Receive gitter room chat log in chronological order

recv_gitter.sh

#!/usr/bin/env bash
#
# Retrieves chat messages in chronological order for a Gitter room.
# Each chat message is outputted per line and is formatted like:
#
#   (sent) username: text
#

if [ $# -ne 2 ]; then
    echo "Retrieves gitter room's chat log in chronological order." 1>&2
    echo "Supply your authorization token and room name" 1>&2
    echo "" 1>&2
    echo "usage:   recv_gitter.sh AUTH_TOKEN ROOM_NAME" 1>&2
    echo "example: recv_gitter.sh afe48192... your/chat" 1>&2
    exit 1
fi

hash egrep > /dev/null 2>&1
if [ $? -ne 0 ]; then
    echo "error: you will need the egrep executable installed." 1>&2
fi
hash curl > /dev/null 2>&1
if [ $? -ne 0 ]; then
    echo "error: you will need the curl executable installed." 1>&2
    echo "  see: https://curl.haxx.se/"
fi
hash jq > /dev/null 2>&1
if [ $? -ne 0 ]; then
    echo "error: you will need the jq executable installed." 1>&2
    echo "  see: https://stedolan.github.io/jq/"
fi

AUTH_TOKEN="$1"
ROOM_NAME="$2"

echo "Retrieving log for $ROOM_NAME" 1>&2

ROOM_ID=$(curl -s \
    -H "Accept: application/json"                                         \
    -H "Authorization: Bearer $AUTH_TOKEN"                                \
    "https://api.gitter.im/v1/rooms"                                    | \
    jq -r '.[] | [.id, .name] | @csv'                                   | \
    grep "$ROOM_NAME"                                                   | \
    egrep -o '"[0-9a-f]+"' | tr -d '"')

echo "The room id is $ROOM_ID" 1>&2

before_messages() {
    ROOM_ID="$1"
    if [ -n "$2" ]; then
        BEFORE_ID_PARAM="&beforeId=$2"
    else
        BEFORE_ID_PARAM=""
    fi

    MESSAGES=$(curl -s \
        -H "Accept: application/json" \
        -H "Authorization: Bearer $AUTH_TOKEN" \
        "https://api.gitter.im/v1/rooms/$ROOM_ID/chatMessages?limit=200$BEFORE_ID_PARAM")

    echo "$MESSAGES"
    return 0
}

at_message() {
    ROOM_ID="$1"
    MESSAGE_ID="$2"

    MESSAGE=$(curl -s \
        -H "Accept: application/json" \
        -H "Authorization: Bearer $AUTH_TOKEN" \
        "https://api.gitter.im/v1/rooms/$ROOM_ID/chatMessages/$MESSAGE_ID")

    echo "$MESSAGE"
    return 0
}

after_messages() {
    ROOM_ID="$1"
    if [ -n "$2" ]; then
        AFTER_ID_PARAM="&afterId=$2"
    else
        AFTER_ID_PARAM=""
    fi

    MESSAGES=$(curl -s \
        -H "Accept: application/json" \
        -H "Authorization: Bearer $AUTH_TOKEN" \
        "https://api.gitter.im/v1/rooms/$ROOM_ID/chatMessages?limit=200$AFTER_ID_PARAM")

    echo "$MESSAGES"
    return 0
}

find_first_msg_id() {
    ROOM_ID="$1"
    MESSAGES=$(before_messages $ROOM_ID)

    MESSAGE_COUNT=$(echo $MESSAGES | jq 'length')
    while [ $MESSAGE_COUNT -gt 0 ]; do
        FIRST_ID=$(echo $MESSAGES | jq '.[0].id' | tr -d '"')
        MESSAGES=$(before_messages $ROOM_ID $FIRST_ID)
        MESSAGE_COUNT=$(echo $MESSAGES | jq 'length')
    done

    echo "$FIRST_ID"
    return 0
}

FIRST_MSG_ID=$(find_first_msg_id $ROOM_ID)
echo "Found first message id: $FIRST_MSG_ID" 1>&2

# Log first message
echo $(at_message $ROOM_ID $FIRST_MSG_ID | jq '"(\(.sent)) \(.fromUser.username): \(.text)"') | sed 's#^"\(.*\)"$#\1#g'

# Log each block after, until empty
MESSAGES=$(after_messages $ROOM_ID $FIRST_MSG_ID)
MESSAGE_COUNT=$(echo $MESSAGES | jq 'length')
echo "$MESSAGES" | jq '.[] | "(\(.sent)) \(.fromUser.username): \(.text)"' | sed 's#^"\(.*\)"$#\1#g'
while [ $MESSAGE_COUNT -gt 0 ]; do
    LAST_ID=$(echo $MESSAGES | jq '. | .[length - 1].id' | tr -d '"')
    MESSAGES=$(after_messages $ROOM_ID $LAST_ID)
    MESSAGE_COUNT=$(echo $MESSAGES | jq 'length')
    echo "$MESSAGES" | jq '.[] | "(\(.sent)) \(.fromUser.username): \(.text)"' | sed 's#^"\(.*\)"$#\1#g'
done