NAME

DDC::Client - Client socket object and utilities for DDC::Concordance

SYNOPSIS

use DDC::Client;

##---------------------------------------------------------------------
## Constructors, etc.

$dc = DDC::Client->new( url=>"inet://localhost:50000" );

##---------------------------------------------------------------------
## Common Requests

$rsp     = $dc->request($request);           ##-- generic request
$rsp     = $dc->requestNC($request);         ##-- generic request, no close()
$data    = $dc->requestJson($request);       ##-- generic JSON request

$version = $dc->version();                   ##-- get server version string
$status  = $dc->status();                    ##-- get server status HASH-ref
$vstatus = $dc->vstatus();                   ##-- get verbose status HASH-ref
$info    = $dc->info();                      ##-- get server info HASH-ref
$nodes   = $dc->nodes();                     ##-- get server nodes ARRAY-ref

$rsp     = $dc->expand_terms(\@pipeline, \@terms);  ##-- raw term expansion
@terms   = $dc->expand(\@pipeline, \@terms);        ##-- parsed term expansion

$hits    = $dc->query($query_string);        ##-- fetch and parse hits
$hits    = $dc->queryJson($query_string);    ##-- fetch and parse JSON-formatted hits
$buf     = $dc->queryRaw($query_string);     ##-- fetch raw query result buffer
$buf     = $dc->queryRawNC($query_string);   ##-- fetch raw query result, no close()
@bufs    = $dc->queryMulti(@query_strings);  ##-- fetch multiple request results without intervening close()

$rsp     = $dc->get_first_hits($query);      ##-- low-level request
$rsp     = $dc->get_hit_strings();           ##-- low-level request
$rsp     = $dc->run_query($corpus,$query);   ##-- low-level request

##---------------------------------------------------------------------
## Low-level Communications

$connect = $dc->parseAddr();       ##-- parse connection parameters
$urlstr  = $dc->addrStr();         ##-- get connection parameter string

$io_socket = $dc->open();          ##-- open the connection
undef      = $dc->close();         ##-- close the connection

$dc->send(@command);               ##-- send a command (prepends size)
$dc->sendfh($fh,@command);         ##-- ... to specified filehandle

$size = $dc->readSize();           ##-- get size of return message from client socket
$size = $dc->readSize($fh);        ##-- ... or from a given filehandle

$buf  = $dc->readBytes($size);     ##-- read a sized return buffer from client socket
$buf  = $dc->readBytes($size,$fh); ##-- ... or from a given filehandle

$buf  = $dc->readData();           ##-- same as $dc->readBytes($dc->readSize())
$buf  = $dc->readData($fh);        ##-- ... same as $dc->readBytes($dc->readSize($fh),$fh)

$hits = $dc->parseData($buf);      ##-- parse a return buffer
$hits = $dc->parseJsonData($buf);  ##-- parse a return buffer in 'json' mode
$hits = $dc->parseTextData($buf);  ##-- parse a return buffer in 'text' mode
$hits = $dc->parseTableData($buf); ##-- parse a return buffer in 'table' mode
$hits = $dc->parseHtmlData($buf);  ##-- parse a return buffer in 'html' mode

@terms = $dc->parseExpandTermsResponse($buf);  ##-- parse an expand_terms response buffer

DESCRIPTION

Globals

Variable: $ifmt

pack()-format to use for integer sizes passed to and from a DDC server. The default value ('V') should be right for ddc-2.x (always 32-bit unsigned little endian). For ddc-1.x, the machine word size and endian-ness should match the those native to the machine running the DDC server.

Variable: $ilen

Length of message size integer used for DDC protocol in bytes. If you change $ifmt, you should make sure to change $ilen appropriately, e.g. by setting:

$ilen = length(pack($ifmt,0));

Variable: $JSON_BACKEND

Name of module to use for JSON response decoding via decodeJson(), defaults to JSON. Set this to JSON::PP or set the environment variable PERL_JSON_BACKEND=JSON::PP if you are using multiple DDC clients via the threads module.

