Feature/get logo contentType from blob

The property `type` contains the MIME type[^1] which can be forwarded to
the caller.

[^1]:https://developer.mozilla.org/en-US/docs/Web/API/Blob/type

Fixes #4172

apps/api/src/app/logo/logo.controller.ts

@@ -26,12 +26,13 @@ export class LogoController {
     @Res() response: Response
   ) {
     try {
-      const buffer = await this.logoService.getLogoByDataSourceAndSymbol({
+      const { buffer, type } =
+        await this.logoService.getLogoByDataSourceAndSymbol({
           dataSource,
           symbol
         });
 
-      response.contentType('image/png');
+      response.contentType(type);
       response.send(buffer);
     } catch {
       response.status(HttpStatus.NOT_FOUND).send();
@@ -44,9 +45,9 @@ export class LogoController {
     @Res() response: Response
   ) {
     try {
-      const buffer = await this.logoService.getLogoByUrl(url);
+      const { buffer, type } = await this.logoService.getLogoByUrl(url);
 
-      response.contentType('image/png');
+      response.contentType(type);
       response.send(buffer);
     } catch {
       response.status(HttpStatus.NOT_FOUND).send();

apps/api/src/app/logo/logo.service.ts

@@ -38,12 +38,12 @@ export class LogoService {
     return this.getBuffer(assetProfile.url);
   }
 
-  public async getLogoByUrl(aUrl: string) {
+  public getLogoByUrl(aUrl: string) {
     return this.getBuffer(aUrl);
   }
 
-  private getBuffer(aUrl: string) {
+  private async getBuffer(aUrl: string) {
-    return fetch(
+    const blob = await fetch(
       `https://t0.gstatic.com/faviconV2?client=SOCIAL&type=FAVICON&fallback_opts=TYPE,SIZE,URL&url=${aUrl}&size=64`,
       {
         headers: { 'User-Agent': 'request' },
@@ -51,8 +51,11 @@ export class LogoService {
           this.configurationService.get('REQUEST_TIMEOUT')
         )
       }
-    )
+    ).then((res) => res.blob());
-      .then((res) => res.arrayBuffer())
+
-      .then((buffer) => Buffer.from(buffer));
+    return {
+      buffer: await blob.arrayBuffer().then((ab) => Buffer.from(ab)),
+      type: blob.type
+    };
   }
 }