Зеркалирование Maven Central

build.gradle

@@ -21,6 +21,8 @@ dependencies {
 
 	annotationProcessor('org.springframework.boot:spring-boot-configuration-processor')
 	implementation('org.springframework.boot:spring-boot-starter-web')
+
+	implementation('com.squareup.okhttp3:okhttp:4.9.3')
 }
 
 tasks.named('compileJava') {

src/main/java/ru/di9/mirror/config/Config.java

@@ -0,0 +1,14 @@
+package ru.di9.mirror.config;
+
+import okhttp3.OkHttpClient;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+public class Config {
+
+    @Bean
+    public OkHttpClient okHttpClient() {
+        return new OkHttpClient();
+    }
+}

src/main/java/ru/di9/mirror/services/MavenCentralStorageService.java

@@ -1,26 +1,46 @@
 package ru.di9.mirror.services;
 
+import lombok.SneakyThrows;
+import okhttp3.OkHttpClient;
+import okhttp3.Request;
+import okhttp3.Response;
 import org.springframework.stereotype.Service;
 import ru.di9.mirror.domain.FileRecord;
-import ru.di9.mirror.domain.WalkerResult;
 
-import java.io.InputStream;
+import java.io.IOException;
+import java.util.Objects;
 import java.util.Optional;
 
 @Service
-public class MavenCentralStorageService implements StorageService {
+public class MavenCentralStorageService extends MirrorService {
+
+    private static final String MAVEN_CENTRAL_URL = "https://repo1.maven.org/maven2";
+    private final OkHttpClient okHttpClient;
+
+    public MavenCentralStorageService(OkHttpClient okHttpClient) {
+        this.okHttpClient = okHttpClient;
+    }
+
     @Override
+    @SneakyThrows
     public Optional<FileRecord> getFile(String path) {
+        Request request = new Request.Builder()
+                .url(MAVEN_CENTRAL_URL + path)
+                .build();
+
+        Response response = okHttpClient.newCall(request).execute();
+        if (!response.isSuccessful()) {
+            if (response.code() == 404) {
                 return Optional.empty();
             }
 
-    @Override
-    public void putFile(String path, InputStream inputStream) {
-        throw new UnsupportedOperationException();
+            throw new IOException("Unexpected code " + response);
         }
 
-    @Override
-    public Optional<WalkerResult> walker(String path) {
-        throw new UnsupportedOperationException();
+        return Optional.of(new FileRecord(
+                path,
+                Long.parseLong(Objects.requireNonNull(response.header("Content-Length"))),
+                Objects.requireNonNull(response.body()).byteStream()
+        ));
     }
 }

src/main/java/ru/di9/mirror/services/MirrorService.java

@@ -0,0 +1,19 @@
+package ru.di9.mirror.services;
+
+import ru.di9.mirror.domain.WalkerResult;
+
+import java.io.InputStream;
+import java.util.Optional;
+
+public abstract class MirrorService implements StorageService{
+
+    @Override
+    public void putFile(String path, InputStream inputStream) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public Optional<WalkerResult> walker(String path) {
+        throw new UnsupportedOperationException();
+    }
+}

src/main/java/ru/di9/mirror/services/MirroredStorageService.java

@@ -5,18 +5,19 @@ import ru.di9.mirror.domain.FileRecord;
 import ru.di9.mirror.domain.WalkerResult;
 
 import java.io.InputStream;
+import java.util.List;
 import java.util.Optional;
 
 @Service
 public class MirroredStorageService implements StorageService {
 
     private final FileStorageService fileStorageService;
-    private final MavenCentralStorageService mavenCentralStorageService;
+    private final List<MirrorService> mirrors;
 
     public MirroredStorageService(FileStorageService fileStorageService,
-                                  MavenCentralStorageService mavenCentralStorageService) {
+                                  List<MirrorService> mirrors) {
         this.fileStorageService = fileStorageService;
-        this.mavenCentralStorageService = mavenCentralStorageService;
+        this.mirrors = mirrors;
     }
 
     @Override
@@ -28,9 +29,14 @@ public class MirroredStorageService implements StorageService {
             return optional;
         }
 
-        mavenCentralStorageService.getFile(path).ifPresent(fileRecord ->
-                fileStorageService.putFile(fileRecord.name(), fileRecord.inputStream()));
-
+        for (StorageService mirror : mirrors) {
+            optional = mirror.getFile(path);
+            if (optional.isPresent()) {
+                FileRecord fileRecord = optional.get();
+                fileStorageService.putFile(fileRecord.name(), fileRecord.inputStream());
+                break;
+            }
+        }
 
         return fileStorageService.getFile(path);
     }