Allow migrating attachments from other places (#2807)

#### What type of PR is this?

/kind improvement
/area core
/milestone 2.0.0

#### What this PR does / why we need it:

This PR provides an ability to migrate attachments from other places, like Halo 1.x or Wordpress.

We could simply configure resource mappings to support attachments migration:

```yaml
halo:
  attachment:
    resource-mappings:
      - pathPattern: /upload/**
        locations:
          - upload
          - migrate-from-1.x
      - pathPattern: /wp-content/uploads/**
        locations:
          - migrate-from-wp
```

Meanwhile, I refactored LocalAttachmentUploadHandler for managing attachments from migration in the future.

#### Which issue(s) this PR fixes:

Fixes #2585

#### Special notes for your reviewer:

**Steps to test:**
1. Try to configure the resource mappings
2. Put some static resources into the corresponding location
3. Access it from Browser

At last, please make sure the functionalities of attachment are ok as before.

#### Does this PR introduce a user-facing change?

```release-note
None
```

src/main/java/run/halo/app/config/WebFluxConfig.java

@@ -3,21 +3,26 @@
 import static org.springframework.util.ResourceUtils.FILE_URL_PREFIX;
 import static org.springframework.web.reactive.function.server.RequestPredicates.GET;
 import static org.springframework.web.reactive.function.server.RouterFunctions.route;
+import static run.halo.app.infra.utils.FileUtils.checkDirectoryTraversal;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 import java.net.URI;
+import java.time.Duration;
 import java.time.Instant;
 import java.util.List;
+import java.util.Objects;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.http.CacheControl;
 import org.springframework.http.codec.CodecConfigurer;
 import org.springframework.http.codec.HttpMessageWriter;
 import org.springframework.http.codec.ServerCodecConfigurer;
 import org.springframework.http.codec.json.Jackson2JsonDecoder;
 import org.springframework.http.codec.json.Jackson2JsonEncoder;
 import org.springframework.lang.NonNull;
+import org.springframework.web.reactive.config.ResourceHandlerRegistration;
 import org.springframework.web.reactive.config.ResourceHandlerRegistry;
 import org.springframework.web.reactive.config.WebFluxConfigurer;
 import org.springframework.web.reactive.function.BodyInserters;
@@ -114,15 +119,36 @@ private Mono<ServerResponse> redirectConsole(ServerRequest request) {
     @Override
     public void addResourceHandlers(ResourceHandlerRegistry registry) {
         var attachmentsRoot = haloProp.getWorkDir().resolve("attachments");
-        registry.addResourceHandler("/upload/**")
-            .addResourceLocations(FILE_URL_PREFIX + attachmentsRoot + "/");
+
+        // Mandatory resource mapping
+        var uploadRegistration = registry.addResourceHandler("/upload/**")
+            .addResourceLocations(FILE_URL_PREFIX + attachmentsRoot.resolve("upload") + "/")
+            .setUseLastModified(true)
+            .setCacheControl(CacheControl.maxAge(Duration.ofDays(365)));
 
         // For console project
         registry.addResourceHandler("/console/**")
             .addResourceLocations(haloProp.getConsole().getLocation())
             .resourceChain(true)
             .addResolver(new EncodedResourceResolver())
             .addResolver(new PathResourceResolver());
+
+        // Additional resource mappings
+        var staticResources = haloProp.getAttachment().getResourceMappings();
+        staticResources.forEach(staticResource -> {
+            ResourceHandlerRegistration registration;
+            if (Objects.equals(staticResource.getPathPattern(), "/upload/**")) {
+                registration = uploadRegistration;
+            } else {
+                registration = registry.addResourceHandler(staticResource.getPathPattern());
+            }
+            staticResource.getLocations().forEach(location -> {
+                var path = attachmentsRoot.resolve(location);
+                checkDirectoryTraversal(attachmentsRoot, path);
+                registration.addResourceLocations(FILE_URL_PREFIX + path + "/");
+            });
+        });
+
     }
 
