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HTTP server for Tarantool 1.7.5+

Static analysis Test Coverage Status

Note: In Tarantool 1.7.5+, a full-featured HTTP client is available aboard. For Tarantool 1.6.5+, both HTTP server and client are available here.

http v2 has gone

http v2 that was implemented in #90 has been reverted in a master branch (commits 01004d7..e7e00ea) and a limited number of reverted commits were reimplemented on top of http v1. However http v2 changes are still available in a branch http-v2-legacy as well as Lua rockspecs available with name http-v2-legacy instead of http. For reasons of http v2 revert and decisions regarding each reverted commit see #134.

Table of contents

Prerequisites

Installation

You can:

Usage

The server is an object which is configured with HTTP request handlers, routes (paths), templates, and a port to bind to. Unless Tarantool is running under a superuser, port numbers below 1024 may be unavailable.

The server can be started and stopped anytime. Multiple servers can be created.

To start a server:

  1. Create it with httpd = require('http.server').new(...).
  2. Configure routing with httpd:route(...).
  3. Start it with httpd:start().

To stop the server, use httpd:stop().

Creating a server

httpd = require('http.server').new(host, port[, { options } ])

host and port must contain:

options may contain:

Using routes

It is possible to automatically route requests between different handlers, depending on the request path. The routing API is inspired by Mojolicious API.

Routes can be defined using:

Route examples:

'/'                 -- a simple route
'/abc'              -- a simple route
'/abc/:cde'         -- a route using a simple regular expression
'/abc/:cde/:def'    -- a route using a simple regular expression
'/ghi*path'         -- a route using an extended regular expression

To configure a route, use the route() method of the httpd object:

httpd:route({ path = '/path/to' }, 'controller#action')
httpd:route({ path = '/', template = 'Hello <%= var %>' }, handle1)
httpd:route({ path = '/:abc/cde', file = 'users.html.el' }, handle2)
httpd:route({ path = '/objects', method = 'GET' }, handle3)
...

To delete a named route, use delete() method of the httpd object:

httpd:route({ path = '/path/to', name = 'route' }, 'controller#action')
httpd:delete('route')

The first argument for route() is a Lua table with one or more keys:

The second argument is the route handler to be used to produce a response to the request.

The typical usage is to avoid passing file and template arguments, since they take time to evaluate, but these arguments are useful for writing tests or defining HTTP servers with just one "route".

The handler can also be passed as a string of the form 'filename#functionname'. In that case, the handler body is taken from a file in the {app_dir}/controllers directory.

Contents of app_dir

Route handlers

A route handler is a function which accepts one argument (Request) and returns one value (Response).

function my_handler(req)
    -- req is a Request object
    -- resp is a Response object
    local resp = req:render({text = req.method..' '..req.path })
    resp.headers['x-test-header'] = 'test';
    resp.status = 201
    return resp
end

Fields and methods of the Request object

Fields and methods of the Response object

Examples

function my_handler(req)
    return {
        status = 200,
        headers = { ['content-type'] = 'text/html; charset=utf8' },
        body = [[
            <html>
                <body>Hello, world!</body>
            </html>
        ]]
    }
end

Working with stashes

function hello(self)
    local id = self:stash('id')    -- here is :id value
    local user = box.space.users:select(id)
    if user == nil then
        return self:redirect_to('/users_not_found')
    end
    return self:render({ user = user  })
end

httpd = httpd.new('127.0.0.1', 8080)
httpd:route(
    { path = '/:id/view', template = 'Hello, <%= user.name %>' }, hello)
httpd:start()

Special stash names

Working with cookies

To get a cookie, use:

function show_user(self)
    local uid = self:cookie('id')

    if uid ~= nil and string.match(uid, '^%d$') ~= nil then
        local user = box.select(users, 0, uid)
        return self:render({ user = user })
    end

    return self:redirect_to('/login')
end

To set a cookie, use the setcookie() method of a response object and pass to it a Lua table defining the cookie to be set:

function user_login(self)
    local login = self:param('login')
    local password = self:param('password')

    local user = box.select(users, 1, login, password)
    if user ~= nil then
        local resp = self:redirect_to('/')
        resp:setcookie({ name = 'uid', value = user[0], expires = '+1y' })
        return resp
    end

    -- to login again and again and again
    return self:redirect_to('/login')
end

The table must contain the following fields:

Rendering a template

Lua can be used inside a response template, for example:

<html>
    <head>
        <title><%= title %></title>
    </head>
    <body>
        <ul>
            % for i = 1, 10 do
                <li><%= item[i].key %>: <%= item[i].value %></li>
            % end
        </ul>
    </body>
</html>

To embed Lua code into a template, use:

A few control characters may follow %:

A Lua statement inside the template has access to the following environment:

  1. Lua variables defined in the template,
  2. stashed variables,
  3. variables standing for keys in the render table.

Template helpers

Helpers are special functions that are available in all HTML templates. These functions must be defined when creating an httpd object.

