@darwino/darwino/src/JsonHttpClient.js

A set of Javascript classes and utilities

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 *
 * Darwino Inc Confidential.
 *
 * (c) Copyright Darwino Inc. 2014-2016.
 *
 * Notice: The information contained in the source code for these files is the property 
 * of Darwino Inc. which, with its licensors, if any, owns all the intellectual property 
 * rights, including all copyright rights thereto.  Such information may only be used 
 * for debugging, troubleshooting and informational purposes.  All other uses of this information, 
 * including any production or commercial uses, are prohibited. 
 */

import Utils from "./Utils"
import DEV_OPTIONS from "./dev";
 
export function makeUrl(url,parts,params,useQueryParams) {
	// Add the URL parts
	if(parts && parts.length) {
		let p = "";
		for(let i=0; i<parts.length; i++) {
			let part = parts[i].toString();
			if(useQueryParams) {
				if(part.indexOf('/')>=0) {
					params["$$"+i] = part;
					part = "$$"+i;
				}
			}
			p += "/" + encodeURIComponent(part);
		}
		url = Utils.removeTrailingSep(url) + p;
	}
	// Add the query string
	if(params) {
		let qs = "";
		for(let pa in params) {
			let v = params[pa].toString();
			qs += (qs ? '&' : "?") + encodeURIComponent(pa) + (v ? ('=' + encodeURIComponent(v)) : "");
		}
		url = Utils.removeTrailingSep(url) + qs;
	}
	return url;
};

function convertEmpty(xhr) {
	return null;
}
function convertText(xhr) {
	return xhr.responseText;
}
function convertJson(xhr) {
	return Utils.fromJson(xhr.responseText);
}
function convertXml(xhr) {
	return Utils.parseXml(xhr.responseText);
}

function findConvert(xhr) {
	let ct = xhr.getResponseHeader('content-type');
	if(ct=='application/json') {
		return convertJson;
	}
	if(ct=='application/xml') {
		return convertXml;
	}
	return convertText;
}

// TODO: use fetch instead?
export default class JsonHttpClient {

	constructor(url) {
		this.USE_HTTP_OVERRIDE = false;
		this.async = true;
		this._url = url;
		this._useQueryParams = false;
	}

	setQueryParams(queryParams) {
		this._useQueryParams = queryParams;
	}

	isError(status,xhr) {
		return status<200 || status>299;
	}

	getBaseUrl() {
		return this._url;
	}

	_makeUrl(parts,params) {
		return makeUrl(this._url,parts,params,this._useQueryParams);
	}

	_ajax(method,parts,params,contentType,content,cb,convert,mime) {
		// Calculate if the request should be async
		let async = this.async;
		if(cb && cb.async!==undefined) {
			async = cb.async;
		}
		// Return a Promise is async and there is no cb
		if(async && !cb) {
			let _this = this;
			return new Promise(function(resolve,reject){
				_this._ajax(method,parts,params,contentType,content,{success:resolve,failure:reject},convert,mime);
			});
		}
		let client = this;
		let headers = {};
		if(this.USE_HTTP_OVERRIDE && (method=="PUT" || method=="DELETE")) {
			headers["x-http-method-override"] = method;
			method = "POST";
		}
		let url = this._makeUrl(parts,params);
		let xhr = new XMLHttpRequest();
		if(DEV_OPTIONS.credentials=="include") xhr.withCredentials = true
		xhr.open(method,url,async);
		xhr.onreadystatechange = function() {
			// http://xhr.spec.whatwg.org/#dom-xmlhttprequest-readystate
			if (xhr.readyState == 4 && cb) {
				if(client.isError(xhr.status,xhr)) {
					if(cb.failure) {
						cb.failure("Error "+xhr.status+" while executing asynchronous request, "+method+", "+url,findConvert(xhr)(xhr),xhr);
					}
				} else {
					let val = (convert||findConvert(xhr))(xhr);
					if(Utils.isArray(val)) {
						let meta = xhr.getResponseHeader("X-MetaData");
						if(meta) {
							val._meta = meta;
						}
					}
					(cb.success||cb)(val,xhr);
				}
			}
		};
		if(mime) {
			xhr.overrideMimeType(mime);
		}
		if(content) {
			if(contentType) {
				xhr.setRequestHeader("Content-Type", contentType);
			}
			xhr.send(content);
		} else {
			xhr.send();
		}
		if(!async) {
			// Synchronized return
			if(client.isError(xhr.status,xhr)) {
				if(!cb || !cb.failure) {
					throw new Error("Error "+xhr.status+" while executing synchronous request, "+method+", "+url);
				}
			} else {
				let val = (convert||findConvert(xhr))(xhr);
				if(Utils.isArray(val)) {
					let meta = xhr.getResponseHeader("X-MetaData");
					if(meta) {
						val._meta = meta;
					}
				}
				return val;
			}
		}
	}

	getAsEmpty(parts,params,cb) {
		return this._ajax('GET',parts,params,null,null,cb,convertEmpty);
	}
	getAsText(parts,params,cb) {
		return this._ajax('GET',parts,params,null,null,cb,convertText);
	}
	getAsJson(parts,params,cb) {
		return this._ajax('GET',parts,params,null,null,cb,convertJson);
	}
	getAsXml(parts,params,cb) {
		return this._ajax('GET',parts,params,null,null,cb,convertXml);
	}
	getAsBinaryString(parts,params,cb) {
		return this._ajax('GET',parts,params,null,null,cb,convertText,'text\/plain; charset=x-user-defined')
	}

	deleteAsEmpty(parts,params,cb) {
		return this._ajax('DELETE',parts,params,null,null,cb,convertEmpty);
	}
	deleteAsJson(parts,params,cb) {
		return this._ajax('DELETE',parts,params,null,null,cb,convertJson);
	}

	putJsonAsJson(parts,params,content,cb) {
		return this._ajax('PUT',parts,params,'application/json',Utils.toJson(content),cb,convertJson);
	}
	putEmptyAsJson(parts,params,cb) {
		return this._ajax('PUT',parts,params,null,null,cb,convertJson);
	}

	postJsonAsEmpty(parts,params,content,cb) {
		return this._ajax('POST',parts,params,'application/json',Utils.toJson(content),cb,convertEmpty);
	}
	postJsonAsJson(parts,params,content,cb) {
		return this._ajax('POST',parts,params,'application/json',Utils.toJson(content),cb,convertJson);
	}
}