streamlet-examples/pdftotext
author František Kučera <franta-hg@frantovo.cz>
Fri, 24 Jan 2020 16:53:31 +0100
branchv_0
changeset 58 4679f67a8324
parent 50 22ed5647b235
permissions -rwxr-xr-x
parallel processing: put some common code in FilesystemCommand + use POSIX semaphores for STDOUT synchronization across sub-processes

#!/bin/bash

# Relational pipes
# Copyright © 2020 František Kučera (Frantovo.cz, GlobalCode.info)
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, version 3 of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.


# This streamlet provides a single attribute: plain text content of given PDF file. It calls the tool pdftotext.
# n.b. the plain text content must fit into memory and shell variable and command-line argument (it usually will)


. "$(dirname "$(realpath "$0")")/streamlet-common.sh"

processMessage_WAITING_FOR_OUTPUT_ATTRIBUTES_METADATA() {
	send OUTPUT_ATTRIBUTE_METADATA "${outputAttributeAliases[0]-pdftotext}"    "string"
	send WAITING_FOR_INPUT_ATTRIBUTES
}

processMessage_WAITING_FOR_OUTPUT_ATTRIBUTES() {
	value="$(pdftotext "$currentFile" - | tr -d \\f)"; # tr just removes page breaks
	if   [[ "x$?" == "x0" ]]; then isNull="false"; else value=""; isNull="true"; fi
	send OUTPUT_ATTRIBUTE "$value"    "$isNull";
	send WAITING_FOR_INPUT_ATTRIBUTES;
}

initialize
processMessages