* Re: Is it possible to make xml.load a bit more 'verbose' when it encounters errors?
2020-05-13 21:00 Is it possible to make xml.load a bit more 'verbose' when it encounters errors? Gerben Wierda
@ 2020-05-14 6:53 ` Hans van der Meer
0 siblings, 0 replies; 2+ messages in thread
From: Hans van der Meer @ 2020-05-14 6:53 UTC (permalink / raw)
To: NTG ConTeXt
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Gerben,
Maybe this is of some use. The Lua code in the file checks the xml and returns info when something is wrong.
I am using it for example in my takenotes module as:
<notes file="events/na-30416155-5-48v.xml" checkxml="yes"/>
And this is a sketch of how it is embedded in that module:
% Prerun an xml check.
\doifinset{\xmlatt{#1}{checkxml}}{yes,on,true}%
{\xmlcommand{#1}{.}{xmlcommon:checkxml}}
% Execute this code if no error was found.
etc.
dr. Hans van der Meer
> On 13 May 2020, at 23:00, Gerben Wierda <gerben.wierda@rna.nl> wrote:
>
> I am loading an xml.file. I sometimes make mistakes editing that file and then xml.load creates a string that contains
>
> <error>invalid xml file - parsed text</error>
>
> At that point I check my file and sometimes (like now) I cannot find the error.
>
> Is there a way to make xml.load somewhat more verbose about where it encounters the error?
>
> G
> ___________________________________________________________________________________
> If your question is of interest to others as well, please add an entry to the Wiki!
>
> maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
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> ___________________________________________________________________________________
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\startluacode
-- Define our namespace as hvdm
hvdm = hvdm or {}
-- Function checks the correctness of an XML tree.
hvdm.checkXMLtree = function (xml, linesep)
local xml = xml and xml or ""
local linesep = linesep and linesep or "\n"
local badspace = {}
-- Empty files do not need processing.
if xml == "" then
return ""
end
-- Step one is remove leading characters before first node.
local leadingnode = string.find(xml, "<", 1) or 1
if leadingnode ~= 1 then
xml = string.sub(xml, leadingnode, -1)
end
-- Strip all comments <!-- --> but node pairs inside make it complicated.
local c1, c2 = string.find(xml, "<!--", 1, true)
while c1 do
-- Search for closing of comment.
local c3, c4 = string.find(xml, "-->", c2 + 1, true)
if c3 then
-- Remove comment.
xml = string.sub(xml, 1, c1 - 1) .. string.sub(xml, c4 + 1, -1)
-- Search for next comment.
c1, c2 = string.find(xml, "<!--", 1, true)
else
badspace[#badspace + 1] = " >>> Open comment <!-- Fix this first"
c1 = nil
end
end
-- Strip <?xml version ... ?> and DOCTYPE nodes.
if string.find(xml, "<%?xml.*%?>") then
xml = string.gsub(xml, "<%?xml.*%?>", "")
else
badspace[#badspace + 1] =
" >>> missing or incorrect <?xml ?>"
end
xml = string.gsub(xml, "<.*DOCTYPE[^>]*>", "")
-- Strip everything between > and <.
xml = string.gsub(xml, ">[^<]*<", "><")
-- Spot all cases of '< node', etc. which have bad spaces.
for node in string.gmatch(xml, "</?%s+[^>]*") do
badspace[#badspace + 1] = " >>> erroneous whitespace in " .. node .. ">"
end
for node in string.gmatch(xml, "<[^>]*%s+/?>") do
badspace[#badspace + 1] = " >>> erroneous whitespace in " .. node
end
-- Remove the bad spaces.
if #badspace > 0 then
xml = string.gsub(xml, "<%s+", "<")
xml = string.gsub(xml, "</%s+", "</")
xml = string.gsub(xml, "%s+>", ">")
xml = string.gsub(xml, "%s+/>", "/>")
end
-- Strip all <xx/> nodes, must be done before stripping attributes.
xml = string.gsub(xml, "<[^>]*/>", "")
-- Strip attributes.
local fa1, fa2, fa3 = 0, 0, 0
while fa3 do
local fa1,fa2 = string.find(xml, "<%S+%s+", 1)
if fa1 then
_, fa3 = string.find(xml, ">", fa2, true)
if fa3 then
xml = string.sub(xml, 1, fa2-1) .. string.sub(xml, fa3, -1)
end
end
end
-- Strip all remaining whitespace.
xml = string.gsub(xml, "%s", "")
local function nextnode(str, last)
local newlast
if last ~= nil then
last, newlast = string.find(str, "</?[^>]*>", last + 1)
end
return newlast
end
-- At this point we have the bare <node> tree.
