Develop Reference

HTTP Request from Web to Android

How can I make an HTTP request from a web application (like node js) to an android app?
The goal is to read if the response is a success, for example, from Web to Web I make an HTTP request to the IP/URL and, if it returns 200, I have success. It would work as a "ping" to check if the android app is "alive".
Note: I don't know apps architecture
Thanks!

Using web sockets ( example here: https://www.html5rocks.com/en/tutorials/websockets/basics/ ) will help u to achieve it

Res.redirect() vs res. Json(). Server for web and mobile

I am new to web development. I had a web project with EJS templating. It redirects directly from the server. Using res.redirect() . I want to create a server for web and mobile both.
Question is... When i use res.json() it sends JSON data to client side. Can work for both.
It is possible to use res.redirect() for both. Web and mobile.
Pros and cons of res.rediret and res.json
Please explain. I appreciate your suggestions in adv. Thanks.

It is possible to use res.redirect() for both. Web and mobile.
If you mean can you use res.redirect() as an alternative to res.json() then the answer is NO. res.redirect() is not an alternative to res.json. res.redirect() only sends a code and a URL back to the client, there is no data in the response. You will still need to use res.json or res.send to get the data you need. Every time you use res.redirect() you are sending a response to the client telling them to make a brand new request to another location. You're not sending any real data. The android app will not get any content till you use res.json or res.send. Redirects just tell the client go get the data from somewhere else.
Below are example responses to an android app when the server uses res.json and res.redirect
res.redirect("/user")
//Response to Android app
302 /user
The response above means what you want is located at "/user" so the mobile app will need to make a request to
res.json(user)
//Response to Android app
{
name: "Arpit Yadav",
phone: 555-555
}

res.redirect sends status code 302 (if not specified), and location (route) to browser, after which browser redirects the request to the specified location, whereas res.json sets Content-Type: application/json and sends data to the browser.
Redirection is generally meant for browser only, but, you can use it for mobile. In that case, you have to handle the logic to re-request with updated location received from server that is not recommended.
In nutshell, both have different purpose. res.redirect to move clients to different route and res.json to actually sends the data.

Jhipster Jwt Authentication for Mobile API

I have a jHipster project with Jwt Authentication but I can't get it to work outside de webapp. I'm currently developping a Android application and the authentication process get harder than I expected.
Basically I'm sending the parameters of the LoginDTO, to UserJwtController#authorize ('/api/authenticate'). At first I was getting Unauthorized, both on Android or Postman (I'm using it to test the requests).
If I change the '/api' to permitAll, I'm getting 405, Request method 'POST' not supported.
EDIT
It was a wrong typo on Android :/

It works fine for me against /api/authenticate, so either you use wrong URL (e.g. /api/authorize) or your JSON payload is wrong. The only issue you could have is with CORS. You should consider testing with curl as it is easier than PostMan for reporting here what you really do and also the curl options are already built for you in JHipster swagger page.

Authenticating a file stream from android to wcf

I have an app that makes request to a wcf service. Usually I authenticate all of the requests using a hash value that is sent in the body of the request and then authenticated on the server. All most all of the request are sent via json and it is easy for me to add the hash value to the body of the request. The issue I am facing is that when I send a file stream I cannot add the hash to the body of the request so I am wondering how I can authenticate that the request came from my app and not from some where else. All suggestions are greatly appreciated.

Adding an authorization item in the header is a possible solution. So, if anyone is interested, read this and this.

android - build application to authenticate with web server

I'm trying to make an application that needs authentication :- when user type username and pw in the text boxes it should check with the DB in the server and authenticate.
how can i do this in the android?
can please any one help me??
thank you,

If you are a web developer you can do this authentication very easily. You can follow the following steps,
First, get the username and password from the user and put in the variables.
Create the HTTP connection to the web server (Your data posting URL).
Post the data to the URL with specified data using HTTP Get or Post method(Post is preferable for authentication)
Get the posted value using server side script and do the authentication.
send the response status to the client by using JSON encoding or some other format whether the authentication is succeeded of failure.
Get the response in android and create the InputStream and decode the JSON or some specified encoding format which you done in the server side and shown the response in mobile.
Thats it.