refactor: improve error handling and validation for PDF field metadata parsing

packages/lib/server-only/pdf/auto-place-fields.ts

@@ -1,4 +1,6 @@
+import { AppError, AppErrorCode } from '@documenso/lib/errors/app-error';
 import { type TFieldAndMeta, ZEnvelopeFieldAndMetaSchema } from '@documenso/lib/types/field-meta';
+import { logger } from '@documenso/lib/utils/logger';
 import { PDF, rgb } from '@libpdf/core';
 import type { FieldType, Recipient } from '@prisma/client';
 
@@ -114,14 +116,49 @@ export const extractPlaceholdersFromPDF = async (pdf: Buffer): Promise<Placehold
 
       const recipient = recipientOrMeta;
 
-      const rawFieldMeta = parseRawFieldMetaFromPlaceholder(fieldMetaData);
+      /*
+        Parse and validate the field metadata. A malformed selection placeholder
+        (e.g. an unknown validation rule or a default value that doesn't match an
+        option) is skipped like an invalid field type rather than aborting the whole
+        upload, which may contain other valid placeholders and files.
+      */
+      let fieldAndMeta: TFieldAndMeta;
 
-      const parsedFieldMeta = parseFieldMetaFromPlaceholder(rawFieldMeta, fieldType);
+      try {
+        const rawFieldMeta = parseRawFieldMetaFromPlaceholder(fieldMetaData);
+        const parsedFieldMeta = parseFieldMetaFromPlaceholder(rawFieldMeta, fieldType);
 
-      const fieldAndMeta: TFieldAndMeta = ZEnvelopeFieldAndMetaSchema.parse({
-        type: fieldType,
-        fieldMeta: parsedFieldMeta,
-      });
+        const parsedFieldAndMeta = ZEnvelopeFieldAndMetaSchema.safeParse({
+          type: fieldType,
+          fieldMeta: parsedFieldMeta,
+        });
+
+        /*
+          Surface schema failures as INVALID_BODY (400) instead of letting the raw
+          ZodError bubble up to the caller as an INTERNAL_SERVER_ERROR (500).
+        */
+        if (!parsedFieldAndMeta.success) {
+          throw new AppError(AppErrorCode.INVALID_BODY, {
+            message: `Invalid field metadata for placeholder "${placeholder}": ${parsedFieldAndMeta.error.message}`,
+          });
+        }
+
+        fieldAndMeta = parsedFieldAndMeta.data;
+      } catch (error) {
+        const appError = AppError.parseError(error);
+
+        logger.warn(
+          {
+            placeholder,
+            page: page.index + 1,
+            code: appError.code,
+            message: appError.message,
+          },
+          'Skipping placeholder with invalid field metadata',
+        );
+
+        continue;
+      }
 
       /*
         LibPDF returns bbox in points with bottom-left origin.

packages/lib/server-only/pdf/helpers.ts

@@ -198,12 +198,6 @@ const getDefaultFieldMetaValue = (rawFieldMeta: Record<string, string>) => {
   return defaultValue ? normalizePlaceholderSelectionValue(defaultValue) : undefined;
 };
 
-const getCheckedFieldMetaValues = (rawFieldMeta: Record<string, string>) => {
-  const checkedValue = rawFieldMeta.checked;
-
-  return checkedValue ? parsePlaceholderOptions(checkedValue) : [];
-};
-
 const parseCheckboxValidationRule = (value: string): string => {
   const validationRule = CHECKBOX_VALIDATION_RULE_BY_ALIAS[value];
 
@@ -268,7 +262,7 @@ const applyRadioFieldOptions = (parsedFieldMeta: Record<string, unknown>, rawFie
 
 const applyCheckboxFieldOptions = (parsedFieldMeta: Record<string, unknown>, rawFieldMeta: Record<string, string>) => {
   const options = parseSelectionFieldOptions(rawFieldMeta, FieldType.CHECKBOX);
-  const checkedValues = getCheckedFieldMetaValues(rawFieldMeta);
+  const checkedValues = rawFieldMeta.checked ? parsePlaceholderOptions(rawFieldMeta.checked) : [];
 
   if (!options && checkedValues.length > 0) {
     throw new AppError(AppErrorCode.INVALID_BODY, {
@@ -328,21 +322,37 @@ const applyDropdownFieldOptions = (parsedFieldMeta: Record<string, unknown>, raw
   }
 };
 
+/*
+  Generic field metadata properties are simple properties consisting of a key and a value.
+  E.g. 'required=true', 'fontSize=12', 'textAlign=left'
+  They don't require special handling.
+
+  Special field metadata properties are complex properties consisting of a key and a value with multiple parts.
+  E.g. 'options=Card/Check|Bank Transfer', 'checked=Card|Check', 'selected=Bank Transfer'
+  They require special handling.
+*/
 const shouldSkipGenericFieldMetaParsing = (property: string, fieldType: FieldType): boolean => {
   if (property === 'options' || property === 'default' || property === 'selected') {
     return true;
   }
 
-  if (fieldType !== FieldType.CHECKBOX && fieldType !== FieldType.RADIO && fieldType !== FieldType.DROPDOWN) {
+  const isSelectionField =
+    fieldType === FieldType.CHECKBOX || fieldType === FieldType.RADIO || fieldType === FieldType.DROPDOWN;
+
+  if (!isSelectionField) {
     return false;
   }
 
-  return (
+  if (
     property === 'label' ||
     property === 'placeholder' ||
     property === 'defaultValue' ||
-    (property === 'checked' && fieldType === FieldType.CHECKBOX)
-  );
+    (fieldType === FieldType.CHECKBOX && property === 'checked')
+  ) {
+    return true;
+  }
+
+  return false;
 };
 
 /*
@@ -404,17 +414,11 @@ export const parseFieldMetaFromPlaceholder = (
     }
   }
 
-  if (fieldType === FieldType.RADIO) {
-    applyRadioFieldOptions(parsedFieldMeta, rawFieldMeta);
-  }
-
-  if (fieldType === FieldType.CHECKBOX) {
-    applyCheckboxFieldOptions(parsedFieldMeta, rawFieldMeta);
-  }
-
-  if (fieldType === FieldType.DROPDOWN) {
-    applyDropdownFieldOptions(parsedFieldMeta, rawFieldMeta);
-  }
+  match(fieldType)
+    .with(FieldType.RADIO, () => applyRadioFieldOptions(parsedFieldMeta, rawFieldMeta))
+    .with(FieldType.CHECKBOX, () => applyCheckboxFieldOptions(parsedFieldMeta, rawFieldMeta))
+    .with(FieldType.DROPDOWN, () => applyDropdownFieldOptions(parsedFieldMeta, rawFieldMeta))
+    .otherwise(() => undefined);
 
   return parsedFieldMeta;
 };