MarkWalters-dev · February 13, 2021 04:24 · Feb 13, 2021
diff --git a/urlqueue b/urlqueue
@@ -0,0 +1,102 @@
+#!/usr/bin/env bash
+# Parially copied from https://stackoverflow.com/questions/37318999/multiprocess-queue-in-bash
+# Requires: nc, tee, grep, and bash
+#
+# Example usage:
+#   urlqueue -s
+#   urlqueue https://www.youtube.com/watch?v=J5cnM1ODU0Y
+#   urlqueue -q -p | while read -r URL    # read until end of list
+#   do
+#     youtube-dl $URL
+#   done
+
+# or
+
+#   while true           # run forever, waiting for something to download
+#   do
+#      URL=$(urlqueue -q -p)
+#      if [ -z "$URL" ]; then
+#        sleep 30
+#      else
+#        youtube-dl $URL
+#      fi
+#   done
+
+addit() {
+    echo "$URL"|tee -a "$LOGFILE" >> /dev/tcp/127.0.0.1/4444
+    exit 0
+}
+
+popit() {
+    TIMEOUT=$(( 3 * 10 )) # 3 seconds
+    (: < /dev/tcp/localhost/4444) 2>/dev/null || error "URL queue server not running."
+    while ! { read -r a < /dev/tcp/localhost/4445; } 2>/dev/null
+    do
+        sleep .1
+        DURATION=$(( DURATION + 1 ))
+        [ $DURATION -ge $TIMEOUT ] && error "Error: Timeout."
+    done
+    [ -z "$a" ] && error "Error: Received no data"
+    echo "$a"
+    exit 0
+}
+
+startqueserver() {
+    nc -k -l 4444 | while read -r a
+    do
+        echo "$a" | nc -l 4445
+    done
+}
+
+killqueueserver() {
+    # TODO: Plan on saving the pid of the subprocess to a file
+    #       Not seeing how to get the pid of both nc processes right now
+    #       $$, $!, $BASHPID, and cut -d' ' -f4 < /proc/self/stat aren't doing it
+    #       Might have to move startqueserver into its own file to make it easier to kill
+    #       Or maybe have it watch for a touched file to shutdown on its own
+    #       Or just rewrite everything in python.
+    #       Or look for an existing python script that works far better than mine ever could.
+    #       For now I will be rude and killall
+    killall -9 nc
+    exit 0
+}
+
+error () {
+    [ -z "$SILENT" ] && echo "$1" 1>&2
+    exit 1
+}
+
+usage() {
+    printf "Usage: %s [ -q ] [ -s | -k | -p | URL ]
+       URL    Add URL to the queue
+        -s    Start URL queue server
+        -k    Kill URL queue server
+        -p    Pop 1 item off the queue
+        -q    Quiet or silent mode\n" "$(basename "$0")"
+    exit 1
+}
+
+ARG="$1"
+LOGHOME=$HOME/.local/share/urlqueue
+mkdir -p "$LOGHOME"
+LOGFILE=$LOGHOME/url.log
+
+[ -z "$ARG" ] && usage
+
+[[ "$ARG" == "-q" ]] && {  # I know this doesn't work if you do -p -q because of its position
+    SILENT=1
+    shift
+    ARG=$1
+}
+[[ "$ARG" == "-s" ]] && {
+    (: < /dev/tcp/localhost/4444) 2>/dev/null && error "URL queue server already running."
+    startqueserver &
+    exit 0
+}
+[[ "$ARG" == "-k" ]] && killqueueserver
+[[ "$ARG" == "-p" ]] && popit
+
+URL=$ARG
+grep -E "^$URL$" "$LOGFILE" >/dev/null 2>&1 || addit
+
+error "URL previously queued."