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Asked: 2026-06-02T04:53:11+00:00

Having a hard time parsing XML created from a web-form using POST. Here’s the

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Having a hard time parsing XML created from a web-form using POST.

Here’s the scenario:

1) User comes to a web-page, enters their name into a text-field, and clicks SUBMIT

2) This calls a PHP file (called “makeXML.php”) which generates an XML file containing that user’s name in a tag called “currentUserName”

3) an iPhone App then loads this “makeXML.php” file (using ‘loadXMLByURL’) and parses it, looking specifically to output the contents of the “currentUserName” tag into a UILabel object.

Should be pretty simple – but for some reason, the contents of the “currentUserName” tag are coming up empty in the App – though they show up perfectly well in the generated XML code in the browser.

What’s even stranger, is that if I instead hard-code a value to “uName” in the PHP file (“makeXML.php”) – as opposed to getting that value from the FORM (using $_POST[“userName”];) – it all works perfectly well. I’m able to grab the value from the “currentUserName” tag and output it to the UILabel object.

NSXMLParser seems to just not like POST’ed values for some reason.

Any ideas?

Here’s the code:

portal.html:

<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Web-Form</title>
</head>

<body>

<form name="form1" method="post" action="makeXML.php">
  <p>Enter your name:</p>
  <p>
    <input name="userName" type="text" />
  </p>
  <p>
    <input type="submit" value="SUBMIT" />
  </p>
</form>

</body>
</html>

Here is “makeXML.php”:

<?php
header("Content-type: text/xml");
echo "<?xml version=\"1.0\" encoding=\"UTF-8\" ?>";

echo "<document>";

$uName = $_POST["userName"]; 

echo "Here is the name you typed:";
echo "<br/>";
echo "<theUsersName>$uName</theUsersName>";

echo "</document>";

?>

Here is the outputted code from makeXML.php: (Note that this code comes out all on one line – is that how its supposed to be? Shouldn’t the “br” tag be working and forcing a line break there?)

<?xml version="1.0" encoding="UTF-8" ?><document>Here is the name you typed:<br/><theUsersName>johnson</theUsersName></document>

Again, note that if I replace:

    $uName = $_POST["userName"];

with plain-old:

    $uName = "John";

Everything works perfectly and the name “John” appears correctly in my UILabel…

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1 Answer

  1. Editorial Team

    As psoft alluded to in his comments, it is hard to concretely answer a question such as this since your end goal seems somewhat unclear. I will assume that you are just starting to experiment with all of the involved technologies.

    Your PHP script will work, I have tested it on my local Apache server. Although there are some oddities; Such as inserting an html <br/> into XML. XML is a data format(At least in this context), not really intended for presentation. Your html file also works fine.

    There are three super-obvious ways to go from where you are.

    1) Do what your above comment says. Use a script to write to a database then use another to access it. The first from a webpage the second from objective-c code. I’m fairly sure this is not something you want to try right now.

    2) Interrupt the sending of the post from a UIWebView in your application. Send that data to your server by other means and parse the results.

    3) Ignore the web-view and just send the arguments to the server directly.

    Both 2 & 3 are very related. The main difference is the origin of the NSURLRequest.

    For 2, obtaining the post request is pretty easy. First you would set some object, let’s say your view controller, as the web-view’s delegate. Then implement the following method.

    -(BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType{
    // Very simple example of checking for the php script in the url
    if ([request.URL.absoluteString.lastPathComponent isEqualToString:@"makeXML.php"]){
        // Use the "request" parameter to
        // post the request yourself
        return NO; // Because you will handle it.
    } else {
        return YES;
    }
}

    For 3, You simply create the NSURLRequest yourself and configure it for your needs. This requires the NSMutableURLRequest subclass.

    NSString *nameToPost = @"Mr Ducky";

NSURL *url = [[NSURL alloc] initWithString:@"http://Address&FolderOfScriptHere/makeXML.php"];
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:url];
request.HTTPMethod = @"POST";
[request setHTTPBody:[[NSString stringWithFormat:@"userName=%@",nameToPost] dataUsingEncoding:NSUTF8StringEncoding]];

    And then in either case (2 or 3) you can use request to load the data to be parsed. Here is, for example, a very bad (synchronous) way to load the data.

    NSData *xmlData = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];

    This data can then be fed to a parser or for testing simply be logged:

    NSString *xmlString = [[NSString alloc] initWithData:xmlData encoding:NSUTF8StringEncoding];
NSLog(@"xml:%@",xmlString);
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