Preparing APS Certificates for node-apn

aps-node

After requesting the certificate from Apple, export your private key as a .p12 file and 
download the .cer file (usually named aps_production.cer or aps_development.cer) from 
the iOS Provisioning Portal.

Now, in the directory containing cert.cer and key.p12 execute the following commands to 
generate your .pem files:



openssl x509 -in aps_development.cer -inform DER -outform PEM -out aps_development.pem
openssl x509 -in aps_production.cer -inform DER -outform PEM -out aps_production.pem
openssl pkcs12 -in key.p12 -out key.pem -nodes




If you are using a development certificate you may wish to name them differently to 
enable fast switching between development and production. The filenames are configurable
within the module options, so feel free to name them something more appropriate.

It is also possible to supply a PFX (PFX/PKCS12) package containing your certificate, 
key and any relevant CA certificates. The method to accomplish this is left as an 
exercise to the reader. It should be possible to select the relevant items in 
"Keychain Access" and use the export option with ".p12" format.

source : 
https://github.com/argon/node-apn/wiki/Preparing-Certificates
https://www.npmjs.org/package/node-pushserver