当放置在if（！isset）时，$ _GET值被删除 [英] php $_GET value erased when placed in if(!isset)

问题描述

这工作正常：

  $ username = $ _GET [username]; 
 $ query =INSERT INTO test（latitude）VALUES（'$ username'）; 
 mysql_query（$ query）或死（mysql_error（error））; 
 mysql_close（）; 
  

这不起作用：

<$ p $如果（！isset（$ _ POST ['submit']））
{
}
else
{
$ username = $ _GET [ 用户名];
$ query =INSERT INTO test（latitude）VALUES（'$ username'）;
mysql_query（$ query）或死（mysql_error（error））;
mysql_close（）;

$ / code $ / pre
$ b $ p如果$ username被设置为除get之外的其他值，比如'7 。

GET从目标c中检索一个值。如果我没有把它放在一个if语句中，它会自动进入我的数据库数百次。如果我把它放在'if'语句中，它只会输入一次，但是值将为零。我完全被难住了。任何帮助将是伟大的。

编辑：
我想因为我得到的答案，我没有解释得很好。澄清：我使用POST来发布user_id，answer_body。我使用GET作为从Core Location导入纬度和经度的一种方式（即使我将它命名为用户名，它是纬度）。我希望他们都进入相同的条目，这就是为什么要将GET连接到isset_POST。此外，当GET（用户名）独自使用INSERT查询时，它会在数据库中创建数百个重复项。这里是Objective-C脚本：

pre $ //将任何用户名设置为数据库
float username = location.coordinate.latitude;
NSString * theValue = [NSString stringWithFormat：@％f，username];
NSString * hostStr = [NSString stringWithFormat：@http://mysite.com/page.php?username=%@，theValue];
NSData * dataURL = [NSData dataWithContentsOfURL：[NSURL URLWithString：hostStr]];
NSString * serverOutput = [[NSString alloc] initWithData：dataURL encoding：NSUTF8StringEncoding];
NSLog（@服务器输出：％@，serverOutput）;


表单代码为：

 < form action =gpstestertwo.phpmethod =post>< center> 
 $< input type =textname =answer_bodymaxlentgh =5style =height：3em;/> 
< input type =submitvalue =submitname =submitstyle =height：2em; width：5em; font-size：19px
 /> 
< / center> 
< / form> 
  

解决方案

$ _ POST ['submit '] 和 $ _ GET ['username'] ...为什么不使用 $ _ POST ['username'] 。

您如何发送 FORM 数据， POST 或 GET ？或者使用 $ _ REQUEST ['username'] 来确定。

在使用查询前转义用户名

$ b 编辑（总是在 POSTs < code $，而不是 GETs ）：

  if（！ strcasecmp（$ _ SERVER ['REQUEST_METHOD']，'POST'））{
 //发布操作，在这里工作只有
 if（！empty（$ _ POST ['username']））{
 // ...在这里做最坏的... 
} 
} 
  

GETs 是默认请求，您可能最终在数据库中被轰炸。 POSTs 是特殊的。因此，在做 POST 处理之前，确保 REQUEST_METHOD 是 POST 。

This works fine:

$username= $_GET["username"];
$query= "INSERT INTO test (latitude) VALUES ('$username')";
mysql_query($query) or die (mysql_error("error"));
mysql_close();

This does not work:

if(!isset($_POST['submit']))
{
}
else
{
$username= $_GET["username"];
$query= "INSERT INTO test (latitude) VALUES ('$username')";
mysql_query($query) or die (mysql_error("error"));
mysql_close();
}

It works if $username is set to something other than get, like '7'.

The GET retrieving a value from objective c. If I don't put it in an if statement it will just enter itself into my database hundreds of times. If I put it in the 'if' statement it will only enter once, but the value will be zero. I'm totally stumped. Any help would be great.

EDIT: I think because of the answers I'm getting that i didn't explain well. to clarify: I am using POST to post user_id, answer_body. I am using GET as a way to import the latitude and longitude from Core Location (even though I named it username, it is the latitude). I want them all to go into the same entry, which is why im tying GET to isset_POST. Further, when GET(username) is on its own, with an INSERT query, it will make hundreds of duplicates in my database. Here is the objective-C script:

//sends whatever username is set to, to database
float username = location.coordinate.latitude;
NSString *theValue = [NSString stringWithFormat:@"%f", username];
NSString *hostStr =[NSString stringWithFormat:@"http://mysite.com/page.php?username=%@", theValue];
NSData *dataURL =  [NSData dataWithContentsOfURL: [ NSURL URLWithString: hostStr ]];
NSString *serverOutput = [[NSString alloc] initWithData:dataURL encoding: NSUTF8StringEncoding];
NSLog(@"Server output: %@", serverOutput);

The form code is:

<form action="gpstestertwo.php" method="post"><center>
                $<input type="text" name="answer_body" maxlentgh= "5"  style="height:3em;"/>
                <input type="submit" value="submit" name="submit" style="height:2em; width:5em; font-size:19px " 
                 />
                 </center>
            </form>

解决方案

$_POST['submit'] and $_GET['username']... why not use $_POST['username'].

How are you sending the FORM data, POST or GET? Or use $_REQUEST['username'] to be sure.

Not to mention the need to escape the username before using in query.

EDIT (always do the processing on POSTs, not GETs):

if(!strcasecmp($_SERVER['REQUEST_METHOD'], 'POST')){
    // post operation, do your work HERE only
    if(!empty($_POST['username'])){
        // ... do your worst here ...
    }
}

GETs are the default request and you might end up bombarded in your database. POSTs are the special ones. So make sure the REQUEST_METHOD is POST before doing POST handling.

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