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fix: convert errors, return error from match_cmp_type #14

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fix: convert errors, return error from match_cmp_type #14

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151 changes: 115 additions & 36 deletions jsonpath.lua
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Original file line number Diff line number Diff line change
Expand Up @@ -100,6 +100,18 @@
]]--
local M = {}

local codes = {
SUCCESS = 200,
BAD_REQUEST = 400,
NOT_FOUND = 404,
INTERNAL_ERR = 500,
}

local errors = require('errors')

local JsonPathError = errors.new_class("JsonPathError")
local JsonPathNotFoundError = errors.new_class("JsonPathNotFoundError")

local ffi = require('ffi')

-- Use Roberto Ierusalimschy's fabulous LulPeg pattern-matching library
Expand Down Expand Up @@ -286,6 +298,11 @@ local jsonpath_grammer = (function()
return jsonpath
end)()

local function Bad_request_error(err)
local err = JsonPathError:new(err)
err.rc = codes.BAD_REQUEST
return err
end

-- Helper: evaluate abstract syntax tree. Called recursively.
local function eval_ast(ast, obj)
Expand All @@ -297,15 +314,18 @@ local function eval_ast(ast, obj)
return not op1, nil
else
if type(op2) == 'string' then
return nil, "cannot compare boolean with string"
return nil, Bad_request_error("cannot compare boolean with string")
end
if type(op2) == 'number' then
if compare then
return nil, "cannot compare boolean with number"
return nil, Bad_request_error("cannot compare boolean with number")
end
return op2 ~= 0, nil
end
if type(op2) == 'boolean' then
if compare then
return nil, Bad_request_error("cannot compare boolean with boolean")
end
return op2, nil
end
return (op2 and true or false), nil
Expand All @@ -317,7 +337,7 @@ local function eval_ast(ast, obj)
if type(op2) == 'string' then
local num = tonumber(op2)
if num == nil then
return nil, "cannot compare number with non-numeric string"
return nil, Bad_request_error("cannot compare number with non-numeric string")
end
return num, nil
end
Expand All @@ -326,7 +346,7 @@ local function eval_ast(ast, obj)
return tonumber(op2), nil
elseif is_null(op1) then
if compare then
return nil, "cannot compare null with other values"
return nil, Bad_request_error("cannot compare null with other values")
end
return op2, nil
end
Expand All @@ -347,10 +367,12 @@ local function eval_ast(ast, obj)
-- Helper helper: evaluate variable expression inside abstract syntax tree
local function eval_var(expr, obj)
if obj == nil then
return nil, 'object is not set'
return nil, Bad_request_error('object is not set')
end
if type(obj) ~= "table" then
return nil, 'object is primitive'
local err = JsonPathNotFoundError:new('object is primitive')
err.rc = codes.NOT_FOUND
return nil, err
end
for i = 2, #expr do
-- [1] is "var"
Expand All @@ -361,7 +383,9 @@ local function eval_ast(ast, obj)
member = type(member) == 'number' and member + 1 or member
obj = obj[member]
if is_nil(obj) then
return nil, 'object doesn\'t contain an object or attribute "' .. member .. '"'
local err = JsonPathNotFoundError:new('object doesn\'t contain an object or attribute "'.. member ..'"')
err.rc = codes.NOT_FOUND
return nil, err
end
end
return obj
Expand All @@ -378,7 +402,10 @@ local function eval_ast(ast, obj)
local function eval_union(expr, obj)
local matches = {} -- [1] is "union"
for i = 2, #expr do
local result = eval_ast(expr[i], obj)
local result, err = eval_ast(expr[i], obj)
if err then
return nil, err
end
if type(result) == 'table' then
for _, j in ipairs(result) do
table.insert(matches, j)
Expand All @@ -392,16 +419,31 @@ local function eval_ast(ast, obj)

-- Helper helper: evaluate 'filter' expression inside abstract syntax tree
local function eval_filter(expr, obj)
return eval_ast(expr[2], obj) and true or false
local result, err = eval_ast(expr[2], obj)
if err then
if err.rc == codes.NOT_FOUND then
return false
end
return nil, err
end
return result and true or false
end

