biblatex-ext (report from Moritz, 26 Nov 2018 09:47:10)

git-svn-id: svn://tug.org/texlive/trunk@49255 c570f23f-e606-0410-a88d-b1316a301751

1 files changed, 252 insertions, 0 deletions

diff --git a/Master/texmf-dist/tex/latex/biblatex-ext/blxextdoiapi.lua b/Master/texmf-dist/tex/latex/biblatex-ext/blxextdoiapi.lua
new file mode 100644
index 00000000000..a784fe047b1
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/biblatex-ext/blxextdoiapi.lua
@@ -0,0 +1,252 @@
+blxextdoiapi = blxextdoiapi or {}
+
+local blxextdoiapi_module = {
+  name          = "blxextdoiapi",
+  version       = "v0.6",
+  date          = "2018/11/23",
+  description   = "Obtain open access information from DOI via unpaywall.org",
+  author        = "Moritz Wemheuer",
+  license       = "LPPL v1.3c",
+  url           = "https://github.com/moewew/biblatex-ext/",
+}
+-- inspired by Eric Marsden's answer to https://tex.stackexchange.com/q/459449/
+
+local err, warn, info, log = luatexbase.provides_module(blxextdoiapi_module)
+
+local error   = err  or
+  (function (s) luatexbase.module_error(blxextdoiapi_module.name, s) end)
+local warning = warn or
+  (function (s) luatexbase.module_warning(blxextdoiapi_module.name, s) end)
+local info    = info or
+  (function (s) luatexbase.module_info(blxextdoiapi_module.name, s) end)
+local log     = log  or
+  (function (s) luatexbase.module_info(blxextdoiapi_module.name, s) end)
+
+
+local http        = require("socket.http")
+local json        = utilities.json
+local os_time     = os.time
+local os_date     = os.date
+local os_difftime = os.difftime
+local format      = string.format
+local gsub        = string.gsub
+local byte        = string.byte
+local texwrite    = tex.write
+
+local catpackage
+if luatexbase.catcodetables then
+  catpackage = luatexbase.catcodetables["latex-package"]          -- luatexbase
+else
+  catpackage = luatexbase.registernumber("catcodetable@atletter") -- ltluatex
+end
+
+local function texsprint(s)
+  tex.sprint(catpackage, s)
+end
+
+-- global database of DOIs
+-- is going to be loaded from \jobname.oai beforehand
+-- if the file exists
+oadb = oadb or {}
+
+-- parse YYYY-MM-DD date as string (UTC time!)
+-- os.time is usually local time, hence the utc_offset to get UTC
+-- see also https://stackoverflow.com/q/4105012
+local function ymdstr_to_date(date_str)
+  local date_pattern = "(%d+)-(%d+)-(%d+)"
+  local utc_offset = os_difftime(os_time(), os_time(os_date("!*t")))
+  local year, month, day = date_str:match(date_pattern)
+
+  if year and month and day then
+    return os_time({year = year, month = month, day = day, sec=utc_offset})
+  end
+
+  return nil
+end
+
+local TODAY_STR = os_date("!%Y-%m-%d")
+local TODAY = ymdstr_to_date(TODAY_STR)
+
+local SECONDS_PER_DAY = 86400
+
+-- info in oadb expires after blxextdoiapi.cache_expire days
+-- if the info is older than that is_recent_info will return false
+-- can be set with \SetDOIAPICacheExpiration
+local cache_expire = 7
+
+-- this includes a test if there is info at all
+local function is_recent_info(doi, days, api)
+  if oadb[doi] and oadb[doi]["cache_date_" .. api] then
+    return os_difftime(TODAY, ymdstr_to_date(oadb[doi]["cache_date_" .. api]))
+           < days * SECONDS_PER_DAY
+  end
+
+  return false
+end
+
+local function chr_to_perchex (chr)
+  return format("%%%02X", byte(chr))
+end
+
+local function url_encode(url)
+  if url then
+    return gsub(url, "([%W])", chr_to_perchex)
+  end
+
+  return nil
+end
+
+local function query_json_api(url)
+  body, code, headers = http.request(url)
+  if body then
+    -- JSON escapes don't quite work for Lua
+    -- https://tools.ietf.org/html/rfc8259, §7
+    -- http://lua-users.org/lists/lua-l/2017-04/msg00100.html
+    -- query DOI 10.1371/journal.pbio.2005099 from Unpaywall
+    -- to see what goes wrong
+    body = body:gsub("\\u(%x%x%x%x)","\\u{%1}")
+    return json.tolua(body), code
+  end
+
+  return nil, code
+end
+
+local function get_doi_info(doi)
+  local url = "https://doi.org/api/handles/" .. url_encode(doi)
+  local doi_info, code  = query_json_api(url)
+
+  if doi_info then
+    oadb[doi] = oadb[doi] or {}
+    oadb[doi]["cache_date_doi"] = TODAY_STR
+    oadb[doi]["is_valid"] = (doi_info["responseCode"] == 1)
+    info("Successfully queried doi.org for info on\n" .. doi)
+    return oadb[doi]["is_valid"]
+  end
+
+  warning("Failed to obtain DOI info\nfrom doi.org for\n"
