Allow to use custom unflattener

Closes #52 (moves responsibility to an user of the library).

Author: Totktonada

Makefile

@@ -4,7 +4,7 @@ default:
 .PHONY: lint
 lint:
 	luacheck graphql/*.lua test/local/*.lua test/testdata/*.lua \
-		test/common/*test.lua test/common/lua/*.lua \
+		test/common/*.test.lua test/common/lua/*.lua \
 		--no-redefined --no-unused-args
 
 .PHONY: test

graphql/accessor_general.lua

@@ -574,7 +574,13 @@ end
 --- Nothing returned, but after necessary count of invokes `state.objs` will
 --- hold list of resulting objects.
 local function process_tuple(state, tuple, opts)
-    local function maybe_unflatten(model, tuple, obj)
+    local function maybe_unflatten(model, tuple, obj, opts)
+        if obj ~= nil then
+            return obj
+        end
+        if opts.unflatten_tuple ~= nil then
+            return opts.unflatten_tuple(opts.collection_name, tuple)
+        end
         local ok, obj = model.unflatten(tuple)
         assert(ok, 'cannot unflat tuple: ' .. tostring(obj))
         return obj
@@ -597,15 +603,15 @@ local function process_tuple(state, tuple, opts)
     -- skip all items before pivot (the item pointed by offset)
     local obj = nil
     if not state.pivot_found and pivot_filter then
-        obj = maybe_unflatten(model, tuple, obj)
+        obj = maybe_unflatten(model, tuple, obj, opts)
         local match = utils.is_subtable(obj, pivot_filter)
         if not match then return true end
         state.pivot_found = true
         return true -- skip pivot item too
     end
 
     -- convert tuple -> object, then filter out or continue
-    obj = maybe_unflatten(model, tuple, obj)
+    obj = maybe_unflatten(model, tuple, obj, opts)
     local match = utils.is_subtable(obj, filter)
     if do_filter then
         if not match then return true end
@@ -723,7 +729,9 @@ local function select_internal(self, collection_name, from, filter, args, extra)
         do_filter = not full_match,
         pivot_filter = nil, -- filled later if needed
         resulting_object_cnt_max = self.settings.resulting_object_cnt_max,
-        fetched_object_cnt_max = self.settings.fetched_object_cnt_max
+        fetched_object_cnt_max = self.settings.fetched_object_cnt_max,
+        collection_name = collection_name,
+        unflatten_tuple = self.funcs.unflatten_tuple,
     }
 
     if index == nil then
@@ -803,6 +811,11 @@ local function validate_funcs(funcs)
     assert(type(funcs.get_primary_index) == 'function',
         'funcs.get_primary_index must be a function, got ' ..
         type(funcs.get_primary_index))
+    if funcs.unflatten_tuple ~= nil then
+        assert(type(funcs.unflatten_tuple) == 'function',
+            'funcs.unflatten_tuple must be a function, got ' ..
+            type(funcs.unflatten_tuple))
+    end
 end
 
 --- Create a new data accessor.
@@ -818,10 +831,10 @@ end
 --- value is 10,000)_
 ---
 --- @tparam table funcs set of functions (`is_collection_exists`, `get_index`,
---- `get_primary_index`) allows this abstract data accessor behaves in the
---- certain way (say, like space data accessor or shard data accessor);
---- consider the `accessor_space` and the `accessor_shard` modules documentation
---- for this functions description
+--- `get_primary_index`, `unflatten_tuple`) allows this abstract data accessor
+--- behaves in the certain way (say, like space data accessor or shard data
+--- accessor); consider the `accessor_space` and the `accessor_shard` modules
+--- documentation for this functions description
 ---
 --- For examples of `opts.schemas` and `opts.collections` consider the
 --- @{tarantool_graphql.new} function description.