-- Helper helper: evaluate 'slice' expression inside abstract syntax tree
local function eval_slice(expr, obj)
local matches = {} -- [1] is "slice"
if #expr == 4 then
local from = tonumber(eval_ast(expr[2], obj))
local to = tonumber(eval_ast(expr[3], obj))
local step = tonumber(eval_ast(expr[4], obj))
local from_result, err = eval_ast(expr[2], obj)
if err then return nil, err end
local to_result, err = eval_ast(expr[3], obj)
if err then return nil, err end
local step_result, err = eval_ast(expr[4], obj)
if err then return nil, err end

local from = tonumber(from_result)
local to = tonumber(to_result)
local step = tonumber(step_result)

if (from == nil) or (from < 0) or (to == nil) or (to < 0) then
local len = eval_var_length(obj)
if from == nil then
Expand Down Expand Up @@ -431,7 +473,8 @@ local function eval_ast(ast, obj)
for i = 3, #expr, 2 do
local operator = expr[i]
if operator == nil then
return nil, 'missing expression operator'
local err = Bad_request_error('missing expression operator')
return nil, err
end
local op2, err = eval_ast(expr[i + 1], obj)
if is_nil(op2) then
Expand All @@ -441,31 +484,31 @@ local function eval_ast(ast, obj)
if is_str_or_int(op1) and is_str_or_int(op2) then
op1 = tonumber(op1) + tonumber(op2)
else
return nil, "Only operations on strings and numbers are allowed."
return nil, Bad_request_error("Only operations on strings and numbers are allowed.")
end
elseif operator == '-' then
if is_str_or_int(op1) and is_str_or_int(op2) then
op1 = tonumber(op1) - tonumber(op2)
else
return nil, "Only operations on strings and numbers are allowed."
return nil, Bad_request_error("Only operations on strings and numbers are allowed.")
end
elseif operator == '*' then
if is_str_or_int(op1) and is_str_or_int(op2) then
op1 = tonumber(op1) * tonumber(op2)
else
return nil, "Only operations on strings and numbers are allowed."
return nil, Bad_request_error("Only operations on strings and numbers are allowed.")
end
elseif operator == '/' then
if is_str_or_int(op1) and is_str_or_int(op2) then
op1 = tonumber(op1) / tonumber(op2)
else
return nil, "Only operations on strings and numbers are allowed."
return nil, Bad_request_error("Only operations on strings and numbers are allowed.")
end
elseif operator == '%' then
if is_str_or_int(op1) and is_str_or_int(op2) then
op1 = tonumber(op1) % tonumber(op2)
else
return nil, "Only operations on strings and numbers are allowed."
return nil, Bad_request_error("Only operations on strings and numbers are allowed.")
end
op1 = tonumber(op1) % tonumber(op2)
elseif operator:upper() == 'AND' or operator == '&&' then
Expand Down Expand Up @@ -509,7 +552,7 @@ local function eval_ast(ast, obj)
end
op1 = op1 <= op2
else
return nil, 'unknown expression operator "' .. operator .. '"'
return nil, Bad_request_error('unknown expression operator "' .. operator .. '"')
end
end
return op1
Expand All @@ -529,8 +572,7 @@ local function eval_ast(ast, obj)
elseif ast[1] == 'filter' then
return eval_filter(ast, obj)
elseif ast[1] == 'slice' then
local result = eval_slice(ast, obj)
return result
return eval_slice(ast, obj)
end

