'Unable to set private key file' attempting to send push using php - php

Question

I'm using the Ray Wenderlich push tutorial as a reference to set up push for my app, something I have done dozens of times before, literally dozens, and its always gone smoothly, until now.
When executing the php file to manually test sending the push I'm getting the error:
'Unable to set private key file ... ck.pem'
at the last line:
$ctx = stream_context_create();
stream_context_set_option($ctx, 'ssl', 'local_cert', 'ck.pem');
stream_context_set_option($ctx, 'ssl', 'passphrase', $passphrase);
// Open a connection to the APNS server
$fp = stream_socket_client(
'ssl://gateway.sandbox.push.apple.com:2195', $err,
$errstr, 60, STREAM_CLIENT_CONNECT|STREAM_CLIENT_PERSISTENT, $ctx);
ck.pem is a concatentation of the ssl certificate and private key and I CAN use these sussesfully with the following command:
openssl s_client -connect gateway.sandbox.push.apple.com:2195 -cert PushCert.pem -key PushKey.pem
When I execute this I get a big spiel and output regarding SSK handshake reading/writing N bytes which indicates it was sucessful and thus the certificate and key must be valid.
So I don't understand why there is no problem using the certificate and key separately when used as arguments to the openssl command line above but there is when used in the concatenated from in the php file.
After getting the problem initially I deleted everything - I clearned out all the certificates and keys from the keychain, deleted all the provisioning profiles etc. The whole lot and started with a clean slate again to make sure I didn't make a mistake somewhere. Same results - keep getting the 'Unable to set private key file'.
I saw a past posting where somebody had the same problem and they solved it by executing the php file using sudo, but that didn't work for me.
Any suggestions, this is driving me mad, especially as I've done it before dozens of times previously sucessfully.

Answer 1

I had this once, after many hours of frustration I tracked the problem down to the fact that I was using TextEdit to edit the .php file's contents and TextEdit was inserting invisible characters.
Not at the end of the line, actually in the line itself i.e. if the original text in the Ray Wenderlich file is like this:
// Put your private key's passphrase here:
$passphrase = ‘cpushchat';
Then after using TextEdit to change the password it looked like this when you viewed it:
// Put your private key's passphrase here:
$passphrase = ‘mypassword';
But if you viewed it in a hex edited, what TextEdit has actually done was to insert invisible (invisible in the in the text viewer) characters like this:
// Put your private key's passphrase here:
$passphrase = ‘E28098mypassword';
Which resulted in the password being incorrect of course and thus leading to that message.