Constructors etc

new

$dc = $CLASS_OR_OBJ->new(%args);

accepted %args are keys of %$dc:

(
 ##-- connection options
 connect  =>\%connectArgs,   ##-- passed to IO::Socket::(INET|UNIX)->new(), depending on $connectArgs{Domain}
                             ##   + you can also specify connect=>{url=>$url} or connect=>$url ; see parseAddr() method
 mode     =>$mode,           ##-- query mode; one of qw(json table text html raw); default='json'
 linger   =>\@linger,        ##-- SO_LINGER socket option (default=[1,0]: immediate termination)

 ##-- query options (formerly only in DDC::Client::Distributed)
 start    =>$start,          ##-- index of first hit to fetch (default=0)
 limit    =>$limit,          ##-- maximum number of hits to fetch (default=10)
 timeout  =>$secs,           ##-- query timeout in seconds (lower bound, default=60)

 ##-- hit parsing options (mostly obsolete)
 optFile  =>$filename,       ##-- parse meta names, separators from DDC *.opt file
 parseMeta=>$bool,           ##-- if true, hit metadata will be parsed to $hit->{_meta} (default=1)
 parseContext=>$bool,        ##-- if true, hit context data will be parsed to $hit->{_ctx} (default=1)
 keepRaw  =>$bool,           ##-- if false, raw context buffer $hit->{_raw} will be deleted after parsing context data (default=false)
 encoding =>$enc,            ##-- DDC server encoding (default='UTF-8')
 fieldSeparator => $str,     ##-- intra-token field separator (default="\x{1f}": ASCII unit separator); 'text' and 'table' modes only
 tokenSeparator => $str,     ##-- inter-token separator       (default="\x{1e}": ASCII record separator); 'text' and 'table' modes only
 metaNames      => \@names,  ##-- metadata names for 'text' and 'html' modes; default=none

 textHighlight => [$l0,$r0,$l1,$r1],  ##-- highlighting strings, text mode (default=[qw(&& && _& &_)])
 htmlHighlight => [$l0,$r0,$l1,$r1],  ##-- highlighting strings, html mode (default=[('<STRONG><FONT COLOR=red>','</FONT></STRONG>') x 2])
 tableHighlight => [$l0,$r0,$l1,$r1], ##-- highlighting strings, table mode (default=[qw(&& && _& &_)])
)

default \%connectArgs:

Domain=>'INET',              ##-- also accepts 'UNIX'
PeerAddr=>'localhost',
PeerPort=>50000,
Proto=>'tcp',
Type=>SOCK_STREAM,
Blocking=>1,

Examples

#-- connect to an INET socket on C<$HOST:$PORT>:
$dc = DDC::Client->new(connect=>{Domain=>'INET',PeerAddr=>$HOST,PeerPort=>$Port});
#
# ... syntactic sugar:
$dc = DDC::Client->new(connect=>{url=>"inet://$HOST:$PORT"})
$dc = DDC::Client->new(connect=>"inet://$HOST:$PORT")
$dc = DDC::Client->new(connect=>"$HOST:$PORT")

#-- connect to an INET socket on localhost port C<$PORT>, setting socket timeout $TIMEOUT
$dc = DDC::Client->new(connect=>{PeerPort=>$PORT,Timeout=>$TIMEOUT});
$dc = DDC::Client->new(connect=>":$PORT?Timeout=$TIMEOUT")

#-- connect to a UNIX socket at C<$SOCKPATH> on the local host:
$dc = DDC::Client->new(connect=>{Domain=>'UNIX',Peer=>$SOCKPATH});
#
# ... syntactic sugar:
$dc = DDC::Client->new(connect=>{url=>"unix://$SOCKPATH"})
$dc = DDC::Client->new(connect=>"unix://$SOCKPATH")

Querying

queryRaw

$buf = $dc->queryRaw($query_string);

Send a query string to the selected server and returns the raw result buffer. Implicitly close()s the connection.

