feature: provide a way to reuse table in ngx.req.get_uri_args (#288)

Author: spacewander

lib/resty/core/request.lua

@@ -10,6 +10,7 @@ local subsystem = ngx.config.subsystem
 local FFI_BAD_CONTEXT = base.FFI_BAD_CONTEXT
 local FFI_DECLINED = base.FFI_DECLINED
 local FFI_OK = base.FFI_OK
+local clear_tab = base.clear_tab
 local new_tab = base.new_tab
 local C = ffi.C
 local ffi_cast = ffi.cast
@@ -192,7 +193,7 @@ function ngx.req.get_headers(max_headers, raw)
 end
 
 
-function ngx.req.get_uri_args(max_args)
+function ngx.req.get_uri_args(max_args, tab)
     local r = get_request()
     if not r then
         error("no request found")
@@ -202,13 +203,17 @@ function ngx.req.get_uri_args(max_args)
         max_args = -1
     end
 
+    if tab then
+        clear_tab(tab)
+    end
+
     local n = C.ngx_http_lua_ffi_req_get_uri_args_count(r, max_args, truncated)
     if n == FFI_BAD_CONTEXT then
         error("API disabled in the current context", 2)
     end
 
     if n == 0 then
-        return {}
+        return tab or {}
     end
 
     local args_len = C.ngx_http_lua_ffi_req_get_querystring_len(r)
@@ -218,7 +223,7 @@ function ngx.req.get_uri_args(max_args)
 
     local nargs = C.ngx_http_lua_ffi_req_get_uri_args(r, strbuf, kvbuf, n)
 
-    local args = new_tab(0, nargs)
+    local args = tab or new_tab(0, nargs)
     for i = 0, nargs - 1 do
         local arg = kvbuf[i]
 

t/request.t

@@ -8,7 +8,7 @@ use t::TestCore;
 
 repeat_each(2);
 
-plan tests => repeat_each() * (blocks() * 5 + 2);
+plan tests => repeat_each() * (blocks() * 4 + 19);
 
 #no_diff();
 #no_long_string();
@@ -612,3 +612,70 @@ hello
 [error]
 --- skip_nginx
 2: < 1.21.1
+
+
+
+=== TEST 20: get_uri_args allows to reuse table
+--- config
+    location = /t {
+        set $foo hello;
+        content_by_lua_block {
+            local base = require "resty.core.base"
+            local args = base.new_tab(0, 3)
+            local id = tostring(args)
+            for i = 1, 5 do
+                base.clear_tab(args)
+                args = ngx.req.get_uri_args(-1, args)
+                assert(tostring(args) == id)
+            end
+            local keys = {}
+            for k, _ in pairs(args) do
+                keys[#keys + 1] = k
+            end
+            table.sort(keys)
+            for _, k in ipairs(keys) do
+                local v = args[k]
+                if type(v) == "table" then
+                    ngx.say(k, ": ", table.concat(v, ", "))
+                else
+                    ngx.say(k, ": ", v)
+                end
+            end
+        }
+    }
+--- request
+GET /t?a=3%200&foo%20bar=&a=hello&blah
+--- response_body
+a: 3 0, hello
+blah: true
+foo bar: 
+--- no_error_log
+[error]
+
+
+
+=== TEST 21: get_uri_args allows to reuse table (empty)
+--- config
+    location = /t {
+        set $foo hello;
+        content_by_lua_block {
+            local base = require "resty.core.base"
+            local args = base.new_tab(0, 3)
+            local id = tostring(args)
+            for i = 1, 5 do
+                args = ngx.req.get_uri_args(-1, args)
+                assert(tostring(args) == id)
+            end
+            local n_key = 0
+            for k, _ in pairs(args) do
+                n_key = n_key + 1
+            end
+            ngx.say(n_key)
+        }
+    }
+--- request
+GET /t
+--- response_body
+0
+--- no_error_log
+[error]