aboutsummaryrefslogtreecommitdiffstats
path: root/lib/inets/doc/src/ftp.xml
blob: b081fabc91c43bd2fdcc8b6f98514d0f654a0db2 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
<?xml version="1.0" encoding="iso-8859-1" ?>
<!DOCTYPE erlref SYSTEM "erlref.dtd">

<erlref>
  <header>
    <copyright>
      <year>1997</year><year>2011</year>
      <holder>Ericsson AB. All Rights Reserved.</holder>
    </copyright>
    <legalnotice>
      The contents of this file are subject to the Erlang Public License,
      Version 1.1, (the "License"); you may not use this file except in
      compliance with the License. You should have received a copy of the
      Erlang Public License along with this software. If not, it can be
      retrieved online at http://www.erlang.org/.

      Software distributed under the License is distributed on an "AS IS"
      basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
      the License for the specific language governing rights and limitations
      under the License.

    </legalnotice>

    <title>ftp</title>
    <prepared>Peter H&ouml;gfeldt</prepared>
    <docno></docno>
    <date>1997-11-05</date>
    <rev>B</rev>
    <file>ftp.xml</file>
  </header>
  <module>ftp</module>
  <modulesummary>A File Transfer Protocol client</modulesummary>

  <description>

    <p>The <c>ftp</c> module implements a client for file transfer
      according to a subset of the File Transfer Protocol (see <term
      id="RFC"></term>959). </p>

    <p>Starting from inets version 4.4.1 the ftp
      client will always try to use passive ftp mode and only resort
      to active ftp mode if this fails. There is a start option 
      <seealso marker="#mode">mode</seealso> where this default behavior 
      may be changed. </p>

    <marker id="two_start"></marker>

    <p>There are two ways to start an ftp client. One is using the 
      <seealso marker="#service_start">Inets service framework</seealso>
      and the other is to start it directy as a standalone process 
      using the <seealso marker="#open">open</seealso> function. </p>

    <p>For a simple example of an ftp session see 
      <seealso marker="ftp_client">Inets User's Guide.</seealso></p>

    <p>In addition to the ordinary functions for receiving and sending
      files (see <c>recv/2</c>, <c>recv/3</c>, <c>send/2</c> and
      <c>send/3</c>) there are functions for receiving remote files as
      binaries (see <c>recv_bin/2</c>) and for sending binaries to to be
      stored as remote files (see <c>send_bin/3</c>).</p>

    <p>There is also a set of functions for sending and receiving
      contiguous parts of a file to be stored in a remote file (for send
      see <c>send_chunk_start/2</c>, <c>send_chunk/2</c> and
      <c>send_chunk_end/1</c> and for receive see
      <c>recv_chunk_start/2</c> and <c>recv_chunk/</c>).</p>

    <p>The particular return values of the functions below depend very
      much on the implementation of the FTP server at the remote
      host. In particular the results from <c>ls</c> and <c>nlist</c>
      varies. Often real errors are not reported as errors by <c>ls</c>,
      even if for instance a file or directory does not
      exist. <c>nlist</c> is usually more strict, but some
      implementations have the peculiar behaviour of responding with an
      error, if the request is a listing of the contents of directory
      which exists but is empty.</p>

    <marker id="service_start"></marker>
  </description>

  <section>
    <title>FTP CLIENT SERVICE START/STOP </title>
    
    <p>The FTP client can be started and stopped dynamically in runtime by
      calling the Inets application API 
      <c>inets:start(ftpc, ServiceConfig)</c>,
      or <c>inets:start(ftpc, ServiceConfig, How)</c>, and
      <c>inets:stop(ftpc, Pid)</c>. 
      See <seealso marker="inets">inets(3)</seealso> for more info. </p>
    <p>Below follows a description of
      the available configuration options.</p>
    
    <taglist>
      <tag>{host, Host}</tag>
      <item>
        <marker id="host"></marker>
	<p>Host = <c>string() | ip_address()</c> </p>
      </item>

