Read a JSON file into a Lua string / table

[Lunarovich]

Hello, I would like to take a JSON file and read its content into a normal Lua string.

 

Even better, I would like to put a JSON text into a Lua table directly, if it's possible.

 

So far, I've found this Lua lib for converting a JSON string into a Lua table and vice versa. However, I don't see how to read a whole file as a string.

 

Thank you in advance!

 

P.S. I know how to read an individual line with this function.

[Rick]

http://www.leadwerks.com/werkspace/page/api-reference/_/stream/

 

http://www.leadwerks.com/werkspace/page/api-reference/_/filesystem/

 

http://www.leadwerks.com/werkspace/page/api-reference/_/filesystem/filesystemgetappdatapath-r801

 

 

Note that file i/o will not work with the game launcher if you care about that. Also you might have to pay attention of where you are reading/writing the file. I don't think it can be part of the zip file as you won't know the pw to open it. So normally these files need to be somewhere else.

[Lunarovich]

Thank you!

 

Actually, I know the API, I was rather asking if anyone has ready to use solution that demads less tinkering.

[Rick]

My question would be why JSON? Is there a specific reason to pick that format?

[Lunarovich]

Sure! Because that's the format delivered by the third party

 

Anyway, it does not matter if it's JSON. I just want to read in the string as is and have it in the Lua var.

[Rick]

Using the example of the API as reference something like the below should do that

 

local stream = FileSystem:ReadFile(path)

if (stream==nil)then Debug:Error("Failed to read file.") end

local json = nil
while (not stream:EOF()) do
json = json..stream:ReadLine
end
stream:Release() 

[Lunarovich]

Thank you Rick. This is a solution I came up with. It's similar to yours. It puts a JSON string into a Lua table:

 

--Load JSON (http://regex.info/blog/lua/json) library
JSON = (loadfile "lua/JSON.lua")() -- put the lib in "lua" folder
path = "pathToJSON"
stream = FileSystem:OpenFile(path)
jsonString = ""

if (stream) then
while (not stream:EOF()) do
 jsonString = jsonString .. stream:ReadString()
end
data = JSON:decode(Swinglets.jsonString)
else
System:Print("Stream not found")
end

[Vladimir]

On 11/21/2015 at 8:44 PM, Lunarovich said:

Thank you Rick. This is a solution I came up with. It's similar to yours. It puts a JSON string into a Lua table:

 

 

--Load JSON (http://regex.info/blog/lua/json) library
JSON = (loadfile "lua/JSON.lua")() -- put the lib in "lua" folder
path = "pathToJSON"
stream = FileSystem:OpenFile(path)
jsonString = ""

if (stream) then
while (not stream:EOF()) do
 jsonString = jsonString .. stream:ReadString()
end
data = JSON:decode(Swinglets.jsonString)
else
System:Print("Stream not found")
end

 

 

Can you tell me why i get the following error:

"attempt to index a nil value (global 'FileSystems')"

and also in the path variable i have to initialize the path of the json that i want to parse right ? 

Thank you ! 

[Thirsty Panther]

FileSystems should be FileSystem

[Slastraf]

Personally I would use leadwerks stream and make my own parser and file system depending on what I need
for example
names.data
foo

bar
then loop trough all the lines and read all the data into an array