Develop Reference

Sending HTTP request from Android app

Currently in cURL I can run a basic request like this:
curl -u username:token https://api.mywebsite.com -H "Accept: application/custom-header"
It authenticates, it picks up the custom header and everything is great.
However, I want to do this from an Android app. I had a look at HttpClient but it was deprecated at API level 22. So now I'm trying to find something else to do the job.
What is the current/best way to do this from an Android app?
Thanks

You can use Volley Library of google for the Network call check this Volley site

Get url & parameters of a POST request made from an android app. (Hack an application)

1> Is it possible to fetch the end-point of a http post request made from an android app?
2> Is it possible to fetch the parameters (key & value) of that request ?
If it is not possible to fetch the exact end-point & the parameter list for a post request made from an android device, can we assume that it is very hard to hack that particular end-point?
Edit 1 :
Say, in my android app, I am using an end-point like - http://abc.xyz.com/buyItem with 2 parameters : itemCode=value1, price=value2
(how)Can the url, parameter list & values be fetched by a hacker?

Yes it is possible to monitor network traffic and get those values.
It is pretty easy to set-up with something like a basic (cheap) network hub (not a switch) and a PC attached and a few network tools like tcpdump or ngrep.
A tcpdump example would be:
tcpdump -A -i eth3 > t.dump
Change eth3 to your network interface. You can look over the file t.dump in a text editor or use less or more.
NOTE: SSL / HTTPS connections are encrypted, so tcpdump will only give you parameters over HTTP.
There are other ways as well.
You could get lucky and simply unpack the apk and grep for something like ://. For example
grep -R '://' ./unpacked-apk/*
Update: Added a tcpdump example.

I would recommend using Fiddler for this purpose, it is a tool that has a nice UI and you would not need to write any complicated command line commands. Here is a documentation article on how to configure Fiddler to capture traffic on Nexus device.

What is Apache-HttpClient/UNAVAILABLE error (Android, Google App Engine)?

I am confronting myself with a problem that I do not know how to interpret. I am doing a project using Android and Google App Engine. When I am trying to save information in Google App Engine's Big Table, directly from the servlet (hardcoded) - the save is performed with no problem. But when I am trying to save data from my Android device, the save is not performed and the log indicates Apache-HttpClient/UNAVAILABLE error. To be more specific:
405 55ms 0kb Apache-HttpClient/UNAVAILABLE (java 1.4)
82.155.246.249 - - [10/Jun/2013:05:20:59 -0700] "POST /servletnamehere HTTP/1.1" 405 306 - "Apache-HttpClient/UNAVAILABLE (java 1.4)" "appnamehere.appspot.com" ms=56 cpu_ms=21 cpm_usd=0.000034 app_engine_release=1.8.0 instance=00c61b117cede3f754aa1ece730dc88287a20199
I have seen that 405 HTTP error appears in the context of a POST method ( "405 errors often arise with the POST method. You may be trying to introduce some kind of input form on the Web site, but not all ISPs allow the POST method necessary to process the form." ) => indeed, I am trying to perform add (the object is a JPA Entity) in the database using a POST method. The data I am receiving from my Android device is serialized, through an input stream (in my case, working with JSON is not an option, these are the specifications).
Also, 306 HTTP error reffers to switch proxy. While the porevious error might be a bit intuitive, this one is beyond my student knowledge.
I have followed the instructions of this tutorial (http://trumpy.cs.elon.edu/joel/sigcse2011/), which is indeed what I need, but I really cannot figure out what I did wrong. I took again the procedure, stept by step, but I don't see the flaw.
Any help will be indeed appreciated. If I should post some code, I'll gladly do it.
Best wishes,
Cropcircles
LATER EDIT:
Now I get 417 HTTP error expectation failed. I have seen that I am supposed to set a certain parameter on false, but this workaround was available only for .NET. Is there anyone who knows what's the correspondent of the following, in Java? I am really really confused.
<system.net>
<settings>
<servicePointManager expect100Continue="false" />
</settings>
</system.net>

This is not an answer, but is too long for a comment and may be helpful, so here goes...
First, it's hard to tell what's going on here because there is limited info. Try to post more of the logging either on the client or on the server. Go to the server console and get more info, for instance, or add debugging in the client. I'd start by trying to make the POST from a debug/testing tool like hurl.it: http://www.hurl.it/ (hurl is a nice web front end to a command line HTTP client named curl, see curl itself if you want a more advanced peek). That way you can test and poke around and make SURE your server side works as you expect with a generic client. Then build other clients (like Android).
Second, "Apache-HttpClient/UNAVAILABLE" is not an error, it's just the user-agent String -- so ignore that part. (UNAVAILABLE is where the version typically is, but some impls don't have access to the version sometimes, it seems.)
Third, the 405 response code IS an error, it means POST is not allowed at the server you are trying to POST to. That can either be because POST is not allowed at all on said server, or you're violating some security policy (such as same origin).
If it's AppEngine, first check the APP you are using and make sure it supports POST (look for info on how to do POST at AppEngine to solve, for instance: google app engine: 405 method not allowed). When you say you can do it directly from a "servlet," do you mean that a POST from a different client works? (Servlet is a server side technology, so that's a little confusing.) If so then make sure your Android app is doing the client part the same way to the same host (multipart vs urlencoded, etc).
For a little more on the security stuff, which could be involved, see this post: Google App Engine + jQuery Ajax = 405 Method Not Allowed.