      <tag>{port, Port}</tag>
      <item>
        <marker id="port"></marker>
	<p>Port = <c>integer() > 0</c> </p>
	<p>Default is 21.</p>
      </item>

      <tag>{mode, Mode}</tag>
      <item>
        <marker id="mode"></marker>
	<p>Mode = <c>active | passive</c> </p>
	<p>Default is <c>passive</c>. </p> 
      </item>

      <tag>{verbose, Verbose}</tag>
      <item>
        <marker id="verbose"></marker>
	<p>Verbose = <c>boolean()</c> </p>
	<p>This determines if the FTP communication should be
	  verbose or not. </p>
	<p>Default is <c>false</c>. </p>
      </item>

      <tag>{debug, Debug}</tag>
      <item>
        <marker id="debug"></marker>
	<p>Debug = <c>trace | debug | disable</c> </p>
	<p>Debugging using the dbg toolkit. </p>
	<p>Default is <c>disable</c>. </p>
      </item>

      <tag>{ipfamily, IpFamily}</tag>
      <item>
        <marker id="ipfamily"></marker>
	<p>IpFamily = <c>inet | inet6 | inet6fb4</c> </p>
	<p>With <c>inet6fb4</c> the client behaves as before 
	  (it tries to use IPv6 and only if that does not work, it 
          uses IPv4). </p>
	<p>Default is <c>inet</c> (IPv4). </p>
      </item>

      <tag>{timeout, Timeout}</tag>
      <item>
        <marker id="timeout"></marker>
	<p>Timeout = <c>non_neg_integer()</c> </p>
	<p>Connection timeout. </p>
	<p>Default is 60000 (milliseconds). </p>
      </item>

      <tag>{dtimeout, DTimeout}</tag>
      <item>
        <marker id="dtimeout"></marker>
	<p>DTimeout = <c>non_neg_integer() | infinity</c> </p>
	<p>Data Connect timeout. 
	The time the client will wait for the server to connect to the 
	data socket. </p>
	<p>Default is infinity. </p>
      </item>

      <tag>{progress, Progress}</tag>
      <item>
        <marker id="progress"></marker>
	<p>Progress = <c>ignore | {CBModule, CBFunction, InitProgress}</c></p>
	<p>CBModule = <c>atom()</c>, CBFunction = <c>atom()</c> </p>
	<p>InitProgress = <c>term()</c> </p>
	<p>Default is <c>ignore</c>. </p>
      </item>  

    </taglist>
  
    <p>The progress option is intended to be used by applications that
      want to create some type of progress report such as a progress bar in
      a GUI.  The default value for the progress option is ignore
      e.i. the option is not used.  When the progress option is
      specified the following will happen when ftp:send/[3,4] or
      ftp:recv/[3,4] are called.</p>
    
    <list type="bulleted">
      <item>
	<p>Before a file is transfered the following call will
	  be made to indicate the start of the file transfer and how big
	  the file is. The return value of the callback function
	  should be a new value for the UserProgressTerm that will
	  bu used as input next time the callback function is
	  called.</p>
	<br></br>
	<p><c>
	  CBModule:CBFunction(InitProgress, File, {file_size, FileSize})
	</c></p>
	<br></br>
      </item>
      
      <item>
	<p>Every time a chunk of bytes is transfered the
	  following call will be made:</p>
	<br></br>
	<p><c>
	    CBModule:CBFunction(UserProgressTerm, File, {transfer_size, TransferSize})             </c></p>
	<br></br>
      </item>

      <item>
	<p>At the end of the file the following call will be
	  made to indicate the end of the transfer.</p>
	<br></br>
	<p><c>
	    CBModule:CBFunction(UserProgressTerm, File, {transfer_size, 0})             </c></p>
	<br></br>
      </item>
    </list>
    
    <p>The callback function should be defined as </p>

    <p><c>
	CBModule:CBFunction(UserProgressTerm, File, Size) -> UserProgressTerm        </c></p>
    
