fix(field-suggestions): Fix block-field-suggestions rule throwing Bod…

internal/business/proxy/proxy.go

@@ -32,25 +32,36 @@ func NewProxy(cfg Config, blockFieldSuggestions *block_field_suggestions.BlockFi
 			KeepAlive: cfg.KeepAlive,
 		}).DialContext,
 	}
-	proxy.ModifyResponse = func(res *http.Response) error {
+	proxy.ModifyResponse = modifyResponse(blockFieldSuggestions)
+
+	return proxy, nil
+}
+
+func modifyResponse(blockFieldSuggestions *block_field_suggestions.BlockFieldSuggestionsHandler) func(res *http.Response) error {
+	return func(res *http.Response) error {
 		if !blockFieldSuggestions.Enabled() {
 			return nil
 		}
 
-		decoder := json.NewDecoder(res.Body)
+		// read raw response bytes
+		bodyBytes, _ := io.ReadAll(res.Body)
 		defer res.Body.Close()
 
 		var response map[string]interface{}
-		err := decoder.Decode(&response)
+		err := json.Unmarshal(bodyBytes, &response)
 		if err != nil {
 			// if we cannot decode just return
+			// make sure to set body back to original bytes
+			res.Body = io.NopCloser(bytes.NewBuffer(bodyBytes))
 			return nil
 		}
 
 		modified := blockFieldSuggestions.ProcessBody(response)
 		bts, err := json.Marshal(modified)
 		if err != nil {
 			// if we cannot marshall just return
+			// make sure to set body back to original bytes
+			res.Body = io.NopCloser(bytes.NewBuffer(bodyBytes))
 			return nil
 		}
 
@@ -61,6 +72,4 @@ func NewProxy(cfg Config, blockFieldSuggestions *block_field_suggestions.BlockFi
 
 		return nil
 	}
-
-	return proxy, nil
 }

internal/business/proxy/proxy_test.go

@@ -0,0 +1,144 @@
+package proxy
+
+import (
+	"github.com/ldebruijn/go-graphql-armor/internal/business/block_field_suggestions"
+	"github.com/stretchr/testify/assert"
+	"io"
+	"net/http"
+	"strings"
+	"testing"
+)
+
+func Test_modifyResponse(t *testing.T) {
+	type args struct {
+		blockFieldSuggestions *block_field_suggestions.BlockFieldSuggestionsHandler
+		response              *http.Response
+	}
+	tests := []struct {
+		name string
+		args args
+		want func(res *http.Response)
+	}{
+		{
+			name: "nothing if disabled",
+			args: args{
+				blockFieldSuggestions: func() *block_field_suggestions.BlockFieldSuggestionsHandler {
+					return block_field_suggestions.NewBlockFieldSuggestionsHandler(block_field_suggestions.Config{
+						Enabled: false,
+					})
+				}(),
+				response: func() *http.Response {
+					return &http.Response{
+						Status:        "200",
+						StatusCode:    200,
+						Body:          io.NopCloser(strings.NewReader("this is not valid json")),
+						Proto:         "HTTP/1.1",
+						ProtoMajor:    1,
+						ProtoMinor:    1,
+						ContentLength: 0,
+						Header:        map[string][]string{},
+					}
+				}(),
+			},
+			want: func(res *http.Response) {
+				body, _ := io.ReadAll(res.Body)
+				assert.Equal(t, 200, res.StatusCode)
+				assert.Equal(t, "200", res.Status)
+				assert.Equal(t, "this is not valid json", string(body))
+			},
+		},
+		{
+			name: "handles non-json gracefully",
+			args: args{
+				blockFieldSuggestions: func() *block_field_suggestions.BlockFieldSuggestionsHandler {
+					return block_field_suggestions.NewBlockFieldSuggestionsHandler(block_field_suggestions.Config{
+						Enabled: true,
+					})
+				}(),
+				response: func() *http.Response {
+					return &http.Response{
+						Status:        "200",
+						StatusCode:    200,
+						Body:          io.NopCloser(strings.NewReader("this is not valid json")),
+						Proto:         "HTTP/1.1",
+						ProtoMajor:    1,
+						ProtoMinor:    1,
+						ContentLength: 0,
+						Header:        map[string][]string{},
+					}
+				}(),
+			},
+			want: func(res *http.Response) {
+				body, _ := io.ReadAll(res.Body)
+				assert.Equal(t, 200, res.StatusCode)
+				assert.Equal(t, "200", res.Status)
+				assert.Equal(t, "this is not valid json", string(body))
+			},
+		},
+		{
+			name: "handles invalid-json gracefully",
+			args: args{
+				blockFieldSuggestions: func() *block_field_suggestions.BlockFieldSuggestionsHandler {
+					return block_field_suggestions.NewBlockFieldSuggestionsHandler(block_field_suggestions.Config{
+						Enabled: true,
+					})
+				}(),
+				response: func() *http.Response {
+					return &http.Response{
+						Status:        "200",
+						StatusCode:    200,
+						Body:          io.NopCloser(strings.NewReader("{ \"this\": \" is not valid json }")),
+						Proto:         "HTTP/1.1",
+						ProtoMajor:    1,
+						ProtoMinor:    1,
+						ContentLength: 0,
+						Header:        map[string][]string{},
+					}
+				}(),
+			},
+			want: func(res *http.Response) {
+				body, _ := io.ReadAll(res.Body)
+				assert.Equal(t, 200, res.StatusCode)
+				assert.Equal(t, "200", res.Status)
+				assert.Equal(t, "{ \"this\": \" is not valid json }", string(body))
+			},
+		},
+		{
+			name: "handles json gracefully",
+			args: args{
+				blockFieldSuggestions: func() *block_field_suggestions.BlockFieldSuggestionsHandler {
+					return block_field_suggestions.NewBlockFieldSuggestionsHandler(block_field_suggestions.Config{
+						Enabled: true,
+						Mask:    "[masked]",
+					})
+				}(),
+				response: func() *http.Response {
+					return &http.Response{
+						Status:        "200",
+						StatusCode:    200,
+						Body:          io.NopCloser(strings.NewReader("{ \"errors\": [{\"message\": \"Did you mean \"}] }")),
+						Proto:         "HTTP/1.1",
+						ProtoMajor:    1,
+						ProtoMinor:    1,
+						ContentLength: 0,
+						Header:        map[string][]string{},
+					}
+				}(),
+			},
+			want: func(res *http.Response) {
+				body, _ := io.ReadAll(res.Body)
+				assert.Equal(t, 200, res.StatusCode)
+				assert.Equal(t, "200", res.Status)
+				assert.Equal(t, "{\"errors\":[{\"message\":\"[masked]\"}]}", string(body))
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := modifyResponse(tt.args.blockFieldSuggestions)
+
+			_ = result(tt.args.response)
+			tt.want(tt.args.response)
+		})
+	}
+}