fix: send JSON headers to avoid malformed responses (#2624)

src/app/services/HttpClient.ts

@@ -2,6 +2,11 @@ import { Contracts, Http } from "@arkecosystem/platform-sdk";
 import fetch from "isomorphic-fetch";
 
 export class HttpClient extends Http.Request {
+	private readonly headers: Record<string, string> = {
+		Accept: "application/json",
+		"Content-Type": "application/json",
+	};
+
 	protected async send(
 		method: string,
 		url: string,
@@ -12,20 +17,16 @@ export class HttpClient extends Http.Request {
 	): Promise<Contracts.HttpResponse> {
 		let response;
 
-		if (data?.query) {
-			const hasQueryKeys: boolean = Object.keys(data.query).length > 0;
-
-			if (hasQueryKeys) {
-				url = `${url}?${new URLSearchParams(data.query as any)}`;
-			}
+		if (data?.query && Object.keys(data?.query).length > 0) {
+			url = `${url}?${new URLSearchParams(data.query as any)}`;
 		}
 
 		if (method === "GET") {
-			response = await fetch(url);
+			response = await fetch(url, { headers: this.headers });
 		}
 
 		if (method === "POST") {
-			response = await fetch(url, { method: "POST", body: JSON.stringify(data?.data) });
+			response = await fetch(url, { method: "POST", body: JSON.stringify(data?.data), headers: this.headers });
 		}
 
 		return new Http.Response({