I followed the demo client/server tutorial that Android docs have provided (http://developer.android.com/google/gcm/demo.html). Everything worked exactly as advertised when I first tried it out. The servlet first came up with "No devices registered!" screen, then started the demo app on my device and I was able to send the demo messages to the device just fine.
Then I shutdown my Tomcat server that deployed the gcm-demo war and closed the demo client app on my device (which is not an emulator, Nexus 7). I started the tomcat server back up, I see it did deploy the gcm-demo war as expected however when I go to the URL of the servlet (the one that originally said "No devices registered!") it now says that No devices are registered. I opened up the app on my device and it says that device is already registered on server. Why is the servlet not seeing my device that IS registered?
I appreciate any help, thank you.
I didn't take the Tomcat/servlet approach myself, opting for an Apache/PHP/MySQL way instead, so I've no direct experience, but reading the sample code I see as the comment in the server's Datastore.java, this:
/**
* Simple implementation of a data store using standard Java collections.
* <p>
* This class is thread-safe but not persistent (it will lost the data when the
* app is restarted) - it is meant just as an example.
*/
So basically when you restart Tomcat it's forgotten your regId.
#NickT is right. If you want persistent storage of regIds you can back it up with a java.util.Properties that stores the data into a properties file or write a simple file store yourself.
Reset the state of your client app by deleting the cache or re-installing the app.
Related
I want to create a pair of Android app (Server - Client) using Socket to communicate with each other in real time. I found the sample here http://androidsrc.net/android-client-server-using-sockets-server-implementation/ which works. The client can connect to the server. Now I think about making the server a... "web server" (I don't know if I'm calling it the right way) that can display what they (server and client) are communicating (maybe showing their chat or calculation...).
But when I type in the address and port (eg: http://172.16.1.21:8080/) into the browser (Chrome), the result is
172.16.1.21 sent an invalid response. ERR_INVALID_HTTP_RESPONSE
I guess it was responding but with some other kind of format that the browser doesn't understand. I tried calling with postman and got the error:
Could not get any response There was an error connecting to
172.16.1.21:8080.
I tried putting an index.html to the root of the storage (/storage/emulated/0/) but no luck
The idea would be the same as the app "Websharing" on store. All you need is that the phone and the Computer is on the same network. When access the app, the browser will show the content of the phone.
My idea is to show other information. I though about creating another "display-app" to show the result, but then what if I wan't to send some custom message to all client, then I will need an another phone, which is so difficult to have. Opening another tab is much easier. I don't want to risk using online service like Firebase because the internet connection may not be stable. Just local connection is fine for me.
I don't know that is it called, a keyword would be appreciated. I tried googling and found some suggestion that to run an app called "Tiny web server", I haven't tried it but I don't wan't to use a third-party app because the installation will be complicated and not support full customization.
Thank you for your time.
I've looked around trying to find an answer to this question, but have so far been unsuccessful. I have a current version of an Android mobile application that stores items in the local database, and I'm trying to hook it up to a 'cloud' database (not sure if this is the right term) so that other people that download the app will be able to view and post things to the database.
I have an ec2 service set up, with my LAMP stack installed. I have the database set up on this server ready to go. How do I go about hooking up the Android application so that it can communicate (insert/view/delete items) with the database? I am a new developer so any help/insight/guidance you have is much appreciated!
You haven't mentioned the type of database you have setup on cloud.
I am assuming it to be some kind of relational database (e.g. MySQL).
You can use standard JDBC connection from a regular java code but it is not yet possible (supported) to do it directly from Android code.
I faced a similar issue, what I did was this:
Create a Servlet and deployed it on GAE (Google App Engine).
Make an HTTP request from your android application code to this Servlet (SELECT/UPDATE/DELETE).
Initiate a JDBC connection to your database (on EC2) from that Servlet.
Shoot the SQL statement to the database.
Get the result and send the response back from servlet to your android code.
There may be other better solutions but I could not find any and tried this on my own, it worked like a charm, multiple times.
After writing the previous answer, I kept on thinking of alternate solution.
FYI: This may or may NOT work !
Instead of hosting your servlet on GAE, you can host it on the same EC2 instance as your database, using tomcat or any other package.
This way your android code would communicate directly with the instance that has servlet and database deployed together.
In the servlet, you can shoot SQL queries internally and send the results back to android code.
How to host a servlet in Tomcat 7
Adding new security group and linking it with my instance..worked for me
I am trying to write a http proxy server that would run on the device itself. In fact, need to find a way to capture the outbound http traffic generated by the device.
The code I have so far is compiling OK, it is based on the code found here: http://www.jtmelton.com/2007/11/27/a-simple-multi-threaded-java-http-proxy-server/
The problem is that the http request to the actual server would block and never return .
Is there a better way to write such a service without rooting the device?
You should check SandroProxy.
Can caputre traffic on non rooted device if os proxy settings are used, or with iptables rules on rooted one.
Traffic is stored it in local sqlite database. Captured data can be also examined by chrome devtools. To capture traffic in your app you should check source code for plugins. It has all the code for iptables redirections and proper settings.