I've had the same trouble and in my case It was an error due to no write permission on server side area.
I was following an android test to write on a file a value transmitted in async way via POST method.
Apache received the POST request but was not able to write the data on the file due to security permission on it.

Android WebView full page

I am creating an aplication that involves an WebView. The thing is that I want to load the full page and not the mobile one, so I have changed the User Agent. Nevertheless there are pages that loads the mobile version.
Here are two versions of code that I have tried:
1.webview.getSettings().setUserAgentString("Mozila ");
2.
String DESKTOP_USERAGENT = webview.getSettings().getUserAgentString ();
DESKTOP_USERAGENT = DESKTOP_USERAGENT.replace("Mobile ","");
webview.getSettings().setUserAgentString(DESKTOP_USERAGENT);
This are exemples of webpages that loads the mobile version in any cases:
http://www.jurnalul.ro
http://www.androidzoom.com
1.Does anyone knows how I can trick the server and tell him I am using a desktop and not a mobile?
2.How does a website knows that I am using a mobile version?
Thank you very much,
Razvan

The problem may be that if you are using a device that your carrier is routing all your HTTP requests through a proxy, and that the proxy is changing the User-Agent. Check on the other end, with your own server, using nc -l 80 -vvv that your request is indeed sending the User-Agent that you have modified.
EDIT: Some specific troubleshooting steps
Forward a port 9090 on your router to your desktop machine or laptop.
Download netcat
Run netcat with the command "nc -l 9090 -vvv"
In your Android application's WebView, make an HTTP request with the User-Agent you are injecting to http://your.ip.address:9090
In the terminal you ran netcat, you will see the HTTP request dump in plain text. There you can check the HTTP header User-Agent to see if it has been changed by a proxy server or not.
You cannot test this stuff with Wireshark or Fiddler because it is happening in the WAN. You need to test it on the receiving end, either on a server, or on your own desktop machine.

webview.getSettings().setUserAgent(1);//for desktop 1 or mobil 0.

How to debug http calls on Android devices?

I'm writing a Lovefilm client for Android, and it's not going too badly except I keep having problems with the remote calls to retrieve data from the API.
Does anyone have any tips for debugging remote calls like this? Can I tcpdump on Android or is there a native way of doing it?
For example, I'm using the Scribe-java library for OAuth to access the Lovefilm API, I can authenticate find and retrieve a list of films on the users account fine when the device is running Gingerbread, but trying to retrieve the accessToken on Froyo causes a blank response & and apparent response code of -1, I'd like to be able to see what's going on under the cvers their.
Another example I'd like to be able to the raw http for is trying to run a search, I get and IOError that says "Received authentication challenge is null"

I've used Fiddler (http-proxy for debugging http calls) with the android emulator in these cases. Just start the proxy, and start the emulator with the correct proxy address (-http-proxy ).

Fiddler is the most useful option. On the emulator #Scythe answer will work, but on a real device you will need to set the proxy in the Apache Http Client. The following code will do that:
HttpHost proxy = new HttpHost("youripaddr", 8888);
params.setParameter(ConnRoutePNames.DEFAULT_PROXY, proxy);
If you are using https, fiddler is not so useful. In that case can enable the build in logging support in Apache Http Client. The following code does that:
Headers only:
java.util.logging.Logger apacheHeaderLog = java.util.logging.Logger.getLogger("org.apache.http.headers");
apacheHeaderLog.setLevel(java.util.logging.Level.FINEST);
Headers & Wire:
java.util.logging.Logger apacheWireLog = java.util.logging.Logger.getLogger("org.apache.http.wire");
apacheWireLog.setLevel(java.util.logging.Level.FINEST);
Note that this will have to have a java.util.logging Handler configured at finest level and the default handler is configured to log to logcat, which will filter DEBUG (finest) entries by default.

If your system can share the wi-fi connection you should be able to route packets from any device through your system and then using wireshark you can get monitor your calls or get a tcpdump.
Also , and more importantly , it would be best if you log your network calls and responses as suggested by #Matthew
Windows 7 wi-fi connection sharing : http://www.winsupersite.com/article/faqtip/windows-7-tip-of-the-week-use-wireless-hosted-networking-to-share-an-internet-connection-wirelessly.aspx

Since I always run into similar troubles and it seems a lot of people having the same issues over and over again I wrote up a quick tutorial for debugging client-server communication by using netcat and cURL.
That of course only works for the simplified case that you always 'fake' on side of the connection.
For eavesdropping you can use tools like tcpdump or Wireshark. Which will definitely be easier if you're able to run the server instance directly on your local machine.

Stetho is a great tool from FB which helps in debugging android Apps. You can have access to local data and have a check on your network using this.
http://facebook.github.io/stetho/