fix: Handle JSON preferences correctly in dynamic converter

CommunitySolidServer · Nov 8, 2021 · 4d319d2 · 4d319d2
1 parent c6544fa
commit 4d319d2
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Showing 2 changed files with 41 additions and 0 deletions.
diff --git a/src/storage/conversion/DynamicJsonToTemplateConverter.ts b/src/storage/conversion/DynamicJsonToTemplateConverter.ts
@@ -24,6 +24,8 @@ import type { RepresentationConverterArgs } from './RepresentationConverter';
  * describing the content-type of that template.
  *
  * The output of the result depends on the content-type matched with the template.
+ * In case JSON is the most preferred output type,
+ * the input representation will be returned unless a JSON template is defined.
  */
 export class DynamicJsonToTemplateConverter extends RepresentationConverter {
   private readonly templateEngine: TemplateEngine;
@@ -51,6 +53,11 @@ export class DynamicJsonToTemplateConverter extends RepresentationConverter {
     const typeMap = this.constructTypeMap(identifier, representation);
     const type = this.findType(typeMap, preferences.type);
 
+    // No conversion needed if JSON is requested and there is no specific JSON template
+    if (type === APPLICATION_JSON && typeMap[APPLICATION_JSON].length === 0) {
+      return representation;
+    }
+
     const json = JSON.parse(await readableToString(representation.data));
 
     const rendered = await this.templateEngine.render(json, { templateFile: typeMap[type] });
@@ -69,6 +76,11 @@ export class DynamicJsonToTemplateConverter extends RepresentationConverter {
       .map((quad): Term => quad.object)
       .filter((term: Term): boolean => term.termType === 'NamedNode') as NamedNode[];
 
+    // This handler should only cover cases where templates are defined
+    if (templates.length === 0) {
+      throw new NotImplementedHttpError('No templates found.');
+    }
+
     // Maps all content-types to their template
     const typeMap: Record<string, string> = {};
     for (const template of templates) {
@@ -77,6 +89,12 @@ export class DynamicJsonToTemplateConverter extends RepresentationConverter {
         typeMap[type] = template.value;
       }
     }
+
+    // Not using a template is always an option unless there is a specific JSON template
+    if (!typeMap[APPLICATION_JSON]) {
+      typeMap[APPLICATION_JSON] = '';
+    }
+
     return typeMap;
   }
 

diff --git a/test/unit/storage/conversion/DynamicJsonToTemplateConverter.test.ts b/test/unit/storage/conversion/DynamicJsonToTemplateConverter.test.ts
@@ -1,9 +1,11 @@
 import { DataFactory } from 'n3';
 import { BasicRepresentation } from '../../../../src/http/representation/BasicRepresentation';
 import type { Representation } from '../../../../src/http/representation/Representation';
+import { RepresentationMetadata } from '../../../../src/http/representation/RepresentationMetadata';
 import type { RepresentationPreferences } from '../../../../src/http/representation/RepresentationPreferences';
 import { DynamicJsonToTemplateConverter } from '../../../../src/storage/conversion/DynamicJsonToTemplateConverter';
 import type { RepresentationConverterArgs } from '../../../../src/storage/conversion/RepresentationConverter';
+import { NotImplementedHttpError } from '../../../../src/util/errors/NotImplementedHttpError';
 import { readableToString } from '../../../../src/util/StreamUtil';
 import type { TemplateEngine } from '../../../../src/util/templates/TemplateEngine';
 import { CONTENT_TYPE_TERM, SOLID_META } from '../../../../src/util/Vocabularies';
@@ -50,6 +52,12 @@ describe('A DynamicJsonToTemplateConverter', (): void => {
     await expect(converter.canHandle(input)).resolves.toBeUndefined();
   });
 
+  it('rejects JSON input if no templates are defined.', async(): Promise<void> => {
+    preferences.type = { 'application/json': 1 };
+    representation.metadata = new RepresentationMetadata('application/json');
+    await expect(converter.canHandle(input)).rejects.toThrow(NotImplementedHttpError);
+  });
+
   it('uses the input JSON as parameters for the matching template.', async(): Promise<void> => {
     const result = await converter.handle(input);
     await expect(readableToString(result.data)).resolves.toBe('<html>');
@@ -64,4 +72,19 @@ describe('A DynamicJsonToTemplateConverter', (): void => {
     const result = await converter.handle(input);
     await expect(readableToString(result.data)).resolves.toBe('<html>');
   });
+
+  it('returns the input representation if JSON is preferred.', async(): Promise<void> => {
+    input.preferences.type = { 'application/json': 1, 'text/html': 0.5 };
+    await expect(converter.handle(input)).resolves.toBe(input.representation);
+  });
+
+  it('still converts if JSON is preferred but there is a JSON template.', async(): Promise<void> => {
+    input.preferences.type = { 'application/json': 1 };
+    const templateNode = namedNode(templateFile);
+    representation.metadata.add(SOLID_META.terms.template, templateNode);
+    representation.metadata.addQuad(templateNode, CONTENT_TYPE_TERM, 'application/json');
+    const result = await converter.handle(input);
+    await expect(readableToString(result.data)).resolves.toBe('<html>');
+    expect(result.metadata.contentType).toBe('application/json');
+  });
 });