Name

lua-resty-http - Lua HTTP client driver for ngx_lua

Example

server {
  location /test {
    content_by_lua '
      local http   = require "resty.http"
      local client = http:new()
      client:set_timeout(1000) -- 1 sec

      local ok, err = client:connect("checkip.amazonaws.com", 80)
      if not ok then
        ngx.say("failed to connect: ", err)
        return
      end

      local res, err = client:request({ path = "/" })
      if not res then
        ngx.say("failed to retrieve: ", err)
        return
      end

      -- close connection, or put it into the connection pool
      if res.headers["connection"] == "close" then
        local ok, err = client:close()
        if not ok then
          ngx.say("failed to close: ", err)
          return
        end
      else
        client:set_keepalive(0, 100)
      end

      if res.status >= 200 and res.status < 300 then
        ngx.say("My IP is: " .. res.body)
      else
        ngx.say("Query returned a non-200 response: " .. res.status)
      end
    ';
  }
}

API

new

syntax: client, err = http:new()

Creates a HTTP object.

connect

syntax: ok, err = client:connect(host, port?, conf?)

Attempts to connect to the remote host and port. Port 80 is assumed, when no port is given.

Before actually resolving the host name and connecting to the remote backend, this method will always look up the connection pool for matched idle connections created by previous calls of this method.

An optional Lua conf table can be specified to declare various options:

• scheme : Specifies a scheme, defaults to "http" or "https", depending on the port.
• path : Specifies a default endpoint.

request

syntax: res, err = client:request(opts?)

Attempts to retrieve data from a remote location.

An optional Lua opts table can be specified to declare various options:

• method : Specifies the request method, defaults to 'get'.
• path : Specifies the path, defaults to '/'.
• query : Specifies query parameters. Accepts either a string or a Lua table.
• headers : Specifies request headers. Accepts a Lua table.

Returns a res object containing three attributes:

• res.status (number) : The resonse status, e.g. 200
• res.headers (table) : A Lua table with response headers
• res.body (string) : The plain response body

set_timeout

syntax: client:set_timeout(time)

Sets the timeout (in ms) protection for subsequent operations, including the connect method.

set_keepalive

syntax: ok, err = client:set_keepalive(max_idle_timeout, pool_size)

Puts the current connection immediately into the ngx_lua cosocket connection pool.

You can specify the max idle timeout (in ms) when the connection is in the pool and the maximal size of the pool every nginx worker process.

In case of success, returns 1. In case of errors, returns nil with a string describing the error.

Only call this method in the place you would have called the close method instead. Calling this method will immediately turn the current connection into the closed state. Any subsequent operations other than connect() on the current object will return the closed error.

get_reused_times

syntax: times, err = client:get_reused_times()

This method returns the (successfully) reused times for the current connection. In case of error, it returns nil and a string describing the error.

close

syntax: ok, err = client:close()

Closes the current connection and returns the status.

In case of success, returns 1. In case of errors, returns nil with a string describing the error.

Licence

Some code and documentation parts were (shamelessly) taken from lua-resty-redis, MIT, Copyright by Yichun Zhang.

Greatly inspired by excon, MIT, Copyright by Wesley Beary.

This code is covered by MIT License. (The MIT License)

Copyright (c) 2013 Black Square Media Ltd

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.