implemented 07-server-mode.md: added server profile with REST API for builds, artifacts, live logs, and control tokens; lifecycle management for watcher; controller and service tests

src/main/kotlin/de/hoennig/gittally/server/ArtifactFileController.kt

@@ -0,0 +1,65 @@
+package de.hoennig.gittally.server
+
+import de.hoennig.gittally.build.ArtifactStore
+import org.springframework.core.io.FileSystemResource
+import org.springframework.core.io.Resource
+import org.springframework.http.HttpHeaders
+import org.springframework.http.MediaType
+import org.springframework.http.MediaTypeFactory
+import org.springframework.http.ResponseEntity
+import org.springframework.web.bind.annotation.GetMapping
+import org.springframework.web.bind.annotation.PathVariable
+import org.springframework.web.bind.annotation.RestController
+import java.nio.file.Files
+import java.nio.file.LinkOption
+import java.nio.file.Path
+
+/**
+ * Streams stored build artifacts. Status pages, JSON, and logs are served with
+ * no-cache headers like legacy, so browsers always see the current build state.
+ */
+@RestController
+class ArtifactFileController(
+    private val artifactStore: ArtifactStore,
+) {
+    @GetMapping("/artifacts/{artifactKey}/{*path}")
+    fun serve(
+        @PathVariable artifactKey: String,
+        @PathVariable path: String,
+    ): ResponseEntity<Resource> {
+        val artifactDir =
+            artifactStore.artifactDir(artifactKey)
+                ?: return ResponseEntity.notFound().build()
+        val relativePath = path.removePrefix("/")
+        if (relativePath.isBlank()) {
+            return ResponseEntity.notFound().build()
+        }
+        val file = artifactDir.resolve(relativePath).normalize()
+        if (!file.startsWith(artifactDir) || !Files.isRegularFile(file, LinkOption.NOFOLLOW_LINKS)) {
+            return ResponseEntity.notFound().build()
+        }
+        val headers = HttpHeaders()
+        headers.contentType = mediaType(file)
+        if (file.extension() in NO_CACHE_EXTENSIONS) {
+            headers.cacheControl = "no-store, max-age=0"
+            headers.pragma = "no-cache"
+            headers.expires = 0
+        }
+        return ResponseEntity.ok().headers(headers).body(FileSystemResource(file))
+    }
+
+    private fun mediaType(file: Path): MediaType =
+        when (file.extension()) {
+            "log" -> MediaType(MediaType.TEXT_PLAIN, Charsets.UTF_8)
+            else ->
+                MediaTypeFactory
+                    .getMediaType(file.fileName.toString())
+                    .orElse(MediaType.APPLICATION_OCTET_STREAM)
+        }
+
+    private fun Path.extension(): String = fileName.toString().substringAfterLast('.', "").lowercase()
+
+    companion object {
+        private val NO_CACHE_EXTENSIONS = setOf("html", "json", "log")
+    }
+}