php

Restful architectures are often used to create client/server network environments. REST, which stands for representational state transfer, is a simpler alternative to SOAP and WSDL services, but still maintains great features like platform-independence and language independence. REST services explicitly use HTTP methods when implementing their calls, therefore any good API should support the basic GET, POST, PUT, and DELETE methods. Along with knowing the HTTP methods you must understand the HTTP status codes as well.

I have recently spent quite a bit of time trying to come up with a better way to implement RESTful service that serve data in JSON. This is because most of our work these days involves writing client-side JavaScript apps that present a rich UI in the browser and then do all server-side interactions via AJAX. In pursuit of the best way to implement RESTful service on the backend, I have tried my hands at Go programming language, D programming language, Lua and of course Java and PHP. I was assuming that the Go or Lua would be much faster than PHP. Well, it turns out that at least without special optimizations, that is not the case.

I wrote the following programs to compare their performance:

<?php

header('Content-Type: application/json');

$db = new PDO('mysql:host=localhost;dbname=db;charset=utf8', 'user', 'pass');
$stmt = $db->query("SELECT * FROM node");
$result = array();
$result['list'] = $stmt->fetchAll(PDO::FETCH_ASSOC);
echo json_encode($result);

<?php

define('DRUPAL_ROOT', getcwd());

require_once DRUPAL_ROOT . '/includes/bootstrap.inc';
drupal_bootstrap(DRUPAL_BOOTSTRAP_DATABASE);
// drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);

header('Content-Type: application/json');

$stmt = db_query("SELECT * FROM node");
$result = array();
$result['list'] = $stmt->fetchAll(PDO::FETCH_ASSOC);
echo json_encode($result);

json = require "cjson"

function json_result(key, data)
  local result = {}
  result[key] = data
  ngx.say(json.encode(result))
end

function json_error(...)
  local result = {}
  result["message"] = string.format(...)
  ngx.status = ngx.HTTP_INTERNAL_SERVER_ERROR
  ngx.say(json.encode(result))
end

mysql = require "resty.mysql"

local db, err = mysql:new()
if not db then
  json_error("failed to instantiate mysql: %s", err)
  return
end

db:set_timeout(1000) -- 1 sec

local ok, err, errno, sqlstate = db:connect{
  host = "127.0.0.1",
  port = 3306,
  database = "db",
  user = "user",
  password = "pass",
  max_packet_size = 1024 * 1024
}

if not ok then
    json_error("failed to connect: %s: %d %d", err, errno, sqlstate)
    return
end

result, err, errno, sqlstate = db:query("SELECT * FROM node")

if not result then
  json_error("failed to query: %s: %d %d", err, errno, sqlstate)
end

json_result("list", result)

The above programs simply query a table and return all rows and columns from that table as a JSON array.

And then I hit the above programs with a bit of load using 'ab' HTTP load testing command. Following are the results ...

While using or coding Drupal, if you come across an error to the effect "mysql server has gone away", right in the middle of a request, you may need to do the following.

Find the my.ini file under MySQL server installation directory (mine is under "data" subdirectory), and in the "[mysqld]" section add the following line (or replace the value if it already exists):

max_allowed_packet=16M

Now restart MySQL server and try again. It should work. If it doesn't, try a value higher than 16M.