---
title: "parser(_:resolveExternalEntityName:systemID:)"
framework: foundation
role: symbol
role_heading: Instance Method
path: "foundation/xmlparserdelegate/parser(_:resolveexternalentityname:systemid:)"
---

# parser(_:resolveExternalEntityName:systemID:)

Sent by a parser object to its delegate when it encounters a given external entity with a specific system ID.

## Declaration

```swift
optional func parser(_ parser: XMLParser, resolveExternalEntityName name: String, systemID: String?) -> Data?
```

## Parameters

- `parser`: A parser object.
- `name`: A string that specifies the external name of an entity.
- `systemID`: A string that specifies the system ID for the external entity.

## Return Value

Return Value An NSData object that contains the resolution of the given external entity.

## Discussion

Discussion The delegate can resolve the external entity (for example, locating and reading an externally declared DTD) and provide the result to the parser object as an NSData object.

## See Also

### Related Documentation

- [parser(_:foundExternalEntityDeclarationWithName:publicID:systemID:)](foundation/xmlparserdelegate/parser(_:foundexternalentitydeclarationwithname:publicid:systemid:).md)
- [parser(_:foundUnparsedEntityDeclarationWithName:publicID:systemID:notationName:)](foundation/xmlparserdelegate/parser(_:foundunparsedentitydeclarationwithname:publicid:systemid:notationname:).md)

### Handling XML

- [parserDidStartDocument(_:)](foundation/xmlparserdelegate/parserdidstartdocument(_:).md)
- [parserDidEndDocument(_:)](foundation/xmlparserdelegate/parserdidenddocument(_:).md)
- [parser(_:didStartElement:namespaceURI:qualifiedName:attributes:)](foundation/xmlparserdelegate/parser(_:didstartelement:namespaceuri:qualifiedname:attributes:).md)
- [parser(_:didEndElement:namespaceURI:qualifiedName:)](foundation/xmlparserdelegate/parser(_:didendelement:namespaceuri:qualifiedname:).md)
- [parser(_:didStartMappingPrefix:toURI:)](foundation/xmlparserdelegate/parser(_:didstartmappingprefix:touri:).md)
- [parser(_:didEndMappingPrefix:)](foundation/xmlparserdelegate/parser(_:didendmappingprefix:).md)
- [parser(_:parseErrorOccurred:)](foundation/xmlparserdelegate/parser(_:parseerroroccurred:).md)
- [parser(_:validationErrorOccurred:)](foundation/xmlparserdelegate/parser(_:validationerroroccurred:).md)
- [parser(_:foundCharacters:)](foundation/xmlparserdelegate/parser(_:foundcharacters:).md)
- [parser(_:foundIgnorableWhitespace:)](foundation/xmlparserdelegate/parser(_:foundignorablewhitespace:).md)
- [parser(_:foundProcessingInstructionWithTarget:data:)](foundation/xmlparserdelegate/parser(_:foundprocessinginstructionwithtarget:data:).md)
- [parser(_:foundComment:)](foundation/xmlparserdelegate/parser(_:foundcomment:).md)
- [parser(_:foundCDATA:)](foundation/xmlparserdelegate/parser(_:foundcdata:).md)