Merge pull request #209 from Hollow111/N_Tatunov/gh-13-c-style-expressions

graphql: implement c-style expressions parser

Author: Totktonada

graphql/accessor_general.lua

@@ -9,12 +9,12 @@ local json = require('json')
 local avro_schema = require('avro_schema')
 local utils = require('graphql.utils')
 local clock = require('clock')
-local bit = require('bit')
-local rex, is_pcre2 = utils.optional_require_rex()
+local rex = utils.optional_require_rex()
 local avro_helpers = require('graphql.avro_helpers')
 local db_schema_helpers = require('graphql.db_schema_helpers')
 local error_codes = require('graphql.error_codes')
 local statistics = require('graphql.statistics')
+local expressions = require('graphql.expressions')
 
 local check = utils.check
 local e = error_codes
@@ -763,16 +763,16 @@ local function validate_collections(collections, schemas)
     end
 end
 
---- Whether an object match set of PCRE.
----
---- @tparam table obj an object to check
+--- Whether an object match set of PCREs.
 ---
 --- @tparam table pcre map with PCRE as values; names are correspond to field
 --- names of the `obj` to match
 ---
+--- @tparam table obj an object to check
+---
 --- @treturn boolean `res` whether the `obj` object match `pcre` set of
 --- regexps.
-local function match_using_re(obj, pcre)
+local function match_using_re(pcre, obj)
     if pcre == nil then return true end
 
     assert(rex ~= nil, 'we should not pass over :compile() ' ..
@@ -785,38 +785,34 @@ local function match_using_re(obj, pcre)
             return false
         end
         if type(re) == 'table' then
-            local match = match_using_re(obj[field_name], re)
+            local match = match_using_re(re, obj[field_name])
             if not match then return false end
-        else
-            local flags = rex.flags()
-            -- emulate behaviour of (?i) on libpcre (libpcre2 supports it)
-            local cfg = 0
-            if not is_pcre2 then
-                local cnt
-                re, cnt = re:gsub('^%(%?i%)', '')
-                if cnt > 0 then
-                    cfg = bit.bor(cfg, flags.CASELESS)
-                end
-            end
-            -- enable UTF-8
-            if is_pcre2 then
-                cfg = bit.bor(cfg, flags.UTF)
-                cfg = bit.bor(cfg, flags.UCP)
-            else
-                cfg = bit.bor(cfg, flags.UTF8)
-                cfg = bit.bor(cfg, flags.UCP)
-            end
-            -- XXX: compile re once
-            local re = rex.new(re, cfg)
-            if not re:match(obj[field_name]) then
-                return false
-            end
+        elseif not utils.regexp(re, obj[field_name]) then
+            return false
         end
     end
 
     return true
 end
 
+--- Whether an object match an expression.
+---
+--- @param expr (table or string) compiled or raw expression
+---
+--- @tparam table obj an object to check
+---
+--- @tparam[opt] table variables variables values from the request
+---
+--- @treturn boolean `res` whether the `obj` object match `expr` expression
+local function match_using_expr(expr, obj, variables)
+    if expr == nil then return true end
+
+    check(expr, 'expression', 'table')
+    local res = expr:execute(obj, variables)
+    check(res, 'expression result', 'boolean')
+    return res
+end
+
 --- Check whether we meet deadline time.
 ---
 --- The functions raises an exception in the case.
@@ -857,6 +853,7 @@ end
 --- * `pivot_filter` (table, set of fields to match the objected pointed by
 ---   `offset` arqument of the GraphQL query),
 --- * `resolveField` (function) for subrequests, see @{impl.new}.
+--- * XXX: describe other fields.
 ---
 --- @return nil
 ---
@@ -887,7 +884,9 @@ local function process_tuple(self, state, tuple, opts)
 
     local collection_name = opts.collection_name
     local pcre = opts.pcre
+    local expr = opts.expr
     local resolveField = opts.resolveField
+    local variables = qcontext.variables
 
     -- convert tuple -> object
     local obj = opts.unflatten_tuple(self, collection_name, tuple,
@@ -918,7 +917,7 @@ local function process_tuple(self, state, tuple, opts)
 
     -- filter out non-matching objects
     local match = utils.is_subtable(obj, truncated_filter) and
-        match_using_re(obj, pcre)
+        match_using_re(pcre, obj) and match_using_expr(expr, obj, variables)
     if do_filter then
         if not match then return true end
     else
@@ -1058,6 +1057,13 @@ local function prepare_select_internal(self, collection_name, from, filter,
         qcontext = qcontext
     }
 
+    -- compile an expression argument if provided and did not compiled yet
+    local expr = args.filter
+    check(expr, 'expression', 'table', 'string', 'nil')
+    if type(expr) == 'string' then
+        expr = expressions.new(expr)
+    end
+
     -- read only process_tuple options
     local select_opts = {
         limit = args.limit,
@@ -1069,6 +1075,7 @@ local function prepare_select_internal(self, collection_name, from, filter,
         use_tomap = self.collection_use_tomap[collection_name] or false,
         default_unflatten_tuple = default_unflatten_tuple,
         pcre = args.pcre,
+        expr = expr,
         resolveField = extra.resolveField,
         is_hidden = extra.is_hidden,
     }

graphql/convert_schema/schema.lua

@@ -1,5 +1,6 @@
 --- Convert extended avro-schema (collections) to GraphQL schema.
 
