This is the scenario.
I do a HTTP POST using the HttpURLConnection class to post to a url say "https://www.abc.com", but this line:
in = new BufferedReader(new InputStreamReader(
httpURLConnector.getInputStream()));
response = in.readLine();
randomly gives me a null response. But if I remove the 's' from the url to become "http://www.abc.com", I get back all responses as expected with no null returns. The weird thing is that it works on the Nexus phone for https but it does not work for the HTC Wildfire. Can someone enlighten me on this? Thanks!
You might want to check the HTTP status code, before trying to read anything. Post some code from the `HttpURLConnector'.
Related
I'm about to code an Android app (using A.Studio 3.5.1) that should connect to a back-end using https. I'm quite new to the techniques so I looked at https://developer.android.com/training/articles/security-ssl.html#HttpsExample
I has four lines of code:
URL url = new URL("https://wikipedia.org");
URLConnection urlConnection = url.openConnection();
InputStream in = urlConnection.getInputStream();
copyInputStreamToOutputStream(in, System.out);
When I try it I get a red text;
new URL gives MalformedURLException
url.openConnection() gives IOException,
urlConnection.getInputStream() also
copyInputStreamToOutputStream is not found.
I have read about copyInputStreamToOutputStream, that it can be solved
copyInputStreamToOutputStream(in, System.out)
and
Easy way to write contents of a Java InputStream to an OutputStream
I tried the first way, using apache commons, with no success.
I'm mostly curious about the exceptions.
I will try another walk-through on
https://codelabs.developers.google.com/codelabs/android-network-security-config/
But it would be nice to learn about this...
I have faced similar situations many times. This occur because the webpage you are trying to reach doesn't return anything as a response after connection is established. So the parsing returns IOException as there is nothing to read in the response of URL after connection.
newURL is returning MalformedURLException because your url contains -- " -- which should be escaped as these are special characters.
Hope this helps.
I'm trying to do a post request with a WebView on Android.
After searching for days and trying dozens of things i couldn't get it work. In SWIFT it's just a few lines of code so i thought there must also be a simple way to do a post request for a webview on android.
As (for 2016) EncodingUtils and HTTPClient are deprecated this are my current approaches:
String url = "http://example.com/php.php";
String postData = null;
postData = "param1=" + URLEncoder.encode("1234567890", "UTF-8");
webcontent.postUrl(url,postData.getBytes());
//or
webcontent.postUrl(url, Base64.encode(postData.getBytes(), Base64.DEFAULT));
Both just result in a blank screen. There is just one parameter to be sent and a string containing html from the server should be received.
In addition, the php on the server returns a html-string with colored background irrespective of any input, but even this isn't displayed so maybe the whole request never reaches the server?
Thanks in advance!
In Android you do not use webView to access the content of the HTTP response. You'll need to use HttpClient for that purpose!
See this nice tutorial which explains the fundamentals! Also see this video if you find it hard!
Hope it helps!
I am almost dead doing this.Need help.
My Requirement :-
I am developing an android app and want to use the cookies(/session) from webview in my java code. I basically want to get the html of other pages of an url after login in webview without opening those pages in webview but through my java code.
What I tried :-
For this I tried HttpClient and HttpURLConnection referring many SO questions but failed.
Can anybody please give me a sample code?
Say I have cookies in a hashmap cookies. How Can I use HttpClient and HttpURLConnection or anything else to get the other page html. The website I am trying with is https:
Please give a sample code
If I am right u are trying to use your webview's cookies to get other pages of site in your activity java code.if yes try this:
BufferedReader reader = null;
try {
URL url2 = new URL("url");
URLConnection con = (URLConnection) url2.openConnection();
CookieManager.getInstance().setAcceptCookie(true);
con.setRequestProperty("Cookie",CookieManager.getInstance().getCookie("logged in url in webview"));
con.setDoOutput(true);
con.connect();
reader = new BufferedReader(new InputStreamReader(con.getInputStream()));
StringBiffer html;
String line = "";
while ((line = reader.readLine()) != null) {
html.append(line);
}
} catch (Exception e) {
e.printStackTrace();
}
It worked for me.
