funkster-http-json
Funkster is a compositional server library. This package provides types and combinators to parse json bodies from requests and respond with json to the client.
Typscript is used to illustrate the examples.
Install
$ npm install funkster-http-jsonBuild
$ npm install && npm run buildTest
$ npm run testParsing JSON from a request body
The parseJson and parseJsonWith combinators can be used to parse JSON data from a request.
In a valid request the Content-Type header contains json and a request body must be present, otherwise a 415 Unsupported Media Type is returned.
Example:
import * as http from 'http';
import { parseJson } from 'funkster-http-json';
import { asRequestListener, Ok } from 'funkster-http';
interface User {
name: string;
}
const greet = parseJson<User>(user => Ok('Hello ' + user.name));
const server = http.createServer(asRequestListener(greet));
// start the node HTTP server and send e.g. a POST with '{ "name": "John Connor" }'.It is possible to use a custom JSON deserializer. The default is JSON.parse.
Custom deserializer:
import * as http from 'http';
import { parseJsonWith } from 'funkster-http-json';
import { asRequestListener, Ok } from 'funkster-http';
interface User {
name: string;
}
function deserializeJson<User>(json: string): User {
return /* your custom json deserialization here */
}
const greet = parseJsonWith<User>(user => Ok('Hello ' + user.name), deserializeJson);
const server = http.createServer(asRequestListener(greet));
// start the node HTTP server and send e.g. a POST with '{ "name": "John Connor" }'.Sending JSON to the client
The sendJson and sendJsonWith combinators can be used to send proper JSON responses to the client.
In a valid request the Accept header allows json, otherwise a 406 Not Acceptable is returned.
Example:
import * as http from 'http';
import { sendJson } from 'funkster-http-json';
import { asRequestListener } from 'funkster-http';
const greet = sendJson({ hello: "John Connor" });
const server = http.createServer(asRequestListener(greet));
// start the node HTTP server and send a simple GET.The Content-Type of the response will be set to application/json; charset=utf-8.
It is possible to specify a custom response handler (default: 200 OK) and JSON serializer (default: JSON.stringify).
Custom response handler and serializer:
import * as http from 'http';
import { compose } from "funkster-core";
import { sendJsonWith } from 'funkster-http-json';
import { setContentType } from "funkster-http-headers-content";
import { Accepted, asRequestListener, HttpPipe } from 'funkster-http';
function respondWithJson(json: string): HttpPipe {
return compose(
setContentType({ type: "application/json", parameters: { charset: "ascii" } }),
Accepted(json));
}
function serialize(obj: any): string {
return /* your custom json serialization here */
}
const greet = sendJsonWith({ hello: "John Connor" }, respondWithJson, serialize);
const server = http.createServer(asRequestListener(greet));
// start the node HTTP server and send a simple GET.Building a JSON api
The mapJson and mapJsonWith combinators allow to build a HttpPipe that consumes JSON requests, maps the data and produces JSON responses.
Example:
import * as http from 'http';
import { mapJson } from 'funkster-http-json';
import { asRequestListener } from 'funkster-http';
interface User {
id: string;
}
interface UserInfo {
name: string;
age: number;
city: string;
}
function lookup(user: User): Promise<UserInfo> {
if(user.id !== 1234) {
return Promise.resolve(null);
}
return Promise.resolve({
name: 'John Connor',
age: 42,
city: 'Los Angeles'
});
}
const getUserInfo = mapJson<User, UserInfo>(lookup);
const server = http.createServer(asRequestListener(getUserInfo));
// start the node HTTP server and send e.g. a POST with '{ "id": "1234" }'.Internally mapJson uses parseJson and sendJson so the same rules apply.
It is possible to specify the parse and send functions via mapJsonWith.
Custom response handling:
import * as http from 'http';
import { mapJson, parseJson, sendJson } from 'funkster-http-json';
import { asRequestListener, NotFound } from 'funkster-http';
interface User {
id: string;
}
interface UserInfo {
name: string;
age: number;
city: string;
}
function lookup(user: User): Promise<UserInfo> {
if(user.id !== 1234) {
return Promise.resolve(null);
}
return Promise.resolve({
name: 'John Connor',
age: 42,
city: 'Los Angeles'
});
}
function sendUserInfo(userInfo?: UserInfo): HttpPipe {
if(!userInfo) {
return NotFound();
}
return sendJson(userInfo);
}
const getUserInfo = mapJsonWith<User, UserInfo>(lookup, parseJson, sendUserInfo);
const server = http.createServer(asRequestListener(getUserInfo));
// start the node HTTP server and send e.g. a POST with '{ "id": "1234" }'.Meta
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