+local log = require('log')
 local core_types = require('graphql.core.types')
 local core_schema = require('graphql.core.schema')
 local gen_arguments = require('graphql.gen_arguments')
@@ -358,6 +359,17 @@ function schema.convert(state, cfg)
         local object_args = state.object_arguments[collection_name]
         local list_args = state.list_arguments[collection_name]
 
+        -- check for names clash
+        for name, _ in pairs(list_args) do
+            if object_args[name] ~= nil then
+                local err = ('the argument "%s" generated from the same ' ..
+                    'named field of the collection "%s" is superseded with ' ..
+                    'the list filtering argument "%s"'):format(name,
+                    collection_name, name)
+                log.warn(err)
+            end
+        end
+
         local args = utils.merge_tables(object_args, list_args)
         state.all_arguments[collection_name] = args
     end

graphql/core/parse.lua

@@ -150,6 +150,7 @@ local function cOperation(...)
 
     for i = 2, #args do
       -- key ~= nil => result['selectionSet'] = <...>
+      --            or result['name'] = <...>
       -- key == nil => result['variableDefinitions'] = <...>
       --            or result['directives'] = <...>
       local key = args[i].kind

graphql/core/rules.lua

@@ -415,6 +415,11 @@ function rules.variableDefaultValuesHaveCorrectType(node, context)
 end
 
 function rules.variablesAreUsed(node, context)
+  local operationName = node.name and node.name.value or ''
+  if context.skipVariableUseCheck[operationName] then
+    return
+  end
+
   if node.variableDefinitions then
     for _, definition in ipairs(node.variableDefinitions) do
       local variableName = definition.variable.name.value
@@ -605,3 +610,5 @@ end
 -- }}}
 
 return rules
+
+-- vim: set ts=2 sw=2 et:

graphql/core/util.lua

@@ -92,6 +92,11 @@ function util.coerceValue(node, schemaType, variables, opts)
     return nil
   end
 
+  -- handle precompiled values
+  if node.compiled ~= nil then
+    return node.compiled
+  end
+
   if node.kind == 'variable' then
     return variables[node.name.value]
   end

graphql/core/validate.lua

@@ -18,7 +18,7 @@ local function getParentField(context, name, count)
   return parent.fields[name]
 end
 
-local visitors = {
+local defaultVisitors = {
   -- <document>
   --
   -- {
@@ -51,6 +51,10 @@ local visitors = {
   -- {
   --   kind = 'operation',
   --   operation = 'query' or 'mutation',
+  --   name = {
+  --     kind = 'name',
+  --     value = <string>,
+  --   } (optional),
   --   selectionSet = <selectionSet>,
   --   variableDefinitions = list of <variableDefinition> (optional),
   --   directives = list of <directive> (optional),
@@ -463,7 +467,7 @@ local visitors = {
   }
 }
 
-return function(schema, tree)
+return function(schema, tree, extraVisitors)
   local context = {
     schema = schema,
     fragmentMap = {},
@@ -472,41 +476,67 @@ return function(schema, tree)
     usedFragments = {},
     objects = {},
     currentOperation = nil,
-    variableReferences = nil
+    variableReferences = nil,
+    skipVariableUseCheck = {}, -- operation name -> boolean
   }
 
   local function visit(node)
-    local visitor = node.kind and visitors[node.kind]
+    local visitors = {}
+    visitors[#visitors + 1] = node.kind and defaultVisitors[node.kind]
+    visitors[#visitors + 1] = node.kind and extraVisitors[node.kind]
+
+    local enterList = {}
+    local ruleList = {}
+    local childrenList = {}
+    local exitRuleList = {}
+    local exitList = {}
+
+    -- collect visitors methods
+    for _, visitor in ipairs(visitors) do
+      enterList[#enterList + 1] = visitor.enter
+
+      if visitor.rules then
+        for _, rule in ipairs(visitor.rules) do
+          ruleList[#ruleList + 1] = rule
+        end
+      end
 
-    if not visitor then return end
+      childrenList[#childrenList + 1] = visitor.children
 
-    if visitor.enter then
-      visitor.enter(node, context)
+      if visitor.rules and visitor.rules.exit then
+        for _, exitRule in ipairs(visitor.rules.exit) do
+          exitRuleList[#exitRuleList + 1] = exitRule
+        end
+      end
+
+      exitList[#exitList + 1] = visitor.exit
     end
 
-    if visitor.rules then
-      for i = 1, #visitor.rules do
-        visitor.rules[i](node, context)
-      end
+    -- invoke visitors methods
+
+    for _, enter in ipairs(enterList) do
+      enter(node, context)
     end
 
-    if visitor.children then
-      local children = visitor.children(node)
-      if children then
-        for _, child in ipairs(children) do
+    for _, rule in ipairs(ruleList) do
+      rule(node, context)
+    end
+
+    for _, children in ipairs(childrenList) do
+      local childs = children(node)
+      if childs then
+        for _, child in ipairs(childs) do
           visit(child)
         end
       end
     end
 
-    if visitor.rules and visitor.rules.exit then
-      for i = 1, #visitor.rules.exit do
-        visitor.rules.exit[i](node, context)
-      end
+    for _, exitRule in ipairs(exitRuleList) do
+      exitRule(node, context)
     end
 
-    if visitor.exit then
-      visitor.exit(node, context)
+    for _, exit in ipairs(exitList) do
+      exit(node, context)
     end
   end