queryRawNC

$buf = $dc->queryRawNC($query_string);

Send a query string to the selected server and returns the raw result buffer. No implicit close().

queryMulti

@bufs = $dc->queryMulti(@query_strings);

Sends a series of query strings or requests to the server, and returns a list of raw result buffers. Implicitly close()s the client after all requests have been sent, but not between individual requests.

query

$hits = $dc->query($query_string);

Send a query string to the selected server and parses the result into a list of hits.

get_first_hits

$buf = $dc->get_first_hits($query,$timeout?,$limit?,$hint?);

Requests IDs of the first $limit hit(s) for query $query, using optional navigation hint $hint, and returns the raw DDC response buffer. The optional parameters default to the %$dc keys of the same name.

get_hit_strings

$buf = $dc->get_hit_strings($format?,$start?,$limit?)

Requests the full strings for up to $limit hits beginning at logical offset $start formatted as $format. $format defaults to $dc->{mode}, and the remaining optional parameters default to the %$dc keys of the same name.

run_query

$buf = $dc->run_query($corpus,$query,$format?,$start?,$limit?,$timeout?,$hint?)

Requests a complete query evaluation of up to $limit hit(s) beginning at offset $start for query $query, formatted as $format with server-side timeout lower bound $timeout and optional navigation hint $hint. If $corpus is specified as undef, it defaults to the string "Distributed". Optional parameters default to the %$dc keys of the same name. Note that this method returns the raw DDC response; see the query() method for a more comfortable alternative.

Common Requests

request

$rsp = $dc->request($request_string);

Send a raw DDC request and return the server's response as a raw byte-string.

requestJson

$data = $dc->requestJson($request_string);

Send a raw DDC request and decode the server's response as JSON data.

version

$server_version = $dc->version();

Request the current running version of the selected server, wraps $dc->request("version").

status

$status = $dc->status();
$status = $dc->status($timeout);

Get basic server status; wraps $dc->requestJson("status $timeout").

vstatus

$vstatus = $dc->vstatus();
$vstatus = $dc->vstatus($timeout);

Get verbose server status; wraps $dc->requestJson("vstatus $timeout").

info

$info = $dc->info();
$info = $dc->info($timeout);

Get verbose server information; wraps $dc->requestJson("info $timeout").

nodes

$info = $dc->nodes();
$info = $dc->nodes($depth);

Get ARRAY-ref of accessible server nodes suitable for use with the ':' query-operator; wraps $dc->requestJson("nodes $depth").

expand_terms

$expandRaw = $dc->expand_terms($pipeline, $term);
$expandRaw = $dc->expand_terms($pipeline, $term, $timeout);
$expandRaw = $dc->expand_terms($pipeline, $term, $timeout, $subcorpus);

Perform server-side term-expansion for the term $term via pipeline $pipeline. Both $term and $pipeline may be specified as ARRAY-refs or bare strings. Returns the raw response data string.

expand

@terms = $dc->expand($pipeline, $term);
@terms = $dc->expand($pipeline, $term, $timeout);
@terms = $dc->expand($pipeline, $term, $timeout, $subcorpus);

Perform server-side term-expansion for the term $term via pipeline $pipeline and parses the response with parseExpandTermsResponse. Returns an array @terms of server expansions in list-context; in scalar context returns the reference \@terms to such an array.

query

$hits = $dc->query($query_string);

Send a query string to the selected server and parses the result into a DDC::HitList object.

queryRaw

$buf = $dc->queryRaw($query_string);
$buf = $dc->queryRaw(\@raw_strings);

Send a query string to the selected server and returns the raw result buffer. The second form is equivalent to

$dc->queryRaw(join("\x01",@raw_strings));

Implicitly close()s the connection.

queryRawNC

$buf = $dc->queryRawNC($query_string);

Send a query string to the selected server and returns the raw result buffer. No implicit close().

queryMulti

@bufs = $dc->queryMulti(@query_strings);

