Set cookie without escaping and change escaping algorithm

Method resp:setcookie() implicitly escapes cookie values. Commit adds
ability to set cookie without any escaping with option 'raw':

resp:setcookie('name', 'value', {
    raw = true
})`

Also added escaping for cookie path, and changed escaping algorithm
according to RFC 6265 "HTTP State Management Mechanism", see [1].

This change was added as a part of http v2 support in commit 'Added
ability to set and get cookie without escaping'
(42e3002) and later reverted in scope
of ticket with discard v2.

1. https://tools.ietf.org/html/rfc6265

Follows up #126
Part of #134

README.md

@@ -240,8 +240,9 @@ end
 * `resp.status` - HTTP response code.
 * `resp.headers` - a Lua table with normalized headers.
 * `resp.body` - response body (string|table|wrapped\_iterator).
-* `resp:setcookie({ name = 'name', value = 'value', path = '/', expires = '+1y', domain = 'example.com'))` -
-  adds `Set-Cookie` headers to `resp.headers`.
+* `resp:setcookie({ name = 'name', value = 'value', path = '/', expires = '+1y', domain = 'example.com'}, {raw = true})` -
+  adds `Set-Cookie` headers to `resp.headers`, if `raw` option was set then cookie will not be escaped,
+  otherwise cookie's value and path will be escaped
 
 ### Examples
 

http/server.lua

@@ -23,18 +23,57 @@ local function sprintf(fmt, ...)
     return string.format(fmt, ...)
 end
 
+local function valid_cookie_value_byte(byte)
+    -- https://tools.ietf.org/html/rfc6265#section-4.1.1
+    -- US-ASCII characters excluding CTLs, whitespace DQUOTE, comma, semicolon,
+    -- and backslash.
+    return 32 < byte and byte < 127 and byte ~= string.byte('"') and
+            byte ~= string.byte(",") and byte ~= string.byte(";") and byte ~= string.byte("\\")
+end
+
+local function valid_cookie_path_byte(byte)
+    -- https://tools.ietf.org/html/rfc6265#section-4.1.1
+    -- <any CHAR except CTLs or ";">
+    return 32 <= byte and byte < 127 and byte ~= string.byte(";")
+end
+
+local function escape_char(char)
+    return string.format('%%%02X', string.byte(char))
+end
+
+local function unescape_char(char)
+    return string.char(tonumber(char, 16))
+end
+
+local function escape_string(str, byte_filter)
+    local result = {}
+    for i = 1, str:len() do
+        local char = str:sub(i,i)
+        if byte_filter(string.byte(char)) then
+            result[i] = char
+        else
+            result[i] = escape_char(char)
+        end
+    end
+    return table.concat(result)
+end
+
+local function escape_value(cookie_value)
+    return escape_string(cookie_value, valid_cookie_value_byte)
+end
+
+local function escape_path(cookie_path)
+    return escape_string(cookie_path, valid_cookie_path_byte)
+end
+
 local function uri_escape(str)
     local res = {}
     if type(str) == 'table' then
         for _, v in pairs(str) do
             table.insert(res, uri_escape(v))
         end
     else
-        res = string.gsub(str, '[^a-zA-Z0-9_]',
-            function(c)
-                return string.format('%%%02X', string.byte(c))
-            end
-        )
+        res = string.gsub(str, '[^a-zA-Z0-9_]', escape_char)
     end
     return res
 end
@@ -50,11 +89,7 @@ local function uri_unescape(str, unescape_plus_sign)
             str = string.gsub(str, '+', ' ')
         end
 
-        res = string.gsub(str, '%%([0-9a-fA-F][0-9a-fA-F])',
-            function(c)
-                return string.char(tonumber(c, 16))
-            end
-        )
+        res = string.gsub(str, '%%([0-9a-fA-F][0-9a-fA-F])', unescape_char)
     end
     return res
 end
@@ -265,7 +300,8 @@ local function expires_str(str)
     return os.date(fmt, gmtnow + diff)
 end
 
