Ionic CORS issue with JIRA API - ionic-framework

Question

Problem description : I have built a ionic app which uses JIRA rest api to fetch issue (GET data), create issue (POST data). I always get CORS error's like preflight request did not succeed or same origin policy which are expected when we use ionic serve but the same is not working when I build and release the signed apk.
My ionic server runs on localhost:8100 (ionic version -4) &
Jira server runs on localhost:8089 (JIRA version - core 7)
What I have done so far :
followed the proxy approach as mentioned in ionic blog --No success
enabled CORS filter plugin in JIRA server and whitelisted ionic server --No success
Added headers for Allow control origin -- No success
Build the apk file using --prod release signed and tried the same on device --No sucess
Here is my auth.ts file reference if any-one can help and advise here about what I am doing wrong here.
import { HttpClient, HttpHeaders } from '#angular/common/http';
import { Injectable } from '#angular/core';
import { Observable } from 'rxjs/Observable';
import { AuthProvider } from '../auth/auth';
import { Issue } from '../../models/issue'
#Injectable()
export class JiraProvider {
apiVersion: string = '2'; // The API version we want to use
jiraInstanceUrl: string = 'http://localhost:8089' // The Jira instance URL
urlString: string = `${this.jiraInstanceUrl}/rest/api/${this.apiVersion}`; // Concat those together
constructor(
public http: HttpClient,
public auth: AuthProvider
) {
}
// Authenticate the user against Jira's profile endpoint.
public authenticateUser(username: string, password: string): Observable<Object> {
return this.http.get(`${this.urlString}/myself`, {
headers: new HttpHeaders()
.append('Authorization', `Basic ${btoa(username + ':' + password)}`)
.append("Access-Control-Allow-Origin","*")
});
}
// Get issue details based on the provided key.
public getIssue(key: string): Observable<Issue> {
return this.http.get<Issue>(`${this.urlString}/issue/${key}`, {
headers: new HttpHeaders()
.append('Authorization', `Basic ${this.auth.getAuthString()}`)
.append("Access-Control-Allow-Origin","*")
});
}
public getAllIssue():Observable<any> {
return this.http.get(`${this.urlString}/search?jql=project=PM`,{
headers: new HttpHeaders()
.append('Authorization', `Basic ${this.auth.getAuthString()}`)
.append("Access-Control-Allow-Origin","*")
});
}
public postIssue(data):Observable<any>{
return this.http.post(`${this.urlString}/issue`,JSON.stringify(data),{
headers: new HttpHeaders()
.append('Authorization', `Basic ${this.auth.getAuthString()}`)
.append('Content-Type','application/json')
.append("X-Atlassian-Token", "no-check")
.append("User-Agent", "xx")
.append("Access-Control-Allow-Origin","*")
});
}
}
Added screenshot as per request(please not I changed the JIRA server intentionally to 8089 updated the question accordingly)

Answer 1

I soved this issue by using a CORS proxy in a container (Docker) for when you need to Access-Control-Allow-Origin: *`! this acts like a proxy https://github.com/imjacobclark/cors-container and now I am able to route the requests.
Hope it helps others !!