SwarmUtils.lua #1

local SwarmUtils = {}

local cjson = require "cjson"
local curl = require "cURL.safe"
SwarmUtils.SwarmAPI = "v9"
SwarmUtils.version = nil

local utils = {}

-- Function to convert the cURL/Swarm return values into something
-- easier for consuming functions to use.

function curlResponseFmt( url, ok, data )
  local msg = "Error getting data from Swarm (" .. url .. "):  "

  if not ok then
    return false, url, msg .. tostring( data )
  end

  if data[ "error" ] ~= nil then
    return false, url, msg .. data[ "error" ]
  end

  return true, url, data
end

-- Connect to a Swarm instance and convert the JSON response to
-- a table.  Verifies the Swarm host's TLS certificate.

function getData( address, type )
  local c = curl.easy()
  local rsp = ""
  -- todo: ensure there's a trailing slash on the address
  local url = address .. "api/" .. SwarmUtils.SwarmAPI .. "/" .. type

  c:setopt( curl.OPT_URL, url )
  -- Store all the data in memory in the 'rsp' variable.
  c:setopt( curl.OPT_WRITEFUNCTION, function( chunk ) rsp = rsp .. chunk end )
  -- https://curl.haxx.se/docs/caextract.html
  c:setopt_cainfo( Helix.Core.Server.GetArchDirFileName( "cacert.pem" ) )
  c:setopt_useragent( utils.getID() )
  c:setopt( curl.OPT_SSL_VERIFYPEER,true );
  c:setopt( curl.OPT_SSL_VERIFYHOST, true );

  local ok, err = c:perform()
  c:close()

  return curlResponseFmt( url, ok, ok and cjson.decode( rsp ) or err )
end

function SwarmUtils.getReviews( address, author )
  return getData( address, "reviews?author=" .. author )
end

function SwarmUtils.checkVersion( address )
  local ok, url, data = getData( address, "version" )

  -- This relies on the fact that we hardcode the 'v9' API and if that doesn't
  -- exist, Swarm returns an error - we don't actually care about the version
  -- returned here - we just want to know that the API version is supported.

  if ok then
    SwarmUtils.version = data[ "version" ]
  end

  return ok  
end

function SwarmUtils.init( us )
  utils = us
  local url = utils.gCfgData[ "Swarm-URL" ]

  if url ~= nil then
     SwarmUtils.checkVersion( url )
  end
end

return SwarmUtils