/*!

\if MANPAGES
\page dcmrecv Simple DICOM storage SCP (receiver)
\else
\page dcmrecv dcmrecv: Simple DICOM storage SCP (receiver)
\endif

\section dcmrecv_synopsis SYNOPSIS

\verbatim
dcmrecv [options] port
\endverbatim

\section dcmrecv_description DESCRIPTION

The \b dcmrecv application implements a Service Class Provider (SCP) for the
Storage Service Class.  In contrast to the well-known \b storescp utility,
\b dcmrecv has less options and might, therefore, be easier to use - this also
explains the term "simple" in the title.  The main purpose of this application
is to receive a whole bunch of DICOM datasets from a Storage Service Class User
(SCU) and store them to a configurable directory and file structure.

\section dcmrecv_parameters PARAMETERS

\verbatim
port  tcp/ip port number to listen on
\endverbatim

\section dcmrecv_options OPTIONS

\subsection dcmrecv_general_options general options
\verbatim
  -h    --help
          print this help text and exit

        --version
          print version information and exit

        --arguments
          print expanded command line arguments

  -q    --quiet
          quiet mode, print no warnings and errors

  -v    --verbose
          verbose mode, print processing details

  -d    --debug
          debug mode, print debug information

  -ll   --log-level  [l]evel: string constant
          (fatal, error, warn, info, debug, trace)
          use level l for the logger

  -lc   --log-config  [f]ilename: string
          use config file f for the logger

  +v    --verbose-pc
          show presentation contexts in verbose mode
\endverbatim


\subsection dcmrecv_network_options network options
\verbatim
association negotiation profile from configuration file:

  -xf   --config-file  [f]ilename, [p]rofile: string
          use profile p from configuration file f

application entity title:

  -aet  --aetitle  [a]etitle: string
          set my AE title (default: DCMRECV)

  -uca  --use-called-aetitle
          always respond with called AE title

other network options:

  -ta   --acse-timeout  [s]econds: integer (default: 30)
          timeout for ACSE messages

  -td   --dimse-timeout  [s]econds: integer (default: unlimited)
          timeout for DIMSE messages

  -pdu  --max-pdu  [n]umber of bytes: integer (4096..131072)
          set max receive pdu to n bytes (default: 16384)

  -dhl  --disable-host-lookup  disable hostname lookup
\endverbatim

\subsection dcmrecv_tls_options transport layer security (TLS) options
\verbatim
transport protocol stack:

  -tls  --disable-tls
          use normal TCP/IP connection (default)

  +tls  --enable-tls  [p]rivate key file, [c]ertificate file: string
          use authenticated secure TLS connection

private key password (only with --enable-tls):

  +ps   --std-passwd
          prompt user to type password on stdin (default)

  +pw   --use-passwd  [p]assword: string
          use specified password

  -pw   --null-passwd
          use empty string as password

key and certificate file format:

  -pem  --pem-keys
          read keys and certificates as PEM file (default)

  -der  --der-keys
          read keys and certificates as DER file

certification authority:

  +cf   --add-cert-file  [f]ilename: string
          add certificate file to list of certificates

  +cd   --add-cert-dir  [d]irectory: string
          add certificates in d to list of certificates

  +crl  --add-crl-file  [f]ilename: string
          add certificate revocation list file
          (implies --enable-crl-vfy)

  +crv  --enable-crl-vfy
          enable leaf CRL verification

  +cra  --enable-crl-all
          enable full chain CRL verification

security profile:

  +py   --profile-bcp195-nd
          Non-downgrading BCP 195 TLS Profile (default)

  +px   --profile-bcp195
          BCP 195 TLS Profile

  +pz   --profile-bcp195-ex
          Extended BCP 195 TLS Profile

  +pb   --profile-basic
          Basic TLS Secure Transport Connection Profile (retired)

  +pa   --profile-aes
          AES TLS Secure Transport Connection Profile (retired)

  +pn   --profile-null
          Authenticated unencrypted communication
          (retired, was used in IHE ATNA)

ciphersuite:

  +cc   --list-ciphers
          show list of supported TLS ciphersuites and exit

  +cs   --cipher  [c]iphersuite name: string
          add ciphersuite to list of negotiated suites

  +dp   --dhparam  [f]ilename: string
          read DH parameters for DH/DSS ciphersuites

pseudo random generator:

  +rs   --seed  [f]ilename: string
          seed random generator with contents of f

  +ws   --write-seed
          write back modified seed (only with --seed)

  +wf   --write-seed-file  [f]ilename: string (only with --seed)
          write modified seed to file f

peer authentication:

  -rc   --require-peer-cert
          verify peer certificate, fail if absent (default)

  -vc   --verify-peer-cert
          verify peer certificate if present

  -ic   --ignore-peer-cert
          don't verify peer certificate
\endverbatim

\subsection dcmrecv_output_options output options
\verbatim
general:

