Question :
I have an Android application that should request a JSON to a web application, however to access the method it is necessary to log in to the site.
How do I perform this identification via code?
Webservice.java
package br.ufscar.dc.controledepatrimonio.Util.Webservice;
import android.util.Log;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.ProtocolException;
import java.net.URL;
public class Webservice {
private URL url;
private HttpURLConnection con = null;
public Webservice(String url) {
try {
this.url = new URL(url);
con = (HttpURLConnection) this.url.openConnection();
} catch (MalformedURLException ex) {
Log.d("MalformedURLException", ex.getMessage());
} catch (IOException ex) {
Log.d("IOException", ex.getMessage());
}
}
public String getJSON() {
try {
con.setRequestMethod("GET");
con.setRequestProperty("Content-length", "0");
con.setUseCaches(false);
con.setAllowUserInteraction(false);
con.connect();
int status = con.getResponseCode();
switch (status) {
case 200:
case 201:
BufferedReader br = new BufferedReader(new InputStreamReader(con.getInputStream()));
StringBuilder sb = new StringBuilder();
String line;
while ((line = br.readLine()) != null) {
sb.append(line + "n");
}
br.close();
return sb.toString();
}
} catch (ProtocolException ex) {
Log.d("ProtocolException", ex.getMessage());
} catch (IOException ex) {
Log.d("IOException", ex.getMessage());
} finally {
if (con != null) {
try {
con.disconnect();
} catch (Exception ex) {
Log.d("Exception", ex.getMessage());
}
}
}
return null;
}
}
LocalTask.java
package br.ufscar.dc.controledepatrimonio.Util.Webservice;
import android.content.Context;
import android.os.AsyncTask;
import android.util.Log;
public class LocalTask extends AsyncTask<Void, Void, String> {
private Context ctx;
private ITask iTask;
private String retorno = null;
public LocalTask(Context ctx, ITask iTask) {
this.ctx = ctx;
this.iTask = iTask;
}
@Override
protected String doInBackground(Void... params) {
Webservice webservice = new Webservice("http://192.168.0.10:8080/Patrimonio/local/index.json");
retorno = webservice.getJSON();
return retorno;
}
@Override
protected void onPostExecute(String s) {
iTask.getJSON(retorno);
}
}
When executing the command retorno = webservice.getJSON(); the return that I have is the HTML of the login page, not JSON.
Answer :
I solved my problem by adapting the code from an example I found on the internet.
It was as follows
Webservice.java
package br.ufscar.dc.controledepatrimonio.Util.Webservice;
import android.util.Log;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;
import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.CookieHandler;
import java.net.CookieManager;
import java.net.HttpURLConnection;
import java.net.ProtocolException;
import java.net.URL;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.List;
public class Webservice {
private URL urlJSOn;
private String url;
private HttpURLConnection con = null;
private final String URL_AUTENTICAR = "http://192.168.0.10:8080/Patrimonio/j_spring_security_check";
private final String USER_AGENT = "Mozilla/5.0";
private List<String> cookies;
private HttpURLConnection conn;
public Webservice(String url) {
this.url = url;
autenticar();
}
public String getJSON() {
try {
this.urlJSOn = new URL(url);
con = (HttpURLConnection) this.urlJSOn.openConnection();
con.setRequestMethod("GET");
con.setRequestProperty("Content-length", "0");
con.setUseCaches(false);
con.setAllowUserInteraction(false);
con.connect();
int status = con.getResponseCode();
switch (status) {
case 200:
case 201:
BufferedReader br = new BufferedReader(new InputStreamReader(con.getInputStream()));
StringBuilder sb = new StringBuilder();
String line;
while ((line = br.readLine()) != null) {
sb.append(line + "n");
}
br.close();
return sb.toString();
}
} catch (ProtocolException ex) {
Log.d("ProtocolException", ex.getMessage());
} catch (IOException ex) {
Log.d("IOException", ex.getMessage());
} finally {
if (con != null) {
try {
con.disconnect();
} catch (Exception ex) {
Log.d("Exception", ex.getMessage());
}
}
}
return null;
}
private void autenticar() {
CookieHandler.setDefault(new CookieManager());
try {
String page = getPageContent(URL_AUTENTICAR);
String postParams = getFormParams(page, "membro", "membro");
sendPost(URL_AUTENTICAR, postParams);
String result = getPageContent(url);
}
catch(Exception ex) {
ex.printStackTrace();
}
}
private void sendPost(String url, String postParams) throws Exception {
URL obj = new URL(url);
conn = (HttpURLConnection) obj.openConnection();
conn.setUseCaches(false);
conn.setRequestMethod("POST");
conn.setRequestProperty("Host", "accounts.google.com");
conn.setRequestProperty("User-Agent", USER_AGENT);
conn.setRequestProperty("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
conn.setRequestProperty("Accept-Language", "en-US,en;q=0.5");
conn.setRequestProperty("Connection", "keep-alive");
conn.setRequestProperty("Referer", "https://accounts.google.com/ServiceLoginAuth");
conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
conn.setRequestProperty("Content-Length", Integer.toString(postParams.length()));
conn.setDoOutput(true);
conn.setDoInput(true);
DataOutputStream wr = new DataOutputStream(conn.getOutputStream());
wr.writeBytes(postParams);
wr.flush();
wr.close();
int responseCode = conn.getResponseCode();
BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
String inputLine;
StringBuffer response = new StringBuffer();
while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
}
in.close();
}
private String getPageContent(String url) throws Exception {
URL obj = new URL(url);
conn = (HttpURLConnection) obj.openConnection();
conn.setRequestMethod("GET");
conn.setUseCaches(false);
conn.setRequestProperty("User-Agent", USER_AGENT);
conn.setRequestProperty("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
conn.setRequestProperty("Accept-Language", "en-US,en;q=0.5");
int responseCode = conn.getResponseCode();
BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
String inputLine;
StringBuffer response = new StringBuffer();
while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
}
in.close();
return response.toString();
}
public String getFormParams(String html, String username, String password) throws UnsupportedEncodingException {
Document doc = Jsoup.parse(html);
Element loginform = doc.getElementById("loginForm");
Elements inputElements = loginform.getElementsByTag("input");
List<String> paramList = new ArrayList<String>();
for (Element inputElement : inputElements) {
String key = inputElement.attr("name");
String value = inputElement.attr("value");
if (key.equals("j_username"))
value = username;
else if (key.equals("j_password"))
value = password;
paramList.add(key + "=" + URLEncoder.encode(value, "UTF-8"));
}
StringBuilder result = new StringBuilder();
for (String param : paramList) {
if (result.length() == 0) {
result.append(param);
} else {
result.append("&" + param);
}
}
return result.toString();
}
}
With this, just give new in the class, and invoke the getJSON method soon after.