使用 localhost 測試 Facebook login

2018-10 開始 Facebook login 強制使用 HTTPS 了，若要在 localhost 測試也是得用 HTTPS 才行。以下的參考連結說明 MAMP 的作法：
https://gist.github.com/jfloff/5138826

Facebook login 以前做過幾次，都是針對活動網站的，這次也不例外。一陣子沒做了，想說依照官方範例，應該不會有太大問題，但結果還是卡了一兩個小時。以下列出卡到的點：

1. 在設定 Facebook app 時，在「設定」〉「基本資料」，「應用程式網域」和「網站網址」的域名請一致。（設定介面經常在變，規則也是）

2. 在「Facebook 登入」〉「設定」裡，「對重新導向 URI 使用 Strict 模式」現在預設是設定為開啟，而且不能變更。所以一定要在「有效的 OAuth 重新導向 URI」填寫正確的 redirect uri。

3. 使用 facebook/graph-sdk 時，可以直接 copy sample code 去改，但記得在 login.php 和 fb-callback.php 裡都要先以 session_start() 啟動 session 功能。因為 FacebookRedirectLoginHelper 的 CSRF 是寫在 session 裡的。

在 MAMP localhost 上使用自簽的 https

參考
https://gist.github.com/jfloff/5138826

1. Backup your /Applications/MAMP/conf/ dir.
2. Generate a (dummy) SSL Certificate

   $ cd ~
   
   # generate a private key (will request a password twice)
   $ openssl genrsa -des3 -out server.key 1024
    
   # generate certificate signing request (same password as above)
   $ openssl req -new -key server.key -out server.csr
    
   # Answer the questions
   Country Name (2 letter code) [AU]: CA
   State or Province Name (full name) [Some-State]: Quebec
   Locality Name (eg, city) []: Montreal
   Organization Name (eg, company) [Internet Widgits Pty Ltd]: Your Company
   Organizational Unit Name (eg, section) []: Development
   Common Name (eg, YOUR name) []: localhost
   Email Address []: your_email@domain.com
   A challenge password []: # leave this empty
   An optional company name []: # leave this empty
    
   # generate the certificate
   $ openssl x509 -req -days 365 -in server.csr -signkey server.key -out server.crt
    
   # remove the password from the server key
   $ cp server.key server.tmp
   $ openssl rsa -in server.tmp -out server.key
    
   # Move the certificate into your MAMP apache configuration folder
   $ cp server.crt /Applications/MAMP/conf/apache
   $ cp server.key /Applications/MAMP/conf/apache
   

3. Open /Applications/MAMP/conf/apache/httpd.conf and uncomment Include /Applications/MAMP/conf/apache/extra/httpd-ssl.conf.
4. Keep your vhost in /Applications/MAMP/conf/apache/extra/httpd-vhosts.conf just the same.
5. In /Applications/MAMP/conf/apache/extra/httpd-ssl.conf, find the following block and edit the fields Server Name and Document Root with the values you already have in your vhost.

   #   General setup for the virtual host
   DocumentRoot "/Applications/MAMP/Library/htdocs"
   ServerName www.example.com:443
   ServerAdmin you@example.com
   ErrorLog "/Applications/MAMP/Library/logs/error_log"
   TransferLog "/Applications/MAMP/Library/logs/access_log"
   and edit in your DocumentRoot and ServerName settings: