Add a page:json function

[louis77]

Since returning JSON content is such a common case now, I propose to add a json function to the page module, where I just pass a variable plus options (which are passed to dkjson), like so:

page:json( data, { indent = true })

This essentially should do:

local json = require "dkjson"
page.theme = nil
page.layout = nil
page.r.content_type = 'application/json'
page:write(json.encode(data, {indent=true}))

What do you think?

[felipedaragon]

I like the idea of having JSON features in Sailor. This would mean shipping a new Lua library with it though (would not be a problem I think).

[Etiene]

I also don't have any issues with shipping a json module with it :+1:

[louis77]

Any preferences/experience to share with the available JSON libraries? Personally I like https://luarocks.org/modules/dhkolf/dkjson because it's free of dependencies, fast and I never had any decoding issues with it.

[Etiene]

seems great :dancers:

[leonardoaraujosantos]

Guys did I do something wrong here?

json = require "dkjson"

-- As everything in lua it's a table
local main = {}

function main.index(page)
    page:render('index')

    -- Send a message to the view
    page:render("index", { msg = "Hello"})
end

-- http://localhost:8080/?r=main/imgCaption
-- Check how to enable friendly URLs....
function main.imgCaption(page)
    print("Recebido algo")

    -- http://dkolf.de/src/dkjson-lua.fsl/home
    local someData = {
      animals = { "dog", "cat", "aardvark" },
      instruments = { "violin", "trombone", "theremin" },
      bugs = json.null,
      trees = nil
    }

    -- Encode on json
    local string_json = json.encode (someData, { indent = true })
    print(string_json)

    -- Give back json (BAD here null json)
    page:json( someData, { indent = true })

    -- Write directly on the page
    --page:write( "Hello world!")
    --page:print( "Hello world!")

    -- Render the view
    --page:render('imgCaption')
end

-- Always need to return main on the end
return main

I'm getting this error

./controllers/main.lua:31: attempt to call method 'json' (a nil value)
stack traceback:
    ./controllers/main.lua:31: in function <./controllers/main.lua:15>
    [C]: in function 'xpcall'
    /home/laraujo/torch/install/share/lua/5.1/sailor.lua:196: in function 'handlefunc'
    /home/laraujo/torch/install/share/lua/5.1/remy.lua:167: in function 'run'
    /home/laraujo/torch/install/share/lua/5.1/sailor.lua:43: in function 'launch'
    index.lua:2: in main chunk
    [C]: in function 'xpcall'
    /home/laraujo/torch/install/share/lua/5.1/cgilua.lua:169: in function 
    [C]: in function 'xpcall'
    /home/laraujo/torch/install/share/lua/5.1/cgilua.lua:169: in function 'pcall'
    /home/laraujo/torch/install/share/lua/5.1/cgilua.lua:630: in function 'main'
    /home/laraujo/torch/install/share/lua/5.1/wsapi/sapi.lua:53: in function 
    [C]: in function 'run_app'
    [string "  local app_name, bootstrap_code, is_file = ...."]:68: in function <[string "  local app_name, bootstrap_code, is_file = ...."]:65>

[leonardoaraujosantos]

I've also tested the presence of dkjson itself (I'm using through torch)

laraujo@lindev:~/work/densecap/testWeb/hey_arnold$ th

  ______             __   |  Torch7 
 /_  __/__  ________/ /   |  Scientific computing for Lua. 
  / / / _ \/ __/ __/ _ \  |  Type ? for help 
 /_/  \___/_/  \__/_//_/  |  https://github.com/torch 
                          |  http://torch.ch 

th> require "dkjson"
{
  addnewline : function: 0x414d6358
  encodeexception : function: 0x40ea83a0
  use_lpeg : function: 0x417fc118
  decode : function: 0x41625f30
  quotestring : function: 0x414ce208
  null : {...}
  encode : function: 0x408b9dc8
  version : "dkjson 2.5"
}

[xspager]

The page table is supposed to have a method json?

On Oct 16, 2016 10:35 AM, "Leonardo Araujo dos Santos" < notifications@github.com> wrote:

I've also tested the presence of dkjson itself (I'm using through torch)

laraujo@lindev:~/work/densecap/testWeb/hey_arnold$ th

__ | Torch7 / / ____/ / | Scientific computing for Lua. / / / \/ **/ / \ | Type ? for help // _**/_/ _///_/ | https://github.com/torch | http://torch.ch

th> require "dkjson" { addnewline : function: 0x414d6358 encodeexception : function: 0x40ea83a0 use_lpeg : function: 0x417fc118 decode : function: 0x41625f30 quotestring : function: 0x414ce208 null : {...} encode : function: 0x408b9dc8 version : "dkjson 2.5" }

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[leonardoaraujosantos]

Oh sorry mabe thats is the issue do you know how could i check if this page should have a json?

[Etiene]

I didn't make a new release of sailor yet after this function was added, this is not present on 0.5. You'd have to install the dev environment of sailor to have this available! try luarocks install https://github.com/sailorproject/sailor/blob/master/rockspecs/sailor-current-1.rockspec

[leonardoaraujosantos]

Ok @Etiene thanks

[leonardoaraujosantos]

Hi @Etiene I've sucessully installed after I called

apt-get install openssl libssl-dev luarocks build https://raw.githubusercontent.com/sailorproject/sailor/master/rockspecs/sailor-current-1.rockspec

Super cool now I can calculate something on the GPU and give back to the browser as JSON. Thanks a lot guys! (Obrigado @Etiene )

--json = require "dkjson"
require 'torch'
require 'nn'
require 'image'
require 'cutorch'

-- As everything in lua it's a table
local main = {}

function main.index(page)
    page:render('index')

    -- Send a message to the view
    page:render("index", { msg = "Hello"})
end

-- http://localhost:8080/?r=main/imgCaption
-- Check how to enable friendly URLs....
function main.imgCaption(page)
    -- Disable theme, layout and set content to application/json
    page.theme = nil    
    page.layout = nil
    page.r.content_type = 'application/json'

    print("Something received doing some Math")
    local a = torch.rand(5,3)
    local b = torch.rand(3,4)
    local c = torch.Tensor(5,4)
    c:mm(a,b)    

    print("Moving to the GPU!")
    local a = a:cuda()
    local b = b:cuda()
    local c_gpu = c:cuda()
    c_gpu:mm(a,b) -- done on GPU
    local c_tab = torch.totable(c)                  

    -- Give back json        
    page:json( c_tab, { indent = true })           
end

-- Always need to return main on the end
return main