Compiling and Installing Apache

1. Download the latest source distribution (v2.2.15 for me) from: http://httpd.apache.org
2. Extract the source: tar -xvf httpd-2.2.15.tar.gz
3. Create an install directory (I put it in /usr/local): sudo makedir /usr/local/apache2
4. Configure the makefile with the following options: ./configure --prefix=/usr/local/apache2 --enable-ssl --enable-setenvif --enable-proxy --enable-headers
5. Compile the source code: make
6. Install apache: sudo make install
7. Create your self-signed SSL keys by following this tutorial: http://developer.apple.com/internet/serverside/modssl.html
   • Scroll down to the Configuring SSL section and start from there
   • You will need to download mod_ssl to get the sign.sh script mentioned in the tutorial but that’s all you need it for. You’ll notice the mod_ssl site says it’s only for Apache 1.3.X. That is because Apache2 has built in SSL support which we enabled in the makefile configuration above so mod_ssl is no longer needed.
8. Edit your httpd.conf file: sudo vi /usr/local/apache2/conf/httpd.conf
9. Add the following configuration to the bottom of the file to proxy all HTTP and HTTPS requests to port 3000, i.e., Rails:
   • This assumes Rails is running on port 3000 on your machine
   • This assumes you put the SSL keys where the tutorial told you to
   • The last tag might already be in your httpd.conf file, if so, no need to repeat it here

     # Apache needs to know you want to accept connections over HTTPS
     Listen 443
     
     SSLCertificateFile /etc/httpd/ssl.key/server.crt
     SSLCertificateKeyFile /etc/httpd/ssl.key/server.key
     
     # Below is optional, but was helpful to me in debugging this setup
     CustomLog logs/ssl_request_log  "%t %h %{SSL_PROTOCOL}x %{SSL_CIPHER}x \"%r\" %b" 
     
     <VirtualHost *:80>
         ServerName localhost
         ServerAlias 127.0.0.1
     
         ProxyPass / <a href="http://localhost:3000/">http://localhost:3000/</a>
         ProxyPassReverse / <a href="http://localhost:3000">http://localhost:3000</a>
         ProxyPreserveHost on
     
     <VirtualHost *:443>
         SSLEngine On
         ServerName localhost
         ServerAlias 127.0.0.1
     
         ProxyPass / <a href="http://localhost:3000/">http://localhost:3000/</a>
         ProxyPassReverse / <a href="http://localhost:3000">http://localhost:3000</a>
         ProxyPreserveHost on
         RequestHeader set X_FORWARDED_PROTO 'https'
     
     <ifmodule ssl_module>
         SSLRandomSeed startup builtin
         SSLRandomSeed connect builtin
     </ifmodule>
     

Auto-starting Apache

If you’d like to have apache start automatically whenever your computer starts do the following:

1. Create a new plist file for apache with a unique name: sudo vi /Library/LaunchDaemons/org.apache.httpd
2. Put the following in the file (assuming you installed apache in /usr/local/apache2):

   <?xml version="1.0" encoding="UTF-8"?>
   <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
   <plist version="1.0">
       <dict>
           <key>KeepAlive</key>
           <true />
           <key>Label</key>
           <string>org.apache.httpd</string>
           <key>ProgramArguments</key>
           <array>
               <string>/usr/local/apache2/bin/apachectl</string>
               <string>start</string>
           </array>
           <key>RunAtLoad</key>
           <true />
           <key>UserName</key>
           <string>root</string>
           <key>WorkingDirectory</key>
           <string>/usr/local/apache2</string>
       </dict>
   </plist>
   

3. Test it out with launchd: sudo launchctl load -w /Library/LaunchDaemons/org.apache.httpd; You should see several instances of httpd running if you do a: ps aux | grep httpd

Testing it out

1. Fire up Rails on whatever port you are forwarding your HTTP/HTTPS requests to
2. Request an action with HTTP
3. Request an action with HTTPS

Possible Problems

I encountered the following cryptic error in FireFox when I was testing out an Apache install on a second dev box:

SEC_ERROR_REUSED_ISSUER_AND_SERIAL

I found out by reading through some forums that each SSL certificate needs to have a unique serial number. Since I had followed the above procedure to install Apache and SSL on both my laptop and the second dev box I already had a certificate with the same serial number stored in my browser (for my local machine) as the one on the second dev box. If you follow the above process the serial number of your certificate will be 01. So to fix this do the following on your new certificate (for me it was the one on the dev box):

sudo openssl x509 -req -days 365 -in server.csr -CA ca.crt -CAkey ca.key -set_serial 02 -out server.crt

This simply assigns 02 to the second certificate and keeps FireFox happy. You probably will not encounter this problem unless you are testing SSL on multiple machines like I was but I figured I’d mention it anyways. Note, you can see the serial number of a certificate in FireFox by going to:

Firefox > Preferences > Advanced > View Certificates (button)


Then double click on a certificate of interest. Also note that Chrome did not complain about this but FireFox won’t even let you visit a site with a duplicate serial number.

If you get stuck…

Try one of the following resources that I used to get this up and running:

• Testing SSL Requirements on Rails
• Using mod_ssl on Mac OS X
• Same Serial Number of Certificate Error

$ killall Dock

Share and enjoy!