-local function setcookie(resp, cookie)
+local function setcookie(resp, cookie, options)
+    options = options or {}
     local name = cookie.name
     local value = cookie.value
 
@@ -276,9 +312,16 @@ local function setcookie(resp, cookie)
         error('cookie.value is undefined')
     end
 
-    local str = sprintf('%s=%s', name, uri_escape(value))
+    if not options.raw then
+        value = escape_value(value)
+    end
+    local str = sprintf('%s=%s', name, value)
     if cookie.path ~= nil then
-        str = sprintf('%s;path=%s', str, cookie.path)
+        local cookie_path = cookie.path
+        if not options.raw then
+            cookie_path = escape_path(cookie.path)
+        end
+        str = sprintf('%s;path=%s', str, cookie_path)
     end
     if cookie.domain ~= nil then
         str = sprintf('%s;domain=%s', str, cookie.domain)
@@ -1280,7 +1323,12 @@ local exports = {
         }
 
         return self
-    end
+    end,
+
+    internal = {
+        response_mt = response_mt,
+        request_mt = request_mt,
+    }
 }
 
 return exports

test/integration/http_server_requests_test.lua

@@ -252,6 +252,54 @@ g.test_get_escaped_cookie = function()
     t.assert_equals(r.body, 'name=' .. str_non_escaped, 'body with escaped cookie')
 end
 
+-- Set escaped cookie (Günter -> G%C3%BCnter).
+g.test_set_escaped_cookie = function(g)
+    local str_escaped = 'G%C3%BCnter'
+    local str_non_escaped = 'Günter'
+
+    local httpd = g.httpd
+    httpd:route({
+        path = '/cookie'
+    }, function(req)
+        local resp = req:render({
+            text = ''
+        })
+        resp:setcookie({
+            name = 'name',
+            value = str_non_escaped
+        })
+        return resp
+    end)
+
+    local r = http_client.get(helpers.base_uri .. '/cookie')
+    t.assert_equals(r.status, 200, 'response status')
+    t.assert_equals(r.headers['set-cookie'], 'name=' .. str_escaped, 'header with escaped cookie')
+end
+
+-- Set raw cookie (Günter -> Günter).
+g.test_set_raw_cookie = function(g)
+    local cookie = 'Günter'
+    local httpd = g.httpd
+    httpd:route({
+        path = '/cookie'
+    }, function(req)
+        local resp = req:render({
+            text = ''
+        })
+        resp:setcookie({
+            name = 'name',
+            value = cookie
+        }, {
+            raw = true
+        })
+        return resp
+    end)
+
+    local r = http_client.get(helpers.base_uri .. '/cookie')
+    t.assert_equals(r.status, 200, 'response status')
+    t.assert_equals(r.headers['set-cookie'], 'name=' .. cookie, 'header with raw cookie')
+end
+
 -- Request object methods.
 g.test_request_object_methods = function()
     local httpd = g.httpd

