通过Google App Engine上的PHP使用HTML Contact-Us表单发送电子邮件

Question

我正在处理的此应用已部署在Google App Engine上。

我正在使用HTML页面显示一个Contact-Us表单。此表单经过验证并通过Javascript，contact.js进一步提交，如下所示：

$(document).ready(function(){
            $('#send_message').click(function(e){

                //stop the form from being submitted
                e.preventDefault();

                /* declare the variables, var error is the variable that we use on the end
                to determine if there was an error or not */
                var error = false;
                var name = $('#name').val();
                var email = $('#email').val();
                var subject = $('#subject').val();
                var message = $('#message').val();

                /* in the next section we do the checking by using VARIABLE.length
                where VARIABLE is the variable we are checking (like name, email),
                length is a javascript function to get the number of characters.
                And as you can see if the num of characters is 0 we set the error
                variable to true and show the name_error div with the fadeIn effect. 
                if it's not 0 then we fadeOut the div( that's if the div is shown and
                the error is fixed it fadesOut. 

                The only difference from these checks is the email checking, we have
                email.indexOf('@') which checks if there is @ in the email input field.
                This javascript function will return -1 if no occurence have been found.*/
                if(name.length == 0){
                    var error = true;
                    $('#name_error').fadeIn(500);
                }else{
                    $('#name_error').fadeOut(500);
                }
                if(email.length == 0 || email.indexOf('@') == '-1'){
                    var error = true;
                    $('#email_error').fadeIn(500);
                }else{
                    $('#email_error').fadeOut(500);
                }
                if(subject.length == 0){
                    var error = true;
                    $('#subject_error').fadeIn(500);
                }else{
                    $('#subject_error').fadeOut(500);
                }
                if(message.length == 0){
                    var error = true;
                    $('#message_error').fadeIn(500);
                }else{
                    $('#message_error').fadeOut(500);
                }

                //now when the validation is done we check if the error variable is false (no errors)
                if(error == false){
                    //disable the submit button to avoid spamming
                    //and change the button text to Sending...
                    $('#send_message').attr({'disabled' : 'true', 'value' : 'Sending...' });

                    /* using the jquery's post(ajax) function and a lifesaver
                    function serialize() which gets all the data from the form
                    we submit it to send_email.php */
                    $.post("send_email.php", $("#contact_form").serialize(),function(result){
                        //and after the ajax request ends we check the text returned
                        if(result == 'sent'){
                            //if the mail is sent remove the submit paragraph
                             $('#button').remove();
                            //and show the mail success div with fadeIn
                            $('#mail_success').fadeIn(500);
                        }else{
                            //show the mail failed div
                            $('#mail_fail').fadeIn(500);
                            //reenable the submit button by removing attribute disabled and change the text back to Send The Message
                            $('#send_message').removeAttr('disabled').attr('value', 'Submit');
                        }
                    });
                }
            });    
        });

如上面的这个脚本所示，提交后，contact-us来自send_email.php脚本：

<?php

    require_once 'google/appengine/api/mail/Message.php';
    use google\appengine\api\mail\Message;

    $name     =   $_POST['name'];  
    $email    =   $_POST['email'];
    $subject  =   $_POST['subject'];
    $message  =   $_POST['message'];
    $message_body = "...";

    $mail_options = [
        "sender" => "myemail@gmail.com",
        "to" => $email,
        "subject" => $subject,
        "textBody" => $message_body
    ];

    try {
            $message = new Message($mail_options);
            $message->send();
            echo 'sent';

} catch (InvalidArgumentException $e) {
            echo $e->getMessage();
            echo 'failed';
}

?>

在这种情况下，没有发送电子邮件。日志显示此"POST /send_email.php HTTP/1.1" 200 0 "

我试过每个论坛，但没有找到帮助！我在哪里犯错，必须有一个，因为没有从联系我们的html表单发送电子邮件。

提前致谢！