Install SSH2 for PHP 7.1 on MAMP (to support SFTP read/write via file_put_contents, etc.)

sftp_on_php_and_MAMP.txt

// add the repo that has all the PHP goodness
brew tap Homebrew/homebrew-php

// install the ssh2 library
brew install php71-ssh2

// verify you've got ssh2 loaded - should return something like:
// Additional .ini files parsed => /usr/local/etc/php/7.1/conf.d/ext-ssh2.ini
// Registered PHP Streams => https, ftps, compress.zlib, compress.bzip2, php, file, glob, data, http, ftp, phar, zip, ssh2.shell, ssh2.exec, ssh2.tunnel, ssh2.scp, ssh2.sftp
// ssh2
// libssh2 version => 1.8.0
// banner => SSH-2.0-libssh2_1.8.0
php -i | grep ssh

// move the so/library to your MAMP directory
cp /usr/local/Cellar/php71-ssh2/1.1.2/ssh2.so /Applications/MAMP/bin/php/php7.1.8/lib/php/extensions/no-debug-non-zts-20160303/

// enable the extension
vim /Applications/MAMP/bin/php/php7.1.8/conf/php.ini

// add this line anywhere in the extensions area
extension=ssh2.so

// then restart MAMP web server and you're good to go.  
// visit http://localhost:8888/MAMP/index.php?page=phpinfo&language=English and search 
// for ssh to confirm you have the library available

// THEN you can do something like this to write files over SFTP in PHP
file_put_contents("ssh2.sftp://User:Pass@server.com:22/path/on/remote/server/filename.txt", "file contents goes here!");

Doesn't work with PHP 8.2 (installed via MAMP). Any idea?