Feat: Add deprecated file controller for getting old files temporarily.

src/main/kotlin/com/wafflestudio/csereal/core/resource/mainImage/api/DeprecatedFileController.kt

@@ -0,0 +1,63 @@
+package com.wafflestudio.csereal.core.resource.mainImage.api
+
+import jakarta.servlet.http.HttpServletRequest
+import org.springframework.beans.factory.annotation.Value
+import org.springframework.core.io.Resource
+import org.springframework.core.io.UrlResource
+import org.springframework.http.HttpHeaders
+import org.springframework.http.HttpStatus
+import org.springframework.http.ResponseEntity
+import org.springframework.util.AntPathMatcher
+import org.springframework.web.bind.annotation.GetMapping
+import org.springframework.web.bind.annotation.PathVariable
+import org.springframework.web.bind.annotation.RequestMapping
+import org.springframework.web.bind.annotation.RequestParam
+import org.springframework.web.bind.annotation.RestController
+import java.net.URLEncoder
+import java.nio.file.Paths
+
+@RestController
+@RequestMapping("/api/sites/default/files")
+class DeprecatedFileController (
+        @Value("\${oldFiles.path}")
+        private val oldFilesPath: String,
+) {
+    @GetMapping("/{map}/**")
+    fun serveOldFile(
+            @PathVariable map: String, // Just for ensure at least one path variable
+            @RequestParam(defaultValue = "false") download: Boolean,
+            request: HttpServletRequest
+    ): ResponseEntity<Resource> {
+        // Extract path from pattern
+        val fileSubDir = AntPathMatcher().extractPathWithinPattern(
+                "/api/sites/default/files/**",
+                request.servletPath
+            ).substringAfter("/api/sites/default/files/")
+
+        val file = Paths.get(oldFilesPath, fileSubDir)
+        val resource = UrlResource(file.toUri())
+
+        return if (resource.exists() || resource.isReadable) {
+            val contentType: String? = request.servletContext.getMimeType(resource.file.absolutePath)
+            val headers = HttpHeaders()
+
+            headers.contentType =
+                    org.springframework.http.MediaType.parseMediaType(contentType ?: "application/octet-stream")
+
+            if (download) {
+                val originalFilename = fileSubDir.substringAfterLast("/")
+
+                val encodedFilename = URLEncoder.encode(originalFilename, Charsets.UTF_8.toString()).replace("+", "%20")
+
+                headers.add(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename*=UTF-8''$encodedFilename")
+            }
+
+            ResponseEntity.ok()
+                    .headers(headers)
+                    .body(resource)
+        } else {
+            ResponseEntity.status(HttpStatus.NOT_FOUND).build()
+        }
+    }
+
+}