fix(api): match plc.directory success content-types in thin compatibility

2 files changed, 48 insertions, 5 deletions

diff --git a/internal/api/plc_compatibility_test.go b/internal/api/plc_compatibility_test.go
index a669f0c..8787902 100644
--- a/internal/api/plc_compatibility_test.go
+++ b/internal/api/plc_compatibility_test.go
@@ -78,6 +78,10 @@ func TestPLCCompatibilityGetDataShape(t *testing.T) {
 		t.Fatalf("status: got %d want 200", resp.StatusCode)
 	}
 
+	if got := resp.Header.Get("Content-Type"); got != "application/json; charset=utf-8" {
+		t.Fatalf("content-type mismatch: got %q want %q", got, "application/json; charset=utf-8")
+	}
+
 	var body map[string]any
 
 	if err := json.NewDecoder(resp.Body).Decode(&body); err != nil {
@@ -126,6 +130,10 @@ func TestPLCCompatibilityGetLogOrdered(t *testing.T) {
 		t.Fatalf("status: got %d want 200", resp.StatusCode)
 	}
 
+	if got := resp.Header.Get("Content-Type"); got != "application/json; charset=utf-8" {
+		t.Fatalf("content-type mismatch: got %q want %q", got, "application/json; charset=utf-8")
+	}
+
 	var ops []map[string]any
 
 	if err := json.NewDecoder(resp.Body).Decode(&ops); err != nil {
@@ -352,6 +360,41 @@ func TestPLCCompatibilityTombstonedDIDReturnsNotAvailable404(t *testing.T) {
 	check("/" + tombDID + "/data")
 }
 
+func TestPLCCompatibilitySuccessContentTypesMatchUpstreamStyle(t *testing.T) {
+	ts, _, _, cleanup := newCompatibilityServer(t)
+	defer cleanup()
+
+	tests := []struct {
+		path string
+		want string
+	}{
+		{path: "/did:plc:alice", want: "application/did+ld+json; charset=utf-8"},
+		{path: "/did:plc:alice/data", want: "application/json; charset=utf-8"},
+		{path: "/did:plc:alice/log", want: "application/json; charset=utf-8"},
+		{path: "/did:plc:alice/log/last", want: "application/json; charset=utf-8"},
+		{path: "/did:plc:alice/log/audit", want: "application/json; charset=utf-8"},
+	}
+
+	for _, tc := range tests {
+		resp, err := http.Get(ts.URL + tc.path)
+		if err != nil {
+			t.Fatalf("get %s: %v", tc.path, err)
+		}
+
+		if resp.StatusCode != http.StatusOK {
+			_ = resp.Body.Close()
+			t.Fatalf("%s status: got %d want 200", tc.path, resp.StatusCode)
+		}
+
+		got := resp.Header.Get("Content-Type")
+		_ = resp.Body.Close()
+
+		if got != tc.want {
+			t.Fatalf("%s content-type mismatch: got %q want %q", tc.path, got, tc.want)
+		}
+	}
+}
+
 func newCompatibilityServer(t *testing.T) (*httptest.Server, *storage.PebbleStore, []types.ExportRecord, func()) {
 	t.Helper()
 
diff --git a/internal/api/server.go b/internal/api/server.go
index 284c2b2..a3b4513 100644
--- a/internal/api/server.go
+++ b/internal/api/server.go
@@ -513,7 +513,7 @@ func (s *Server) handleGetDIDCompatibility(w http.ResponseWriter, r *http.Reques
 	status := http.StatusOK
 	deactivated := false
 
-	writeJSONWithContentType(w, status, "application/did+ld+json", buildPLCDIDDocument(did, data, deactivated))
+	writeJSONWithContentType(w, status, "application/did+ld+json; charset=utf-8", buildPLCDIDDocument(did, data, deactivated))
 }
 
 func (s *Server) handleGetDIDLogCompatibility(w http.ResponseWriter, r *http.Request, did string) {
@@ -549,7 +549,7 @@ func (s *Server) handleGetDIDLogCompatibility(w http.ResponseWriter, r *http.Req
 		ops = append(ops, rec.Operation)
 	}
 
-	writeJSONWithContentType(w, http.StatusOK, "application/json", ops)
+	writeJSONWithContentType(w, http.StatusOK, "application/json; charset=utf-8", ops)
 }
 
 func (s *Server) handleGetDIDLogLastCompatibility(w http.ResponseWriter, r *http.Request, did string) {
@@ -579,7 +579,7 @@ func (s *Server) handleGetDIDLogLastCompatibility(w http.ResponseWriter, r *http
 		return
 	}
 
-	w.Header().Set("Content-Type", "application/json")
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
 	w.WriteHeader(http.StatusOK)
 
 	_, _ = w.Write(rec.Operation)
@@ -624,7 +624,7 @@ func (s *Server) handleGetDIDLogAuditCompatibility(w http.ResponseWriter, r *htt
 		})
 	}
 
-	writeJSONWithContentType(w, http.StatusOK, "application/json", audit)
+	writeJSONWithContentType(w, http.StatusOK, "application/json; charset=utf-8", audit)
 }
 
 func (s *Server) handleGetDIDDataCompatibility(w http.ResponseWriter, r *http.Request, did string) {
@@ -665,7 +665,7 @@ func (s *Server) handleGetDIDDataCompatibility(w http.ResponseWriter, r *http.Re
 		return
 	}
 
-	writeJSONWithContentType(w, http.StatusOK, "application/json", data)
+	writeJSONWithContentType(w, http.StatusOK, "application/json; charset=utf-8", data)
 }
 
 func (s *Server) resolveCompatibilityState(w http.ResponseWriter, r *http.Request, did string) (types.StateV1, bool) {