test/unit/http_setcookie_test.lua

@@ -0,0 +1,205 @@
+local t = require('luatest')
+
+local http_server = require('http.server')
+
+local g = t.group()
+
+local function get_object()
+    return setmetatable({}, http_server.internal.response_mt)
+end
+
+g.test_values_escaping = function()
+    local test_table = {
+        whitespace = {
+            value = "f f",
+            result = 'f%20f',
+        },
+        dquote = {
+            value = 'f"f',
+            result = 'f%22f',
+        },
+        comma = {
+            value = "f,f",
+            result = "f%2Cf",
+        },
+        semicolon = {
+            value = "f;f",
+            result = "f%3Bf",
+        },
+        backslash = {
+            value = "f\\f",
+            result = "f%5Cf",
+        },
+        unicode = {
+            value = "fюf",
+            result = "f%D1%8Ef"
+        },
+        unprintable_ascii = {
+            value = string.char(15),
+            result = "%0F"
+        }
+    }
+
+    for byte = 33, 126 do
+        if byte ~= string.byte('"') and
+           byte ~= string.byte(",") and
+           byte ~= string.byte(";") and
+           byte ~= string.byte("\\") then
+                test_table[byte] = {
+                    value = "f" .. string.char(byte) .. "f",
+                    result = "f" .. string.char(byte) .. "f",
+                }
+        end
+    end
+
+    for case_name, case in pairs(test_table) do
+        local resp = get_object()
+        resp:setcookie({
+            name='name',
+            value = case.value
+        })
+        t.assert_equals(resp.headers['set-cookie'], {
+            "name=" .. case.result
+        }, case_name)
+    end
+end
+
+g.test_values_raw = function()
+    local test_table = {}
+    for byte = 0, 127 do
+        test_table[byte] = {
+            value = "f" .. string.char(byte) .. "f",
+            result = "f" .. string.char(byte) .. "f",
+        }
+    end
+
+    test_table.unicode = {
+        value = "fюf",
+        result = "fюf"
+    }
+
+    for case_name, case in pairs(test_table) do
+        local resp = get_object()
+        resp:setcookie({
+                name='name',
+                value = case.value
+            }, {
+                raw = true
+        })
+        t.assert_equals(resp.headers['set-cookie'], {
+            "name=" .. case.result
+        }, case_name)
+    end
+end
+
+g.test_path_escaping = function()
+    local test_table = {
+        semicolon = {
+            path = "f;f",
+            result = "f%3Bf",
+        },
+        unicode = {
+            path = "fюf",
+            result = "f%D1%8Ef"
+        },
+        unprintable_ascii = {
+            path = string.char(15),
+            result = "%0F"
+        }
+    }
+
+    for byte = 32, 126 do
+        if byte ~= string.byte(";") then
+            test_table[byte] = {
+                path = "f" .. string.char(byte) .. "f",
+                result = "f" .. string.char(byte) .. "f",
+            }
+        end
+    end
+
+    for case_name, case in pairs(test_table) do
+        local resp = get_object()
+        resp:setcookie({
+            name='name',
+            value = 'value',
+            path = case.path
+        })
+        t.assert_equals(resp.headers['set-cookie'], {
+            "name=value;" .. 'path=' .. case.result
+        }, case_name)
+    end
+end
+
+g.test_path_raw = function()
+    local test_table = {}
+    for byte = 0, 127 do
+        test_table[byte] = {
+            path = "f" .. string.char(byte) .. "f",
+            result = "f" .. string.char(byte) .. "f",
+        }
+    end
+
+    test_table.unicode = {
+        path = "fюf",
+        result = "fюf"
+    }
+
+    for case_name, case in pairs(test_table) do
+        local resp = get_object()
+        resp:setcookie({
+                name='name',
+                value = 'value',
+                path = case.path
+            }, {
+                raw = true
+        })
+        t.assert_equals(resp.headers['set-cookie'], {
+            "name=value;" .. 'path=' .. case.result
+        }, case_name)
+    end
+end
+
+g.test_set_header = function()
+    local test_table = {
+        name_value = {
+            cookie = {
+                name = 'name',
+                value = 'value'
+            },
+            result = {"name=value"},
+        },
+        name_value_path = {
+            cookie = {
+                name = 'name',
+                value = 'value',
+                path = 'path'
+            },
+            result = {"name=value;path=path"},
+        },
+        name_value_path_domain = {
+            cookie = {
+                name = 'name',
+                value = 'value',
+                path = 'path',
+                domain = 'domain',
+            },
+            result = {"name=value;path=path;domain=domain"},
+        },
+        name_value_path_domain_expires = {
+            cookie = {
+                name = 'name',
+                value = 'value',
+                path = 'path',
+                domain = 'domain',
+                expires = 'expires'
+            },
+            result = {"name=value;path=path;domain=domain;expires=expires"},
+        },
+    }
+
+    for case_name, case in pairs(test_table) do
+        local resp = get_object()
+        resp:setcookie(case.cookie)
+        t.assert_equals(resp.headers["set-cookie"], case.result, case_name)
+    end
+end