feat: Added fetchRequestInitGenerator option

--

In scenarios where elements contain multiple URLs, including both internal and public links, there arises a need to supply distinct RequestInit configurations for various fetch requests.

Presently, the limitation lies in the fact that we can only provide a single fetchRequestInit, and this configuration is globally applied to all fetch calls for that element.

This proposed feature aims to enhance flexibility by enabling the provision of providing RequestInit configurations tailored to individual fetch requests based on their respective URLs. This enhancement ensures more granular control over the customization of fetch request behaviors, facilitating better handling of internal and public URLs.

src/dataurl.ts

@@ -81,9 +81,12 @@ export async function resourceToDataURL(
 
   let dataURL: string
   try {
+    const requestInit = options.fetchRequestInit
+      ? options.fetchRequestInit
+      : options.fetchRequestInitGenerator?.(resourceUrl)
     const content = await fetchAsDataURL(
       resourceUrl,
-      options.fetchRequestInit,
+      requestInit,
       ({ res, result }) => {
         if (!contentType) {
           // eslint-disable-next-line no-param-reassign

src/embed-webfonts.ts

@@ -35,14 +35,13 @@ async function embedFonts(data: Metadata, options: Options): Promise<string> {
       url = new URL(url, data.url).href
     }
 
-    return fetchAsDataURL<[string, string]>(
-      url,
-      options.fetchRequestInit,
-      ({ result }) => {
-        cssText = cssText.replace(loc, `url(${result})`)
-        return [loc, result]
-      },
-    )
+    const requestInit = options.fetchRequestInit
+      ? options.fetchRequestInit
+      : options.fetchRequestInitGenerator?.(url)
+    return fetchAsDataURL<[string, string]>(url, requestInit, ({ result }) => {
+      cssText = cssText.replace(loc, `url(${result})`)
+      return [loc, result]
+    })
   })
 
   return Promise.all(loadFonts).then(() => cssText)

src/types.ts

@@ -91,4 +91,12 @@ export interface Options {
    *
    */
   fetchRequestInit?: RequestInit
+
+  /**
+   * Function that generates a RequestInit based on a given URL.
+   * This function is intended to provide a convenient way to customize the RequestInit configuration for
+   * fetching the data from a specific URL.
+   *
+   */
+  fetchRequestInitGenerator?: (url: string) => RequestInit | undefined
 }

test/spec/options.spec.ts

@@ -173,4 +173,19 @@ describe('work with options', () => {
       .then(done)
       .catch(done)
   })
+
+  it('should support fetchRequestInitGenerator', (done) => {
+    bootstrap('images/node.html', 'images/style.css')
+      .then(
+        assertTextRendered(['PNG', 'JPG'], {
+          fetchRequestInitGenerator: (url: string) => {
+            return url.includes("/test")
+              ? { credentials: 'include' } as RequestInit
+              : undefined
+          },
+        }),
+      )
+      .then(done)
+      .catch(done)
+  })
 })