Fix #408: validate characters of document field names

src/main/java/io/stargate/sgv2/jsonapi/config/constants/DocumentConstants.java

@@ -1,12 +1,18 @@
 package io.stargate.sgv2.jsonapi.config.constants;
 
 import io.stargate.sgv2.jsonapi.api.model.command.clause.filter.JsonType;
+import java.util.regex.Pattern;
 
 public interface DocumentConstants {
   /** Names of "special" fields in Documents */
   interface Fields {
     /** Primary key for Documents stored; has special handling for many operations. */
     String DOC_ID = "_id";
+
+    // Current definition of valid JSON API names: note that this only validates
+    // characters, not length limits (nor empty nor "too long" allowed but validated
+    // separately)
+    Pattern VALID_NAME_PATTERN = Pattern.compile("[a-zA-Z0-9_]*");
   }
 
   interface KeyTypeId {

src/main/java/io/stargate/sgv2/jsonapi/exception/ErrorCode.java

@@ -37,6 +37,8 @@ public enum ErrorCode {
 
   SHRED_DOC_LIMIT_VIOLATION("Document size limitation violated"),
 
+  SHRED_DOC_KEY_NAME_VIOLATION("Document key name constraints violated"),
+
   SHRED_BAD_EJSON_VALUE("Bad EJSON value"),
 
   INVALID_FILTER_EXPRESSION("Invalid filter expression"),

src/main/java/io/stargate/sgv2/jsonapi/service/shredding/Shredder.java

@@ -229,20 +229,30 @@ private void validateObjectValue(DocumentLimitsConfig limits, JsonNode objectVal
     var it = objectValue.fields();
     while (it.hasNext()) {
       var entry = it.next();
-      final String key = entry.getKey();
-      if (key.length() > documentLimits.maxPropertyNameLength()) {
-        throw new JsonApiException(
-            ErrorCode.SHRED_DOC_LIMIT_VIOLATION,
-            String.format(
-                "%s: Property name length (%d) exceeds maximum allowed (%s)",
-                ErrorCode.SHRED_DOC_LIMIT_VIOLATION.getMessage(),
-                key.length(),
-                limits.maxPropertyNameLength()));
-      }
+      validateObjectKey(limits, entry.getKey());
       validateDocValue(limits, entry.getValue(), depth);
     }
   }
 
+  private void validateObjectKey(DocumentLimitsConfig limits, String key) {
+    if (key.length() > documentLimits.maxPropertyNameLength()) {
+      throw new JsonApiException(
+          ErrorCode.SHRED_DOC_LIMIT_VIOLATION,
+          String.format(
+              "%s: Property name length (%d) exceeds maximum allowed (%s)",
+              ErrorCode.SHRED_DOC_LIMIT_VIOLATION.getMessage(),
+              key.length(),
+              limits.maxPropertyNameLength()));
+    }
+    if (!DocumentConstants.Fields.VALID_NAME_PATTERN.matcher(key).matches()) {
+      throw new JsonApiException(
+          ErrorCode.SHRED_DOC_KEY_NAME_VIOLATION,
+          String.format(
+              "%s: Property name ('%s') contains character(s) not allowed",
+              ErrorCode.SHRED_DOC_KEY_NAME_VIOLATION.getMessage(), key));
+    }
+  }
+
   private void validateStringValue(DocumentLimitsConfig limits, JsonNode stringValue) {
     final String value = stringValue.textValue();
     if (value.length() > limits.maxStringLength()) {

src/test/java/io/stargate/sgv2/jsonapi/service/shredding/ShredderDocLimitsTest.java

@@ -178,7 +178,7 @@ class ValidationDocAtomicSizeViolations {
     public void allowNotTooLongNames() {
       final ObjectNode doc = objectMapper.createObjectNode();
       doc.put("_id", 123);
-      doc.put("prop-123456789-123456789-123456789-123456789", true);
+      doc.put("prop_123456789_123456789_123456789_123456789", true);
       assertThat(shredder.shred(doc)).isNotNull();
     }
 
@@ -188,7 +188,7 @@ public void catchTooLongNames() {
       doc.put("_id", 123);
       ObjectNode ob = doc.putObject("subdoc");
       final String propName =
-          "property-with-way-too-long-name-123456789-123456789-123456789-123456789";
+          "property_with_way_too_long_name_123456789_123456789_123456789_123456789";
       ob.put(propName, true);
 
       Exception e = catchException(() -> shredder.shred(doc));
@@ -205,11 +205,28 @@ public void catchTooLongNames() {
                   + ")");
     }
 
+    @Test
+    public void catchInvalidNames() {
+      final ObjectNode doc = objectMapper.createObjectNode();
+      doc.put("_id", 123);
+      final String invalidName = "$date"; // property names must not start with $
+      doc.put(invalidName, 123456);
+
+      Exception e = catchException(() -> shredder.shred(doc));
+      assertThat(e)
+          .isNotNull()
+          .isInstanceOf(JsonApiException.class)
+          .hasFieldOrPropertyWithValue("errorCode", ErrorCode.SHRED_DOC_KEY_NAME_VIOLATION)
+          .hasMessageStartingWith(ErrorCode.SHRED_DOC_KEY_NAME_VIOLATION.getMessage())
+          .hasMessageEndingWith(
+              "Document key name constraints violated: Property name ('$date') contains character(s) not allowed");
+    }
+
     @Test
     public void allowNotTooLongStringValues() {
       final ObjectNode doc = objectMapper.createObjectNode();
       doc.put("_id", 123);
-      // Max is 16_000 so do bit less
+      // Max is 16_000 so do a bit less
       doc.put("text", RandomStringUtils.randomAscii(12_000));
       assertThat(shredder.shred(doc)).isNotNull();
     }