help request: when content-type is application/x-www-form-urlencoded;charset=utf-8 can't match route

[saiyoofan]

Description

modify ctx.lua to support content-type application/x-www-form-urlencoded;charset=utf-8 to match route
like this:

253             elseif core_str.has_prefix(key, "post_arg_") then
 254                 -- only match default post form
 255                 local con_t = request.header(nil, "Content-Type")
 256                 local con_t_s = sub_str(con_t, 1, 33)
 257                 if con_t_s == "application/x-www-form-urlencoded" then
 258                     local arg_key = sub_str(key, 10)
 259                     local args = request.get_post_args()[arg_key]
 260                     if args then
 261                         if type(args) == "table" then
 262                             val = args[1]
 263                         else
 264                             val = args
 265                         end
 266                     end
 267                 end

get some errors:

[error] 51#51: *10048 lua entry thread aborted: runtime error: /usr/local/apisix/apisix/core/ctx.lua:256: bad argument #1 to 'sub_str' (string expected, got nil)
stack traceback:
coroutine 0:
	[C]: in function 'sub_str'
	/usr/local/apisix/apisix/core/ctx.lua:256: in function '__index'
	/usr/local/apisix//deps/share/lua/5.1/resty/expr/v1.lua:291: in function 'eval'
	/usr/local/apisix/apisix/plugins/traffic-split.lua:253: in function 'phase_func'
	/usr/local/apisix/apisix/plugin.lua:720: in function 'run_plugin'
	/usr/local/apisix/apisix/init.lua:471: in function 'http_access_phase

so ,how can I repair it.
thx.

Environment

• APISIX version (run apisix version):
• Operating system (run uname -a):
• OpenResty / Nginx version (run openresty -V or nginx -V):
• etcd version, if relevant (run curl http://127.0.0.1:9090/v1/server_info):
• APISIX Dashboard version, if relevant:
• Plugin runner version, for issues related to plugin runners:
• LuaRocks version, for installation issues (run luarocks --version):

[soulbird]

As the error log， con_t is nil.

[saiyoofan]

[saiyoofan]

also get some errors!

[error] 53#53: *5332 lua entry thread aborted: runtime error: /usr/local/apisix/apisix/init.lua:361: attempt to index field 'var' (a nil value)
stack traceback:
coroutine 0:
	/usr/local/apisix/apisix/init.lua: in function 'http_access_phase

[tzssangglass]

Instead of changing the source code, you can use vars to do the matching.

ref:

apisix/t/core/ctx2.t

Lines 246 to 291 in 9d450d7

	=== TEST 11: parsed post args is cached under ctx
	--- config
	location /t {
	content_by_lua_block {
	local t = require("lib.test_admin").test
	local code, body = t('/apisix/admin/routes/1',
	ngx.HTTP_PUT,
	[=[{
	"upstream": {
	"nodes": {
	"127.0.0.1:1980": 1
	},
	"type": "roundrobin"
	},
	"plugins": {
	"serverless-pre-function": {
	"phase": "rewrite",
	"functions" : ["return function(conf, ctx) ngx.log(ngx.WARN, 'find ctx.req_post_args.test: ', ctx.req_post_args.test ~= nil) end"]
	}
	},
	"uri": "/hello",
	"vars": [["post_arg_test", "==", "test"]]
	}]=]
	)
	if code >= 300 then
	ngx.status = code
	end
	ngx.say(body)
	}
	}
	--- response_body
	passed
	=== TEST 12: hit
	--- request
	POST /hello
	test=test
	--- more_headers
	Content-Type: application/x-www-form-urlencoded
	--- response_body
	hello world
	--- error_log
	find ctx.req_post_args.test: true

[saiyoofan]

            elseif core_str.has_prefix(key, "post_arg_") then
                -- only match default post form
                if request.header(nil, "Content-Type") ~= nil then
                    local con_t = sub_str(request.header(nil, "Content-Type"),1,33)
                    if con_t == "application/x-www-form-urlencoded" then
                    local arg_key = sub_str(key, 10)
                    local args = request.get_post_args()[arg_key]
                    if args then
                        if type(args) == "table" then
                            val = args[1]
                        else
                            val = args
                        end
                    end
                    end
                end
            elseif core_str.has_prefix(key, "body_arg_") then
                -- only match default  body json
                if request.header(nil, "Content-Type") ~= nil then
                    local con_t = sub_str(request.header(nil, "Content-Type"),1,16)
                    if con_t == "application/json" then
                    local body, err = request.get_body()
                    if not body then
                        return nil, "failed to read body data, " .. (err or "request body has zero size")
                        end
                    local arg_key = sub_str(key, 10)
                    local res
                    res, err = json.decode(body)
                    if not res then
                        return nil, "failed to read body data, " .. err
                    end

                    if not res[arg_key] then
                        return nil, "failed to read body data, json body[" ..
                                    arg_key .. "] is nil"
                    end
                    val = res[arg_key]
                    end
                end

The above code seems to work fine.

But I'm not sure if there will be other problems.
If you have better suggestions, I hope to help correct me, thank you

[tzssangglass]

But I'm not sure if there will be other problems.
If you have better suggestions, I hope to help correct me, thank you

I don't have a suggestion.

1. a better way to test the stability of your code is to feed back upstream;
2. but APISIX already supports the feature, so I think we will reject this change;

[saiyoofan]

Thanks for your enthusiastic help