# database.yml
development:
  adapter: mysql
  database: my_development
  username: me
  password: password
  host: localhost
  port: 3306

test:
  adapter: mysql
  database: my_test
  username: me
  password: password
  host: localhost
  port: 3306

production:
  development

Bj was getting an ActiveRecord::ConnectionNotEstablished exception but was swallowing it.  The solution was to explicitly define the production database connection in database.yml.

Let’s say you have the following declarations:

class SubscriptionsApi < ActionWebService::API::Base
  api_method(
    :create_subscription,
    :expects => [
      { :customer => Logical::Customer },
      { :payment_method => Logical::PaymentMethod }
    ]
  )
end
module Logical
  class PaymentMethod < ActionWebService::Struct
  end
  class CreditCard < PaymentMethod
    member :card_number, :string
    # ...
  end
  class PayPal < PaymentMethod
    member :login, :string
    # ...
  end
end

Now you want to make a call to the service method and pass either a CreditCard or a PayPal. XML-RPC will encode the request like so:

<methodCall>
  <methodName>create_subscription</methodName>
  <param>
    <struct>
      <member>
        <name>card_number</name>
        <value>4111-1111-1111-1111</value>
      </member>
    </struct>
  </param>
</methodCall>

This provides no type information to the server so the server will attempt to instantiate a Logical::PaymentMethod which will of course not have a card_number member as it’s specific to the CreditCard subclass. SOAP, on the other hand, does encode the parameter types allowing you to utilize this type of polymorphism in your service parameters. Here’s the same request encoded in SOAP.

<?xml version="1.0" encoding="utf-8" ?>
<env:Envelope xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:env="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<env:Body>
  <n1:CreateSubscription xmlns:n1="urn:ActionWebService" env:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
    <payment_method xmlns:n2="http://www.ruby-lang.org/xmlns/ruby/type/custom" xsi:type="n2:Logical..CreditCard">
      <card_number xsi:type="xsd:string">1</card_number>
    </payment_method>
  </n1:CreateSubscription>
 </env:Body>
</env:Envelope>

The current implementation of ActionWebService resurrected by datanoise did not support this type of polymorphism in SOAP requests. However, I submitted a patch recently which provides for this functionality. Hopefully it’s accepted.

If you attempt to update a column that does not allow NULL to NULL, MySQL will set the column’s value to the default value for that column’s data type.  This is true only when you are not running MySQL strict mode.  Here’s an example to illustrate.

mysql> create table null_test (id int not null unique(id), name varchar(25)
null default null);
Query OK, 0 rows affected (0.01 sec)

mysql> show create table null_test;
+-----------+--------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table     | Create Table                                                                                                                                           |
+-----------+--------------------------------------------------------------------------------------------------------------------------------------------------------+
| null_test | CREATE TABLE `null_test` (
  `id` int(11) NOT NULL,
  `name` varchar(25) default NULL,
  UNIQUE KEY `id` (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 |
+-----------+--------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> insert into null_test (id, name) values (1, 'Jane');
Query OK, 1 row affected (0.00 sec)

mysql> update null_test set id = null;
Query OK, 0 rows affected (0.00 sec)
Rows matched: 0  Changed: 0  Warnings: 0

mysql> select * from null_test where name = 'Jane';
+----+------+
| id | name |
+----+------+
|  0 | Jane |
+----+------+
1 row in set (0.00 sec)

More information about this bug can be found in the bug report submitted Janurary 4, 2008.

Unfortunately, MySQL does not support check constraints out of the box.  This makes the task of enforcing business logic in the database layer difficult, but not impossible.  I recently found this approach to implementing check constraints in MySQL.  It’s not as pretty and clean as I’d like, but, it’s the best approach that I’ve found so far.

Now. why would you want to encode business logic in the database?  Can’t you make due with your ActiveRecord::Validations?

Well, have you ever updated the database directly?  Have you ever called update_attribute on an object?  How about save_with_validation(false)?   Yeah, I thought so.  Read more about why you should treat your database as a fortress in Dan Chak’s recently released book, Enterprise Rails (review coming soon). ]]> http://www.jasonfox.com/2009/02/check-constraints-and-mysql/feed/ 0 http://www.jasonfox.com/2009/02/rewriting-sub-selects-as-joins/ http://www.jasonfox.com/2009/02/rewriting-sub-selects-as-joins/#comments Mon, 02 Feb 2009 23:07:14 +0000 admin http://www.jasonfox.com/?p=68 Your RDBMS will usually rewrite your sub-selects behind the scenes as joins.  However, there are times where you’ll want to do this yourself.  For example, past versions of MySQL did not play well with sub-selects.  Here are a couple examples of how to rewrite sub-selects as joins.

select *
from   table_a
where  id not in (select a_id from table_b);
-- can be rewritten as...
select *
from   table_a
left   outer join table_b on table_a.id = table_b.a_id
where  table_b.a_id is null;

select *
from   table_a
where  id in (select a_id from table_b);
-- can be rewritten as...
select *
from   table_a
left outer join table_b on table_a.id = table_b.a_id
where  table_b.a_id is not null;