Sub2API v1.0 - AI API 网关（二开初始版本，基于上游 Wei-Shaw/sub2api）

backend/internal/service/upstream_path_guard_test.go

@@ -0,0 +1,198 @@
+package service
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/gin-gonic/gin"
+	"github.com/stretchr/testify/require"
+)
+
+func TestSanitizedUpstreamPathSuffixRejectsNonConformingSegments(t *testing.T) {
+	// 到达业务代码的 URL.Path 已是百分号解码后的结果，因此用例按解码后的形态书写。
+	rejected := []string{
+		"/..",
+		"/../..",
+		"/../../x/y",
+		"/./compact",
+		"/compact/..",
+		`/..\..\x`,
+		`/compact\..`,
+		"/?a=b",
+		"/compact?a=b",
+		"/compact#frag",
+		"/compact%2f..",
+		"/100%",
+		"//double",
+		"/compact//detail",
+		"/compact/",
+		"/ compact",
+		"/compact\x00",
+		"/compact\nX-Injected: 1",
+		"/模型",
+		"compact",
+		"/a:b",
+		"/a;b",
+		"/a,b",
+		"/a=b",
+		"/a&b",
+		// 允许清单是闭集：`\w` + `-` + `.` 以外的字符一律拒绝，
+		// 不依赖任何"已知坏字符"清单。
+		"/a~b",
+		"/a@b",
+		"/a+b",
+		"/a|b",
+		"/a*b",
+		"/a$b",
+		"/a(b)",
+		"/a'b",
+		"/a\"b",
+		"/a<b",
+		"/a\tb",
+		"/a b",
+		"/a∕b", // DIVISION SLASH
+		"/a／b", // FULLWIDTH SOLIDUS
+		// 只由点组成的片段一律拒绝（各实现对其解释不一致）。
+		"/...",
+		"/....",
+		"/compact/...",
+	}
+	for _, suffix := range rejected {
+		t.Run("reject_"+suffix, func(t *testing.T) {
+			got, ok := sanitizedUpstreamPathSuffix(suffix)
+			require.False(t, ok, "suffix %q must be rejected", suffix)
+			require.Empty(t, got)
+		})
+	}
+
+	accepted := map[string]string{
+		"":                          "",
+		"/compact":                  "/compact",
+		"/compact/detail":           "/compact/detail",
+		"/resp_68f0a1b2c3d4/cancel": "/resp_68f0a1b2c3d4/cancel",
+		"/gemini-2.5-pro_v1.2":      "/gemini-2.5-pro_v1.2",
+		"/a.b.c":                    "/a.b.c",
+	}
+	for suffix, want := range accepted {
+		t.Run("accept_"+suffix, func(t *testing.T) {
+			got, ok := sanitizedUpstreamPathSuffix(suffix)
+			require.True(t, ok, "suffix %q must be accepted", suffix)
+			require.Equal(t, want, got)
+		})
+	}
+}
+
+func TestSanitizedUpstreamPathSuffixEnforcesBounds(t *testing.T) {
+	longSegment := "/"
+	for i := 0; i < maxUpstreamPathSegmentLen+1; i++ {
+		longSegment += "a"
+	}
+	_, ok := sanitizedUpstreamPathSuffix(longSegment)
+	require.False(t, ok, "over-long segment must be rejected")
+
+	deep := ""
+	for i := 0; i <= maxUpstreamPathSegments; i++ {
+		deep += "/a"
+	}
+	_, ok = sanitizedUpstreamPathSuffix(deep)
+	require.False(t, ok, "over-deep suffix must be rejected")
+}
+
+// TestOpenAIResponsesRequestPathSuffixRejectsNonConformingSubpaths 锁定不变式：
+// /responses/*subpath 的子路径不得改变上游请求的路径结构；不合规时既不参与拼接，
+// 也不会被误判成 compact 请求。
+func TestOpenAIResponsesRequestPathSuffixRejectsNonConformingSubpaths(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	nonConformingPaths := []string{
+		"/v1/responses/../../x/y",
+		"/v1/responses/..%2f..%2fx/y",
+		"/v1/responses/%2e%2e/%2e%2e/x",
+		"/responses/%2e%2e%2fx",
+		"/backend-api/codex/responses/../../../x",
+		`/v1/responses/..\..\x`,
+		"/v1/responses/%3fa=b",
+		"/v1/responses/x%23frag",
+		"/v1/responses//double",
+	}
+	for _, path := range nonConformingPaths {
+		t.Run(path, func(t *testing.T) {
+			c := newResponsesSuffixTestContext(t, path)
+
+			require.False(t, IsForwardableOpenAIResponsesRequestPath(c),
+				"path %q must be rejected at the gateway edge", path)
+			require.Empty(t, openAIResponsesRequestPathSuffix(c),
+				"path %q must never contribute an upstream path suffix", path)
+			require.Equal(t, chatgptCodexURL,
+				appendOpenAIResponsesRequestPathSuffix(chatgptCodexURL, openAIResponsesRequestPathSuffix(c)))
+			require.False(t, isOpenAIResponsesCompactPath(c))
+		})
+	}
+
+	// 合法子路径必须保持原样转发。
+	for path, want := range map[string]string{
+		"/v1/responses":                        "",
+		"/v1/responses/compact":                "/compact",
+		"/v1/responses/input_tokens":           "/input_tokens",
+		"/responses/compact/":                  "/compact",
+		"/backend-api/codex/responses/compact": "/compact",
+	} {
+		t.Run("forwardable_"+path, func(t *testing.T) {
+			c := newResponsesSuffixTestContext(t, path)
+			require.True(t, IsForwardableOpenAIResponsesRequestPath(c))
+			require.Equal(t, want, openAIResponsesRequestPathSuffix(c))
+		})
+	}
+}
+
+func TestIsOpenAIResponsesInputTokensRequestPath(t *testing.T) {
+	for _, path := range []string{"/v1/responses/input_tokens", "/responses/input_tokens", "/backend-api/codex/responses/input_tokens"} {
+		c := newResponsesSuffixTestContext(t, path)
+		require.True(t, IsOpenAIResponsesInputTokensRequestPath(c), "path=%s", path)
+	}
+	c := newResponsesSuffixTestContext(t, "/v1/responses/compact")
+	require.False(t, IsOpenAIResponsesInputTokensRequestPath(c))
+}
+
+func TestIsOpenAIResponsesCompactPathUsesLegacyEndpointShape(t *testing.T) {
+	legacyPaths := []string{
+		"/v1/responses/compact",
+		"/v1/responses/compact/detail",
+		"/responses/compact/",
+	}
+	for _, path := range legacyPaths {
+		t.Run("legacy_"+path, func(t *testing.T) {
+			c := newResponsesSuffixTestContext(t, path)
+			require.True(t, IsOpenAIResponsesCompactPath(c))
+		})
+	}
+
+	nonLegacyPaths := []string{
+		"/v1/responses",
+		"/openai/v1/responses",
+		"/responses",
+		"/backend-api/codex/responses",
+		"/v1/responses/resp_123/cancel",
+	}
+	for _, path := range nonLegacyPaths {
+		t.Run("non_legacy_"+path, func(t *testing.T) {
+			c := newResponsesSuffixTestContext(t, path)
+			require.False(t, IsOpenAIResponsesCompactPath(c))
+		})
+	}
+}
+
+func TestAppendOpenAIResponsesRequestPathSuffixRefusesUnsafeSuffix(t *testing.T) {
+	// 调用方漏了校验时，拼接函数本身也不得把不合规片段带进上游 URL。
+	require.Equal(t, chatgptCodexURL, appendOpenAIResponsesRequestPathSuffix(chatgptCodexURL, "/../../x"))
+	require.Equal(t, chatgptCodexURL, appendOpenAIResponsesRequestPathSuffix(chatgptCodexURL, "/?a=b"))
+	require.Equal(t, chatgptCodexURL+"/compact", appendOpenAIResponsesRequestPathSuffix(chatgptCodexURL, "/compact"))
+}
+
+func newResponsesSuffixTestContext(t *testing.T, path string) *gin.Context {
+	t.Helper()
+	c, _ := gin.CreateTestContext(httptest.NewRecorder())
+	c.Request = httptest.NewRequest(http.MethodPost, path, nil)
+	return c
+}