Unable to get proper table key from nginx lua?

Question

Currently posting this data:

{"test":"hello","test2":"world"}

Header is this:

"Content-Type: application/json"

Currently trying to loop through the json but in my code, it already treats the posted data as table for some reason. So its useless even when I tried to encode & decode the json to table.

Anyways, when I loop through it, I'm getting only one loop where the key is like this:

"test":"hello"

I'm wondering what went wrong here. I'm trying to loop through each key & set the value to redis.

They key is supposed to be like this:

test

Here is my content_by_lua part:

content_by_lua '
             local cjson = require "cjson"
             local redis = require "resty.redis"
             local red = redis:new()
             red:set_timeout(1000) -- 1 sec

             local ok, err = red:connect("127.0.0.1", 6379)
             if not ok then
                ngx.say("failed to connect: ", err)
                return
             end


             ngx.header.content_type = "application/json; charset=utf-8"
             ngx.req.read_body()

             local data, err = ngx.req.get_post_args()
             if not data then
               ngx.say("err: ",err)
               return
             end

             ngx.status = ngx.HTTP_OK

             for key, val in pairs(data) do
                   ok, err = red:set(key, val)
                   if not ok then
                     ngx.say("failed to set key: ", err)
                     return
                   end
             end
           ';

What did I do wrong here?

brianolive brianolive · Accepted Answer · 2018-07-03T11:07:22

If the code is expecting a a Lua table to iterate through, then it will not handle the JSON-formatted string that you are testing with:

{"test":"hello","test2":"world"}

As a Lua table, it should be:

{"test" = "hello", "test2" = "world"}

Now, why it is not properly decoding the JSON, etc. that I cannot tell from the code you have posted.

Unable to get proper table key from nginx lua?

1 Answers