    <p><c>
	CBModule = CBFunction = atom()
      </c></p>

    <p><c>
	UserProgressTerm = term()
      </c></p>

    <p><c>
	File = string()
      </c></p>

    <p><c>
	Size = {transfer_size, integer()} | {file_size, integer()} | {file_size, unknown}        </c></p>
    
    <p>Alas for remote files it is not possible for ftp to determine the
      file size in a platform independent way. In this case the size
      will be <c>unknown</c> and it is left to the application to find
      out the size. </p>
    
    <note>
      <p>The callback is made by a middleman process, hence the
	file transfer will not be affected by the code in the progress
	callback function. If the callback should crash this will be
	detected by the ftp connection process that will print an
	info-report and then go one as if the progress option was set
	to ignore. </p>
    </note>
    
    <p>The file transfer type is set to the default of the FTP server
      when the session is opened. This is usually ASCCI-mode.
    </p>
    
    <p>The current local working directory (cf. <c>lpwd/1</c>) is set to
      the value reported by <c>file:get_cwd/1</c>. the wanted
      local directory.
    </p>
    
    <p>The return value <c>Pid</c> is used as a reference to the
      newly created ftp client in all other functions, and they should
      be called by the process that created the connection. The ftp
      client process monitors the process that created it and
      will terminate if that process terminates.</p>   
  </section>
  
  <section>
    <title>COMMON DATA TYPES </title>
    <p>Here follows type definitions that are used by more than one
      function in the FTP client API. </p>
    <p><c> pid() - identifier of an ftp connection.</c></p>
    <p><c> string() = list of ASCII characters.</c></p>
    <p><c> shortage_reason() = etnospc | epnospc</c></p>
    <p><c> restriction_reason() = epath | efnamena | elogin | enotbinary
      - note not all restrictions may always relevant to all functions
    </c></p>
    <p><c>common_reason() = econn | eclosed | term() - some kind of
      explanation of what went wrong.</c></p>

    <marker id="account"></marker>
  </section>

  <funcs>
    <func>
      <name>account(Pid, Account) -> ok | {error, Reason}</name>
      <fsummary>Specify which account to use.</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>Account = string()</v>
        <v>Reason = eacct | common_reason()</v>
      </type>
      <desc>
        <p>If an account is needed for an operation set the account
          with this operation.</p>

       <marker id="append"></marker>
       <marker id="append2"></marker>
       <marker id="append3"></marker>
      </desc>
    </func>

    <func>
      <name>append(Pid, LocalFile) -> </name>
      <name>append(Pid, LocalFile, RemoteFile) -> ok | {error, Reason}</name>
      <fsummary>Transfer file to remote server, and append it to Remotefile.</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>LocalFile = RemoteFile = string()</v>
        <v>Reason = epath | elogin | etnospc | epnospc | efnamena | common_reason</v>
      </type>
      <desc>
        <p>Transfers the file <c>LocalFile</c> to the remote server. If 
          <c>RemoteFile</c> is specified, the name of the remote file that the
          file will be appended to is set to <c>RemoteFile</c>; otherwise 
          the name is set to <c>LocalFile</c> If the file does not exists the
          file will be created.</p>

       <marker id="append_bin"></marker>
      </desc>
    </func>

    <func>
      <name>append_bin(Pid, Bin, RemoteFile) -> ok | {error, Reason}</name>
      <fsummary>Transfer a binary into a remote file.</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>Bin = binary()()</v>
        <v>RemoteFile = string()</v>
        <v>Reason =  restriction_reason()| shortage_reason() | common_reason()</v>
      </type>
      <desc>
        <p>Transfers the binary <c>Bin</c> to the remote server and append 
          it to the file <c>RemoteFile</c>. If the file does not exists it 
          will be created.</p>

       <marker id="append_chunk"></marker>
      </desc>
    </func>

    <func>
      <name>append_chunk(Pid, Bin) -> ok | {error, Reason}</name>
      <fsummary>append a chunk to the remote file.</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>Bin = binary()</v>
        <v>Reason = echunk | restriction_reason() | common_reason()</v>
      </type>
      <desc>
        <p>Transfer the chunk <c>Bin</c> to the remote server, which 
          append it into the file specified in the call to 
          <c>append_chunk_start/2</c>. </p>
        <p>Note that for some errors, e.g. file system full, it is 
          necessary to to call <c>append_chunk_end</c> to get the 
          proper reason.</p>

