Annotation of loncom/homework/lonr.pm, revision 1.5
1.1 www 1: # The LearningOnline Network with CAPA
2: # Interface routines to R CAS
3: #
1.5 ! www 4: # $Id: lonr.pm,v 1.4 2009/04/18 23:43:50 www Exp $
1.1 www 5: #
6: # Copyright Michigan State University Board of Trustees
7: #
8: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
9: #
10: # LON-CAPA is free software; you can redistribute it and/or modify
11: # it under the terms of the GNU General Public License as published by
12: # the Free Software Foundation; either version 2 of the License, or
13: # (at your option) any later version.
14: #
15: # LON-CAPA is distributed in the hope that it will be useful,
16: # but WITHOUT ANY WARRANTY; without even the implied warranty of
17: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18: # GNU General Public License for more details.
19: #
20: # You should have received a copy of the GNU General Public License
21: # along with LON-CAPA; if not, write to the Free Software
22: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23: #
24: # /home/httpd/html/adm/gpl.txt
25: #
26: # http://www.lon-capa.org/
27: #
28:
29: package Apache::lonr;
30:
31: use strict;
32: use IO::Socket;
33: use Apache::lonnet;
34: use Apache::response();
35: use LONCAPA;
1.5 ! www 36: ### Commented out for now: use Tie::IxHash::Easy; # autoties all subhashes to keep index order
! 37:
! 38: my $errormsg='';
! 39:
! 40: #
! 41: # Rcroak: for use with R-error messages
! 42: #
! 43: sub Rcroak {
! 44: $errormsg=$_[0];
! 45: }
! 46:
! 47: #
! 48: #
! 49: # Rpeel takes a string containing serialized values from R,
! 50: # peels off the first syntactically complete unit (number, string or array),
! 51: # and returns a list (first unit, remainder).
! 52: #
! 53: sub Rpeel {
! 54: my $x = $_[0]; # the string containing the serialized R object(s)
! 55: if ($x =~ /^((?:i|d):(.+?);)(.*)$/) {
! 56: return ($1, $+); # x starts with a number
! 57: }
! 58: elsif ($x =~ /^s:(\d+):/) {
! 59: my $n = $1; # x starts with a string of length n
! 60: if ($x =~ /^(s:\d+:\"(.{$n})\";)(.*)$/) {
! 61: return ($1, $+); # x starts with a valid string
! 62: } else {
! 63: &Rcroak('invalid string detected');
! 64: }
! 65: }
! 66: elsif ($x =~ /^a:/) {
! 67: # x starts with an array -- need to find the closing brace
! 68: my $i = index $x, '{', 0; # position of first opening brace
! 69: if ($i < 0) {
! 70: &Rcroak('array with no opening brace');
! 71: }
! 72: my $open = 1; # counts open braces
! 73: my $j = index $x, '}', $i; # position of first closing brace
! 74: $i = index $x, '{', $i + 1; # position of next opening brace (if any)
! 75: my $pos = -1; # position of final closing brace
! 76: do {
! 77: if (($i < $j) && ($i > 0)) {
! 78: # encounter another opening brace before next closing brace
! 79: $open++;
! 80: $i = index $x, '{', $i + 1; # find the next opening brace
! 81: } elsif ($j > 0) {
! 82: # next brace encountered is a closing brace
! 83: $open--;
! 84: $pos = $j;
! 85: $j = index $x, '}', $j + 1;
! 86: } else {
! 87: &Rcroak('unmatched left brace');
! 88: }
! 89: } until ($open eq 0);
! 90: # array runs from start to $pos
! 91: my $a = substr $x, 0, $pos + 1; # array
! 92: my $b = substr $x, $pos + 1; # remainder
! 93: return ($a, $b);
! 94: } else {
! 95: &Rcroak('unrecognized R value');
! 96: }
! 97: }
! 98: # --- end Rpeel ---
! 99:
! 100: #
! 101: # Rreturn accepts a string containing a serialized R object
! 102: # and returns either the object's value (if it is scalar) or a reference
! 103: # to a hash containing the contents of the object. Any null keys in the hash
! 104: # are replaced by 'capaNNN' where NNN is the index of the entry in the original
! 105: # R array.
! 106: #
! 107: sub Rreturn {
! 108: my $x = $_[0]; # the string containing the serialized R object(s)
! 109: $errormsg='';
! 110: if ($x =~ /^(?:i|d):(.+?);$/) {
! 111: return $1; # return the value of the number
! 112: } elsif ($x =~ /^s:(\d+):\"(.*)\";$/) {
! 113: # string -- verify the length
! 114: if (length($2) eq $1) {
! 115: return $2; # return the string
! 116: } else {
! 117: return 'mismatch in string length';
! 118: }
! 119: } elsif ($x =~ /^a:(\d+):\{(.*)\}$/) {
! 120: # array
! 121: my $dim = $1; # array size
! 122: $x = $2; # array contents
! 123: tie(my %h,'Tie::IxHash::Easy'); # start a hash
! 124: keys(%h) = $dim; # allocate space for the hash
! 125: my $key;
! 126: my $y;
! 127: for (my $i = 0; $i < $dim; $i++) {
! 128: ($y, $x) = &Rpeel($x); # strip off the entry for the key
! 129: if ($y eq '') {
! 130: &Rcroak('ran out of keys');
! 131: }
! 132: $key = &Rreturn($y);
! 133: if ($key eq '') {
! 134: $key = "capa$i"; # correct null key
! 135: }
! 136: ($y, $x) = &Rpeel($x); # strip off the value
! 137: if ($y eq '') {
! 138: &Rcroak('ran out of values');
! 139: }
! 140: if ($y =~ /^a:/) {
! 141: $h{$key} = \&Rreturn($y); # array value: store as reference
! 142: } else {
! 143: $h{$key} = &Rreturn($y); # scalar value: store the entry in the hash
! 144: }
! 145: }
! 146: if ($errormsg) { return $errormsg; }
! 147: return \%h; # return a reference to the hash
! 148: }
! 149: }
! 150: # --- end Rreturn ---
! 151:
! 152: #
! 153: # Rentry takes a list of indices and gets the entry in a hash generated by Rreturn.
! 154: # Call: Rentry(Rvalue, index1, index2, ...) where Rvalue is a hash returned by Rreturn.
! 155: # Rentry will return the first scalar value it encounters (ignoring excess indices).
! 156: # If an invalid key is given, Rentry returns undef.
! 157: #
! 158: sub Rentry {
! 159: my $hash = shift; # pointer to hash
! 160: my $x;
! 161: my $i;
! 162: if (ref($hash) ne 'HASH') {
! 163: &Rcroak('argument to Rentry is not a hash');
! 164: }
! 165: while ($i = shift) {
! 166: if (exists $hash->{$i}) {
! 167: $hash = $hash->{$i};
! 168: } else {
! 169: return undef;
! 170: }
! 171: if (ref($hash) eq 'REF') {
! 172: $hash = $$hash; # dereference one layer
! 173: } elsif (ref($hash) ne 'HASH') {
! 174: return $hash; # drilled down to a scalar
! 175: }
! 176: }
! 177: }
! 178: # --- end Rentry ---
! 179:
1.1 www 180:
181: sub connect {
182: return IO::Socket::UNIX->new(Peer => $Apache::lonnet::perlvar{'lonSockDir'}.'/rsock',
183: Type => SOCK_STREAM,
184: Timeout => 10);
185: }
186:
187: sub disconnect {
188: my ($socket)=@_;
189: if ($socket) { close($socket); }
190: }
191:
192: sub rreply {
193: my ($socket,$cmd)=@_;
194: if ($socket) {
195: print $socket &escape($cmd)."\n";
196: my $reply=<$socket>;
197: chomp($reply);
198: if ($reply=~/^Incorrect/) { $reply='Error: '.$reply; }
199: return &unescape($reply);
200: } else {
201: return 'Error: no connection.';
202: }
203: }
204:
205: sub blacklisted {
206: my ($cmd)=@_;
207: foreach my $forbidden (
1.3 www 208: 'read','write','scan','save','socket','connections',
209: 'open','close',
210: 'plot','X11','windows','quartz',
1.2 www 211: 'postscript','pdf','png','jpeg',
212: 'dev\.list','dev\.next','dev\.prev','dev\.set',
1.3 www 213: 'dev\.off','dev\.copy','dev\.print','graphics',
214: 'library','package','source','sink','objects',
1.4 www 215: 'Sys\.','unlink','file\.','on\.exit','error',
