add Gradle Build Cache support with handler and tests

internal/handler/gradle.go

@@ -0,0 +1,147 @@
+package handler
+
+import (
+	"errors"
+	"io"
+	"net/http"
+	"regexp"
+	"strconv"
+	"strings"
+
+	"github.com/git-pkgs/proxy/internal/storage"
+)
+
+const (
+	gradleBuildCacheContentType = "application/vnd.gradle.build-cache-artifact.v2"
+	gradleBuildCachePathPrefix  = "cache/"
+	gradleBuildCacheStorageRoot = "_gradle/http-build-cache"
+)
+
+var gradleBuildCacheKeyPattern = regexp.MustCompile(`^[A-Za-z0-9][A-Za-z0-9._-]*$`)
+
+// GradleBuildCacheHandler handles Gradle HttpBuildCache GET/HEAD/PUT requests.
+//
+// Gradle clients commonly use paths like /cache/{key}, but this handler also
+// accepts /{key} so it can be mounted under flexible base URLs.
+type GradleBuildCacheHandler struct {
+	proxy *Proxy
+}
+
+// NewGradleBuildCacheHandler creates a Gradle HttpBuildCache handler.
+func NewGradleBuildCacheHandler(proxy *Proxy, _ string) *GradleBuildCacheHandler {
+	return &GradleBuildCacheHandler{proxy: proxy}
+}
+
+// Routes returns the HTTP handler for Gradle HttpBuildCache requests.
+func (h *GradleBuildCacheHandler) Routes() http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		switch r.Method {
+		case http.MethodGet, http.MethodHead, http.MethodPut:
+		default:
+			http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+			return
+		}
+
+		key, statusCode := h.parseCacheKey(r.URL.Path)
+		if statusCode != http.StatusOK {
+			if statusCode == http.StatusNotFound {
+				http.NotFound(w, r)
+				return
+			}
+			http.Error(w, "invalid cache key", statusCode)
+			return
+		}
+
+		if r.Method == http.MethodPut {
+			h.handlePut(w, r, key)
+			return
+		}
+
+		h.handleGetOrHead(w, r, key)
+	})
+}
+
+func (h *GradleBuildCacheHandler) parseCacheKey(urlPath string) (string, int) {
+	keyPath := strings.TrimPrefix(urlPath, "/")
+	if keyPath == "" {
+		return "", http.StatusNotFound
+	}
+
+	if containsPathTraversal(keyPath) {
+		return "", http.StatusBadRequest
+	}
+
+	keyPath = strings.TrimPrefix(keyPath, gradleBuildCachePathPrefix)
+
+	if keyPath == "" || strings.Contains(keyPath, "/") {
+		return "", http.StatusNotFound
+	}
+
+	if !gradleBuildCacheKeyPattern.MatchString(keyPath) {
+		return "", http.StatusBadRequest
+	}
+
+	return keyPath, http.StatusOK
+}
+
+func (h *GradleBuildCacheHandler) cacheStoragePath(key string) string {
+	return gradleBuildCacheStorageRoot + "/" + key
+}
+
+func (h *GradleBuildCacheHandler) handleGetOrHead(w http.ResponseWriter, r *http.Request, key string) {
+	storagePath := h.cacheStoragePath(key)
+
+	reader, err := h.proxy.Storage.Open(r.Context(), storagePath)
+	if err != nil {
+		if errors.Is(err, storage.ErrNotFound) {
+			http.NotFound(w, r)
+			return
+		}
+		h.proxy.Logger.Error("failed to open gradle build cache entry", "key", key, "error", err)
+		http.Error(w, "failed to read cache entry", http.StatusInternalServerError)
+		return
+	}
+	defer func() { _ = reader.Close() }()
+
+	w.Header().Set("Content-Type", gradleBuildCacheContentType)
+	if size, err := h.proxy.Storage.Size(r.Context(), storagePath); err == nil && size >= 0 {
+		w.Header().Set("Content-Length", strconv.FormatInt(size, 10))
+	}
+
+	w.WriteHeader(http.StatusOK)
+	if r.Method == http.MethodHead {
+		return
+	}
+
+	_, _ = io.Copy(w, reader)
+}
+
+func (h *GradleBuildCacheHandler) handlePut(w http.ResponseWriter, r *http.Request, key string) {
+	storagePath := h.cacheStoragePath(key)
+
+	exists, err := h.proxy.Storage.Exists(r.Context(), storagePath)
+	if err != nil {
+		h.proxy.Logger.Error("failed to check gradle build cache entry", "key", key, "error", err)
+		http.Error(w, "failed to write cache entry", http.StatusInternalServerError)
+		return
+	}
+
+	defer func() { _ = r.Body.Close() }()
+	size, hash, err := h.proxy.Storage.Store(r.Context(), storagePath, r.Body)
+	if err != nil {
+		h.proxy.Logger.Error("failed to store gradle build cache entry", "key", key, "error", err)
+		http.Error(w, "failed to write cache entry", http.StatusInternalServerError)
+		return
+	}
+
+	w.Header().Set("Content-Length", "0")
+	w.Header().Set("ETag", `"`+hash+`"`)
+	w.Header().Set("X-Cache-Size", strconv.FormatInt(size, 10))
+
+	if exists {
+		w.WriteHeader(http.StatusOK)
+		return
+	}
+
+	w.WriteHeader(http.StatusCreated)
+}

