shift DOM parsing to readAsXML to allow for customizability in fetcher

Author: chocolatkey

navigator/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@readium/navigator",
-  "version": "2.3.0",
+  "version": "2.4.0-alpha.8",
   "type": "module",
   "description": "Next generation SDK for publications in Web Apps",
   "author": "readium",

navigator/src/epub/frame/FrameBlobBuilder.ts

@@ -76,14 +76,8 @@ export default class FrameBlobBuilder {
 
         // Load the HTML resource
         const link = await this.currentResource.link();
-        const txt = await this.currentResource.readAsString();
-        if(!txt) throw new Error(`Failed reading item ${link.href}`);
-        
-        const doc = new DOMParser().parseFromString(
-            txt,
-            link.mediaType.string as DOMParserSupportedType
-        );
-
+        const doc = await this.currentResource.readAsXML() as HTMLDocument;
+        if(!doc) throw new Error(`Failed reading item ${link.href}`);
         const perror = doc.querySelector("parsererror");
         if (perror) {
             const details = perror.querySelector("div");

shared/src/fetcher/HttpFetcher.ts

@@ -108,15 +108,15 @@ export class HttpResource implements Resource {
     return await resp.text();
   }
 
-  async readAsXML(): Promise<XMLDocument> {
+  async readAsXML(): Promise<Document> {
     const resp = await this.client(this.url);
     if (!resp.ok)
       throw new Error(
         `http GET request for ${this.url} failed with HTTP status code ${resp.status}`
       ); // TODO
     return new DOMParser().parseFromString(
       await resp.text(),
-      'application/xml'
+      this._link.mediaType.isHTML ? (this._link.mediaType.string as 'application/xhtml+xml' | 'text/html') : 'text/xml'
     );
   }
 }

shared/src/fetcher/Resource.ts

@@ -27,11 +27,11 @@ export abstract class Resource {
       return JSON.parse(str);
     });
   }
-  readAsXML(): Promise<XMLDocument | undefined> {
-    return this.readAsString().then(str => {
+  readAsXML(): Promise<Document | undefined> {
+    return this.link().then(l => this.readAsString().then(str => {
       if (str === undefined) return str;
-      return new DOMParser().parseFromString(str, 'text/xml');
-    });
+      return new DOMParser().parseFromString(str, l.mediaType.isHTML ? (l.mediaType.string as 'application/xhtml+xml' | 'text/html') : 'text/xml');
+    }));
   }
   abstract close(): void;
 }