fix: Let Representations always have a body

This is relevant when the request has a content-type
but no data.

src/http/Operation.ts

@@ -29,7 +29,7 @@ export interface Operation {
    */
   permissionSet?: PermissionSet;
   /**
-   * Optional representation of the body.
+   * Representation of the body and metadata headers.
    */
-  body?: Representation;
+  body: Representation;
 }

src/http/input/body/BodyParser.ts

@@ -19,4 +19,4 @@ export interface BodyParserArgs {
  * Parses the body of an incoming {@link HttpRequest} and converts it to a {@link Representation}.
  */
 export abstract class BodyParser extends
-  AsyncHandler<BodyParserArgs, Representation | undefined> {}
+  AsyncHandler<BodyParserArgs, Representation> {}

src/http/input/body/RawBodyParser.ts

@@ -13,7 +13,7 @@ export class RawBodyParser extends BodyParser {
 
   // Note that the only reason this is a union is in case the body is empty.
   // If this check gets moved away from the BodyParsers this union could be removed
-  public async handle({ request, metadata }: BodyParserArgs): Promise<Representation | undefined> {
+  public async handle({ request, metadata }: BodyParserArgs): Promise<Representation> {
     const {
       'content-type': contentType,
       'content-length': contentLength,
@@ -26,7 +26,7 @@ export class RawBodyParser extends BodyParser {
     // some still provide a Content-Length of 0 (but without Content-Type).
     if ((!contentLength || (/^0+$/u.test(contentLength) && !contentType)) && !transferEncoding) {
       this.logger.debug('HTTP request does not have a body, or its empty body is missing a Content-Type header');
-      return;
+      return new BasicRepresentation([], metadata);
     }
 
     // While RFC7231 allows treating a body without content type as an octet stream,

src/http/input/body/SparqlUpdateBodyParser.ts

@@ -38,6 +38,7 @@ export class SparqlUpdateBodyParser extends BodyParser {
       binary: true,
       data: guardedStreamFrom(sparql),
       metadata,
+      isEmpty: false,
     };
   }
 }

src/http/ldp/PatchOperationHandler.ts

@@ -32,9 +32,9 @@ export class PatchOperationHandler extends OperationHandler {
     // Solid, §2.1: "A Solid server MUST reject PUT, POST and PATCH requests
     // without the Content-Type header with a status code of 400."
     // https://solid.github.io/specification/protocol#http-server
-    if (!operation.body?.metadata.contentType) {
-      this.logger.warn('No Content-Type header specified on PATCH request');
-      throw new BadRequestHttpError('No Content-Type header specified on PATCH request');
+    if (!operation.body.metadata.contentType) {
+      this.logger.warn('PATCH requests require the Content-Type header to be set');
+      throw new BadRequestHttpError('PATCH requests require the Content-Type header to be set');
     }
     await this.store.modifyResource(operation.target, operation.body as Patch, operation.conditions);
     return new ResetResponseDescription();

src/http/ldp/PostOperationHandler.ts

@@ -31,9 +31,9 @@ export class PostOperationHandler extends OperationHandler {
     // Solid, §2.1: "A Solid server MUST reject PUT, POST and PATCH requests
     // without the Content-Type header with a status code of 400."
     // https://solid.github.io/specification/protocol#http-server
-    if (!operation.body?.metadata.contentType) {
-      this.logger.warn('No Content-Type header specified on POST request');
-      throw new BadRequestHttpError('No Content-Type header specified on POST request');
+    if (!operation.body.metadata.contentType) {
+      this.logger.warn('POST requests require the Content-Type header to be set');
+      throw new BadRequestHttpError('POST requests require the Content-Type header to be set');
     }
     const identifier = await this.store.addResource(operation.target, operation.body, operation.conditions);
     return new CreatedResponseDescription(identifier);

src/http/ldp/PutOperationHandler.ts

@@ -31,9 +31,9 @@ export class PutOperationHandler extends OperationHandler {
     // Solid, §2.1: "A Solid server MUST reject PUT, POST and PATCH requests
     // without the Content-Type header with a status code of 400."
     // https://solid.github.io/specification/protocol#http-server
-    if (!operation.body?.metadata.contentType) {
-      this.logger.warn('No Content-Type header specified on PUT request');
-      throw new BadRequestHttpError('No Content-Type header specified on PUT request');
+    if (!operation.body.metadata.contentType) {
+      this.logger.warn('PUT requests require the Content-Type header to be set');
+      throw new BadRequestHttpError('PUT requests require the Content-Type header to be set');
     }
     await this.store.setRepresentation(operation.target, operation.body, operation.conditions);
     return new ResetResponseDescription();

src/http/representation/BasicRepresentation.ts

@@ -24,6 +24,11 @@ export class BasicRepresentation implements Representation {
   public readonly metadata: RepresentationMetadata;
   public readonly binary: boolean;
 
+  /**
+   * An empty Representation
+   */
+  public constructor();
+
   /**
    * @param data - The representation data
    * @param metadata - The representation metadata
@@ -86,13 +91,15 @@ export class BasicRepresentation implements Representation {
   );
 
   public constructor(
-    data: Readable | any[] | string,
-    metadata: RepresentationMetadata | MetadataRecord | MetadataIdentifier | string,
+    data?: Readable | any[] | string,
+    metadata?: RepresentationMetadata | MetadataRecord | MetadataIdentifier | string,
     metadataRest?: MetadataRecord | string | boolean,
     binary?: boolean,
   ) {
     if (typeof data === 'string' || Array.isArray(data)) {
       data = guardedStreamFrom(data);
+    } else if (!data) {
+      data = guardedStreamFrom([]);
     }
     this.data = guardStream(data);
 
@@ -110,4 +117,11 @@ export class BasicRepresentation implements Representation {
     }
     this.binary = binary;
   }
+
+  /**
+   * Data should only be interpreted if there is a content type.
+   */
+  public get isEmpty(): boolean {
+    return !this.metadata.contentType;
+  }
 }

src/http/representation/Representation.ts

@@ -19,4 +19,10 @@ export interface Representation {
    * (as opposed to complex objects).
    */
   binary: boolean;
+  /**
+   * Whether the data stream is empty.
+   * This being true does not imply that the data stream has a length of more than 0,
+   * only that it is a possibility and should be read to be sure.
+   */
+  isEmpty: boolean;
 }