       <marker id="append_chunk_start"></marker>
      </desc>
    </func>

    <func>
      <name>append_chunk_start(Pid, File) -> ok | {error, Reason}</name>
      <fsummary>Start transfer of file chunks for appending to File.</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>File = string()</v>
        <v>Reason = restriction_reason() | common_reason()</v>
      </type>
      <desc>
        <p>Start the transfer of chunks for appending to the file 
          <c>File</c> at the remote server. If the file does not exists 
          it will be created.</p>

       <marker id="append_chunk_end"></marker>
      </desc>
    </func>

    <func>
      <name>append_chunk_end(Pid) -> ok | {error, Reason}</name>
      <fsummary>Stop transfer of chunks for appending.</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>Reason = echunk | restriction_reason() | shortage_reason() </v>
      </type>
      <desc>
        <p>Stops transfer of chunks for appending to the remote server. 
          The file at the remote server, specified in the call to 
          <c>append_chunk_start/2</c> is closed by the server.</p>

       <marker id="cd"></marker>
      </desc>
    </func>

    <func>
      <name>cd(Pid, Dir) -> ok | {error, Reason}</name>
      <fsummary>Change remote working directory.</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>Dir = string()</v>
        <v>Reason = restriction_reason() | common_reason() </v>
      </type>
      <desc>
        <p>Changes the working directory at the remote server to 
          <c>Dir</c>.</p>

       <marker id="close"></marker>
      </desc>
    </func>
    
    <func>
      <name>close(Pid) -> ok</name>
      <fsummary>End the ftp session.</fsummary>
      <type>
	<v>Pid = pid()</v>
      </type>
      <desc>
	<p>Ends an ftp session, created using the 
          <seealso marker="#open">open</seealso> function. </p>

       <marker id="delete"></marker>
      </desc>
    </func>

    <func>
      <name>delete(Pid, File) -> ok | {error, Reason}</name>
      <fsummary>Delete a file at the remote server..</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>File = string()</v>
        <v>Reason = restriction_reason() | common_reason()</v>
      </type>
      <desc>
        <p>Deletes the file <c>File</c> at the remote server.</p>

       <marker id="append"></marker>
      </desc>
    </func>

    <func>
      <name>formaterror(Tag) -> string()</name>
      <fsummary>Return error diagnostics.</fsummary>
      <type>
        <v>Tag = {error, atom()} | atom()</v>
      </type>
      <desc>
        <p>Given an error return value <c>{error, AtomReason}</c>,
          this function returns a readable string describing the error.</p>

       <marker id="lcd"></marker>
      </desc>
    </func>

    <func>
      <name>lcd(Pid, Dir) -> ok | {error, Reason}</name>
      <fsummary>Change local working directory.</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>Dir = string()</v>
        <v>Reason = restriction_reason()</v>
      </type>
      <desc>
        <p>Changes the working directory to <c>Dir</c> for the local client. </p>

       <marker id="lpwd"></marker>
      </desc>
    </func>

    <func>
      <name>lpwd(Pid) -> {ok, Dir}</name>
      <fsummary>Get local current working directory.</fsummary>
      <type>
        <v>Pid = pid()</v>
      </type>
      <desc>
        <p>Returns the current working directory at the local client.</p>

       <marker id="ls"></marker>
       <marker id="ls1"></marker>
       <marker id="ls2"></marker>
      </desc>
    </func>