test/local/unflatten_tuple.result

@@ -0,0 +1,210 @@
+RESULT
+---
+order_collection:
+- order_id: order_id_1
+  description: first order of Ivan$
+  user_connection:
+    user_id: user_id_1
+    last_name: Ivanov$
+    first_name: Ivan$
+...
+
+RESULT
+---
+user_collection:
+- user_id: user_id_1
+  last_name: Ivanov$
+  first_name: Ivan$
+  order_connection:
+  - order_id: order_id_1
+    description: first order of Ivan$
+  - order_id: order_id_2
+    description: second order of Ivan$
+...
+
+RESULT
+---
+user_collection:
+- user_id: user_id_42
+  last_name: last name 42$
+  first_name: first name 42$
+  order_connection:
+  - order_id: order_id_1574
+    description: order of user 42$
+  - order_id: order_id_1575
+    description: order of user 42$
+  - order_id: order_id_1576
+    description: order of user 42$
+  - order_id: order_id_1577
+    description: order of user 42$
+  - order_id: order_id_1578
+    description: order of user 42$
+  - order_id: order_id_1579
+    description: order of user 42$
+  - order_id: order_id_1580
+    description: order of user 42$
+  - order_id: order_id_1581
+    description: order of user 42$
+  - order_id: order_id_1582
+    description: order of user 42$
+  - order_id: order_id_1583
+    description: order of user 42$
+...
+
+RESULT
+---
+user_collection:
+- user_id: user_id_42
+  last_name: last name 42$
+  first_name: first name 42$
+  order_connection:
+  - order_id: order_id_1602
+    description: order of user 42$
+  - order_id: order_id_1603
+    description: order of user 42$
+...
+
+RESULT
+---
+user_collection: []
+...
+
+RESULT
+---
+user_collection:
+- user_id: user_id_42
+  last_name: last name 42$
+  first_name: first name 42$
+  order_connection:
+  - order_id: order_id_1564
+    description: order of user 42$
+  - order_id: order_id_1565
+    description: order of user 42$
+  - order_id: order_id_1566
+    description: order of user 42$
+  - order_id: order_id_1567
+    description: order of user 42$
+  - order_id: order_id_1568
+    description: order of user 42$
+  - order_id: order_id_1569
+    description: order of user 42$
+  - order_id: order_id_1570
+    description: order of user 42$
+  - order_id: order_id_1571
+    description: order of user 42$
+  - order_id: order_id_1572
+    description: order of user 42$
+  - order_id: order_id_1573
+    description: order of user 42$
+  - order_id: order_id_1574
+    description: order of user 42$
+  - order_id: order_id_1575
+    description: order of user 42$
+  - order_id: order_id_1576
+    description: order of user 42$
+  - order_id: order_id_1577
+    description: order of user 42$
+  - order_id: order_id_1578
+    description: order of user 42$
+  - order_id: order_id_1579
+    description: order of user 42$
+  - order_id: order_id_1580
+    description: order of user 42$
+  - order_id: order_id_1581
+    description: order of user 42$
+  - order_id: order_id_1582
+    description: order of user 42$
+  - order_id: order_id_1583
+    description: order of user 42$
+  - order_id: order_id_1584
+    description: order of user 42$
+  - order_id: order_id_1585
+    description: order of user 42$
+  - order_id: order_id_1586
+    description: order of user 42$
+  - order_id: order_id_1587
+    description: order of user 42$
+  - order_id: order_id_1588
+    description: order of user 42$
+  - order_id: order_id_1589
+    description: order of user 42$
+  - order_id: order_id_1590
+    description: order of user 42$
+  - order_id: order_id_1591
+    description: order of user 42$
+  - order_id: order_id_1592
+    description: order of user 42$
+  - order_id: order_id_1593
+    description: order of user 42$
+  - order_id: order_id_1594
+    description: order of user 42$
+  - order_id: order_id_1595
+    description: order of user 42$
+  - order_id: order_id_1596
+    description: order of user 42$
+  - order_id: order_id_1597
+    description: order of user 42$
+  - order_id: order_id_1598
+    description: order of user 42$
+  - order_id: order_id_1599
+    description: order of user 42$
+  - order_id: order_id_1600
+    description: order of user 42$
+  - order_id: order_id_1601
+    description: order of user 42$
+  - order_id: order_id_1602
+    description: order of user 42$
+  - order_id: order_id_1603
+    description: order of user 42$
+...
+
+RESULT
+---
+user_collection:
+- user_id: user_id_54
+  last_name: last name 54$
+  first_name: first name 54$
+- user_id: user_id_55
+  last_name: last name 55$
+  first_name: first name 55$
+- user_id: user_id_56
+  last_name: last name 56$
+  first_name: first name 56$
+- user_id: user_id_57
+  last_name: last name 57$
+  first_name: first name 57$
+- user_id: user_id_58
+  last_name: last name 58$
+  first_name: first name 58$
+- user_id: user_id_59
+  last_name: last name 59$
+  first_name: first name 59$
+- user_id: user_id_6
+  last_name: last name 6$
+  first_name: first name 6$
+- user_id: user_id_60
+  last_name: last name 60$
+  first_name: first name 60$
+- user_id: user_id_61
+  last_name: last name 61$
+  first_name: first name 61$
+- user_id: user_id_62
+  last_name: last name 62$
+  first_name: first name 62$
+...
+
+RESULT
+---
+user_collection: []
+...
+
+RESULT
+---
+user_collection: []
+...
+
+RESULT
+---
+order_collection: []
+...
+