-- Strip all adjacent pairs <node></node> recursively.
-- The xml is correct when nothing is left.
local function nextnode(str, last)
local newlast
if last ~= nil then
last, newlast = string.find(str, "</?[^>]*>", last)
end
return newlast
end
-- Remove adjacent pairs <node></node>.
local i1, i2, j1, j2
i1, i2 = 1, nextnode(xml, 1)
if i2 ~= nil then
j1, j2 = i2 + 1, nextnode(xml, i2 + 1)
end
-- Loop until nothing left for a correct xml tree.
while j1 ~= nil do
-- Check if we have node> and /node>.
if string.sub(xml, i1 + 1, i2) == string.sub(xml, j1 + 2, j2) then
-- Here is a matching pair, remove all of them.
local removal = string.sub(xml, i1, i2) .. string.sub(xml, j1, j2)
xml = string.gsub(xml, removal, "")
-- Start over at the beginning.
i1, i2 = 1, nextnode(xml, 1)
if i2 ~= nil then
j1, j2 = i2 + 1, nextnode(xml, i2 + 1)
else
j1 = nil
end
else
-- Shift to next pair of nodes.
if j2 ~= nil then
i1, i2, j1, j2 = j1, j2, j2 + 1, nextnode(xml, j2 + 1)
else
j1 = nil
end
end
end
-- If something is leftover then the xml tree is not correct.
if #xml > 0 then
badspace[#badspace + 1] = " >>> " .. xml
end
-- Note that xml might end up as a single newline chracter.
if #badspace > 0 then
return "XML tree is not correct" .. linesep ..
table.concat(badspace, linesep) .. linesep
end
return ""
end -- end of checkXMLtree
-- Function checks the correctness of an XML tree in given file.
hvdm.checkXMLfile = function (filename)
-- Filename must have suffix .xml.
if hvdm.filesuffix(filename) ~= "xml" then
return "Filename of " .. filename .. " missing suffix .xml"
end
-- Open the file for reading and check.
local inputfile = io.open(filename, "r")
if inputfile then
-- Read contents into a string then close the file.
local xml = inputfile:read("a")
io.close(inputfile)
-- Execute the test.
local outcome = hvdm.checkXMLtree(xml, "\\crlf ")
return outcome == "" and ""
or "XML check of file " .. filename .. " : " .. outcome
-- Note that an empty tree has no errors.
end
end -- end of checkXMLfile
-- Function checks the correctness of an XML tree in given directory.
hvdm.checkXMLfiles = function (directoryname)
-- Make temp file for directory listing and open for writing.
local tempname = "/tmp/hvdm_list_tmp.txt"
local temp = io.open(tempname,"w+")
-- Write diretory listingof .xml files to the temp file.
os.execute("ls -1 " .. directoryname .. "/*" .. ".xml" .. " >" .. tempname)
-- Reset temp file for reading of the directory entries.
temp:seek("set")
-- Retrieve line by line the filenames and put into a table.
local filenames = {}
local filename = temp:read("l")
while filename ~= nil do
filenames[#filenames + 1] = filename
filename = temp:read("l")
end
-- Close the tempfile and remove it and its name.
temp:close()
os.remove(tempname)
-- Initialize combined result.
local outcome = ""
-- Check one by one the xml files from the table.
for _,name in ipairs(filenames) do
outcome = outcome .. hvdm.checkXMLfile(name)
end
-- Return combined outcome.
return outcome
end -- end of checkXMLfiles
\stopluacode
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___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!
maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage : http://www.pragma-ade.nl / http://context.aanhet.net
archive : https://bitbucket.org/phg/context-mirror/commits/
wiki : http://contextgarden.net
___________________________________________________________________________________
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