internal/handler/gradle_test.go

@@ -0,0 +1,173 @@
+package handler
+
+import (
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+func TestGradleBuildCacheHandler_PutGetHead(t *testing.T) {
+	proxy, _, _, _ := setupTestProxy(t)
+	h := NewGradleBuildCacheHandler(proxy, "http://localhost")
+	srv := httptest.NewServer(h.Routes())
+	defer srv.Close()
+
+	key := "a1b2c3d4e5f6"
+	payload := "cache entry content"
+
+	putReq, err := http.NewRequest(http.MethodPut, srv.URL+"/cache/"+key, strings.NewReader(payload))
+	if err != nil {
+		t.Fatalf("failed to create PUT request: %v", err)
+	}
+	putResp, err := http.DefaultClient.Do(putReq)
+	if err != nil {
+		t.Fatalf("PUT request failed: %v", err)
+	}
+	_ = putResp.Body.Close()
+
+	if putResp.StatusCode != http.StatusCreated {
+		t.Fatalf("PUT status = %d, want %d", putResp.StatusCode, http.StatusCreated)
+	}
+
+	getResp, err := http.Get(srv.URL + "/cache/" + key)
+	if err != nil {
+		t.Fatalf("GET request failed: %v", err)
+	}
+	defer func() { _ = getResp.Body.Close() }()
+
+	if getResp.StatusCode != http.StatusOK {
+		t.Fatalf("GET status = %d, want %d", getResp.StatusCode, http.StatusOK)
+	}
+	if getResp.Header.Get("Content-Type") != gradleBuildCacheContentType {
+		t.Fatalf("GET Content-Type = %q, want %q", getResp.Header.Get("Content-Type"), gradleBuildCacheContentType)
+	}
+
+	body, _ := io.ReadAll(getResp.Body)
+	if string(body) != payload {
+		t.Fatalf("GET body = %q, want %q", body, payload)
+	}
+
+	headReq, err := http.NewRequest(http.MethodHead, srv.URL+"/cache/"+key, nil)
+	if err != nil {
+		t.Fatalf("failed to create HEAD request: %v", err)
+	}
+	headResp, err := http.DefaultClient.Do(headReq)
+	if err != nil {
+		t.Fatalf("HEAD request failed: %v", err)
+	}
+	defer func() { _ = headResp.Body.Close() }()
+
+	if headResp.StatusCode != http.StatusOK {
+		t.Fatalf("HEAD status = %d, want %d", headResp.StatusCode, http.StatusOK)
+	}
+	body, _ = io.ReadAll(headResp.Body)
+	if len(body) != 0 {
+		t.Fatalf("HEAD body length = %d, want 0", len(body))
+	}
+}
+
+func TestGradleBuildCacheHandler_RootKeyPath(t *testing.T) {
+	proxy, _, _, _ := setupTestProxy(t)
+	h := NewGradleBuildCacheHandler(proxy, "http://localhost")
+	srv := httptest.NewServer(h.Routes())
+	defer srv.Close()
+
+	key := "rootpathkey"
+	putReq, err := http.NewRequest(http.MethodPut, srv.URL+"/"+key, strings.NewReader("root"))
+	if err != nil {
+		t.Fatalf("failed to create PUT request: %v", err)
+	}
+	putResp, err := http.DefaultClient.Do(putReq)
+	if err != nil {
+		t.Fatalf("PUT request failed: %v", err)
+	}
+	_ = putResp.Body.Close()
+
+	if putResp.StatusCode != http.StatusCreated {
+		t.Fatalf("PUT status = %d, want %d", putResp.StatusCode, http.StatusCreated)
+	}
+
+	getResp, err := http.Get(srv.URL + "/cache/" + key)
+	if err != nil {
+		t.Fatalf("GET request failed: %v", err)
+	}
+	defer func() { _ = getResp.Body.Close() }()
+
+	if getResp.StatusCode != http.StatusOK {
+		t.Fatalf("GET status = %d, want %d", getResp.StatusCode, http.StatusOK)
+	}
+}
+
+func TestGradleBuildCacheHandler_GetMiss(t *testing.T) {
+	proxy, _, _, _ := setupTestProxy(t)
+	h := NewGradleBuildCacheHandler(proxy, "http://localhost")
+	srv := httptest.NewServer(h.Routes())
+	defer srv.Close()
+
+	resp, err := http.Get(srv.URL + "/cache/missing-key")
+	if err != nil {
+		t.Fatalf("GET request failed: %v", err)
+	}
+	defer func() { _ = resp.Body.Close() }()
+
+	if resp.StatusCode != http.StatusNotFound {
+		t.Fatalf("status = %d, want %d", resp.StatusCode, http.StatusNotFound)
+	}
+}
+
+func TestGradleBuildCacheHandler_MethodNotAllowed(t *testing.T) {
+	proxy, _, _, _ := setupTestProxy(t)
+	h := NewGradleBuildCacheHandler(proxy, "http://localhost")
+
+	req := httptest.NewRequest(http.MethodPost, "/cache/key", nil)
+	w := httptest.NewRecorder()
+	h.Routes().ServeHTTP(w, req)
+
+	if w.Code != http.StatusMethodNotAllowed {
+		t.Fatalf("status = %d, want %d", w.Code, http.StatusMethodNotAllowed)
+	}
+}
+
+func TestGradleBuildCacheHandler_PathTraversalRejected(t *testing.T) {
+	proxy, _, _, _ := setupTestProxy(t)
+	h := NewGradleBuildCacheHandler(proxy, "http://localhost")
+
+	req := httptest.NewRequest(http.MethodGet, "/cache/../secret", nil)
+	w := httptest.NewRecorder()
+	h.Routes().ServeHTTP(w, req)
+
+	if w.Code != http.StatusBadRequest {
+		t.Fatalf("status = %d, want %d", w.Code, http.StatusBadRequest)
+	}
+}
+
+func TestGradleBuildCacheHandler_PutOverwriteReturnsOK(t *testing.T) {
+	proxy, _, _, _ := setupTestProxy(t)
+	h := NewGradleBuildCacheHandler(proxy, "http://localhost")
+	srv := httptest.NewServer(h.Routes())
+	defer srv.Close()
+
+	key := "overwrite-key"
+
+	for i, payload := range []string{"first", "second"} {
+		req, err := http.NewRequest(http.MethodPut, srv.URL+"/cache/"+key, strings.NewReader(payload))
+		if err != nil {
+			t.Fatalf("failed to create PUT request: %v", err)
+		}
+		resp, err := http.DefaultClient.Do(req)
+		if err != nil {
+			t.Fatalf("PUT request failed: %v", err)
+		}
+		_ = resp.Body.Close()
+
+		want := http.StatusCreated
+		if i == 1 {
+			want = http.StatusOK
+		}
+		if resp.StatusCode != want {
+			t.Fatalf("PUT #%d status = %d, want %d", i+1, resp.StatusCode, want)
+		}
+	}
+}