+          .. doi .. "\nerror code " .. code)
+  return false
+end
+
+local function is_valid_doi(doi)
+  if is_recent_info(doi, blxextdoiapi.cache_expire, "doi") then
+    return oadb[doi]["is_valid"]
+  end
+
+  return get_doi_info(doi)
+end
+
+-- email is required, error out if not given
+-- Unfortunately, this gives a weird Lua dump as well and one has to scroll
+-- up to see the error, but it felt like cheating shoehorning in
+-- a usual TeX error instead of the generic LuaTeX error provided by ltluatex.
+-- Only makes sense if the DOI is valid.
+local function get_unpaywall_info(doi)
+  if not is_valid_doi(doi) then
+    return nil
+  elseif not blxextdoiapi.mail or blxextdoiapi.mail == "" then
+    error("No mail address supplied.\n" ..
+          "You must give a valid email address\n" ..
+          "to be able to use the Unpaywall API\n")
+    return nil
+  end
+
+  local url = "https://api.unpaywall.org/v2/" .. doi
+              .. "?email=" .. blxextdoiapi.mail
+  local upw_info, code = query_json_api(url)
+
+  if code == 200 and upw_info then
+    oadb[doi] = oadb[doi] or {}
+    oadb[doi]["cache_date_upw"] = TODAY_STR
+    -- Don't read "is_oa", we go to the URL directly.
+    if upw_info["best_oa_location"] then
+      oadb[doi]["oa_url"] = upw_info["best_oa_location"]["url_for_landing_page"]
+                            or upw_info["best_oa_location"]["url"]
+                            or upw_info["best_oa_location"]["url_for_pdf"]
+      -- As it turns out url_for_landing_page might be null
+      -- even though there is a url and a url_for_pdf.
+      -- http://unpaywall.org/data-format does not explicitly list
+      -- url_for_landing_page as String|Null like other null-able objects.
+      -- But request 10.1007/s00163-016-0235-2 to see this issue
+      -- (at least updated: "2018-07-28T00:37:18.524676").
+      -- I don't understand why Unpaywall returns two objects in the first place
+      -- they are clearly the same. Yet the one identified as 'best' has a
+      -- longer, weird URL and no landing page. It was probably chosen because
+      -- it is marked as having been updated more recently.
+    else
+      oadb[doi]["oa_url"] = nil
+    end
+    info("Successfully queried unpaywall.org\n"
+         .. "for info on\n" .. doi)
+    return oadb[doi]["oa_url"]
+  end
+
+  warning("Failed to obtain open access info\n"
+          .. "from unpaywall.org for DOI\n" .. doi .. "\n"
+          .. "error code: " .. code)
+  return nil
+end
+
+
+local function get_openaccess_url(doi)
+  if is_recent_info(doi, blxextdoiapi.cache_expire, "upw") then
+    return oadb[doi]["oa_url"]
+  end
+
+  return get_unpaywall_info(doi)
+end
+
+-- returns false if there is no open access URL since the RHS ~= nil
+local function openaccess_url_is_doi(doi)
+  return get_openaccess_url(doi) == "https://doi.org/" .. doi
+end
+
+local function is_openaccess(doi)
+  return get_openaccess_url(doi) ~= nil
+end
+
+-- For TeX. I'd have liked this better in the .sty, but the whole \ escape
+-- malarkey made that a pain, so the function is here now.
+local function assign_openaccess_url_to(macro, doi)
+  local url = get_openaccess_url(doi)
+  if url then
+    texsprint("\\def"..macro.."{")
+    texwrite(url)
+    texsprint("}")
+  end
+end
+
+-- make conditionals usable as \<...>{<true>}{<false>} directly
+local function texify_conditional(cond)
+  if cond then
+    texsprint("\\@firstoftwo")
+  else
+    texsprint("\\@secondoftwo")
+  end
+end
+
+-- mail is not exported, we just expect the user to set it
+blxextdoiapi = {
+  module                   = module,
+  cache_expire             = cache_expire,
+  is_valid_doi             = is_valid_doi,
+  is_openaccess            = is_openaccess,
+  get_openaccess_url       = get_openaccess_url,
+  assign_openaccess_url_to = assign_openaccess_url_to,
+  openaccess_url_is_doi    = openaccess_url_is_doi,
+  texify_conditional       = texify_conditional,
+}
+
+--
+-- This file is part of the biblatex-ext bundle.
+-- biblatex-ext is released under the LaTeX Project Public License v1.3c
+-- or later.
+--
+-- A complete list of files included in that package can be found in README.md
+-- or - failing that - in ext-standard.bbx.
+--
+-- Official releases of this package are on CTAN
+--   https://www.ctan.org/pkg/biblatex-ext
+-- development takes place on GitHub
+--   https://github.com/moewew/biblatex-ext
+--