  -od   --output-directory  [d]irectory: string (default: ".")
          write received objects to existing directory d

subdirectory generation:

  -s    --no-subdir
          do not generate any subdirectories (default)

  +ssd  --series-date-subdir
          generate subdirectories from series date

filename generation:

  +fd   --default-filenames
          generate filename from instance UID (default)

  +fu   --unique-filenames
          generate unique filename based on new UID

  +fsu  --short-unique-names
          generate short pseudo-random unique filename

  +fst  --system-time-names
          generate filename from current system time

  -fe   --filename-extension  [e]xtension: string (default: none)
          append e to all generated filenames

storage mode:

  -B    --normal
          allow implicit format conversions (default)

  +B    --bit-preserving
          write dataset exactly as received

        --ignore
          ignore dataset, receive but do not store it
\endverbatim

\section dcmrecv_notes NOTES

\subsection dcmrecv_typical_usage Typical Usage

A typical use case of \b dcmrecv is to receive SOP instances that are sent from
a storage SCU and save them as DICOM files.  The following command does exactly
this:

\verbatim
dcmrecv --verbose <port> --config-file storescp.cfg default
\endverbatim

If you prefer some automatically created subdirectory structure, shorter file
names and the extension ".dcm" for all DICOM files, use the following command:

\verbatim
dcmrecv -v -xf storescp.cfg default <port> --series-date-subdir
                                           --short-unique-names
                                           --filename-extension .dcm
\endverbatim

In case of very large SOP instances or if the dataset should be written exactly
as received (e.g. for debugging purposes), the "bit preserving mode" could be
used:

\verbatim
dcmrecv -v -xf storescp.cfg default <port> --bit-preserving
\endverbatim

The received datasets are always stored as DICOM files with the same Transfer
Syntax as used for the network transmission.

\subsection dcmrecv_dicom_conformance DICOM Conformance

Basically, the \b dcmrecv application supports all Storage SOP Classes as an
SCP, including private ones.  This requires, however, that a corresponding
association negotiation profile is loaded from a configuration file.  The format
and semantics of this configuration file are documented in \e asconfig.txt.

By default, that means if no association negotiation profile is loaded,
\b dcmrecv only supports the Verification SOP Class as an SCP (with default
transfer syntax, i.e. Implicit VR Litte Endian).

In the future, there might be additional options that allow for specifying the
list of supported Presentation Contexts (i.e. combination of SOP Class and
Transfer Syntaxes) directly, i.e. without loading a configuration file.

\subsection dcmrecv_subdirectory_generation Subdirectory Generation

The option \e --series-date-subdir allows for generating subdirectories (below
the specified output directory) based on the value of the data element Series
Date (0008,0021) from the received DICOM dataset.  If this value could be
retrieved from the dataset and is valid (i.e. consists of a valid DICOM date
field), the subdirectory structure is as follows:

\verbatim
<output-directory>/data/<year>/<month>/<day>/<filename>
\endverbatim

If the Series Date (0008,0021) cannot be retrieved or is invalid, the current
system date is used for the following subdirectory structure:

\verbatim
<output-directory>/undef/<year><month><day>/<filename>
\endverbatim

In both cases, \<year\> consists of 4 decimal digits and \<month\> as well as
\<day\> of 2 decimal digits.

\subsection dcmrecv_filename_generation Filename Generation

By default, the filenames for storing the received DICOM datasets are generated
according to the following scheme:

\verbatim
<short-modality-prefix>.<sop-instance-uid><filename-extension>
\endverbatim

If the same SOP instance is received twice, a warning message is reported and
the existing file is overwritten.

The option \e --unique-filenames makes sure that each received DICOM dataset is
stored as a separate file, i.e. no files should ever be overwritten.  This is
done by using a newly created unique identifier (UID) for each generated
filename (and the infix ".X" in order to avoid conflicts with real SOP Instance
UID values).  The naming scheme for this option is as follows:

\verbatim
<short-modality-prefix>.X.<unique-identifier><filename-extension>
\endverbatim

When option \e --short-unique-names is used, the filenames are generated
by some pseudo-random name generator, which also makes sure that there are
no conflicts (i.e. existing files are not overwritten).  This is the naming
scheme:

\verbatim
<short-modality-prefix>_<pseudo-random-name><filename-extension>
\endverbatim

With \<pseudo-random-name\> consisting of 16 digits in hexadecimal notation.

Finally, option \e --system-time-names allows for generating filenames based
on the current system time:

\verbatim
<date><time>.<short-modality-prefix><filename-extension>
\endverbatim

With \<date\> consisting of "<year><month><day>" and \<time\> of
"<hour><minute><second>.<micro-second>".  Please note that this scheme
could result in naming conflicts if the resolution of the system time is not
sufficiently high (i.e. does not support microseconds).