internal/server/dashboard.go

@@ -286,6 +286,20 @@ index-url = ` + baseURL + `/pypi/simple/</code></pre>`),
     &lt;/mirror&gt;
   &lt;/mirrors&gt;
 &lt;/settings&gt;</code></pre>`),
+		},
+		{
+			ID:       "gradle",
+			Name:     "Gradle Build Cache",
+			Language: "Java/Kotlin",
+			Endpoint: "/gradle/cache/",
+			Instructions: template.HTML(`<p class="config-note">Configure Gradle to use the proxy for HttpBuildCache:</p>
+<pre><code>// In settings.gradle(.kts)
+buildCache {
+  remote(HttpBuildCache) {
+    url = uri("` + baseURL + `/gradle/cache/")
+    push = true
+  }
+}</code></pre>`),
 		},
 		{
 			ID:       "nuget",

internal/server/server.go

@@ -9,6 +9,7 @@
 //   - /pub/*      - pub.dev registry protocol
 //   - /pypi/*     - PyPI registry protocol
 //   - /maven/*    - Maven repository protocol
+//   - /gradle/*   - Gradle HttpBuildCache protocol
 //   - /nuget/*    - NuGet V3 API protocol
 //   - /composer/* - Composer/Packagist protocol
 //   - /conan/*    - Conan C/C++ protocol
@@ -177,6 +178,7 @@ func (s *Server) Start() error {
 	pubHandler := handler.NewPubHandler(proxy, s.cfg.BaseURL)
 	pypiHandler := handler.NewPyPIHandler(proxy, s.cfg.BaseURL)
 	mavenHandler := handler.NewMavenHandler(proxy, s.cfg.BaseURL)
+	gradleHandler := handler.NewGradleBuildCacheHandler(proxy, s.cfg.BaseURL)
 	nugetHandler := handler.NewNuGetHandler(proxy, s.cfg.BaseURL)
 	composerHandler := handler.NewComposerHandler(proxy, s.cfg.BaseURL)
 	conanHandler := handler.NewConanHandler(proxy, s.cfg.BaseURL)
@@ -194,6 +196,7 @@ func (s *Server) Start() error {
 	r.Mount("/pub", http.StripPrefix("/pub", pubHandler.Routes()))
 	r.Mount("/pypi", http.StripPrefix("/pypi", pypiHandler.Routes()))
 	r.Mount("/maven", http.StripPrefix("/maven", mavenHandler.Routes()))
+	r.Mount("/gradle", http.StripPrefix("/gradle", gradleHandler.Routes()))
 	r.Mount("/nuget", http.StripPrefix("/nuget", nugetHandler.Routes()))
 	r.Mount("/composer", http.StripPrefix("/composer", composerHandler.Routes()))
 	r.Mount("/conan", http.StripPrefix("/conan", conanHandler.Routes()))