216: 'q\(\)'
1.1 www 217: ) {
218: if ($cmd=~/$forbidden/s) { return 1; }
219: }
220: return 0;
221: }
222:
223: sub r_allowed_libraries {
1.2 www 224: return ('boot','class','cluster','datasets','KernSmooth','MASS',
225: 'methods','mgcv','nlme','nnet','rpart','spatial',
226: 'splines','stats','stats4','survival');
1.1 www 227: }
228:
229: sub r_is_allowed_library {
230: my ($library)=@_;
231: foreach my $allowed_library (&r_allowed_libraries()) {
232: if ($library eq $allowed_library) { return 1; }
233: }
234: return 0;
235: }
236:
237: sub runscript {
238: my ($socket,$fullscript,$libraries)=@_;
239: if (&blacklisted($fullscript)) { return 'Error: blacklisted'; }
240: my $reply;
241: $fullscript=~s/[\n\r\l]//gs;
242: if ($libraries) {
243: foreach my $library (split(/\s*\,\s*/,$libraries)) {
244: unless ($library=~/\w/) { next; }
245: if (&r_is_allowed_library($library)) {
246: $reply=&rreply($socket,'library('.$library.');'."\n");
247: if ($reply=~/^Error\:/) { return $reply; }
248: } else {
249: return 'Error: blacklisted';
250: }
251: }
252: }
253: foreach my $line (split(/\;/s,$fullscript)) {
254: if ($line=~/\w/) { $reply=&rreply($socket,$line.";\n"); }
255: if ($reply=~/^Error\:/) { return $reply; }
256: }
257: $reply=~s/^\s*//gs;
258: $reply=~s/\s*$//gs;
259: &Apache::lonxml::debug("r $fullscript \n reply $reply");
260: return $reply;
261: }
262:
263: sub r_cas_formula_fix {
264: my ($expression)=@_;
265: return &Apache::response::implicit_multiplication($expression);
266: }
267:
268: sub r_run {
269: my ($script,$submission,$argument,$libraries) = @_;
270: my $socket=&connect();
271: my @submissionarray=split(/\s*\,\s*/,$submission);
272: for (my $i=0;$i<=$#submissionarray;$i++) {
273: my $n=$i+1;
274: my $fixedsubmission=&r_cas_formula_fix($submissionarray[$i]);
275: $script=~s/RESPONSE\[$n\]/$fixedsubmission/gs;
276: }
277: my @argumentarray=@{$argument};
278: for (my $i=0;$i<=$#argumentarray;$i++) {
279: my $n=$i+1;
280: my $fixedargument=&r_cas_formula_fix($argumentarray[$i]);
281: $script=~s/LONCAPALIST\[$n\]/$fixedargument/gs;
282: }
283: my $reply=&runscript($socket,$script,$libraries);
284: &disconnect($socket);
285: if ($reply=~/^\s*true\s*$/i) { return 'EXACT_ANS'; }
286: if ($reply=~/^\s*false\s*$/i) { return 'INCORRECT'; }
287: return 'BAD_FORMULA';
288: }
289:
290: sub r_eval {
291: my ($script,$libraries) = @_;
292: my $socket=&connect();
293: my $reply=&runscript($socket,$script,$libraries);
294: &disconnect($socket);
295: return $reply;
296: }
297:
298:
299: sub compareterms {
300: my ($socket,$terma,$termb)=@_;
301: my $difference=$terma.'-('.$termb.')';
302: if (&blacklisted($difference)) { return 'Error: blacklisted'; }
303: my $reply=&rreply($socket,$difference.';');
304: if ($reply=~/^\s*0\s*$/) { return 'true'; }
305: if ($reply=~/^Error\:/) { return $reply; }
306: return 'false';
307: }
308:
309: sub r_check {
310: my ($response,$answer,$reterror) = @_;
311: my $socket=&connect();
312: my $reply=&compareterms($socket,$response,$answer);
313: &disconnect($socket);
314: # integer to string mappings come from capaParser.h
315: # 1 maps to 'EXACT_ANS'
316: if ($reply eq 'true') { return 1; }
317: # 11 maps to 'BAD_FORMULA'
318: if ($reply=~/^Error\:/) { return 11; }
319: # 7 maps to 'INCORRECT'
320: return 7;
321: }
322:
323: 1;
324: __END__;
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