cors-builder.ts

import { MiddlwareTarget } from '../models/middlware-target.ts';
import { Response, ServerRequest, RenderResult, ServerResponse } from '../mod.ts';

export class CorsBuilder implements MiddlwareTarget {
    private headers: Map<string, string>;
    private allowAnyOrigin: boolean;
    private allowAnyMethod: boolean;
    private allowAnyHeader: boolean;

    constructor() {
        this.headers = new Map();
        this.allowAnyOrigin = false;
        this.allowAnyMethod = false;
        this.allowAnyHeader = false;
    }

    onPreRequest(request: ServerRequest, response: ServerResponse): Promise<void> {
        return new Promise((resolve, reject) => {
            if (this.allowAnyOrigin) {
                this.headers.set('Access-Control-Allow-Origin', request.headers.get('Origin') || '');
            }
            if (this.allowAnyMethod) {
                this.headers.set(
                    'Access-Control-Allow-Methods',
                    request.headers.get('Access-Control-Request-Method') || '',
                );
            }
            if (this.allowAnyHeader) {
                this.headers.set(
                    'Access-Control-Allow-Headers',
                    request.headers.get('Access-Control-Request-Headers') || '',
                );
            }

            if (request.method == 'OPTIONS') {
                this.onPostRequest(request, response, response as RenderResult);

                response.status = 200;
                response.immediately = true;
            }

            resolve();
        });
    }

    onPostRequest(request: ServerRequest, responce: Response, result?: RenderResult): Promise<void> {
        return new Promise((resolve, rej) => {
            this.headers.forEach((el, key) => {
                if (result && result.headers) {
                    result.headers.set(key, el);
                }
            });
            resolve();
        });
    }

    WithOrigins(origins: string) {
        this.headers.set('Access-Control-Allow-Origin', origins);
        return this;
    }

    WithMethods(methods: string) {
        this.headers.set('Access-Control-Allow-Methods', methods);
        return this;
    }

    WithHeaders(headers: string) {
        this.headers.set('Access-Control-Allow-Headers', headers);
        return this;
    }

    AllowAnyOrigin() {
        this.allowAnyOrigin = true;
        return this;
    }

    AllowAnyMethod() {
        this.allowAnyMethod = true;
        return this;
    }

    AllowAnyHeader() {
        this.allowAnyHeader = true;
        return this;
    }

    AllowCredentials() {
        this.headers.set('Access-Control-Allow-Credentials', 'true');
        return this;
    }
}