1 #!/bin/bash

     2 

     3 # Relational pipes

     4 # Copyright © 2020 František Kučera (Frantovo.cz, GlobalCode.info)

     5 #

     6 # This program is free software: you can redistribute it and/or modify

     7 # it under the terms of the GNU General Public License as published by

     8 # the Free Software Foundation, version 3 of the License.

     9 #

    10 # This program is distributed in the hope that it will be useful,

    11 # but WITHOUT ANY WARRANTY; without even the implied warranty of

    12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

    13 # GNU General Public License for more details.

    14 #

    15 # You should have received a copy of the GNU General Public License

    16 # along with this program. If not, see <http://www.gnu.org/licenses/>.

    17 

    18 

    19 # This streamlet provides various file metadata like EXIF or PDF. It calls the tool exiftool.

    20 # With no options it returns "File:MIMEType" and "exiftool_xml" attributes.

    21 # Specific attributes can be selected using options – e.g. --option 'attribute' '…'

    22 # List of available attributes can be obtained by directly calling the "exiftool -X" command on given file or from the "available_attributes" attribute.

    23 # Two additional attributes are provided by this streamlet:

    24 #  - "exiftool_xml" – all attributes provided by exiftool in form of XML

    25 #  - "available_attributes" – list of available attributes (each file may have different) separated by line-breaks (TODO: return as an array of strings, when this data type is implemented)

    26 

    27 

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

    29 

    30 processMessage_WAITING_FOR_OUTPUT_ATTRIBUTES_METADATA() {

    31 	streamletFields=()

    32 

    33 	for (( i=0; i<${#optionNames[@]}; i++)); do

    34 		if [[ "x${optionNames[$i]}" == "xattribute" ]]; then

    35 			streamletFields+=("${optionValues[$i]}");

    36 		elif [[ "x${optionNames[$i]}" == "xprefix" ]]; then

    37 			pdfPrefix="${optionValues[$i]}";

    38 		else

    39 			echo "Unsupported option: ${optionNames[$i]}" >&2

    40 		fi

    41 	done

    42 

    43 	if [[ -z "$streamletFields" ]]; then

    44 		streamletFields=( "File:MIMEType" "exiftool_xml" );

    45 	fi

    46 

    47 	for (( i=0; i<${#streamletFields[@]}; i++)); do

    48 		# TODO: data type mappings (integers, booleans)

    49 		send OUTPUT_ATTRIBUTE_METADATA "${outputAttributeAliases[$i]-$pdfPrefix${streamletFields[$i]}}"    "string"

    50 	done

    51 

    52 	send WAITING_FOR_INPUT_ATTRIBUTES

    53 }

    54 

    55 processMessage_WAITING_FOR_OUTPUT_ATTRIBUTES() {

    56 	local streamletInfo streamletValid value isNull;

    57 

    58 	[[ -d "$currentFile" ]] || streamletInfo="$(exiftool -X "$currentFile")";

    59 	streamletValid="$?";

    60 

    61 	for (( i=0; i<${#streamletFields[@]}; i++)); do

    62 		if   [[ "x${streamletFields[$i]}" == "xexiftool_xml"  ]]; then value="$streamletInfo";

    63 		elif [[ "x${streamletFields[$i]}" == "xavailable_attributes"  ]]; then

    64 			value=$'available_attributes\nexiftool_xml\n'"$(echo "$streamletInfo" | relpipe-in-xmltable --relation exif --records '/*/*/*' --attribute 'name' string 'name()' | relpipe-out-nullbyte | tr \\0 \\n)";

    65 		else

    66 			value="$(echo "$streamletInfo" | relpipe-in-xmltable --relation exif --records "/*/*/*[name() = '${streamletFields[$i]}']" --attribute 'value' string '.' | relpipe-out-nullbyte | tr -d \\0)";

    67 			# TODO: parse the XML only once

    68 			# TODO: validate parameter or use parametrized XPath

    69 			# TODO: use real namespaces

    70 		fi

    71 

    72 		# n.b. for some files exiftools returns exit code, however it provides some basic properties like file timestamps and <ExifTool:Error>Unknown file type</ExifTool:Error> which is also valid XML and might be useful

    73 		if   [[ ! "x$streamletValid" == "x0" ]] && [[ "x$value" == "x" ]]; then value="";  isNull="true";

    74 		else                                                                               isNull="false";

    75 		fi

    76 

    77 		send OUTPUT_ATTRIBUTE "$value"    "$isNull";

    78 	done

    79 	

    80 	send WAITING_FOR_INPUT_ATTRIBUTES;

    81 }

    82 

    83 initialize

    84 processMessages