Setting or deleting a helper:

-- setting a helper
httpd:helper('time', function(self, ...) return box.time() end)
-- deleting a helper
httpd:helper('some_name', nil)

Using a helper inside an HTML template:

<div>
    Current timestamp: <%= time() %>
</div>

A helper function can receive arguments. The first argument is always the current controller. The rest is whatever is passed to the helper from the template.

Hooks

It is possible to define additional functions invoked at various stages of request processing.

handler(httpd, req)

If handler is present in httpd options, it gets involved on every HTTP request, and the built-in routing mechanism is unused (no other hooks are called in this case).

before_dispatch(httpd, req)

Is invoked before a request is routed to a handler. The first argument of the hook is the HTTP request to be handled. The return value of the hook is ignored.

This hook could be used to log a request, or modify request headers.

after_dispatch(cx, resp)

Is invoked after a handler for a route is executed.

The arguments of the hook are the request passed into the handler, and the response produced by the handler.

This hook can be used to modify the response. The return value of the hook is ignored.

Using a special socket

To use a special socket, override the tcp_server_f field of the HTTP server object with your own function. The function should return an object similar to one returned by socket.tcp_server. It should call opts.handler when a connection occurs and provide read, write and close methods.

Example:

local httpd = require('http.server')
local server = httpd.new(settings.host, settings.port)

-- Use sslsocket.
local sslsocket = require('sslsocket')
server.tcp_server_f = sslsocket.tcp_server

-- Or use your own handler.
server.tcp_server_f = function(host, port, opts)
    assert(type(opts) == 'table')
    local name = opts.name
    local accept_handler = opts.handler
    local http_server = opts.http_server

    <...>
    return <..tcp server object..>
end

server:route(<your settings>)
server:start()

Roles

Tarantool 3 roles could be accessed from this project.

roles.httpd

It allows configuring one or more HTTP servers. Those servers could be reused by several other roles.

Example of the configuration:

roles_cfg:
  roles.httpd:
    default:
    - listen: 8081
    additional:
    - listen: '127.0.0.1:8082'

Server address should be provided either as a URI or as a single port (in this case, 0.0.0.0 address is used).

User can access every working HTTP server from the configuration by name, using require('roles.httpd').get_server(name) method. If the name argument is nil, the default server is returned (its name should be equal to constant require('roles.httpd').DEFAULT_SERVER_NAME, which is "default").

Let's look at the example of using this role. Consider a new role roles/hello_world.lua:

local M = { dependencies = { 'roles.httpd' } }
local server = {}

M.validate = function(conf)
    if conf == nil or conf.httpd == nil then
        error("httpd must be set")
    end
    local server = require('roles.httpd').get_server(conf.httpd)
    if server == nil then
        error("the httpd server " .. conf.httpd .. " not found")
    end
end

M.apply = function(conf)
    server = require('roles.httpd').get_server(conf.httpd)

    server:route({
        path = '/hello/world',
        name = 'greeting',
    }, function(tx)
        return tx:render({text = 'Hello, world!'})
    end)
end

M.stop = function()
    server:delete('greeting')
end

return M

This role accepts a server by name from a config and creates a route to return Hello, world! to every request by this route.

Then we need to write a simple config to start the Tarantool instance via tt:

app:
  file: 'myapp.lua'

groups:
  group001:
    replicasets:
      replicaset001:
        roles: [roles.httpd, roles.hello_world]
        roles_cfg:
          roles.httpd:
            default:
              listen: 8081
            additional:
              listen: '127.0.0.1:8082'
          roles.hello_world:
            httpd: 'additional'
        instances:
          instance001:
            iproto:
              listen:
                - uri: '127.0.0.1:3301'

Next step, we need to start this instance using tt start:

$ tt start
   • Starting an instance [app:instance001]...
$ tt status
 INSTANCE         STATUS   PID      MODE 
 app:instance001  RUNNING  2499387  RW

And then, we can get the greeting by running a simple curl command from a terminal:

$ curl http://127.0.0.1:8082/hello/world
Hello, world!

See also