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Fix example for form handling and file upload in Lua (example for #70)

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This commit is contained in:
bel
2015-03-18 00:46:30 +01:00
parent b91be3b821
commit 50c2f4f11f
3 changed files with 75 additions and 115 deletions
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74
examples/handle_form.lua Normal file
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@@ -0,0 +1,74 @@
mg.write("HTTP/1.0 200 OK\r\n")
mg.write("Connection: close\r\n")
mg.write("Content-Type: text/plain; charset=utf-8\r\n")
mg.write("Cache-Control: max-age=0, must-revalidate\r\n")
mg.write("\r\n")
-- Read the entire body data (POST content) into "bdata" variable.
-- Use a string builder pattern for performance reasons
stringtab = {}
bdata = ""
repeat
local add_data = mg.read()
if add_data then
stringtab[#stringtab+1] = add_data
end
until (add_data == nil);
bdata = table.concat(stringtab)
stringtab = nil
-- Get the boundary string.
bs = "--" .. ((mg.request_info.content_type):upper():match("BOUNDARY=(.*)"));
-- The POST data has to start with the boundary string.
-- Check this and remove the starting boundary.
if bdata:sub(1, #bs) ~= bs then
error "invalid format of POST data"
end
bdata = bdata:sub(#bs)
-- The boundary now starts with CR LF.
bs = "\r\n" .. bs
-- Now loop through all the parts
while #bdata>4 do
-- Find the header of new part.
part_header_end = bdata:find("\r\n\r\n", 1, true)
-- Parse the header.
local form_field_name, file_name
h = bdata:sub(1, part_header_end+2)
for key,val in h:gmatch("([^%:\r\n]*)%s*%:%s*([^\r\n]*)\r\n") do
if key:upper() == "CONTENT-DISPOSITION" then
form_field_name = val:match('name=%"([^%"]*)%"')
file_name = val:match('filename=%"([^%"]*)%"')
end
end
-- Remove the header from "bdata".
bdata = bdata:sub(part_header_end+4)
-- Find the end of the body by locating the boundary string.
local part_body_end = bdata:find(bs, 1, true)
-- Isolate the content, and drop it from "bdata".
local form_field_value = bdata:sub(1,part_body_end-1)
bdata = bdata:sub(part_body_end+#bs)
-- Now the data (file content or field value) is isolated: We know form_field_name and form_field_value.
-- Here the script should do something useful with the data. This example just sends it back to the client.
if form_field_name then
mg.write("Field name: " .. form_field_name .. "\r\n")
end
if file_name then
mg.write("File name: " .. file_name .. "\r\n")
end
local len = #form_field_value
if len<50 then
mg.write("Field value: " .. form_field_value .. "\r\n")
else
mg.write("Field value: " .. form_field_value:sub(1, 40) .. " .. (" .. len .. " bytes)\r\n")
end
mg.write("\r\n")
end

2
test/form.html
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@@ -8,7 +8,7 @@
</head> </head>
<body> <body>
<form action="/handle_form_data.lua" method="POST" enctype="multipart/form-data"> <form action="/handle_form.lua" method="POST" enctype="multipart/form-data">
See <a href="http://www.w3schools.com/html/html_form_input_types.asp">HTML form tutorial</a>.<br /> See <a href="http://www.w3schools.com/html/html_form_input_types.asp">HTML form tutorial</a>.<br />
<fieldset> <fieldset>

114
test/handle_form_data.lua
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@@ -1,114 +0,0 @@
function add_data(data)
local additional_data = mg.read()
if additional_data then
return data .. additional_data, true
end
return data, false
end
function parse_multipart_form(got_field)
local data, ok = add_data("")
if not ok then
return "Can not read data"
end
--[[
local b = mg.request_info.content_type:upper():find("BOUNDARY=");
if b then
b = mg.request_info.content_type:sub(b+9)
end
if not b or #b<16 or #b>1024 then
return false, "Boundary string not reasonable"
end
]]
local b = "--" .. mg.request_info.content_type:upper():match("BOUNDARY=(.*)");
--b = "--" .. b
if data:sub(1, #b) ~= b then
return false, "Multipart body does not start properly"
end
data = data:sub(#b)
b = "\r\n" .. b
-- while there are unread parts
while #data>0 and data~="--\r\n" do
local name = nil
local value = nil
local file_name = nil
local file_type = nil
-- isolate the header of the new part
local part_header_end
repeat
part_header_end = data:find("\r\n\r\n", 1, true)
if not part_header_end then
data, ok = add_data(data)
if not ok then
return false, "protocol violation: header does not end properly"
end
end
until part_header_end
-- parse the header of the new part
local header = {}
for k,v in data:sub(1,part_header_end+2):gmatch("([^%:\r\n]*)%s*%:%s*([^\r\n]*)\r\n") do
header[k] = v
local kupper = k:upper()
if (kupper=="CONTENT-DISPOSITION") then
name = v:match('name=%"([^%"]*)%"')
file_name = v:match('filename=%"([^%"]*)%"')
elseif (kupper=="CONTENT-TYPE") then
file_type = v
end
end
-- isolate the body of the new part
local part_body_end
data = data:sub(part_header_end+4)
repeat
part_body_end = data:find(b, 1, true)
if not part_body_end then
data, ok = add_data(data)
if not ok then
return false, "protocol violation: body does not end properly"
end
end
until part_body_end
local value = data:sub(1,part_body_end-1)
data = data:sub(part_body_end+#b)
data = add_data(data)
-- send the result to the caller
got_field(name, value, file_name, file_type)
end
return true, ""
end
mg.write("HTTP/1.0 200 OK\r\n")
mg.write("Connection: close\r\n")
mg.write("Content-Type: text/plain; charset=utf-8\r\n")
mg.write("Cache-Control: max-age=0, must-revalidate\r\n")
mg.write("\r\n")
mg.write("Parse request:\r\n")
function fetch(k, v, fn, ft)
mg.write(k .. " = " .. v .. "\r\n")
end
ok, errtxt = parse_multipart_form(fetch)
if not ok then
mg.write("Error: " .. errtxt .. "\r\n")
else
mg.write("Parsing OK\r\n")
end