Installing Composer for Windows - unable to find wrapper "https"

This sounds like your installation hasn't got openssl enabled.

Locate your php.ini file (on Windows this is probably in the same place as the php.exe (c:\php on my machine).

Open it in your favourite editor, and locate the line

;extension=php_openssl.dll

remove the semi-colon

extension=php_openssl.dll

HTTPS should now work for you from within php.

It works by using Havenard's answer. Just add '..' to enclose the url

php -r "readfile('http://getcomposer.org/installer');" | php -- --disable-tls

Well, since the solution doesn't seem to work for you for whatever reason, you can observe that all this command is doing is download the file and printing it into another php process. This is a rather simple problem that can be workarounded with minor adaptations.

You can for instance, drop https and use http:

php -r "readfile('http://getcomposer.org/installer');" | php -- --disable-tls

Or let some other tool fetch this file, such as:

wget -s -O - "https://getcomposer.org/installer" | php -- --disable-tls

Or even:

curl -sSk "https://getcomposer.org/installer" | php -- --disable-tls

The option --disable-tls is relevant to the installer script, it will tell it to use http instead of https in the furter downloads it will perform during the installation.