Have you tried to add the cookie as a HTTP header? I am not sure if I have understood you right but you can consider these:
Cookies: If you want to load some resource (no matter if it is a web page, image, css, js or something else) you are making a HTTP request. If the server keeps a session for your user, you are probably given a session cookie. The cookie must be sent with each request to the server as e COOKIE header. So if you want to pass the cookie to your request, add it as a header. Android provides you an easy way to do this with the CookieManager class. You can refer to this.
SSL: If you are trying to access a secured web site (https) you have to use an SSL certificate. Android comes up with a bunch of predistributed certificates for most of the popular web cites (e.g Facebook, Google, Twitter, etc.). You can use them out of the box. If your SSL certificate is not presented, you have to add it manually. Read this for more information.
I hope this was useful :)
i have posted a question for htmlunit in this link: how to use htmlunit with my android project
mainly i have a link, which i have get after login (i have login through web view) this link give me a simple page. in that page there is a textarea and a submit button. and there are some javascript too (i think these javascript run, when i press the submit button). i can do it through webview, but for some reason i don't want to use webview. whene i press submit button, it deliver the value of textarea and some value of hidden field with existing cookies(which are get when i logged in through webview) Post method. i need to do this without webview. now is there any other option beside htmlunit ?? i heard about HttpClient, HttpUrlConnection. but i don't know how to use them to solve my problem, because they are totaly new to me. i think if i use these class i have to run them in a seperate thread from UI tread. one more thing, after submitting it will redirect me to another page. i don't need to do anything with this redirected page.
thank you
this is the same answer which i have given here
i have solve the problem. first of all i was getting the right cookie all time. so what was the problem then. either i was wrong to integrate the cookie with Jsoup or Jsoup was doing something wrong. so, first i have get the page with HttpUrlConnection and then parse it with Jsoup. like this:
URL form = new URL(uri.toString());
HttpUrlConnection connection1 = (HttpURLConnection)form.openConnection();
connection1.setRequestProperty("Cookie", my_cookie);
connection1.setReadTimeout(10000);
StringBuilder whole = new StringBuilder();
BufferedReader in = new BufferedReader(
new InputStreamReader(new BufferedInputStream(connection1.getInputStream())));
String inputLine;
while ((inputLine = in.readLine()) != null)
whole.append(inputLine);
in.close();
Document doc = Jsoup.parse(whole.toString());
any advice about this code would be appreciated.
I have problems with getting the html source code with an url. I am trying to develop an application which takes in an url and upon the button submit by the user, it takes in the url and make calls to the url provided to retrieve the html source code.
I have looked up on various methods of doing it, but have always been presented with errors using the codes provided.
Listed below is one of the codes which I have used but it doesn't seem to work for me, it will throw a Error: null in the exception when I use logcat to debug.
please pardon me if the question sounds simple, I'm new to programming. thanks in advance.
String htmlCode = "";
try {
URL url = new URL("http://www.google.com/");
BufferedReader in = new BufferedReader(new InputStreamReader(url.openStream()));
String inputLine;
while ((inputLine = in.readLine()) != null)
htmlCode += inputLine;
in.close();
} catch (Exception e) {
Log.d(LOG_TAG, "Error: " + e.getMessage());
}
That code seems to be functional and works for me. Can you post the exception/error you are getting when you run the code?
At a glance, the code looks fine. Make sure you add the Internet permission in your AndroidManifest.xml.
<uses-permission android:name="android.permission.INTERNET" />
I just ran this code and its working fine. The error must be coming from somewhere else?
Are you running this in the emulator? The emulator has DNS problems sometimes. It's possible the emulator can't find www.google.com, see this post:
Upgraded to SDK 2.3 - now no emulators have connectivity
a background process or use AsyncTask to perform your network transaction on a background thread will be required.
http://developer.android.com/resources/articles/painless-threading.html