Low-level Communications

parseAddr

\%connect = $dc->parseAddr()
\%connect = $CLASS_OR_OBJECT->parseAddr(\%connect,    $PEER_OR_LOCAL, %options)
\%connect = $CLASS_OR_OBJECT->parserAddr({url=>$url}, $PEER_OR_LOCAL, %options)
\%connect = $CLASS_OR_OBJECT->parserAddr($url,        $PEER_OR_LOCAL, %options)

Parses connect options into a form suitable for use as parameters to IO::Socket::INET::new() rsp. IO::Socket::UNIX::new(). Sets $connect{Domain} to either INET or UNIX. If called as an object method, operates directly on (and updates) $dc->{connect}.

Honors bare URL-style strings $url of the form:

inet://ADDR:PORT?OPT=VAL...   # canonical INET socket URL format
unix://UNIX_PATH?OPT=VAL...   # canonical UNIX socket URL format
unix:UNIX_PATH?OPT=VAL...     # = unix://UNIX_PATH?OPT=val
ADDR?OPT=VAL...               # = inet://ADDR:5000?OPT=VAL...
:PORT?OPT=VAL...              # = inet://localhost:PORT?OPT=VAL...
ADDR:PORT?OPT=VAL...          # = inet://ADDR:PORT?OPT=VAL...
/UNIX_PATH?OPT=VAL...         # = unix:///UNIX_PATH?POT=VAL...

addrStr

$urlstr = $dc->addrStr();
$urlstr = $CLASS_OR_OBJECT->addrStr(\%connect, $PEER_OR_LOCAL);
$urlstr = $CLASS_OR_OBJECT->addrStr($url,  $PEER_OR_LOCAL);
$urlstr = $CLASS_OR_OBJECT->addrStr($sock, $PEER_OR_LOCAL);

Formats specified socket connection parameters (by default those of the calling object if called as an object method) as a URL-style string.

open

$io_socket = $dc->open();

Open the underlying INET- or UNIX-domain socket; returns undef on failure. Most users will never need to call this method, since it will be called implicitly by higher-level methods such as requiest(), query(), status() if required.

close

undef = $dc->close();

Closes the underlying socket if currently open. Most users will never need to call this method, since it will be called implicitly by higher-level methods such as requiest(), query(), status() if required.

send

undef = $dc->send(@message_strings);

Sends @message_strings to the underlying socket as a single message.

sendfh

undef = $dc->sendfh($fh,@message_strings);

Sends @message_strings to filehandle $fh, prepending total length.

readSize

$size = $dc->readSize();
$size = $dc->readSize($fh)

Reads message size from $fh (default=underlying socket).

readBytes

$data = $dc->readBytes($nbytes);
$data = $dc->readBytes($nbytes,$fh)

Reads fixed number of bytes from $fh (default=underlying socket).

readData

$data = $dc->readData();
$data = $dc->readData($fh)

Reads pending data from $fh (default=underlying socket); calls readSize() and readBytes().

Hit Parsing

parseTableData

parseTextData

parseJsonData

\@hits = $dc->parseTableData($buf);
\@hits = $dc->parseTextData($buf);
\@hits = $dc->parseJsonData($buf);

Parses raw DDC data buffer in $buf. Returns an array-ref of DDC::Hit objects representing the individual hits.

JSON parsing requires the JSON module.

parseExpandTermsResponse

\@terms = $dc->parseExpandTermsResponse($buf);
 @terms = $dc->parseExpandTermsResponse($buf);

Parses a DDC server expand_terms response buffer. Returns an array @terms of server expansions in list-context; in scalar context returns the reference \@terms to such an array.

AUTHOR

Bryan Jurish <moocow@cpan.org>

COPYRIGHT AND LICENSE

This package is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.24.1 or, at your option, any later version of Perl 5 you may have available.

To install DDC::Concordance, copy and paste the appropriate command in to your terminal.

cpanm

cpanm DDC::Concordance

CPAN shell

perl -MCPAN -e shell
install DDC::Concordance

For more information on module installation, please visit the detailed CPAN module installation guide.

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