Check out the wiki link on google source code HowToInterceptTrafficOnMyOwn
http://code.google.com/p/sandrop/wiki/HowToInterceptTrafficOnMyOwn
btw: send by sandroproxy support :)
I've been using a piece of software called proxydroid to use my device as a proxy server, and its the only one I've found which doesn't require root. I'm not sure if it will be any help to you, but its an open source project and the code can be found here:
https://github.com/madeye/proxydroid
I have noticed that the application will freeze after a while, or if a large number of request are sent at once, but I've not had chance to find out why this is happening.
Forget about setting proxy, use Facebook Stetho library (http://facebook.github.io/stetho/) to review all http requests and responses from emulator/device
Below I explained what I need and in the answer I would like to get information what technology, what kind of protocols, services etc should I use.
Also I know that there is a massive amount of information on the internet, but because there are so many choices I'm unable to make a decision. Here's what I want to have:
Android application which will sent and receive information from the internet/server
Of course server, which will do some rudimentary computation with the obtained information, then store it and at the end send it back to the client application
I have to admit that the subjects of networking, socketing, protocols, ciphering etc are the ones I've always run away from. Therefore advices such as what domains, databases etc utilize are highly welcome
Update: After a bit of a research I've implemented mechanism based on information from this site [1]. I already have a working MySql database with several tables inside. Also I've added php scripts to my Apache webspace and implemented all that's necessary within my Android app.
Now, as I understand communication between php's scripts and MySql database is safe (I've hardcoded the usr/pass within scripts). Therefore the only thing that has left to be done to secure the connection between my Android application and php scripts (I want to prevent the situation when everybody has an access to my php scripts). So my question should be pretty straightforward now, how can it be achieved?
[1] http://blog.sptechnolab.com/2011/02/10/android/android-connecting-to-mysql-using-php/
I think a simple TCP/IP connection via Sockets will do just fine for your purposes.
The lesson (with more information and some examples) from the Java-Docs can be found here.
The basic workflow is as follows:
Your Android-App opens a Socket-connection to your server on a
given port where a server-application listens.
The Android-App sends it's data (whatever that might be) to the
Server.
The Server reads the send data,
processes it,
stores it...
...then it sends back some response (maybe the computed values) to your
Android-App.
Your app can then figure out if everything went okay and use the
given data.
Answering my second question, all the php scripts has been put into directory with the password on my Apache server. To be able to trigger them I need to give this password which is hardcoded in my application. All the connection is done through HTTPS. Now everything works as planned!
I have an Android App which uses http communication for nearly every operation. I want to be able to demo without connection to the internet by somehow replaying the http exchange. How can this be done? So I want to somehow almost like mock objects but really mock http session so I can always demo the app on or offline. This is really a very cool thing to be able to do. Since you can demo the app easily and reliably. Does anyone know how I could do this. Replicating the whole server side is just not an options its got too much stuff. Its important not to just show screencast but the real data exchange. I just want to be able to run thru the app and replay. Maybe debug as well. Thanks
Here's a hybrid solution using similar ideas from other answers:
You could write a dead simple HTTP server that listens on "localhost:80" (or whatever the port is on the server you're targeting) and point your application to this host instead by factoring out the host name from requests. Your local server has a reference to the actual remote server and does the following:
If ONLINE, forwards the request as-is to the real server, gets the response, saves it locally either in an in-memory cache keyed by the request URL or a file named with the URL as its identifier (munged appropriately)
If OFFLINE, looks up a request in its (in-memory or file system) cache and returns the contents from the cache instead
This is kind of like the record/playback mode that #nicholas.hauschild says.
Now you can just run your app once when ONLINE, causing your localhost server to save away requests that it issues against the real server. Then when you run your app OFFLINE, it just returns these cached contents instead whenever the same URLs are issued.
Hope this helps.
If you're device is rooted, you can use tcpdump as explained in this post: http://www.vbsteven.be/blog/android-debugging-inspectin-network-traffic-with-tcpdump/
or use AndroShark (get if from xda-developers here: http://forum.xda-developers.com/showthread.php?t=725692)
or this one (wifi only): http://www.9bitlabs.com/default.aspx
I would create a "Record Mode", and a "Playback Mode" for my app.
While in Record Mode, I would write out a file each time an http request was made. The file would be named by the endpoint the request is made. The contents of the file would a collection of serialized http requests/responses broken up by line. You could then deserialize lines from this file until you find the proper request, and play back the deserialized response.
This approach would also allow you to create Record/Playback profiles, where you could record multiple different sessions (by placing the files into a different directory) and then playback from whichever profile you choose.
This whole approach could be done with a small wrapper class around the HttpClient object you are using.
One way would be to use an HTTP proxy. Redirect all web traffic to the proxy, which can be running locally on the phone. This could be done with little or no source code change.
find a way using fiddler on pc,and android app take fiddler as proxy.So the http traffic is record.
http://blog.csdn.net/grhunter/article/details/5830199
Simples solution lies in faking it when there is no connection. If there is a error in connection, make sure ur app throws some preset data rather than an error in connection thing.