jedmao/iso-http

import Helpers = require('../Helpers');
import IsoHttp = require('../IsoHttp');
import Types = require('../Types');

module Http {

    export function request(
        options: IsoHttp.RequestOptions,
        resolve?: IsoHttp.ResolveCallback,
        reject?: IsoHttp.RejectCallback) {
        new Agent(options).send(resolve, reject);
    }

    export class Agent extends IsoHttp.Agent {

        constructor(options?: IsoHttp.RequestOptions) {
            super(options);
            var xrw = 'x-requested-with';
            this.headers[xrw] = this.headers[xrw] || 'XMLHttpRequest';
        }

        send(resolve?: IsoHttp.ResolveCallback, reject?: IsoHttp.RejectCallback) {
            var url = (this.method === 'GET')
                ? Helpers.joinUrlWithQuery(this.url, this.data)
                : this.url;
            var xhr = this.createXhr();
            xhr.open(this.method, url, true);
            if (this.withCredentials) {
                xhr.withCredentials = true;
            }
            this.setXhrHeaders(xhr, this.headers);
            xhr.onreadystatechange = () => {
                if (xhr.readyState !== 4) {
                    return;
                }
                if (xhr.status === 0 && typeof reject === 'function') {
                    reject(this.addRequestInfo(new Error('Unspecified client error.')));
                    return;
                }
                if (typeof resolve !== 'function') {
                    return;
                }
                resolve({
                    status: xhr.status,
                    headers: this.parseHeaders(xhr.getAllResponseHeaders()),
                    text: xhr.responseText
                });
            };
            xhr.send(this.method !== 'GET' && JSON.stringify(this.data));
        }

        private setXhrHeaders(xhr: XMLHttpRequest, headers: Types.HashTable<string>) {
            Object.keys(headers).forEach(name => {
                xhr.setRequestHeader(name, headers[name]);
            });
        }

        private createXhr(): XMLHttpRequest {
            try {
                return new XMLHttpRequest();
            } catch (err) {
                throw new Error('Unsupported browser: Failed to create XHR object.');
            }
        }

        private parseHeaders(headers: string) {
            var lines = headers.split(/\r?\n/);
            lines.pop(); // final newline
            var fields: Types.HashTable<string> = {};
            for (var i = 0; i < lines.length; i++) {
                var line = lines[i];
                var pos = line.indexOf(':');
                var field = line.slice(0, pos).toLowerCase();
                var value = line.slice(pos + 1).trim();
                fields[field] = value;
            }
            return fields;
        }

    }

}

export = Http;