test/local/unflatten_tuple.test.lua

@@ -0,0 +1,85 @@
+#!/usr/bin/env tarantool
+
+local fio = require('fio')
+
+-- require in-repo version of graphql/ sources despite current working directory
+package.path = fio.abspath(debug.getinfo(1).source:match("@?(.*/)")
+    :gsub('/./', '/'):gsub('/+$', '')) .. '/../../?.lua' .. ';' ..
+    package.path
+
+local avro = require('avro_schema')
+local graphql = require('graphql')
+local testdata = require('test.testdata.common_testdata')
+
+-- init box, upload test data and acquire metadata
+-- -----------------------------------------------
+
+-- init box and data schema
+box.cfg{background = false}
+testdata.init_spaces()
+
+-- upload test data
+testdata.fill_test_data()
+
+-- acquire metadata
+local metadata = testdata.get_test_metadata()
+local schemas = metadata.schemas
+local collections = metadata.collections
+local service_fields = metadata.service_fields
+local indexes = metadata.indexes
+
+-- build accessor and graphql schemas
+-- ----------------------------------
+
+local accessor = graphql.accessor_space.new({
+    schemas = schemas,
+    collections = collections,
+    service_fields = service_fields,
+    indexes = indexes,
+})
+
+local ok, handle = avro.create(schemas.user)
+assert(ok, 'avro schema create: ' .. tostring(handle))
+local ok, model = avro.compile({handle, service_fields = {'int'}})
+assert(ok, 'avro schema compile: ' .. tostring(model))
+local user_model = model
+
+local ok, handle = avro.create(schemas.order)
+assert(ok, 'avro schema create: ' .. tostring(handle))
+local ok, model = avro.compile({handle})
+assert(ok, 'avro schema compile: ' .. tostring(model))
+local order_model = model
+
+accessor.funcs.unflatten_tuple = function(collection_name, tuple)
+    if collection_name == 'user_collection' then
+        local ok, obj = user_model.unflatten(tuple)
+        assert(ok, 'unflatten: ' .. tostring(obj))
+        obj.first_name = obj.first_name .. '$'
+        obj.last_name = obj.last_name .. '$'
+        return obj
+    elseif collection_name == 'order_collection' then
+        local ok, obj = order_model.unflatten(tuple)
+        assert(ok, 'unflatten: ' .. tostring(obj))
+        obj.description = obj.description .. '$'
+        return obj
+    end
+    error('unexpected collection_name: ' .. tostring(collection_name))
+end
+
+local gql_wrapper = graphql.new({
+    schemas = schemas,
+    collections = collections,
+    accessor = accessor,
+})
+
+-- run queries
+-- -----------
+
+testdata.run_queries(gql_wrapper)
+
+-- clean up
+-- --------
+
+testdata.drop_spaces()
+
+os.exit()