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Ive been trying to send gps data from my android app to a mysql database using php but Im not sure if everything is set up right because I can see through the logcat that the data is being sent from android but its just not getting sucked up by the database.

Aside from some recommendations does any body have any tutorials that would show specifically the php to server code.

Also is it possible to just send the data straight to the database without something like php? I dont think so but I had to ask.

here is the php that I am using with the addresses and stuff taken out for obvious reasons.

<html>
<head>
<title>Send and Rec data to Android Device</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">


</head>


<body>


<?php
//include("dbinfo.php");



///the stuff pointing to my db has been removed for obvious ///reasons ;)


mysql_connect($hostname,$username,$password) or die ("<html><script           
language='JavaScript'>alert('Unable to connect to database! Please try again later.'),history.go(-                
1)     </script></html>");


mysql_select_db($dbname);


// variables coming from Android  app on phone
$id = $_POST["id"];


$lat = $_POST["lat"]; // If data is in DB line 1 (public key), but the publicly displayed PHP is     
not showing data then we know that we aren't really talking to line 1

$lng = $_POST["lng"];


$alt = $_POST["alt"];


$spd = $_POST["spd"];


$acc = $_POST["acc"];


$last_gps = $_POST["lastgps"];


//filler will contain reference to graphic or audio upload directory
$filler = $_POST["filler"];


$lastid = mysql_query("select MAX(id) as maxid from samplemarks");
$row = mysql_fetch_array($lastid);


$nextid = $row[maxid] + 1;


echo "Inserting at next id = ".$nextid."<br />";


if ($lat == "") 

{
 echo "Invalid entry, latitude cannot be blank";

}

  else {
  $query2 = mysql_query("INSERT INTO samplemarks VALUES($nextid,'$lat',     
  $lng,'$alt','$spd','$acc','$last_gps','$filler')");

  mysql_query($query2);


mysql_close();


}
?>


</body>


</html>
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  • all you need to get your db working devzone.zend.com/node/view/id/641 Commented May 24, 2011 at 18:26
  • I have my database working already and its holding data but i cant post new data to it for some reason Commented May 24, 2011 at 18:54

2 Answers 2

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You'll have problems running your code or the corrected code, because you're passing the result from the first mysql_query() as a parameter to the second mysql_query() which won't work. The first mysql_query is enough to execute the SQL, take a look at http://php.net/mysql_query for some good code examples. You also don't need the $conn parameter if you're only dealing with one mysql_connect() connection, as PHP will assume you want to use the most recently opened connection if you don't specify it.

Also, make sure you do some good research on SQL injection attacks in PHP, particularly the article on the PHP site at http://php.net/manual/en/security.database.sql-injection.php - it's very important to protect your SQL queries when they depend on user input.

If you're having problems, strip it back to the basics. Use print_r($_POST) to see what your POST body is being filled with, and try some simple mysql_query() statements to check that your database connection is working correctly.

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11 Comments

In the future I plan on adding different forms of security but for now Im just trying to get things to come together :) I wasnt sure if I needed the second mysql_query but between me and the other guys working on our project the consensus was that it was needed......but maybe its not :p Ill try it with out and re organize my code which Ill update in a while. Ill let everyone on here know how it comes out
It's not so much whether it's needed or not, it's simply that it won't work; mysql_query() returns either a PHP resource or a boolean, neither of which mysql_query() takes as a parameter for it's query. Your first mysql_query() would either return true or false as it's an INSERT statement, which would be typecast to either the string "1" or "" when you passed it as the query parameter to the second mysql_query()
I took a look over the code that I have posted here with my buddy and we actually found a small syntax error in one of our declarations :p The code actually works just as it is even if its not the cleanest or best method. I finally got the data to post to the table on the server. However I will definitely go over your suggestions with the other programmers I work with and make sure what we have works totally smooth come product launch time :)
The first query isn't needed if the field is setup as auto increment, as I stated in the text of my answer.
Unless there's a specific need to do so (and if it's just to get the highest id and add one that isn't a good reason) you're just wasting cpu / time. Let the database server handle it for you automatically. [ sorry about the dual comment, thet'll teach me to go get coffee]
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1

Your mysql_query is missing the connection parameter. When you do the connect, store it in a variable eg

$conn =  mysql_connect($hostname,$username,$password) or die('Blah');

if ($conn) {

    mysql_select_db("mydatabasename", $conn);

   // extract your data
   if (isset($_POST["id"]) && isset($_POST['lat']) && isset($_POST['lng']) {

           $id = $_POST['id'];
           $lat = $_POST['lat'];
           $lng = $_POST['lng'];

           // add the rest of the POST fields so the query below works
           // unless you need a specific $nextid make the field auto increment in the
           // database and user '' instead of $nextid.  

   $query2 = "INSERT INTO samplemarks VALUES($nextid,'$lat',     
     '$lng','$alt','$spd','$acc','$last_gps','$filler')";

    if (mysql_query($query2, $conn))
        echo "data inserted';
    else
        echo "Oh dear ".  mysql_error() ;


       // etc
  }  // end the isset tests
}

Also $lng isn't quoted in your code.

I realise that you are sending data from your android application to your php/db server but you should always sanity check the data from the post, otherwise you're making it easy for someone to use sql injection attacks to compromise your database. Think about protecting your php with ssl and username/password

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7 Comments

Hey thanks for the help Fuzzy. Where you have //extract your data in the code example do you mean extract the data from the stream i just sent or are you talking about extracting it from an existing value in my database? Just a little confused as this is my first time really connecting android to a php to a data base :)
Yes, I just cut it out because I'm lazy ;) - you should probably use isset too so that you don;t get errors when data is not passed. eg if (isset($_POST['id']) $id = $_POST['id']; - remember to to initialise your other vars too. Will edit the answer to clarify.
Hey thanks a lot man when I get back to my computer Ill make sure to add the stuff you showed me in your example to my php page. When using isset, is it checking the data against existing data in the table or something?
If I do : isset($myvariable) I'm testing to see if $myvariable has a value (is set), so for what you want it's a way you can check to see if you android application has POSTed (eg $_POST['lat']) a value called 'lat'.
Downvote, this code is unsafe and the user inputs are not escaped. Also the connection parameter has nothing to do with the original code not working, PHP always uses the last connection. The original code did not work as OP was trying to post a mysql_query resource into a query.
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