json_encode（）输出中的换行符

Question

I am building an output array like so

            if (count($errors)) {
                $success = 'false'; 
                $output['json_msg'] = "Please try your submission again.";
                $output['errors'] = $errors;
            } else {
                $success = 'true';  
                $output['json_msg'] = "Thanks for Becoming a NOLA Insider!";
            }

            $output['success'] = $success;

            header('Content-type:application/json;charset=utf-8');
            if (count($errors)) { http_response_code(500); }
            echo json_encode($output);          
            exit;

But when I look at the response in Chrome's Network pane of the developer tools I see what appears to be a newline in response:

I tried wrapping json_encode() in trim() but this gave garbled output.

How do I eliminate the carriage return?

Answer 1

Do you have a ?> at the end of your PHP file and what's happening when you remove it ?

Because you may have a carriage return at the end of the script which may be sent before your response :

?>

// END OF FILE

This is explained by the fact that PHP is actually a templating language :

Here is a file which defines a function and which displays a text :

<?php
/**
 * @File lib.php
 */
 function sayHello()
 {
     echo "hello";
 }
 ?>
 forgotten text

And here is a file that includes this file.

<?php
/**
 * @file index.php
 */
 include_once('lib.php');
 sayHello();

This will output :

forgotten text
hello

The "forgotten text" is output when the lib.php file is included whereas the "hello" is output after.

(But it may be even simpler and just the point that @nanocv suggested)