 

src/main/java/run/halo/app/core/extension/attachment/Constant.java

@@ -5,7 +5,15 @@ public enum Constant {
 
     public static final String GROUP = "storage.halo.run";
     public static final String VERSION = "v1alpha1";
+    /**
+     * The relative path starting from attachments folder is for deletion.
+     */
     public static final String LOCAL_REL_PATH_ANNO_KEY = GROUP + "/local-relative-path";
+    /**
+     * The encoded URI is for building external url.
+     */
+    public static final String URI_ANNO_KEY = GROUP + "/uri";
+
     public static final String EXTERNAL_LINK_ANNO_KEY = GROUP + "/external-link";
 
     public static final String FINALIZER_NAME = "attachment-manager";

src/main/java/run/halo/app/core/extension/attachment/endpoint/LocalAttachmentUploadHandler.java

@@ -4,8 +4,10 @@
 import static run.halo.app.infra.utils.FileUtils.checkDirectoryTraversal;
 
 import java.io.IOException;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.util.ArrayList;
 import java.util.Map;
 import java.util.Optional;
 import java.util.UUID;
@@ -15,6 +17,7 @@
 import org.springframework.http.MediaType;
 import org.springframework.stereotype.Component;
 import org.springframework.util.StringUtils;
+import org.springframework.web.util.UriComponentsBuilder;
 import reactor.core.Exceptions;
 import reactor.core.publisher.Mono;
 import reactor.core.scheduler.Schedulers;
@@ -49,15 +52,17 @@ public Mono<Attachment> upload(UploadContext uploadOption) {
                 var settingJson = configMap.getData().getOrDefault("default", "{}");
                 var setting = JsonUtils.jsonToObject(settingJson, PolicySetting.class);
 
-                var attachmentsRoot = getAttachmentsRoot();
-                var attachmentRoot = attachmentsRoot;
+                final var attachmentsRoot = getAttachmentsRoot();
+                final var uploadRoot = attachmentsRoot.resolve("upload");
+                final var file = option.file();
+                final Path attachmentPath;
                 if (StringUtils.hasText(setting.getLocation())) {
-                    attachmentRoot = attachmentsRoot.resolve(setting.getLocation());
+                    attachmentPath =
+                        uploadRoot.resolve(setting.getLocation()).resolve(file.filename());
+                } else {
+                    attachmentPath = uploadRoot.resolve(file.filename());
                 }
-                var file = option.file();
-                var attachmentPath = attachmentRoot.resolve(file.filename());
-                // check the directory traversal before saving
-                checkDirectoryTraversal(attachmentsRoot, attachmentPath);
+                checkDirectoryTraversal(uploadRoot, attachmentPath);
 
                 return Mono.fromRunnable(
                         () -> {
@@ -76,8 +81,22 @@ public Mono<Attachment> upload(UploadContext uploadOption) {
                         // TODO check the file extension
                         var metadata = new Metadata();
                         metadata.setName(UUID.randomUUID().toString());
-                        metadata.setAnnotations(Map.of(Constant.LOCAL_REL_PATH_ANNO_KEY,
-                            attachmentsRoot.relativize(attachmentPath).toString()));
+                        var relativePath = attachmentsRoot.relativize(attachmentPath).toString();
+
+                        var pathSegments = new ArrayList<String>();
+                        pathSegments.add("upload");
+                        for (Path p : uploadRoot.relativize(attachmentPath)) {
+                            pathSegments.add(p.toString());
+                        }
+
+                        var uri = UriComponentsBuilder.newInstance()
+                            .pathSegment(pathSegments.toArray(String[]::new))
+                            .encode(StandardCharsets.UTF_8)
+                            .build()
+                            .toString();
+                        metadata.setAnnotations(Map.of(
+                            Constant.LOCAL_REL_PATH_ANNO_KEY, relativePath,
+                            Constant.URI_ANNO_KEY, uri));
                         var spec = new AttachmentSpec();
                         spec.setSize(attachmentPath.toFile().length());
                         file.headers().getContentType();

src/main/java/run/halo/app/core/extension/reconciler/attachment/AttachmentReconciler.java

