How to Use Rest api with React Native; Network Call Issues - mongodb

Question

I am newbie in React Native,
I made a simple back-end using Mongodb and express routes etc in MongoDb atlas. I am successfully able to post/get/patch/Delete operation on mongodb atlas that store Title and Description using Postman. Everything is working fine.
Here comes the problem First when i make a simple frontend in ReactNative that take inputs Title and Description. I want application that take simple input of Title and Description and on Submit Button it store into the the mongodb Atlas just like postman is doing. I tried but its not working code is below. I dont know how to communicate the front end into backend. I watch alot of tutorials but unable to get the point.
Secondly, when i make a server i wrote in pakage.json > "start": "nodemone server.js" and i need to run ReactNative app i update the pakage.json > "start": "expo start" to run app. How can i run server and expo app same time? if i seprate the app folder then how can i connect both of them.
below is my Code.
Routes folder post.js
const express = require( 'express' );
const router = express.Router();
const Post = require ('../models/Post')
//Gets back all the posts
router.get ( '/', async (req, res) =>{
try{
const post = await Post.find();
res.json(post);
}catch (err) {
res.json({message: err })
}
});
//To Submit the Post
router.post('/', async (req, res) =>{
//console.log(req.body);
const post = new Post({
title: req.body.title,
description: req.body.description
});
try{
const savedPost = await post.save();
res.json(savedPost);
}catch (err) {
res.json ({ message: err })
}
});
//Get back specific Post
router.get('/:postId', async (req, res) =>{
try{
const post= await Post.findById(req.params.postId);
res.json(post);
}catch(err) {
res.json({message: err });
}
})
// to delete specific post
router.delete('/:postId', async (req, res) =>{
try{
const removePost= await Post.remove({_id: req.params.postId});
res.json(removePost);
}catch(err) {
res.json({message: err });
}
})
//update Post
router.patch('/:postId', async (req, res) =>{
try{
const updatePost = await Post.updateOne(
{_id: req.params.postId},
{ $set:
{title: req.body.title}
});
res.json(updatePost);
}catch(err) {
res.json({message: err });
}
})
module.exports = router;
Defined Schema Post.js
const mongoos = require( 'mongoose' );
const PostSchema = mongoos.Schema ({
title: {
type: String,
required: true
},
description: {
type: String,
required: true
},
date: {
type: Date,
default: Date.now
}
})
module.exports = mongoos.model ('Post', PostSchema); // giving this schma name Post
server.js
const express = require( 'express' );
const app = express();
var mongo = require('mongodb');
const mongoos = require( 'mongoose' );
const bodyParser = require('body-parser');
require('dotenv/config');
const postRoute = require('./Routes/post');
app.use(bodyParser.json());
app.use ('/post', postRoute);
app.get ( '/', (req, res) =>{
res.send('We are on Home ')
});
// connecting to database
mongoos.connect(
process.env.DB_CONNECTION,
{ useNewUrlParser: true },
() => console.log('Connected to db')
);
app.listen(3000);
Frontend Form.js
import React from 'react';
import { StyleSheet, Text, View, TextInput, TouchableOpacity } from 'react-native';
class Form extends React.Component{
constructor(){
super();
this.State = {
title: '',
description: ''
}
}
getInput(text, field){
if(field == 'title')
{
this.setState({ title: text, })
}
else if(field == 'description')
{
this.setState({ description: text, })
}
//console.warn(text)
}
submit(){
let collection={}
collection.title = this.state.title,
collection.description = this.state.description;
console.warn(collection);
var url = process.env.DB_CONNECTION ;
fetch(url, {
method: 'POST',
headers: {
Accept: 'application/json',
'Content-Type': 'application/json',
},
body: JSON.stringify({
collection
}),
});
}
render() {
return (
<View style={styles.container}>
<TextInput style={styles.inputBox}
underlineColorAndroid= 'rgba(0,0,0,0)'
placeholder='Title'
selectionColor="#fff"
keyboardType="default"
onChangeText = {(text) => this.getInput(text, 'title')}
/>
<TextInput style={styles.inputBox}
multiline = {true}
numberOfLines = {4}
underlineColorAndroid= 'rgba(0,0,0,0)'
placeholder='Description'
selectionColor="#fff"
keyboardType="default"
onChangeText= {(text) => this.getInput(text, 'description')}
/>
<TouchableOpacity onPress={()=>this.submit()} style={styles.btn} >
<Text style={{textAlign: 'center'}}>Submit</Text>
</TouchableOpacity>
</View>
);
}
}
export default Form;

Answer 1

Here comes a very basic solution to your problem:
1: if you are using Rest API based model of communication go for Two separate repos on GITHUB. One for React native app of yours and one for server-side of yours.
2: now to go to Heroku.com and make an app there and attach your card there in order to use the full Free Sandbox functionality
3: create a project there and find an option to deploy from Github.
4: for data communication aka network requests its easy to use axios rather than Fetch
for best practices use :
https://riptutorial.com/react-native/topic/857/getting-started-with-react-native
5: in order to run more than one command in package json able to run multiple scripts in package.json you can either do it like
scripts:{"run": "yarn start" && "react-native-expo"}
6: or if your scripts are like they gonna need to run constantly in the background it's better that you create two separate scripts
scripts:{"run1": "yarn start", "run2":"yarn start2"}
7: I see you are not handling the AsyncAwait Try catch or Promise after the fetch
8: you are also not hitting the server-side URL seemingly you are hitting DB connection url. what you should be doing is that you hit the POST/GET/UPDATE routing endpoint of yours