    <func>
      <name>ls(Pid) -> </name>
      <name>ls(Pid, Pathname) -> {ok, Listing} | {error, Reason}</name>
      <fsummary>List of files.</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>Pathname = string()</v>
        <v>Listing = string()</v>
        <v>Reason = restriction_reason() | common_reason()</v>
      </type>
      <desc>
        <p>Returns a list of files in long format. </p>
        <p><c>Pathname</c> can be a directory, a group of files or 
          even a file. The <c>Pathname</c> string can contain wildcard(s). </p>
        <p><c>ls/1</c> implies the user's current remote directory. </p>
        <p>The format of <c>Listing</c> is operating system dependent 
          (on UNIX it is typically produced from the output of the 
          <c>ls -l</c> shell command).</p>

       <marker id="mkdir"></marker>
      </desc>
    </func>

    <func>
      <name>mkdir(Pid, Dir) -> ok | {error, Reason}</name>
      <fsummary>Create remote directory.</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>Dir = string()</v>
        <v>Reason = restriction_reason() | common_reason()</v>
      </type>
      <desc>
        <p>Creates the directory <c>Dir</c> at the remote server.</p>

       <marker id="nlist"></marker>
       <marker id="nlist1"></marker>
       <marker id="nlist2"></marker>
      </desc>
    </func>

    <func>
      <name>nlist(Pid) -> </name>
      <name>nlist(Pid, Pathname) -> {ok, Listing} | {error, Reason}</name>
      <fsummary>List of files.</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>Pathname = string()</v>
        <v>Listing = string()</v>
        <v>Reason = restriction_reason() | common_reason()</v>
      </type>
      <desc>
        <p>Returns a list of files in short format. </p>
        <p><c>Pathname</c> can be a directory, a group of files or 
          even a file. The <c>Pathname</c> string can contain wildcard(s). </p>
        <p><c>nlist/1</c> implies the user's current remote directory. </p>
        <p>The format of <c>Listing</c> is a stream of
          file names, where each name is separated by &lt;CRLF&gt; or
          &lt;NL&gt;. Contrary to the <c>ls</c> function, the purpose of
          <c>nlist</c> is to make it possible for a program to
          automatically process file name information.</p>

       <marker id="open"></marker>
      </desc>
    </func>

    <func>
      <name>open(Host) -> {ok, Pid} | {error, Reason}</name>
      <name>open(Host, Opts) -> {ok, Pid} | {error, Reason}</name>
      <fsummary>Start an standalone ftp client.</fsummary>
      <type>
	<v>Host = string() | ip_address()</v>
	<v>Opts = options()</v>
	<v>options() = [option()]</v>
	<v>option() = start_option() | open_option()</v>
	<v>start_option() = {verbose, verbose()} | {debug, debug()}</v>
	<v>verbose() = boolean() (defaults to false)</v>
	<v>debug() = disable | debug | trace (defaults to disable)</v>
	<v>open_option() = {ipfamily, ipfamily()} | {port, port()} | {mode, mode()} | {tls, tls_options()} | {timeout, timeout()} | {dtimeout, dtimeout()} | {progress, progress()}</v>
	<v>ipfamily() = inet | inet6 | inet6fb4 (defaults to inet)</v>
	<v>port() = integer() > 0 (defaults to 21)</v>
	<v>mode() = active | passive (defaults to passive)</v>
	<v>tls_options() = [<seealso marker="ssl#type-ssloption">ssl:ssloption()</seealso>]</v>
	<v>timeout() = integer() > 0 (defaults to 60000 milliseconds)</v>
	<v>dtimeout() = integer() > 0 | infinity (defaults to infinity)</v>
	<v>pogress() = ignore | {module(), function(), initial_data()} (defaults to ignore)</v>
	<v>module() = atom()</v>
	<v>function() = atom()</v>
	<v>initial_data() = term()</v>
	<v>Reason = ehost | term()</v>
      </type>

      <desc>
	<p>This function is used to start a standalone ftp client process 
          (without the inets service framework) and 
          open a session with the FTP server at <c>Host</c>. </p>

	<p>If the option <c>{tls, tls_options()}</c> is present, the ftp session will be transported over tls (ftps, see
<url href="http://www.ietf.org/rfc/rfc4217.txt">RFC 4217</url>). The list <c>tls_options()</c> may be empty. The function <seealso marker="ssl:ssl#connect/3"><c>ssl:connect/3</c></seealso> is used for securing both the control connection and the data sessions.
	</p>