@@ -1,13 +1,11 @@
 package run.halo.app.core.extension.reconciler.attachment;
 
-import static java.nio.charset.StandardCharsets.UTF_8;
-
 import java.util.HashSet;
 import java.util.Objects;
 import java.util.Set;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.stereotype.Component;
-import org.springframework.web.util.UriUtils;
+import org.springframework.web.util.UriComponentsBuilder;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 import run.halo.app.core.extension.attachment.Attachment;
@@ -67,15 +65,16 @@ public Result reconcile(Request request) {
             var annotations = attachment.getMetadata().getAnnotations();
             if (annotations != null) {
                 String permalink = null;
-                var localRelativePath = annotations.get(Constant.LOCAL_REL_PATH_ANNO_KEY);
-                if (localRelativePath != null) {
-                    // TODO Add router function here.
-                    var encodedPath = UriUtils.encodePath("/upload/" + localRelativePath, UTF_8);
-                    permalink = externalUrl.get().resolve(encodedPath).normalize().toString();
+                var uri = annotations.get(Constant.URI_ANNO_KEY);
+                if (uri != null) {
+                    permalink = UriComponentsBuilder.fromUri(externalUrl.get())
+                        // The URI has been encoded before, so there is no need to encode it again.
+                        .path(uri)
+                        .build()
+                        .toString();
                 } else {
                     var externalLink = annotations.get(Constant.EXTERNAL_LINK_ANNO_KEY);
                     if (externalLink != null) {
-                        // TODO Set the external link into status
                         permalink = externalLink;
                     }
                 }

src/main/java/run/halo/app/infra/properties/AttachmentProperties.java

@@ -0,0 +1,26 @@
+package run.halo.app.infra.properties;
+
+import java.util.LinkedList;
+import java.util.List;
+import lombok.Data;
+
+@Data
+public class AttachmentProperties {
+
+    private List<ResourceMapping> resourceMappings = new LinkedList<>();
+
+    @Data
+    public static class ResourceMapping {
+
+        /**
+         * Like: {@code /upload/**}.
+         */
+        private String pathPattern;
+
+        /**
+         * The location is a relative path to attachments folder in working directory.
+         */
+        private List<String> locations;
+
+    }
+}

src/main/java/run/halo/app/infra/properties/HaloProperties.java

@@ -45,4 +45,7 @@ public class HaloProperties {
 
     @Valid
     private final ThemeProperties theme = new ThemeProperties();
+
+    @Valid
+    private final AttachmentProperties attachment = new AttachmentProperties();
 }

src/main/resources/application.yaml

@@ -20,6 +20,11 @@ halo:
   work-dir: ${user.home}/.halo2
   plugin:
     plugins-root: ${halo.work-dir}/plugins
+  attachment:
+    resource-mappings:
+      - pathPattern: /upload/**
+        locations:
+          - migrate-from-1.x
 
 springdoc:
   api-docs:

src/main/resources/extensions/attachment-local-policy.yaml

@@ -6,6 +6,22 @@ spec:
   displayName: Local Storage
   settingName: local-policy-template-setting
 ---
+apiVersion: storage.halo.run/v1alpha1
+kind: Policy
+metadata:
+  name: default-policy
+spec:
+  displayName: 本地存储
+  templateName: local
+  configMapName: default-policy-config
+---
+apiVersion: v1alpha1
+kind: ConfigMap
+metadata:
+  name: default-policy-config
+data:
+  default: "{\"location\":\"\"}"
+---
 apiVersion: v1alpha1
 kind: Setting
 metadata:
@@ -18,4 +34,4 @@ spec:
         - $formkit: text
           name: location
           label: 存储位置
-          help: ~/.halo2/attachments 下的子目录
+          help: ~/.halo2/attachments/upload 下的子目录