\subsection dcmrecv_limitations Limitations

Please note that option \e --bit-preserving cannot be used together with
option \e --series-date-subdir since the received dataset is stored directly
to file and the value of the Series Date (0008,0021) is, therefore, not
available before the file has been created.

\section dcmrecv_logging LOGGING

The level of logging output of the various command line tools and underlying
libraries can be specified by the user.  By default, only errors and warnings
are written to the standard error stream.  Using option \e --verbose also
informational messages like processing details are reported.  Option
\e --debug can be used to get more details on the internal activity, e.g. for
debugging purposes.  Other logging levels can be selected using option
\e --log-level.  In \e --quiet mode only fatal errors are reported.  In such
very severe error events, the application will usually terminate.  For more
details on the different logging levels, see documentation of module "oflog".

In case the logging output should be written to file (optionally with logfile
rotation), to syslog (Unix) or the event log (Windows) option \e --log-config
can be used.  This configuration file also allows for directing only certain
messages to a particular output stream and for filtering certain messages
based on the module or application where they are generated.  An example
configuration file is provided in <em>\<etcdir\>/logger.cfg</em>.

\section dcmrecv_command_line COMMAND LINE

All command line tools use the following notation for parameters: square
brackets enclose optional values (0-1), three trailing dots indicate that
multiple values are allowed (1-n), a combination of both means 0 to n values.

Command line options are distinguished from parameters by a leading '+' or '-'
sign, respectively.  Usually, order and position of command line options are
arbitrary (i.e. they can appear anywhere).  However, if options are mutually
exclusive the rightmost appearance is used.  This behavior conforms to the
standard evaluation rules of common Unix shells.

In addition, one or more command files can be specified using an '@' sign as a
prefix to the filename (e.g. <em>\@command.txt</em>).  Such a command argument
is replaced by the content of the corresponding text file (multiple
whitespaces are treated as a single separator unless they appear between two
quotation marks) prior to any further evaluation.  Please note that a command
file cannot contain another command file.  This simple but effective approach
allows one to summarize common combinations of options/parameters and avoids
longish and confusing command lines (an example is provided in file
<em>\<datadir\>/dumppat.txt</em>).

\section dcmrecv_exit_codes EXIT CODES

The \b dcmrecv utility uses the following exit codes when terminating.  This
enables the user to check for the reason why the application terminated.

\subsection dcmrecv_exit_codes_general general
\verbatim
EXITCODE_NO_ERROR                         0
EXITCODE_COMMANDLINE_SYNTAX_ERROR         1
\endverbatim

\subsection dcmrecv_exit_codes_input_file_errors input file errors
\verbatim
EXITCODE_CANNOT_READ_INPUT_FILE          20 (*)
\endverbatim

\subsection dcmrecv_exit_codes_output_file_errors output file errors
\verbatim
EXITCODE_CANNOT_WRITE_OUTPUT_FILE        40 (*)
EXITCODE_INVALID_OUTPUT_DIRECTORY        45
\endverbatim

\subsection dcmrecv_exit_codes_network_errors network errors
\verbatim
EXITCODE_CANNOT_INITIALIZE_NETWORK       60 (*)
EXITCODE_CANNOT_START_SCP_AND_LISTEN     64
EXITCODE_INVALID_ASSOCIATION_CONFIG      66
EXITCODE_CANNOT_CREATE_TRANSPORT_LAYER   71
\endverbatim

(*) Actually, these codes are currently not used by \b dcmrecv but serve as a
placeholder for the corresponding group of exit codes.

\section dcmrecv_environment ENVIRONMENT

The \b dcmrecv utility will attempt to load DICOM data dictionaries specified
in the \e DCMDICTPATH environment variable.  By default, i.e. if the
\e DCMDICTPATH environment variable is not set, the file
<em>\<datadir\>/dicom.dic</em> will be loaded unless the dictionary is built
into the application (default for Windows).

The default behavior should be preferred and the \e DCMDICTPATH environment
variable only used when alternative data dictionaries are required.  The
\e DCMDICTPATH environment variable has the same format as the Unix shell
\e PATH variable in that a colon (":") separates entries.  On Windows systems,
a semicolon (";") is used as a separator.  The data dictionary code will
attempt to load each file specified in the \e DCMDICTPATH environment variable.
It is an error if no data dictionary can be loaded.

\section dcmrecv_files FILES

<em>\<docdir\>/asconfig.txt</em> - configuration file documentation
\n<em>\<etcdir\>/storescp.cfg</em> - example association negotiation profile

\section dcmrecv_see_also SEE ALSO

<b>dcmsend</b>(1), <b>storescu</b>(1), <b>storescp</b>(1)

\section dcmrecv_copyright COPYRIGHT

Copyright (C) 2013-2022 by OFFIS e.V., Escherweg 2, 26121 Oldenburg, Germany.

*/