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25
26## -*- texinfo -*-
27## @deftypefn {} {[@var{ver}, @var{url}] =} get_forge_pkg (@var{name})
28## Try to discover the current version of an Octave Forge package from the web,
29## using a working internet connection and the urlread function.
30## If two output arguments are requested, also return an address from which
31## to download the file.
32## @end deftypefn
33
34function [ver, url] = get_forge_pkg (name)
35
36  ## Verify that name is valid.
37  if (! (ischar (name) && rows (name) == 1 && ndims (name) == 2))
38    error ("get_forge_pkg: package NAME must be a string");
39  elseif (! all (isalnum (name) | name == "-" | name == "." | name == "_"))
40    error ("get_forge_pkg: invalid package NAME: %s", name);
41  endif
42
43  name = tolower (name);
44
45  ## Try to download package's index page.
46  [html, succ] = urlread (sprintf ("https://packages.octave.org/%s/index.html", ...
47                                   name));
48  if (succ)
49    ## Remove blanks for simpler matching.
50    html(isspace (html)) = [];
51    ## Good.  Let's grep for the version.
52    pat = "<tdclass=""package_table"">PackageVersion:</td><td>([\\d.]*)</td>";
53    t = regexp (html, pat, "tokens");
54    if (isempty (t) || isempty (t{1}))
55      error ("get_forge_pkg: could not read version number from package's page");
56    else
57      ver = t{1}{1};
58      if (nargout > 1)
59        ## Build download string.
60        pkg_file = sprintf ("%s-%s.tar.gz", name, ver);
61        url = ["https://packages.octave.org/download/" pkg_file];
62        ## Verify that the package string exists on the page.
63        if (isempty (strfind (html, pkg_file)))
64          warning ("get_forge_pkg: download URL not verified");
65        endif
66      endif
67    endif
68  else
69    ## Try get the list of all packages.
70    [html, succ] = urlread ("https://packages.octave.org/list_packages.php");
71    if (! succ)
72      error ("get_forge_pkg: could not read URL, please verify internet connection");
73    endif
74    t = strsplit (html);
75    if (any (strcmp (t, name)))
76      error ("get_forge_pkg: package NAME exists, but index page not available");
77    endif
78    ## Try a simplistic method to determine similar names.
79    function d = fdist (x)
80      len1 = length (name);
81      len2 = length (x);
82      if (len1 <= len2)
83        d = sum (abs (tolower (name(1:len1)) - tolower (x(1:len1)))) ...
84            + (len2 - len1)*23;
85      else
86        d = sum (abs (tolower (name(1:len2)) - tolower (x(1:len2)))) ...
87            + (len1 - len2)*23;
88      endif
89    endfunction
90    dist = cellfun ("fdist", t);
91    [~, i] = min (dist);
92    error ("get_forge_pkg: package not found: ""%s"".  Did you mean ""%s""?", ...
93           name, t{i});
94  endif
95
96endfunction
97