AMP form submitting with post
I've a website for years with a few forms to login etc. Recently I made it all Google's AMP proof, but the forms stopped working. I'm searching for days now, but I can't find the right answer.
First I included all the necessary scripts and code, just like on this page. After that, the first error came up: "Form submission failed:: Response must contain the AMP-Access-Control-Allow-Source-Origin header".
Then I added headers to the page. After that, the first error is gone, but the second error appears: "Form submission failed:: Unexpected token < in JSON at position 0". I've read here about this, but it contains no real solution for me.
At this stage I'm stuck and I think I'm on the wrong path with such a simple form like this. I simply want to echo the input... Can you please help me?
Kind regards,
Patrick
<?php
header("Access-Control-Allow-Credentials: true");
header("Access-Control-Allow-Origin: *.ampproject.org");
header("AMP-Access-Control-Allow-Source-Origin: https://www.domain.com");
header("Access-Control-Expose-Headers: AMP-Access-Control-Allow-Source-Origin");
?>
<!doctype html>
<html amp>
<head>
<meta charset="utf-8">
<script async src="https://cdn.ampproject.org/v0.js"></script>
<script async custom-element="amp-form" src="https://cdn.ampproject.org/v0/amp-form-0.1.js"></script>
<meta name="viewport" content="width=device-width,minimum-scale=1,initial-scale=1">
<style amp-boilerplate>body{-webkit-animation:-amp-start 8s steps(1,end) 0s 1 normal both;-moz-animation:-amp-start 8s steps(1,end) 0s 1 normal both;-ms-animation:-amp-start 8s steps(1,end) 0s 1 normal both;animation:-amp-start 8s steps(1,end) 0s 1 normal both}@-webkit-keyframes -amp-start{from{visibility:hidden}to{visibility:visible}}@-moz-keyframes -amp-start{from{visibility:hidden}to{visibility:visible}}@-ms-keyframes -amp-start{from{visibility:hidden}to{visibility:visible}}@-o-keyframes -amp-start{from{visibility:hidden}to{visibility:visible}}@keyframes -amp-start{from{visibility:hidden}to{visibility:visible}}</style><noscript><style amp-boilerplate>body{-webkit-animation:none;-moz-animation:none;-ms-animation:none;animation:none}</style></noscript>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<link rel="canonical" href="https://www.domain.com/test.php"/>
<title>AMP form</title>
</head>
<body>
<?php
if(isset($_POST['submitlogin']))
{
$name = $_POST['name'];
echo $name;
} ?>
<form method="post" action-xhr="#" target="_top">
Name:<input type="text" name="name" />
<input type="submit" name="submitlogin" value="Submit" />
</form>
</body>
</html>
Answer
To put it simply: you can't just echo the input.
From the docs:
Use the action-xhr attribute to submit the form via XMLHttpRequest (XHR). You can use amp-mustache templates to show custom success or error messages, using data sent by the server endpoint as JSON. For example, if the server sends {"foo": "bar"}, you can use use {{foo}} in the template to render bar.
So since you are using the action-xhr, you should be returning a JSON, and update the form template accordingly.
Check out this.
Full example, from your code:
<?php
if(isset($_POST['submitlogin']))
{
$name = isset($_POST['name']) ? $_POST['name'] : '' ;
$output = [
'name' => $name
];
header("Content-type: application/json");
header("Access-Control-Allow-Credentials: true");
header("Access-Control-Allow-Origin: *.ampproject.org");
header("AMP-Access-Control-Allow-Source-Origin: https://www.domain.com");
header("Access-Control-Expose-Headers: AMP-Access-Control-Allow-Source-Origin");
echo json_encode($output);
die();
}
?>
<!doctype html>
<html amp>
<head>
<meta charset="utf-8">
<script async src="https://cdn.ampproject.org/v0.js"></script>
<script async custom-element="amp-form" src="https://cdn.ampproject.org/v0/amp-form-0.1.js"></script>
<meta name="viewport" content="width=device-width,minimum-scale=1,initial-scale=1">
<style amp-boilerplate>body{-webkit-animation:-amp-start 8s steps(1,end) 0s 1 normal both;-moz-animation:-amp-start 8s steps(1,end) 0s 1 normal both;-ms-animation:-amp-start 8s steps(1,end) 0s 1 normal both;animation:-amp-start 8s steps(1,end) 0s 1 normal both}@-webkit-keyframes -amp-start{from{visibility:hidden}to{visibility:visible}}@-moz-keyframes -amp-start{from{visibility:hidden}to{visibility:visible}}@-ms-keyframes -amp-start{from{visibility:hidden}to{visibility:visible}}@-o-keyframes -amp-start{from{visibility:hidden}to{visibility:visible}}@keyframes -amp-start{from{visibility:hidden}to{visibility:visible}}</style><noscript><style amp-boilerplate>body{-webkit-animation:none;-moz-animation:none;-ms-animation:none;animation:none}</style></noscript>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<link rel="canonical" href="https://www.domain.com/test.php"/>
<title>AMP form</title>
</head>
<body>
<form method="post" action-xhr="#" target="_top">
Name:<input type="text" name="name" />
<input type="submit" name="submitlogin" value="Submit" />
</form>
<div submit-success>
<template type="amp-mustache">
Success! Thanks for trying the
<code>amp-form</code> demo! The name submited was {{name}}
</template>
</div>
</body>
</html>