return 0
Expand Down Expand Up @@ -562,7 +604,10 @@ local function match_path(ast, path, parent, obj)
end
elseif ast_spec[1] == 'union' or ast_spec[1] == 'slice' then
-- match union or slice expression (on parent object)
local matches = eval_ast(ast_spec, parent)
local matches, err = eval_ast(ast_spec, parent)
if err then
return nil, err
end
--- @cast matches table[]
for _, i in pairs(matches) do
match_component = tostring(i) == tostring(component)
Expand All @@ -572,7 +617,16 @@ local function match_path(ast, path, parent, obj)
end
elseif ast_spec[1] == 'filter' then
-- match filter expression
match_component = eval_ast(ast_spec, obj) and true or false
local filter_result, err = eval_ast(ast_spec, obj)
if err then
if err.rc == codes.NOT_FOUND then
match_component = false
else
return nil, err
end
else
match_component = filter_result and true or false
end
end
else
if ast_spec == '*' then
Expand All @@ -591,7 +645,16 @@ local function match_path(ast, path, parent, obj)
if path_index == #path and ast_spec ~= "array" and match_component then
local _, next_ast_spec = next(ast, ast_key)
if next_ast_spec ~= nil and next_ast_spec[1] == 'filter' then
match_component = eval_ast(next_ast_spec, obj) and true or false
local filter_result, err = eval_ast(next_ast_spec, obj)
if err then
if err.rc == codes.NOT_FOUND then
match_component = false
else
return nil, err
end
else
match_component = filter_result and true or false
end
ast_key, ast_spec = ast_iter(ast, ast_key)
end
end
Expand Down Expand Up @@ -626,7 +689,10 @@ end

local function match_tree(nodes, ast, path, parent, obj, count)
-- Try to match every node against AST
local match = match_path(ast, path, parent, obj)
local match, err = match_path(ast, path, parent, obj)
if err then
return err
end
if match == MATCH_ONE or match == MATCH_DESCENDANTS then
-- This node matches. Add path and value to result
-- (if max result count not yet reached)
Expand All @@ -649,7 +715,10 @@ local function match_tree(nodes, ast, path, parent, obj, count)
table.insert(path1, p)
end
table.insert(path1, type(key) == 'string' and key or (key - 1))
match_tree(nodes, ast, path1, obj, child, count)
local err = match_tree(nodes, ast, path1, obj, child, count)
if err then
return err
end
end
end
end
Expand All @@ -675,15 +744,15 @@ end
--
function M.parse(expr)
if expr == nil or type(expr) ~= 'string' then
return nil, "missing or invalid 'expr' argument"
return nil, Bad_request_error("missing or invalid 'expr' argument")
end

local ast = Ct(jsonpath_grammer * Cp()):match(expr)
if ast == nil or #ast ~= 2 then
return nil, 'invalid expression "' .. expr .. '"'
return nil, Bad_request_error('invalid expression "' .. expr .. '"')
end
if ast[2] ~= #expr + 1 then
return nil, 'invalid expression "' .. expr .. '" near "' .. expr:sub(ast[2]) .. '"'
return nil, Bad_request_error('invalid expression "' .. expr .. '" near "' .. expr:sub(ast[2]) .. '"')
end
return ast[1]
end
Expand All @@ -707,13 +776,16 @@ end
--
function M.nodes(obj, expr, count)
if obj == nil or type(obj) ~= 'table' then
return nil, "missing or invalid 'obj' argument"
local err = Bad_request_error("missing or invalid 'obj' argument")
return nil, err
end
if expr == nil or (type(expr) ~= 'string' and type(expr) ~= 'table') then
return nil, "missing or invalid 'expr' argument"
local err = Bad_request_error("missing or invalid 'expr' argument")
return nil, err
end
if count ~= nil and type(count) ~= 'number' then
return nil, "invalid 'count' argument"
local err = Bad_request_error("invalid 'count' argument")
return nil, err
end

local ast, err
Expand All @@ -725,7 +797,11 @@ function M.nodes(obj, expr, count)
ast = expr
end
if ast == nil then
return nil, err or 'internal error'
if not err then
local err = JsonPathError:new("internal error")
err.rc = codes.INTERNAL_ERR
end
return nil, err
end

if count ~= nil and count == 0 then
Expand All @@ -742,8 +818,10 @@ function M.nodes(obj, expr, count)
end

local matches = {}
match_tree(matches, ast, { '$' }, {}, obj, count)

local err = match_tree(matches, ast, { '$' }, {}, obj, count)
if err then
return nil, err
end
-- Sort results by path
local sorted = {}
for p, v in pairs(matches) do
Expand Down Expand Up @@ -795,7 +873,8 @@ function M.value(obj, expr, count)
return nodes[1].value
end

return nil, 'no element matching expression'
local err = Bad_request_error('no element matching expression')
return nil, err
end


Expand Down
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