        <p>A session opened in this way, is closed using the 
          <seealso marker="#close">close</seealso> function. </p>

       <marker id="pwd"></marker>
      </desc>
    </func>

    <func>
      <name>pwd(Pid) -> {ok, Dir} | {error, Reason}</name>
      <fsummary>Get remote current working directory.</fsummary>
      <type>
	<v>Pid = pid()</v>
	<v>Reason = restriction_reason() | common_reason() </v>
      </type>
      <desc>
	<p>Returns the current working directory at the remote server. </p>
      </desc>
    </func>

    <func>
      <name>pwd(Pid) -> {ok, Dir} | {error, Reason}</name>
      <fsummary>Get remote current working directory.</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>Reason = restriction_reason() | common_reason() </v>
      </type>
      <desc>
        <p>Returns the current working directory at the remote server.</p>

       <marker id="recv"></marker>
       <marker id="recv2"></marker>
       <marker id="recv3"></marker>
      </desc>
    </func>

    <func>
      <name>recv(Pid, RemoteFile) -> </name>
      <name>recv(Pid, RemoteFile, LocalFile) -> ok | {error, Reason}</name>
      <fsummary>Transfer file from remote server.</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>RemoteFile = LocalFile = string()</v>
        <v>Reason = restriction_reason() | common_reason() | file_write_error_reason() </v>
        <v>file_write_error_reason() = see file:write/2</v>
      </type>
      <desc>
        <p>Transfer the file <c>RemoteFile</c> from the remote server
          to the the file system of the local client. If
          <c>LocalFile</c> is specified, the local file will be
          <c>LocalFile</c>; otherwise it will be
          <c>RemoteFile</c>.</p>
        <p>If the file write fails
          (e.g. enospc), then the command is aborted and <c>{error, file_write_error_reason()}</c> is returned. The file is
          however <em>not</em> removed.</p>

       <marker id="recv_bin"></marker>
      </desc>
    </func>

    <func>
      <name>recv_bin(Pid, RemoteFile) -> {ok, Bin} | {error, Reason}</name>
      <fsummary>Transfer file from remote server as a binary.</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>Bin = binary()</v>
        <v>RemoteFile = string()</v>
        <v>Reason = restriction_reason() | common_reason()</v>
      </type>
      <desc>
        <p>Transfers the file <c>RemoteFile</c> from the remote server and 
          receives it as a binary.</p>

       <marker id="recv_chunk_start"></marker>
      </desc>
    </func>

    <func>
      <name>recv_chunk_start(Pid, RemoteFile) -> ok | {error, Reason}</name>
      <fsummary>Start chunk-reading of the remote file.</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>RemoteFile = string()</v>
        <v>Reason = restriction_reason() | common_reason()</v>
      </type>
      <desc>
        <p>Start transfer of the file <c>RemoteFile</c> from the
          remote server.</p>

       <marker id="recv_chunk"></marker>
      </desc>
    </func>

    <func>
      <name>recv_chunk(Pid) -> ok | {ok, Bin} | {error, Reason}</name>
      <fsummary>Receive a chunk of the remote file.</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>Bin = binary()</v>
        <v>Reason = restriction_reason() | common_reason()</v>
      </type>
      <desc>
        <p>Receive a chunk of the remote file (<c>RemoteFile</c> of 
          <c>recv_chunk_start</c>). The return values has the following 
          meaning:</p>
        <list type="bulleted">
          <item><c>ok</c> the transfer is complete.</item>
          <item><c>{ok, Bin}</c> just another chunk of the file.</item>
          <item><c>{error, Reason}</c> transfer failed.</item>
        </list>

       <marker id="rename"></marker>
      </desc>
    </func>

    <func>
      <name>rename(Pid, Old, New) -> ok | {error, Reason}</name>
      <fsummary>Rename a file at the remote server..</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>CurrFile = NewFile = string()</v>
        <v>Reason = restriction_reason() | common_reason()</v>
      </type>
      <desc>
        <p>Renames <c>Old</c> to <c>New</c> at the remote server.</p>

