<div class="screenshot">
<img src="/img/tutorial/request-form-models/image01.png">
</div>

## Forbid Extra Form Fields { #forbid-extra-form-fields }

In some special use cases (probably not very common), you might want to **restrict** the form fields to only those declared in the Pydantic model. And **forbid** any **extra** fields.

/// note

This is supported since FastAPI version `0.114.0`. 🤓

///

	elapsed := time.Since(begin)
	sql, rows := fc()
	fields := []slog.Attr{
		slog.String("duration", fmt.Sprintf("%.3fms", float64(elapsed.Nanoseconds())/1e6)),
		slog.String("sql", sql),
	}

	if rows != -1 {
		fields = append(fields, slog.Int64("rows", rows))
	}

	switch {
	case err != nil && (!l.IgnoreRecordNotFoundError || !errors.Is(err, ErrRecordNotFound)):
		fields = append(fields, slog.String("error", err.Error()))

    /** The tags field. */
    public static final String TAGS = "tags";
    /** The roles field. */
    public static final String ROLES = "roles";
    /** The fields field. */
    public static final String FIELDS = "fields";
    /** The languages field. */
    public static final String LANGUAGES = "languages";

    /** The key for array elements. */
    public static final String ARRAY_KEY = "key";

    }

    @Test
    @DisplayName("Test all constant fields count")
    void testConstantFieldsCount() {
        Field[] fields = SecurityInfo.class.getDeclaredFields();
        long constantCount = Arrays.stream(fields)
                .filter(f -> f.getType() == int.class)
                .filter(f -> Modifier.isStatic(f.getModifiers()))

                return baseConfig.getQueryAdditionalCacheResponseFields(fields);
            }

            @Override
            public String[] getQueryAdditionalHighlightedFields(String... fields) {
                return baseConfig.getQueryAdditionalHighlightedFields(fields);
            }

            @Override
            public String[] getQueryAdditionalSearchFields(String... fields) {

For example, in one of the ways the OAuth2 specification can be used (called "password flow") it is required to send a `username` and `password` as form fields.

The <abbr title="specification">spec</abbr> requires the fields to be exactly named `username` and `password`, and to be sent as form fields, not JSON.

    </class>
    <!-- /BuildProfile support -->
    <class locationTracker="locations">
      <name>InputLocation</name>
      <version>1.2.0+</version>
      <fields>
        <!-- line, column and source fields are auto-generated by Modello -->
      </fields>
      <codeSegments>
        <codeSegment>
          <version>1.2.0+</version>
          <code>

    @Override
    public String toString() {

                if (isExcludeSearchword(words[i], fields != null && fields.length > 0 ? fields[0] : "", langs, analyzer)) {
                    continue;
                }

                final String word = normalizer.normalize(words[i], fields != null && fields.length > 0 ? fields[0] : "", langs);
                final List<String> l = readingConverter.convert(word, fields != null && fields.length > 0 ? fields[0] : "", langs);

            fields cannot be used together. Only one of them should be used at any one time.
          </description>
        </field>
      </fields>
    </class>
    <!-- /BuildProfile support -->
    <class locationTracker="locations">
      <name>InputLocation</name>
      <version>2.0.0+</version>
      <fields>

    }

    /**
     * Test field count to ensure no unexpected fields are added
     */
    public void test_fieldCount() throws Exception {
        Field[] fields = FessLabels.class.getDeclaredFields();
        int labelConstantCount = 0;
        int serialVersionUIDCount = 0;

        for (Field field : fields) {
            if (field.getName().equals("serialVersionUID")) {