8YL9P9wF

1#!/bin/bash
2#
3# Run periodically by cron, and will unarchive data in the
4# ~/auto_unarchive/drop_target directory.
5
6# Where the action happens
7unarchiveDir="~/auto_unarchive/drop_target"
8
9# Time in seconds between checking for new archives
10checkInterval=1.5
11
12# Total number of seconds the script should run for before
13# exiting.
14runTime=59
15
16# If non-empty, some extra messages will be logged.
17# This should be off for long-term cron use, as it will bloat
18# the logs.
19verbose=""
20
21# Flag used to log when killed.
22cleanExit=""
23
24# Will only run if this file doesn't exist
25lockFile="$unarchiveDir/.unarchive.lock"
26
27# Hash table of archive types to their extraction commands.
28# The keys are used to grep the output of the file command.
29# Used by: getNextArchive,
30extractKeys[0]=Zip; extractCmds[0]="unzip"
31extractKeys[1]=gzip; extractCmds[1]="gunzip"
32
33function printUsage()
34{
35    local scr="`basename $0`"
36
37    echo "usage: $scr [--help | -h]"
38}
39
40# Create the unarchive dir if necessary, and return true iff it
41# exists.
42function setupDir()
43{
44    local targetDir="$1"
45
46    if [ ! -d "$targetDir" ]; then
47        log "Creating auto unarchive directory: $targetDir" <(mkdir "$targetDir")
48    fi
49
50    if [ -d "$targetDir" ]; then
51        return 0
52    else
53        return 1
54    fi
55}
56
57# Returns true only if this instance of the script currently
58# owns the lock on the unarchiving directory
59function tryLock()
60{
61    if [ ! -f "$lockFile" ]; then
62        echo "$$" >"$lockFile"
63        return 0
64    else
65        return 1
66    fi
67}
68
69# Releases the lock on the unarchiving directory if this script
70# currently holds it
71function unlock()
72{
73    # If this instance of the script currently owns the lock
74    if [ $$ = "$(cat "$lockFile" 2>/dev/null)" ]; then
75        rm -f "$lockFile"
76        return 0
77    fi
78
79    return 1
80}
81
82# Prints the index of the extract key/command for a file.
83# $1 - the filename whose type to search for
84function findExtractIndex()
85{
86    fileName="$1"
87    i=${#extractKeys[*]}
88    i=$(($i - 1))
89
90    if [ "$fileName" ]; then
91        while [ $i -ge 0 ]; do
92            key="${extractKeys[$i]}"
93
94            if [ "$(file "$line" | grep "$key")" ]; then
95                echo $i
96                return 0
97            fi
98
99            i=$(($i - 1))
100        done
101    fi
102
103    return 1
104}
105
106# Prints the absolute path of a relative path, relative to the
107# current directory.
108# $1 - the path to make absolute
109function absolutePath()
110{
111    path="$1"
112
113    if [ "$1" ]; then
114        # Clean leading ./ (e.g. from find command output)
115        if [ './' = "${path:0:2}" ]; then
116            path="${path:2}"
117        fi
118
119        # Prepend working dir onto non-absolute paths
120        if [ '/' != "${path:0:1}" ]; then
121            echo "$(pwd)/$path"
122        else
123            echo "$path"
124        fi
125    fi
126}
127
128# Prints the extract command for a file, ready-to-run.
129# $1 - the file to get the extract command for
130# $2 - (optional) the index in the extract table. If not
131#      specified, will search the table.
132function getExtractCmd()
133{
134    fileName="$(absolutePath "$1")"
135    index="$2"
136    [ -z "$index" ] && index="$(findExtractIndex "$fileName")"
137
138    if [ "$index" ]; then
139        # Construct the runnable command and return true
140        echo "${extractCmds[$index]} '$fileName'"
141        return 0
142    fi
143
144    return 1
145}
146
147# Prints the name of an archive in the current directory,
148# or nothing if there are no archives.
149# If there is an archive, prints the index in the extract
150# table on the second line.
151function getNextArchive()
152{
153    find . -maxdepth 1 -type f | while read line; do
154        index="$(findExtractIndex "$line")"
155
156        if [ "$index" ]; then
157            echo "$line"
158            echo $index
159            return 0
160        fi
161    done
162
163    return 1
164}
165
166# Extracts a file into directory above unarchive directory.
167# $1 - filename of archive
168# $2 - (optional) index in extract table
169function extractFile()
170{
171    fileName="$1"
172    index="$2"
173    [ -z "$index" ] && index="$(findExtractIndex "$fileName")"
174    cmd="$(getExtractCmd "$curFile" "$index")"
175
176    # Perform the extract and capture the output
177    extractLog="$( (
178        cd ..
179        echo "Changed to directory '$(pwd)'."
180
181        eval $cmd
182    ) 2>&1)"
183    extractResult=$?
184
185    # Log the output
186    echo -n "$extractLog" | log "Found archive '$curFile', extracting: $cmd"
187#     log "Found archive '$curFile', extracting: $cmd"
188#     echo "$extractLog" | while read l; do log "$l"; done
189
190    if [ $extractResult -eq 0 ]; then
191        (
192            [ ! -d "extracted" ] && mkdir extracted
193            mv "$fileName" extracted/
194        ) 2>&1 | log "Extraction successful, deleting '$fileName'..."
195        return 0
196    else
197        log "Extraction failed."
198        return 1
199    fi
200}
201
202function exitHandler()
203{
204    unlock
205
206    if [ "$cleanExit" ]; then
207        [ "$verbose" ] && log "Finished monitoring '$unarchiveDir' (ran for $SECONDS seconds), exiting."
208    else
209        log "Killed after $SECONDS seconds, aborting monitoring '$unarchiveDir'."
210    fi
211}
212
213# Process user-specified flags
214while [ "`echo "$1" | grep -E -e '^-.'`" ]; do
215    case "$1" in
216        --help|-h)
217            printUsage
218            exit 0
219            ;;
220        *)
221            printUsage
222            exit 1
223            ;;
224    esac
225    shift
226done
227
228# Make sure directory is unlocked if the script is killed
229trap "exitHandler" EXIT
230
231if setupDir "$unarchiveDir"; then
232    cd "$unarchiveDir"
233
234    [ "$verbose" ] && log "Monitoring '$unarchiveDir' for $runTime seconds, at $checkInterval intervals..."
235
236    while [ $SECONDS -le "$runTime" ]; do
237        # Only continue if there are no other instances of
238        # this script running.
239        if tryLock; then
240            # Get the filename and index of the next archive
241            nextArchive="$(getNextArchive)"
242
243            # Process all archives in the current directory before sleeping
244            while [ "$nextArchive" ]; do
245                curFile=""
246                curIndex=""
247                cmd=""
248
249                echo "$nextArchive" | (
250                    read line && curFile="$line"
251                    read line && curIndex="$line"
252                    cmd="$(getExtractCmd "$curFile" $curIndex)"
253
254                    extractFile "$curFile" "$curIndex"
255                )
256
257                nextArchive="$(getNextArchive)"
258            done
259
260            unlock
261        fi
262
263        sleep "$checkInterval"
264    done
265
266    cleanExit="true"
267fi