We Keep Coding

Update Android app with HttpClient to OKHttp3

I'm trying to upgrade some Java code to fit in with an android app.
The code references the depreciated the Apache http module which Android no longer supports since Marshmellow.
I need to complete a POST of the XML code.
I'm new to connections and OKHttp3. Is there a way I can achieve a similar result with using OKHttp3?
private static String SubmitXml(String Xml, String Url) throws Exception {
HttpClient client = new DefaultHttpClient();
// Prepare the POST request
HttpPost pxpayRequest = new HttpPost(Url);
pxpayRequest.setEntity(new StringEntity(Xml));
// Execute the request and extract the response
ResponseHandler<String> responseHandler = new BasicResponseHandler();
String responseBody = client.execute(pxpayRequest, responseHandler);
return responseBody;
}
I've searched the web but most OKHttp3 articles I've seen reference sending JSON data or something similar. Nothing with XML.

Android Rest Client

I found so many samples for requesting a REST API, but all together are confusing, can some one please explain me a way to use http requests.
My Requirement is, I want to get data from a REST API by providing username, pwd and a key.
What I have Used was,
HttpClient client = new DefaultHttpClient();
HttpPost post = new HttpPost("REST API url");
post.setHeader("Content-type", "application/json");
JSONObject obj = new JSONObject();
obj.put("username", "un");
obj.put("pwd", "password");
obj.put("key","123456");
post.setEntity(new StringEntity(obj.toString(), "UTF-8"));
HttpResponse response = client.execute(post);
But the response is always null and these working fine when tested with browser tool by posting the same data.Is some thing wrong with my approach? please suggest me the correct way. Thank you

(1) Google I/O video session for developing REST clients
(2) search in android developer blog
(3) https://github.com/darko1002001/android-rest-client
Please try after that post your question,
I can share code snippet from my rest client developed based on (1) & (2)
Do not use Cloud to Device Messaging, instead use the latest cloud approach with android application development.
There is new library called Volley, which looks better than AsyncTask. It should be useful in developing RESTful clients.

You probably forgot to add the internet permission to the manifest file.
Add the following line.
<uses-permission android:name="android.permission.INTERNET" />

I thing you should try this,
HttpContext localContext = new BasicHttpContext();
HttpClient client = new DefaultHttpClient();
HttpPost post = new HttpPost("REST API url");
post.setHeader("Content-type", "application/json");
JSONObject obj = new JSONObject();
obj.put("username", "un");
obj.put("pwd", "password");
obj.put("key","123456");
post.setEntity(new StringEntity(obj.toString(), "UTF-8"));
HttpResponse response = client.execute(post,localContext);
Hope this will help.

By any chance, is the server expecting a GET request for this operation? If so, you may want to use HttpGet instead of HttpPost.

Posting to a form based on what HttpGet returns with Apache's HttpClient

I'm posting data to a website form using Apache's HttpClient class. The form is retrieved using the following lines of code:
HttpGet get = new HttpGet(url);
HttpResponse response = client.execute(get);
The website that I'm retrieving the form from requires authentication to access the form. If the request isn't authenticated, the website redirects the request to a login form page that will subsequently redirect back to the original page on successful authentication.
I want to cleanly detect whether or not the GET request returns the login page or the desired form page so that I can either POST login data or form data. The only way I can think of to do this is by reading from the content InputStream of the entity of the response and parsing each line. But that seems somewhat convoluted. I haven't worked with the Apache HttpComponents api before so I'm not sure if this would be the only and best way to accomplish what I want to accomplish.
EDIT: To clarify question, I'm asking if there is a set way to handle forms with Apache's HttpClient. I somewhat know how to achieve what I'm looking to do, but it looks very ugly and I'm hoping there is an easier and faster way to achieve it. For example, if there was some way to do the following:
HttpGet get = new HttpGet(url);
HttpResponse response = client.execute(get);
if(parseElements(response.getEntity()).hasFormWithId("login")) {
// post authentication data
} else {
// post actual form data
}
Because of my inexperience with Apache's HttpClient api, I'm not sure if what I'm looking for in the API is too abstract for the intent of the API.

You can modify the behavior of the HttpClient by setting the HttpClient Parameters
DefaultHttpClient client = new DefaultHttpClient();
client.setDefaultHttpParams(client.getParams().setBoolean(ClientPNames.HANDLE_REDIRECTS, false));
Which disables handling redirects automatically.
See also:
Automatic redirect handling
HTTP Authentication
DefaultHttpClient API

Call REST GET Service from JSP

I have a JSP that dynamically sets the page header of my application.
However, I want to be able to call the REST Service that gets user details based on the system user. I already have the system user value but need to call the backend service to get the details from the database. This is already implemented but I don't know how to setup the JSP to do this.
I do not want to use javascript as this is being used for the extjs side of things.

In order to call REST from JSP, you could utilize Apache HTTPClient. Once you have that you could walk through the samples as well as the HTTPClient Tutorial. HTTPClient supports all REST API Call including GET/POST and others.
Check also this following HTTPClient template to see how HTTPClient can be used with REST. You need to call a similar code from your JSP.
In particular to REST GET Service, you want to look the following block from the template in the above link
final HttpClient httpClient = new DefaultHttpClient();
HttpConnectionParams.setConnectionTimeout(httpClient.getParams(), 10000);
HttpGet httpget = new HttpGet(SERVER_URL + url);
HttpResponse response = httpClient.execute(httpget);

Wrapper class for HttpGet / Post in Java?

Sorry, I'm quite new to Java.
I've stumbled across HttpGet and HttpPost which seem to be perfect for my needs, but a little long winded. I have written a rather bad wrapper class, but does anyone know of where to get a better one?
Ideally, I'd be able to do
String response = fetchContent("http://url/", postdata);
where postdata is optional.
Thanks!

HttpClient sounds like what you want. You certainly can't do stuff like the above in one line, but it's a fully-fledged HTTP library that wraps up Get/Post requests (and the rest).

I would consider using the HttpClient library. From their documentation, you can generate a POST like this:
PostMethod post = new PostMethod("http://jakarata.apache.org/");
NameValuePair[] data = {
new NameValuePair("user", "joe"),
new NameValuePair("password", "bloggs")
};
post.setRequestBody(data);
// execute method and handle any error responses.
...
InputStream in = post.getResponseBodyAsStream();
// handle response.
There are a number of advanced options for configuring the client should you eventually required those.