Fix TriG documents not being PUT-able

src/storage/mapping/ExtensionBasedMapper.ts

@@ -8,6 +8,10 @@ import { BaseFileIdentifierMapper } from './BaseFileIdentifierMapper';
 import type { FileIdentifierMapperFactory, ResourceLink } from './FileIdentifierMapper';
 
 export class ExtensionBasedMapper extends BaseFileIdentifierMapper {
+  public static readonly mimeFallback: Record<string, string> = {
+    'application/trig': 'trig',
+  };
+
   private readonly types: Record<string, any>;
 
   public constructor(base: string, rootFilepath: string, overrideTypes = { acl: TEXT_TURTLE, meta: TEXT_TURTLE }) {
@@ -42,7 +46,7 @@ export class ExtensionBasedMapper extends BaseFileIdentifierMapper {
     // If the extension of the identifier matches a different content-type than the one that is given,
     // we need to add a new extension to match the correct type.
     } else if (contentType !== await this.getContentTypeFromPath(filePath)) {
-      const extension = mime.extension(contentType);
+      const extension = mime.extension(contentType) || ExtensionBasedMapper.mimeFallback[contentType];
       if (!extension) {
         this.logger.warn(`No extension found for ${contentType}`);
         throw new NotImplementedHttpError(`Unsupported content type ${contentType}`);