Doubts in the web service

Question

personal found the following webservice tutorial: https://www.youtube.com/watch?v=0J87qN3B-dI

seeing the tutorial I was a little confused about.

1- the web service must be made the part of the android application?

for example I create a web service put this web service on the server and then create the application by android studio and make the connection to the web service?

2 - I must create web service by eclipse?

3 - in this tutorial it uses mysql, but I need to use Firebird, in this case I must put the.fdb database somewhere in Tomcat or the database will be accessed in the same way by the same localhost in the tutorial?

4 - I have a desktop system in Delphi, if I do web service in java may occur some conflict?

i don’t know anything about web service I’m the last 3 days researching a lot about, so I appreciate all the information you can share with me.

thank you in advance

Answer 1

1. Yes the Webservice is totally the part of the APP, summarizing the webservice is a "site" that is used only for data transmission via HTTP in a structured way, for example Json or XML instead of HTML, knowing this so your APP will access this site without needing the web browser and so will be the communication, both sending of POST/PUT how much to take data as GET. We can use REST or SOAP, which are no more than two different formats, in case you are likely to prefer the REST, read about it in:

   • What is REST and Restful?

2. To create the webservice does not need Eclipse, it actually creates nothing it is just an IDE to facilitate, in the webservice you do not expose the database directly, because this would be a huge security breach since the Apps would need to have the authentication data from the database.

   Based on the APP makes an HTTP request to a page that returns the data in a structured way, such as Json or XML.

   I’ve searched a lot of images, but I think this one sums it up better:

   

   See that the Client is where are computers, cell phones, tablets and other "station" (or servers, even other sites can order a webservice), this means that the webservice caters to various locations. Web service would be the translation, that is to say it serves customers data via Web or be it outside the APP, applications just request this data or send new data and sometimes keep a local copy for chance be offline or optimize.

   The webservice can be written in many ways totally independent of the IDE as I said before, of course we use the Ides to make it easier, here are some examples of technology to use in the webservice + framework to facilitate development:

   • If your server is PHP:

     • https://lumen.laravel.com
     • http://www.slimframework.com
     • http://silex.sensiolabs.org

   • If use . NET

     • http://www.asp.net/web-api

   • Python:

     • http://flask.pocoo.org
     • https://www.djangoproject.com

In case the connection with the bank will be in charge of the "server-side", in this case PHP, ASP.NET or Python (using framework or not).

App

If the App (app) is for Android can use ADT or Eclipse even to develop, to access a webservice you must make an HTTP request (being android is usually java, example source http://www.mkyong.com/java/how-to-send-http-request-getpost-in-java/).

Picking up data (GET)

String url = "http://[webservice].com";

URL obj = new URL(url);
HttpURLConnection con = (HttpURLConnection) obj.openConnection();

con.setRequestMethod("GET");

int responseCode = con.getResponseCode();
System.out.println("Código de resposta: " + responseCode);

BufferedReader in = new BufferedReader(
        new InputStreamReader(con.getInputStream()));
String inputLine;

//Pega a resposta
StringBuffer response = new StringBuffer();

while ((inputLine = in.readLine()) != null) {
    response.append(inputLine);
}

in.close();

//Mostra a resposta no console
System.out.println(response.toString());

Sending data (POST)

String url = "http://[webservice].com/create";
URL obj = new URL(url);
HttpsURLConnection con = (HttpsURLConnection) obj.openConnection();

//envia via POST
con.setRequestMethod("POST");

//Dados POST
String urlParameters = "arg2=foo&arg2=baz";

//Cria o POST
con.setDoOutput(true);
DataOutputStream wr = new DataOutputStream(con.getOutputStream());
wr.writeBytes(urlParameters);
wr.flush();
wr.close();

int responseCode = con.getResponseCode();
System.out.println("Código de resposta: " + responseCode);

BufferedReader in = new BufferedReader(
        new InputStreamReader(con.getInputStream()));
String inputLine;

StringBuffer response = new StringBuffer();

while ((inputLine = in.readLine()) != null) {
    response.append(inputLine);
}

in.close();

//Mostra a resposta no console
System.out.println(response.toString());

Answer 2

1 - The web service is the part of the Android application or any other application that uses this service.

2 - You can create by Eclipse, PHP, Python or whatever is easy or convenient for you.

3 - The Webservice accesses the MYSQL, FIREBIRD, ORACLE or any other database via IP. So your bank can be on the same machine as the WEBSERVICE or other machine on the network.

4 - Webservice responds to all requests that arrive regardless of who has requested, unless it is programmed not to do so.

http://programmerguru.com/android-tutorial/android-restful-webservice-tutorial-how-to-call-restful-webservice-in-android-part-3/