       <marker id="rmdir"></marker>
      </desc>
    </func>

    <func>
      <name>rmdir(Pid, Dir) -> ok | {error, Reason}</name>
      <fsummary>Remove a remote directory.</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>Dir = string()</v>
        <v>Reason = restriction_reason() | common_reason()</v>
      </type>
      <desc>
        <p>Removes directory <c>Dir</c> at the remote server.</p>

       <marker id="send"></marker>
       <marker id="send2"></marker>
       <marker id="send3"></marker>
      </desc>
    </func>

    <func>
      <name>send(Pid, LocalFile) -></name>
      <name>send(Pid, LocalFile, RemoteFile) -> ok | {error, Reason}</name>
      <fsummary>Transfer file to remote server.</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>LocalFile = RemoteFile = string()</v>
        <v>Reason = restriction_reason() | common_reason() | shortage_reason()</v>
      </type>
      <desc>
        <p>Transfers the file <c>LocalFile</c> to the remote server. If 
          <c>RemoteFile</c> is specified, the name of the remote file is set
          to <c>RemoteFile</c>; otherwise the name is set to <c>LocalFile</c>.</p>

       <marker id="send_bin"></marker>
      </desc>
    </func>

    <func>
      <name>send_bin(Pid, Bin, RemoteFile) -> ok | {error, Reason}</name>
      <fsummary>Transfer a binary into a remote file.</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>Bin = binary()()</v>
        <v>RemoteFile = string()</v>
        <v>Reason = restriction_reason() | common_reason() | shortage_reason()</v>
      </type>
      <desc>
        <p>Transfers the binary <c>Bin</c> into the file <c>RemoteFile</c> 
          at the remote server.</p>

       <marker id="send_chunk"></marker>
      </desc>
    </func>

    <func>
      <name>send_chunk(Pid, Bin) -> ok | {error, Reason}</name>
      <fsummary>Write a chunk to the remote file.</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>Bin = binary()</v>
        <v>Reason = echunk | restriction_reason() | common_reason()</v>
      </type>
      <desc>
        <p>Transfer the chunk <c>Bin</c> to the remote server, which 
          writes it into the file specified in the call to 
          <c>send_chunk_start/2</c>. </p>
        <p>Note that for some errors, e.g. file system full, it is 
          necessary to to call <c>send_chunk_end</c> to get the 
          proper reason.</p>

       <marker id="send_chunk_start"></marker>
      </desc>
    </func>

    <func>
      <name>send_chunk_start(Pid, File) -> ok | {error, Reason}</name>
      <fsummary>Start transfer of file chunks.</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>File = string()</v>
        <v>Reason = restriction_reason() | common_reason()</v>
      </type>
      <desc>
        <p>Start transfer of chunks into the file <c>File</c> at the 
          remote server.</p>

       <marker id="send_chunk_end"></marker>
      </desc>
    </func>

    <func>
      <name>send_chunk_end(Pid) -> ok | {error, Reason}</name>
      <fsummary>Stop transfer of chunks.</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>Reason = restriction_reason() | common_reason() | shortage_reason()</v>
      </type>
      <desc>
        <p>Stops transfer of chunks to the remote server. The file at the
          remote server, specified in the call to <c>send_chunk_start/2</c> 
          is closed by the server.</p>

       <marker id="type"></marker>
      </desc>
    </func>

    <func>
      <name>type(Pid, Type) -> ok | {error, Reason}</name>
      <fsummary>Set transfer type to <c>ascii</c>or <c>binary</c>.</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>Type = ascii | binary</v>
        <v>Reason = etype | restriction_reason() | common_reason()</v>
      </type>
      <desc>
        <p>Sets the file transfer type to <c>ascii</c> or <c>binary</c>. When
          an ftp session is opened, the default transfer type of the
          server is used, most often <c>ascii</c>, which is the default
          according to <url href="http://www.ietf.org/rfc/rfc959.txt">RFC 959</url>.</p>
       <marker id="user3"></marker>
      </desc>
    </func>

