()),
-            CACHE
-          );
+          final Path path = this.service.resolve(project, version, build, download);
+          return JavaArchive.forPath(download, path, CACHE);
         } catch (final IOException e) {
           throw new DownloadFailed(e);
         }
@@ -151,17 +147,23 @@ public ResponseEntity<?> download(
     throw new DownloadNotFound();
   }
 
-  private static class JavaArchive extends ResponseEntity<FileSystemResource> {
-    JavaArchive(final Path path, final CacheControl cache) throws IOException {
-      super(new FileSystemResource(path), headersFor(path, cache), HttpStatus.OK);
+  private static class JavaArchive extends ResponseEntity<AbstractResource> {
+    static JavaArchive forPath(final Build.Download download, final Path path, final CacheControl cache) throws IOException {
+      final FileSystemResource resource = new FileSystemResource(path);
+      final HttpHeaders headers = headersFor(download, cache);
+      headers.setLastModified(Files.getLastModifiedTime(path).toInstant());
+      return new JavaArchive(resource, headers);
+    }
+
+    private JavaArchive(final AbstractResource resource, final HttpHeaders headers) {
+      super(resource, headers, HttpStatus.OK);
     }
 
-    private static HttpHeaders headersFor(final Path path, final CacheControl cache) throws IOException {
+    private static HttpHeaders headersFor(final Build.Download download, final CacheControl cache) {
       final HttpHeaders headers = new HttpHeaders();
       headers.setCacheControl(cache);
-      headers.setContentDisposition(HTTP.attachmentDisposition(path.getFileName()));
+      headers.setContentDisposition(HTTP.attachmentDisposition(download.name()));
       headers.setContentType(HTTP.APPLICATION_JAVA_ARCHIVE);
-      headers.setLastModified(Files.getLastModifiedTime(path).toInstant());
       return headers;
     }
   }

src/main/java/io/papermc/bibliothek/controller/v2/VersionFamilyBuildsController.java

@@ -137,7 +137,7 @@ static VersionFamilyBuildsResponse from(final Project project, final VersionFami
     }
 
     @Schema
-    public static record VersionFamilyBuild(
+    public record VersionFamilyBuild(
       @Schema(name = "version", pattern = Version.PATTERN, example = "1.18")
       String version,
       @Schema(name = "build", pattern = "\\d+", example = "10")