Rework LuCI build system

[project/luci.git] / modules / luci-base / luasrc / http / protocol / conditionals.lua

diff --git a/modules/luci-base/luasrc/http/protocol/conditionals.lua b/modules/luci-base/luasrc/http/protocol/conditionals.lua
new file mode 100644 (file)
index 0000000..75e1f7b
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+++ b/modules/luci-base/luasrc/http/protocol/conditionals.lua
@@ -0,0 +1,153 @@
+--[[
+
+HTTP protocol implementation for LuCI - RFC2616 / 14.19, 14.24 - 14.28
+(c) 2008 Freifunk Leipzig / Jo-Philipp Wich <xm@leipzig.freifunk.net>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+$Id$
+
+]]--
+
+--- LuCI http protocol implementation - HTTP/1.1 bits.
+-- This class provides basic ETag handling and implements most of the
+-- conditional HTTP/1.1 headers specified in RFC2616 Sct. 14.24 - 14.28 .
+module("luci.http.protocol.conditionals", package.seeall)
+
+local date = require("luci.http.protocol.date")
+
+
+--- Implement 14.19 / ETag.
+-- @param stat A file.stat structure
+-- @return             String containing the generated tag suitable for ETag headers
+function mk_etag( stat )
+       if stat ~= nil then
+               return string.format( '"%x-%x-%x"', stat.ino, stat.size, stat.mtime )
+       end
+end
+
+--- 14.24 / If-Match
+-- Test whether the given message object contains an "If-Match" header and
+-- compare it against the given stat object.
+-- @param req  HTTP request message object
+-- @param stat A file.stat object
+-- @return             Boolean indicating whether the precondition is ok
+-- @return             Alternative status code if the precondition failed
+function if_match( req, stat )
+       local h    = req.headers
+       local etag = mk_etag( stat )
+
+       -- Check for matching resource
+       if type(h['If-Match']) == "string" then
+               for ent in h['If-Match']:gmatch("([^, ]+)") do
+                       if ( ent == '*' or ent == etag ) and stat ~= nil then
+                               return true
+                       end
+               end
+
+               return false, 412
+       end
+
+       return true
+end
+
+--- 14.25 / If-Modified-Since
+-- Test whether the given message object contains an "If-Modified-Since" header
+-- and compare it against the given stat object.
+-- @param req  HTTP request message object
+-- @param stat A file.stat object
+-- @return             Boolean indicating whether the precondition is ok
+-- @return             Alternative status code if the precondition failed
+-- @return             Table containing extra HTTP headers if the precondition failed
+function if_modified_since( req, stat )
+       local h = req.headers
+
+       -- Compare mtimes
+       if type(h['If-Modified-Since']) == "string" then
+               local since = date.to_unix( h['If-Modified-Since'] )
+
+               if stat == nil or since < stat.mtime then
+                       return true
+               end
+
+               return false, 304, {
+                       ["ETag"]          = mk_etag( stat );
+                       ["Date"]          = date.to_http( os.time() );
+                       ["Last-Modified"] = date.to_http( stat.mtime )
+               }
+       end
+
+       return true
+end
+
+--- 14.26 / If-None-Match
+-- Test whether the given message object contains an "If-None-Match" header and
+-- compare it against the given stat object.
+-- @param req  HTTP request message object
+-- @param stat A file.stat object
+-- @return             Boolean indicating whether the precondition is ok
+-- @return             Alternative status code if the precondition failed
+-- @return             Table containing extra HTTP headers if the precondition failed
+function if_none_match( req, stat )
+       local h      = req.headers
+       local etag   = mk_etag( stat )
+       local method = req.env and req.env.REQUEST_METHOD or "GET"
+
+       -- Check for matching resource
+       if type(h['If-None-Match']) == "string" then
+               for ent in h['If-None-Match']:gmatch("([^, ]+)") do
+                       if ( ent == '*' or ent == etag ) and stat ~= nil then
+                               if method == "GET" or method == "HEAD" then
+                                       return false, 304, {
+                                               ["ETag"]          = etag;
+                                               ["Date"]          = date.to_http( os.time() );
+                                               ["Last-Modified"] = date.to_http( stat.mtime )
+                                       }
+                               else
+                                       return false, 412
+                               end
+                       end
+               end
+       end
+
+       return true
+end
+
+--- 14.27 / If-Range
+-- The If-Range header is currently not implemented due to the lack of general
+-- byte range stuff in luci.http.protocol . This function will always return
+-- false, 412 to indicate a failed precondition.
+-- @param req  HTTP request message object
+-- @param stat A file.stat object
+-- @return             Boolean indicating whether the precondition is ok
+-- @return             Alternative status code if the precondition failed
+function if_range( req, stat )
+       -- Sorry, no subranges (yet)
+       return false, 412
+end
+
+--- 14.28 / If-Unmodified-Since
+-- Test whether the given message object contains an "If-Unmodified-Since"
+-- header and compare it against the given stat object.
+-- @param req  HTTP request message object
+-- @param stat A file.stat object
+-- @return             Boolean indicating whether the precondition is ok
+-- @return             Alternative status code if the precondition failed
+function if_unmodified_since( req, stat )
+       local h = req.headers
+
+       -- Compare mtimes
+       if type(h['If-Unmodified-Since']) == "string" then
+               local since = date.to_unix( h['If-Unmodified-Since'] )
+
+               if stat ~= nil and since <= stat.mtime then
+                       return false, 412
+               end
+       end
+
+       return true
+end