    <func>
      <name>user(Pid, User, Password) -> ok | {error, Reason}</name>
      <fsummary>User login.</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>User = Password = string()</v>
        <v>Reason = euser | common_reason()</v>
      </type>
      <desc>
        <p>Performs login of <c>User</c> with <c>Password</c>.</p>

       <marker id="user4"></marker>
      </desc>
    </func>

    <func>
      <name>user(Pid, User, Password, Account) -> ok | {error, Reason}</name>
      <fsummary>User login.</fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>User = Password = string()</v>
        <v>Reason = euser | common_reason() </v>
      </type>
      <desc>
        <p>Performs login of <c>User</c> with <c>Password</c> to the account 
          specified by <c>Account</c>.</p>

       <marker id="quote"></marker>
      </desc>
    </func>

    <func>
      <name>quote(Pid, Command) -> [FTPLine]</name>
      <fsummary>Sends an arbitrary FTP command. </fsummary>
      <type>
        <v>Pid = pid()</v>
        <v>Command = string()</v>
        <v>FTPLine = string() - Note the telnet end of line characters, from the ftp protocol definition, CRLF e.g. "\\r\\n" has been removed.</v>
      </type>
      <desc>
        <p>Sends an arbitrary FTP command and returns verbatimly a list
          of the lines sent back by the FTP server. This functions is
          intended to give an application accesses to FTP commands
          that are server specific or that may not be provided by
          this FTP client. </p>
        <note>
          <p>FTP commands that require a data connection can not be
            successfully issued with this function. </p>
        </note>
      </desc>
    </func>
  </funcs>

  <section>
    <title>ERRORS</title>
    <p>The possible error reasons and the corresponding diagnostic strings 
      returned by <c>formaterror/1</c> are as follows:
      </p>
    <taglist>
      <tag><c>echunk</c></tag>
      <item>
        <p>Synchronisation error during chunk sending. 
          </p>
        <p>A call has been made to <c>send_chunk/2</c> or
          <c>send_chunk_end/1</c>, before a call to
          <c>send_chunk_start/2</c>; or a call has been made to another
          transfer function during chunk sending, i.e. before a call
          to <c>send_chunk_end/1</c>.</p>
      </item>
      <tag><c>eclosed</c></tag>
      <item>
        <p>The session has been closed.</p>
      </item>
      <tag><c>econn</c></tag>
      <item>
        <p>Connection to remote server prematurely closed.</p>
      </item>
      <tag><c>ehost</c></tag>
      <item>
        <p>Host not found, FTP server not found, or connection rejected
          by FTP server.</p>
      </item>
      <tag><c>elogin</c></tag>
      <item>
        <p>User not logged in.</p>
      </item>
      <tag><c>enotbinary</c></tag>
      <item>
        <p>Term is not a binary.</p>
      </item>
      <tag><c>epath</c></tag>
      <item>
        <p>No such file or directory, or directory already exists, or
          permission denied.</p>
      </item>
      <tag><c>etype</c></tag>
      <item>
        <p>No such type.</p>
      </item>
      <tag><c>euser</c></tag>
      <item>
        <p>User name or password not valid.</p>
      </item>
      <tag><c>etnospc</c></tag>
      <item>
        <p>Insufficient storage space in system [452].</p>
      </item>
      <tag><c>epnospc</c></tag>
      <item>
        <p>Exceeded storage allocation (for current directory or
          dataset) [552].</p>
      </item>
      <tag><c>efnamena</c></tag>
      <item>
        <p>File name not allowed [553].</p>
      </item>
    </taglist>
  </section>

  <section>
    <title>SEE ALSO</title>
    <p>file, filename, J. Postel and J. Reynolds: File Transfer Protocol
      (<url href="http://www.ietf.org/rfc/rfc959.txt">RFC 959</url>).
      </p>
  </section>
  
</erlref>