未找到Google App Engine中的PHP表单的操作脚本

I have the following directory structure:

/www
  - index.html
  - signUp.html
  - submitEmail.php

And then above this:

/www
app.yaml

Here's my app.yaml file:

runtime: php55
api_version: 1
threadsafe: true

handlers:
- url: /(.+\.php)$
script: www/\1

- url: /
static_files: www/index.html
upload: www/index.html

- url: /(.*)
static_files: www/\1
upload: www/(.*)

When I click my submit form button I receive the following error:

No web page was found for the web address: https://<url>/submitEmail.php HTTP ERROR 404

Here's the form file:

<form class='email_form' action="/www/submitEmail.php" method="post">
            <input class='input_email' id='limitedInput' type="text" name="email" placeholder="Email" autofocus>
            <br>
            <input type='text'>
</form>

I've been trying for hours to get this going but for some reason don't seem to be. Any help would be great thanks :)

The culprit was incorrect handlers in app.yaml. This works:

handlers:
- url: /(.+\.php)$
script: www/\1

- url: /
script: www/index.html

- url: /(.*)
script: www/\1

I think the static_file declaration screwed up the web-server. Unfortunately not versed enough to explain exactly why but hopefully this leads people in the right direction.